![RD, flank wear and tool wear images of AlTiN-and TiAlSiN-coated tools: (a) XRD diffraction patterns, (b) flank wear of cutting length under different v c , and (c) tool flank wear images under different cutting lengths [112]. Reproduced with permission from Ref. [112] from Springer Nature.](https://www.researchgate.net/profile/Jin-Zhang-282/publication/372325750/figure/fig2/AS:11431281174527408@1689253780962/RD-flank-wear-and-tool-wear-images-of-AlTiN-and-TiAlSiN-coated-tools-a-XRD_Q320.jpg)
![Tool wear under different v c : (a) tool wear under different machining conditions [120] and (b) experiment after cutting 21.75 cm 3 and flank wear of finite element method [121]. Reproduced with permissions from Refs. [120,121] from Malaysian Tribology Society and Springer Nature.](https://www.researchgate.net/profile/Jin-Zhang-282/publication/372325750/figure/fig3/AS:11431281174516261@1689253781783/Tool-wear-under-different-v-c-a-tool-wear-under-different-machining-conditions-120_Q320.jpg)
![Cutting temperature and tool wear under different cutting conditions: (a) temperature distribution under different v c conditions and (b) tool wear with different cutting volumes [121]. Reproduced with permission from Ref. [121] from Springer Nature.](https://www.researchgate.net/profile/Jin-Zhang-282/publication/372325750/figure/fig4/AS:11431281174516263@1689253782982/Cutting-temperature-and-tool-wear-under-different-cutting-conditions-a-temperature_Q320.jpg)
![Surface roughness corresponding to different coated tools: (a) SiAlON tool and (b) physical vapor deposition tool [124]. PVD: physical vapor deposition. Reproduced with permission from Ref. [124] from Springer Nature.](https://www.researchgate.net/profile/Jin-Zhang-282/publication/372325750/figure/fig5/AS:11431281174516264@1689253783663/Surface-roughness-corresponding-to-different-coated-tools-a-SiAlON-tool-and-b_Q320.jpg)
Content uploaded by Jin Zhang
Author content
All content in this area was uploaded by Jin Zhang on Jul 13, 2023
Content may be subject to copyright.
Available via license: CC BY 4.0
Content may be subject to copyright.
Energy field-assisted high-speed dry milling green
machining technology for difficult-to-machine
metal materials
Jin ZHANGa,b, Xuefeng HUANGa,b, Xinzhen KANGa,b, Hao YIa,b, Qianyue WANGa,b, Huajun CAO (✉)a,b
aCollegeofMechanicalandVehicleEngineering,ChongqingUniversity,Chongqing400044,China
bStateKeyLaboratoryofMechanicalTransmissions,ChongqingUniversity,Chongqing400044,China
✉Correspondingauthor.E-mail:hjcao@cqu.edu.cn(HuajunCAO)
©TheAuthor(s)2023.Thisarticleispublishedwithopenaccessatlink.springer.comandjournal.hep.com.cn
ABSTRACT Energyfield-assistedmachiningtechnologyhasthepotentialtoovercomethelimitationsofmachining
difficult-to-machinemetalmaterials,suchas poor machinability, low cutting efficiency,andhighenergyconsumption.
High-speeddrymillinghas emerged asatypicalgreenprocessingtechnologydueto its highprocessingefficiencyand
avoidanceofcuttingfluids.However,thelackofnecessarycooling and lubrication in high-speed dry milling makes it
difficult to meet the continuous milling requirements for difficult-to-machine metal materials. The introduction of
advancedenergy-field-assistedgreenprocessingtechnologycanimprovethemachinabilityofsuchmetallicmaterialsand
achieve efficient precision manufacturing, making it a focus of academic and industrial research. In this review, the
characteristics and limitations of high-speed dry milling of difficult-to-machine metal materials, including titanium
alloys,nickel-basedalloys,andhigh-strengthsteel,aresystematicallyexplored.Thelaserenergyfield,ultrasonicenergy
field,andcryogenicminimumquantitylubricationenergyfieldsareintroduced.Byanalyzingtheeffectsofchangingthe
energyfieldandcuttingparametersontoolwear,chipmorphology,cuttingforce,temperature,andsurfacequalityofthe
workpiece during milling, the superiority of energy-field-assisted milling of difficult-to-machine metal materials is
demonstrated. Finally, the shortcomings and technical challenges of energy-field-assisted milling are summarized in
detail, providing feasible ideas for realizing multi-energy field collaborative green machining of difficult-to-machine
metalmaterialsinthefuture.
KEYWORDS difficult-to-machine metal material, green machining, high-speed dry milling, laser energy field-
assistedmilling,ultrasonicenergyfield-assistedmilling,cryogenicminimumquantitylubricationenergyfield-assisted
milling
1Introduction
With continuous improvements in advanced manufac-
turing fields such as aerospace, rail transit, and clean
energy equipment production, various high-performance
alloys (e.g., nickel-based alloys, titanium alloys, and
high-strengthsteels)are widely used.However, they are
regarded as typical difficult-to-machine metal materials
because of their good toughness, high strength, and
excellentwearresistance,whichposeaseriouschallenge
to the high-performance manufacturing process of high-
efficiencyandprecisionmachining[1–3].
The poor machinability of difficult-to-machine metal
materialsisreflectedinthefollowing:
①Chemicallevel
For titanium alloys containing Ti, Mo, Cr, and V,
highly chemically active metal elements can reduce
machinability[4].Furthermore,theαphaseformedinthe
organization of the alloy structure is a hexagonal lattice
structure,whichincreasescuttingdifficulty.
Fornickel-basedalloys,whichexhibitasingleaustenite
structureorganization, Al, Ti,and other oxygen-friendly
elements promote the oxidation of materials at high
temperatures,resulting in tool adhesion. In addition, the
strengthening phases (intermetallic compounds, borides,
and carbides) in the alloy materials form hard particles,
resultinginincreasedtoolwear[5].
ReceivedJuly13,2022;acceptedNovember29,2022
Front.Mech.Eng.2023,18(2):28
https://doi.org/10.1007/s11465-022-0744-9
REVIEWARTICLE
ThecontentsofCr,Mn,Si,Ni, andotherelementsare
high in high-strength steel, which has a tempered
martensite structure. Different vc (cutting speed) values
correspond to different chip morphologies and play a
leading role in improving performance. The addition of
Cr can change the hardness, strength, and toughness of
steel; the presence of Mn can influence its hot
machinability, and the addition of Si can improve its
tensile and yield strength. The addition of Ni can
simultaneously improve the strength and hardness of
metal materials and increase the cutting force and
processingenergyconsumption[6].
②Thermalconductivity
Compared with 45 steel, the thermal conductivity of
titaniumalloysisreducedby80%,whichcaneasilylead
to plastic deformation in the shear zone and at high
temperatures, thus aggravating tool wear and causing
workhardening[7].
Thethermalconductivityofnickel-basedalloysislow,
andheataggregationduringtheprocessingofsuchalloys
can easily occur, resulting in high local temperatures,
which causes surface stress, a considerable temperature
gradientintheworkpiece,andawork-hardeningproblem
[8].
The thermal conductivity of high-strength steel is low
(only 40% of that of 45 steel), which hinders the
transmission of the cutting heat, resulting in the
phenomenon that the temperature of the tool-workpiece
contactsurfacecanbetoohigh,thusleadingtothework-
hardeningproblemoftheworkpiecesurface[9].
③Cuttingmachinability
Titanium alloy cutting, which is a typical shear
machining process, is inclined to produce large shear
angles [10] and the ‘negative shrinkage’ phenomenon,
which has a negative impact on the machining process.
Compared with 45 steel, the machinability of titanium
alloysisintherangeof0.15–0.5[11].
Becauseoftheincreaseinheataccumulation,cracksor
burns on the surface of the workpiece can easily occur,
whichmakesitdifficulttoensurethequalityandintegrity
of the machined surface during the cutting process of
nickel-basedalloys. Compared to 45 steel, the machina-
bilityofnickel-basedalloysislessthan0.15[12].
Theplasticdeformationofhigh-strengthsteelmaterials
is large, and because of the severe friction during the
machining process, it is easy to produce chip tumors.
Furthermore,theunevenstressdistributioncausessevere
tooltipwear,which leads toinstabilityinthemachining
process and reduces the cutting efficiency. Compared
with45steel,themachinabilityofhigh-strengthsteelisin
therangeof0.5–0.65[13].
High-speed cutting has the advantages of improving
machining efficiency and reducing production costs and
is also used in the field of difficult-to-machine metal
materials [14–17]. Because the deformation zone of
materials subjected to high-speed cutting is usually
accompaniedbystrongstrain,ahighstrainrate,andhigh
temperatures[18–20], traditional coolingand lubrication
ofthe cutting deformation zoneby pouring cuttingfluid
isnecessaryduringthecuttingprocess[21,22].Compared
withconventionalmilling (CM),thefrictionbetweenthe
workpieceandthe tool ismoreintenseinthehigh-speed
milling process, and the time at which the deformation
zone remains in a high-temperature state is longer. The
heatofthecuttingfluidisuneven,andlocaldropletscan
start boiling [23]. A large number of microbubbles are
blockedbyanoilfilm,resultinginanincreaseintheheat
transfer resistance and a decrease in the heat exchange
efficiency [24]. In addition, the extensive use of cutting
fluidnotonly endangers thehealth of operators (cancer,
asthma,andskin diseases)butalsoseriouslypollutesthe
environment (air, soil, and water) and increases the
economiccost ofprocessing wasteliquid andchips; the
costofcuttingfluidfrompurchasetoprocessingaccounts
for 16% to 30% of the total cost of manufacturing
difficult-to-machine metal materials, which is much
higherthanthetoolcostofonly7%[25–29].Therefore,
new green and low-carbon processing technologies that
canreplacepouringandcuttingshouldbeexplored.
High-speed dry milling (HSDM) is regarded as a
typicalgreenandefficientmachiningtechnologybecause
it not only improves the machining efficiency but also
eliminates the use of cutting fluids [30–33]. The
developmentoftoolcoatings and high-speed dry cutting
machine tools has enabled the use of HSDM for
machining [34–36]. Lu et al. [37] used coated tools for
the HSDM of hardened steel and found that the cutting
force decreased and the tool life increased. The
ChongqingMachineToolGroup,jointlywithChongqing
University, pioneered high-speed dry cutting machine
tools such as YS3116CNC7 and Y3120CNC7, which
improvedtheproduction efficiency ofmachinetoolsand
reduced the manufacturing cost of workpieces [38].
Considering the inherent characteristics of difficult-to-
machine metal materials, coupled with the high cutting
speedandlackofcuttingfluidnecessaryfor coolingand
lubrication in the HSDM manufacturing process, the
frictionbetweenthe tool andtheworkpieceandbetween
thetool andthechipisextremelyintense,resulting inan
increase in the temperature of both the tool and
workpiece, which affects the machining accuracy of the
workpiece[39,40].Consequently,theHSDMofdifficult-
to-machinemetalmaterialscanachievethedesiredeffect
only in a specific process-feasible regime, and it is
difficult to achieve full-condition adaptation [22].
Therefore, research on innovative HSDM processes is
crucial.
Thermal-assisted machining (TAM) was proposed in
the 1950s [41]. Its advantage is that preheating can not
only reduce the ultimate strength of materials but also
promote plastic deformation of hard materials during
processing. The advantages of TAM also include
improved manufacturing performance, machining
2Front.Mech.Eng.2023,18(2):28
efficiency, and quality of difficult-to-machine metal
materials by increasing the temperature of the cutting
zone through an external heat source. Under ideal
conditions,theshearbandofthematerialinstantaneously
reaches the ideal temperature, and most of the heat is
removedbythechip,therebyavoidingheatgenerationin
theshearzone[42].ForthepositivecontributionofTAM
technologytothecutting process, theheatsourceshould
be local, fast, and controllable. Lasers, induction coils,
plasma,andoxyacetylene torcheshavebeenwidelyused
[43–45].Becauseimproperselectionofaheatsourcewill
lead to adverse changes in the microstructure after
machining [46,47], researchers have mainly focused on
thetwo commonly used heating methods of plasma and
laser in machining. Considering that the laser has the
advantages of a precise and controllable local area, no
need for protective gas, and high spatial accessibility, it
hasemergedas the mostpromisingauxiliaryheatsource
fortheprocessingofdifficult-to-machinemetalmaterials,
and subsequent research has mainly focused on laser-
assistedprocessingtechnology[42].
The implementation process of laser energy field-
assisted milling (LAM) uses a laser to preheat the
workpiece locally in advance to achieve material
softeningandchange the materialpropertiesoftheshear
zonethat isreadytoberemoved,whichcan improvethe
manufacturingperformanceof difficult-to-machinemetal
materials under temperature-assisted conditions [48]. At
present,laserswidelyusedfordifficult-to-machinemetal
materials mainly include carbon dioxide (CO2) lasers,
high-power semiconductor lasers (HPDL), and neody-
mium-doped yttrium aluminum garnet (Nd:YAG) lasers
[42].Aseachofthethreelasershasitsownmerits,itis
necessary to make reasonable choices according to the
properties of the materials to be processed. After the
materialareatoberemovedisheatedbylaserassistance,
thesubsequentmachiningprocesscanreduce the cutting
force,prolongthetoollife,improvethematerialremoval
rate, reduce cutting energy consumption, reduce
manufacturingcosts, and optimize the surface quality of
theworkpiece [49–51]. However,the difficulty ofLAM
machining is the precise control of the preheating
temperature of the workpiece. Studies have shown that
the laser power, heat source size, laser scanning speed,
and heating position have a significant influence on the
preheatingtemperatureofthematerial[52,53].Therefore,
toobtain ideal resultsin the shearregion of difficult-to-
machine metal materials, laser energy field-assisted
machiningparametersshouldbereasonablyselected[54].
The introduction of a laser energy field in CM
machining prolongs the entire machining cycle, and
ultrasonic vibration energy field-assisted milling
(UVAM) with intermittent cutting characteristics can
improvethematerialremovalrate,whichcancompensate
for the disadvantage of the long machining cycle of
LAM. Therefore, UVAM is important. In the UVAM
process, electrical signals are converted into ultrasonic
frequencyvibrations,which act along acertaindirection
ontheworkpieceortool[55,56]torealizetool-workpiece
separationsothatthecutting area is periodically opened
to ensure that the traditional cutting fluid enters the
cutting area and provides rapid cooling at high
temperatures[57].Furthermore,duringtheprocessing of
difficult-to-machine metal materials, the chip removes
most of the heat, and ultrasonic separation can ensure
rapid chip breaking [58–60], thereby avoiding the
accumulationofheatonthetoolandworkpiece.UVAM
alsoexhibitsanacousticsofteningeffect[61].Inaddition
to the above advantages, UVAM can also reduce the
cutting force [62,63], improve the material removal rate
[64], optimize the surface quality of the workpiece
[65,66], extend the tool life [67,68], reduce the
manufacturing costs, and achieve green and low-carbon
machining [69] by regularly changing the contact state
between the workpiece and tool [70,71]. However, the
vibration frequency and amplitude of UVAM signifi-
cantly influence the machining process. Therefore, to
maintain the advantages of UVAM, it is necessary to
controlthevibrationfrequencyandamplitudereasonably.
The minimum quantity lubrication (MQL) technology
can effectively solve the heat transfer problem of
difficult-to-machine metal materials in HSDM. In 1997,
KlockeandEisenblätter[72]proposedaneconomicaland
environmentally friendly MQL technology. In this
process, a very small amount of atomized droplets is
sprayed into the cutting area with high-pressure gas for
lubrication[73],andanycuttingheatpositionisreached
withthehelpofthetrachea,whichcaneffectivelyreduce
the cutting force and cutting heat, prolong the tool life,
andoptimizethesurfacequalityoftheworkpiece[74,75].
However, under some specific conditions, micro-
lubrication technology has some shortcomings: When
usingMQLtoassistinthehigh-speedcuttingofdifficult-
to-machine metal materials, excessive heat production
leadstotheruptureofthelubricatingoilfilm,resultingin
insufficient cooling in the cutting area and lubrication
failure [76,77]. In addition, the cooling performance of
micro-lubricationtechnologywithhigh-pressureatomiza-
tion airflow is limited, and a performance gap remains
between this technology and traditional pouring cutting
[78,79].Therefore, further researchon MQL technology
isneeded.
Nanofluid minimum quantity lubrication (NMQL)
technologyisanenhancementofMQLtechnologythatis
realized by adding nanoparticles in proportion to the
MQL fluid. Compared with ordinary MQL, the thermal
conductivityofnanofluids is higher, whichisdue to the
addition of nanoparticles with excellent antifriction and
antiwear properties [80], thereby reducing the heat
transfer resistance and improving the heat exchange
efficiency and material removal rate. In addition,
nanoparticles with small volumes undergo Brownian
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 3
motionin the base fluid, which can improve lubrication
[81]. Compared to MQL, the lubrication advantages of
NMQL have been confirmed in many studies [82–86].
However, when the cutting temperature is high (600–
1000°C),theheattransferefficiencyofthenanoparticles
is still limited [87]. Although the cutting temperature is
reducedfortitaniumalloys[88],nickel-basedalloys[89],
high-strength steel [90], and other difficult-to-machine
metal materials, the range of the cooling amplitude is
small, and defects such as burns and adhesion on the
surfaceoftheworkpiecestill occur. Therefore, the heat-
exchangeproblemintheNMQL-assistedcutting process
ofdifficult-to-cutmaterialsremains.
Cryogenic technology is generally used to solve the
problem of heat transfer in the cutting process by
injecting a liquid/gaseous medium into the shear
deformation zone [91]. Currently, the main cryogenic
media used for difficult-to-machine metal materials
includeliquidnitrogen(LN2)[92],liquidcarbon dioxide
(LCO2)[93],supercritical carbon dioxide (SCCO2)[94],
and cold air (CA) [95]. Cryogenic processing can not
only improve the material removal rate but also
effectively prolong tool life [96]; thus, the cryogenic
manufacturing cost is far lower than the traditional
pouring processing cost [97,98]. Different temperature
thresholds can be realized using different liquid/gaseous
mediato avoid insufficient cooling or excessive cooling
hardening. However, the lubrication performance of
cryogenic technology is insufficient, and its friction
reduction and wear resistance characteristics must be
improved[99].
Inviewofthehigh-performancemanufacturingprocess
ofdifficult-to-machinemetalmaterials,thecurrentlybest-
recognized method is the combination of the cryogenic
cold medium, MQL (NMQL), and milling, which is
referred to as cryogenic minimum quantity lubrication
energy field-assisted milling (CMQLAM). CMQLAM
not only reduces the temperature of the shear zone but
also retains the lubrication ability of MQL (NMQL).
Apart from being a green low-carbon technology, its
advantages include adequate cooling, reducing cutting
force, optimizing the surface quality of the workpiece,
extending tool life, and reducing manufacturing costs
[100–102].Consideringthatthecryogenicmediumtype,
gaspressure,andMQL flow rate affecttheperformance
ofCMQLAM,itisnecessarytoreasonablyregulatethese
three parameters to obtain the optimal effect of
CMQLAM. Figure1 shows the overall structure of this
review.
It has been widely reported that the processing
performance of HSDM can be improved using LAM,
UVAM, or CMQLAM alone. However, it is difficult to
select an appropriate auxiliary process from multiple
energy fields and to realize machining under various
harsh conditions. Based on this, this paper reviews the
latest research progress of energy-field-assisted green
machining technology for difficult-to-machine metal
materials;summarizestheoperatingmechanisms,techni-
cal difficulties, and application status of HSDM, LAM,
UVAM, and CMQLAM for difficult-to-machine metal
materials; and compares and analyzes the effects on
cutting force, heat, chip morphology, tool life, specific
cuttingenergy,materialremovalrate,andsurfacequality
of titanium alloy, nickel-based alloy, and high-strength
steel compared with traditional milling under energy-
field-assisted conditions. The development direction of
energy-field-assisted green machining technology is
reported in this paper to provide a reference for multi-
energy-fieldcomposite-assistedgreenmachining techno-
logy.
2HSDM of difficult-to-machine metal
materials
Compared with CM pouring cutting, HSDM is a near-
zero-emission green processing technology that elimi-
natestheenvironmentalpollutionandoccupationalhealth
hazards caused by cutting oil and avoids the cleaning
process of cutting oil adhering to the surface of the
workpiece and some iron chips. Under appropriate
process conditions with high-performance coated tools,
HSDMcanreducethecuttingforce,temperature,surface
roughness,andtoolwear.Accordingtothecuttingspeed
rangesoftheHSDM,difficult-to-machinemetalmaterials
can be divided into three parts. The logical structure of
theclassificationisshowninFig.2.
For HSDM of titanium alloys, after finding that the
effectofcuttingparameteroptimizationontoolwearwas
notclear, chemicalvapordeposition(CVD)andphysical
vapor deposition (PVD) tool coatings were utilized to
compare the cutting effect of HSDM. The PVD coating
was more suitable for HSDM. In addition, the effect of
the AlTiN and TiAlSiN multi-nanocomposite structure
coatings were analyzed. The results showed that the
quaternaryTiAlSiNcoatingnotonlyresultedinuniform
chipsbutalsohadhighoxidationresistance,significantly
prolongingtoollife.
To analyze the HSDM of high-strength steel, first,
frictionandwearexperimentsshowedthatHSDMcould
reduce the wear of the machined surface to a greater
extent than CM. Second, the optimal cutting parameters
were obtained when using the CVD coating of Al2O3 +
TiC.Subsequently,threeotheroptimalTiN/TiCN/TiAlN
coatings and their cutting parameters were obtained.
Finally, using the TiCN-NbC coating, the influence of
cuttingparameters onthe surface roughness, microhard-
ness,andresidualstressoftheworkpiecewasanalyzed.
For the HSDM of nickel-based alloys, first, the
influenceof cutting parameters on thecutting force was
investigatedbasedon(Al,Ti)N-coatedtools.Second,the
effect of cutting parameters on tool wear was studied
4Front.Mech.Eng.2023,18(2):28
using TiN/TiAlN-coated tools. Third, the influence of
cuttingparametersonthecuttingforceandtoolwearwas
analyzed using polycrystalline cubic boron nitride
(PCBN) tools. Furthermore, the influences of cutting
Fig. 1Overall structure of this review. HSDM: high-speed dry milling, LAM: laser-assisted milling, UVAM: ultrasonic vibration-
assistedmilling,CMQLAM:cryogenicminimumquantitylubricationenergyfield-assistedmilling.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 5
parameters on the surface roughness when using
TiAlN/TiN PVD nano-multilayer coated tools were
analyzed.Inaddition,theeffectsofcuttingparameterson
thematerialremovalrate,cuttingtemperature,microhard-
ness, and residual stress were briefly described for the
application of the SiAlON ceramic tool. The effects of
thistool andthePVDnano-multilayercoatedtoolonthe
surfaceroughnesswerecompared, and it was foundthat
the SiAlON ceramic tool could obtain better surface
roughness. The effects of cutting parameters on the
surfaceroughness,cuttingtemperature,cuttingforce,and
microhardnesswereanalyzedindetailbasedontheuseof
SiAlON ceramic tools. Finally, to gain a real-time
perceptionofthecuttingforceandcuttingtemperature,a
detailed calculation formula for the cutting force and
cutting temperature was established based on SiAlON
ceramictools,anditsaccuracywasverified.
2.1HSDMoftitaniumalloy
The cutting parameters have a significant impact on the
entire machining process. Krishnaraj et al. [104]
conducted an HSDM experiment on Ti–6Al–4V (TC4).
Basedon theTaguchiexperimentaldesign, theeffectsof
vc, vf (feed speed), and αp (axial cutting depth) on the
cutting force, temperature, and surface roughness were
analyzed.Theexperimental resultsshowthatfz(feedper
tooth) and αp have the greatest impact on the cutting
force, whereas vc has a significant influence on the
cutting temperature and surface roughness. Within the
selected range of these cutting parameters, when vc, vf,
and αp were 150 m/min, 0.075 mm/r, and 0.75 mm,
respectively (for cutting titanium alloy, the high-speed
cuttingrangewasreachedwhenvcwas100m/min[103]),
the cutting effect was the best, and the machining
efficiencywasthehighest[104].However, the influence
of cutting parameters on the tool life and tool wear has
notbeenstudied.
Basedontheaboveresearch,GintingandNouari[105]
studiedtheprocesscapabilityof the HSDM of Ti-6242S
with ordinary uncoated cemented carbide tools. The
impact of vc and fz on tool wear was investigated. By
observingFig.3(a) [105], theauthor found that when vc
and fz were 150 m/min and 0.1 mm/z, respectively, the
tool could work for 22.4 min. When fz increased to
0.15 mm/z, the tool life decreased by a factor of two,
indicating that fz had a great influence on the tool life.
Irrespectiveofwhether fzwas0.1or0.15mm/z, the tool
wearincreasedwith increasingvc,whichsuggeststhat vc
wasanotherimportantfactoraffectingtoollife.Thetool
wearandchipmorphologywereanalyzedusingthefinite
elementmethod(FEM)andscanningelectronmicroscopy
(SEM). It was observed that the tool-wear mechanism
would be transformed from abrasive wear to adhesive
wear if the value of vc increased. The chip gradually
obtained a large serrated curvature when fz was
0.15 mm/z and vc ranged from 60–150 m/min, also
indicating that the radius of the chip curvature was
directly affected by the vc value [105]. Based on the
above studies, the optimal machining effect can be
Fig. 2Logicalstructureofhigh-speeddrymillingdifficult-to-machinemetalmaterials.CVD:chemicalvapordeposition,PVD:physical
vapordeposition,HSDM:high-speeddrymilling.
6Front.Mech.Eng.2023,18(2):28
obtained by appropriately adjusting the process parame-
ters. The influence of changing the parameters on tool
wearwasnotobvious.Therefore,itisnecessarytofurther
explore the influence of other methods (such as tool
coating)ontoolwear.
The influence of cutting force and temperature on the
surface quality of TC4 during the HSDM process at
differentvc values was systematically investigated by Li
et al. [106]. They used CVD-coated tools (Ti(C, N)-
Al2O3)forHSDMofTC4.Theresultsshowed that with
the increase in vc and fz, tool wear aggravated, and tool
life decreased sharply. The reason for the tool injury
would transform from cutting load into thermal damage
with increasing vc value. With the development of the
Fig. 3Influenceofcuttingparametersontoolwear,cutting forceandtemperature:(a)effectofvcandfzontoolwear[105],(b)cutting
forceunderdifferentvc [106], and (c) cutting temperature underdifferentvc[106].Reproducedwithpermissions from Refs. [105,106]
fromElsevierandSpringerNature.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 7
machining process, it was found that the cutting force
(Fig.3(b) [106]) and temperature (Fig.3(c) [106]) were
the main factors affecting the tool wear [106].
Furthermore, the authors found that the average cutting
force decreased significantly with increasing vc, and the
reason for the observed reduction was attributed to the
thermalsofteningoftheworkpiececausedbytheincrease
in cutting temperature. Based on the SEM results, the
surfacemicrostructureandgrainorientationchangedwith
differentfeeddirections,asshowninFig.4(a)[107].The
authorsalsoobservedchipmorphologyduringtheHSDM
processing of TC4 and found that chip morphology
corresponded to different vc values. At the same SEM
doublingrate,thenumberoflamellaealsochanged.With
anincrease in vc, the number of lamellae decreased,but
the lamellar structure became clearer, as shown in
Fig.4(b) [108]. By observing the serrated chip
morphology in Fig.4(c) [108], it was found that the
degreeofserrationincreasedwithincreasingvc,whichis
more conducive to chip breaking [108]. Although these
Fig. 4Influence of cutting parameters on microstructure and chip morphology: (a) workpiece microstructure and deformation zone
underdifferentvc[107],(b)effectofvconchipmorphology[108],and(c)majorsection ofchips atdifferent vc[108]. Reproducedwith
permissionsfromRefs.[107,108]fromTransTechPublicationsLtd.andSpringerNature.
8Front.Mech.Eng.2023,18(2):28
findingsindicatethatCVD-coatedtoolscouldshowgreat
cuttingeffectswithsuitablevcvalues,theauthorsdidnot
studythemillingofTC4withPVD-coatedtools.
Evenwhenusingcoatedtools,thecuttingparametersof
HSDMshouldbereasonablyselected.Safarietal.[109]
tested the surface roughness and microhardness of a
workpiecesurfaceunderdifferentcuttingconditionswith
aPVD-coatedtool(TiAlN/TiN)whenvcrangedfrom100
to 300 m/min and fz from 0.03 to 0.06 mm/z. As vc
increasedfrom100to300m/min,thesurfaceroughness
decreased by 55%. The surface roughness decreased by
40%atavcvalueof100m/minasfzincreasedfrom0.03
to 0.06 mm/z. Tool wear and work-hardening problems
were also observed when vc and fz increased simultane-
ously[109]. Furthermore, the researchers used the same
PVD tool for the HSDM processing of TC4-ELI. The
resultsshowedthatthemachinedsurfaceimprovedas vc
increasedfrom200to300m/min.Whenfzwassmall,the
cuttingforceintheHSDMprocesswaslowerthanthatin
the CM process. Compared to the uncoated tool, the
PVD-coatedtooldidnotsignificantlyimprovethesurface
roughness because of the adverse effect of the large vc
value[110].Theresultsindicatedthat,evenifthecoated
tool was selected, it was difficult to improve the
machining effect if the selection of cutting parameters
wasnotsuitable.
The above studies did not compare the cutting effects
of CVD-coated and PVD-coated tools under the same
conditions. Niu et al. [111] used PVD coating
(TiN/TiAlN) and CVD coating (TiN/Al2O3/TiCN) as
tools for HSDM processing of TC6 titanium alloy.
Relevant research on the HSDM of TC6 regarding the
cuttingforceandsurfaceroughnesswassummarized,and
the difference between the PVD and CVD tool coating
performance was demonstrated from the aspects of the
tool wear evolution and failure mechanism. The milling
forceandsurfaceroughnessofTC6were high when the
vcvaluewashigherthan80m/min.Thisindicatedthatthe
two coated tools were not suitable for the HSDM
processing of the TC6 titanium alloy. However, it is
apparent that the tool wear resistance of PVD-coated
tools is much better than that of CVD-coated tools
becausethe thermalconductivityofAl2O3decreasedand
that of TiAlN increased with increasing cutting
temperature [111]. Considering the influence of tool
coating on HSDM processing, Liu et al. [112] assumed
that the regressive development of tool coating was the
main factor restricting the promotion and application of
HSDM in the industry. Based on this, they reported the
influence of AlTiN-coated tools and TiAlSiN-coated
tools on HSDM processing of TC4. The XRD (X-ray
diffraction) diffraction patterns of the two differently
coated tools, shown in Fig.5(a) [112], were compared.
ComparedtotheAlTiNtool,thetoollifeoftheTiAlSiN-
Fig. 5XRD, flank wear and tool wear images of AlTiN- and TiAlSiN-coated tools: (a) XRD diffraction patterns, (b) flank wear of
cuttinglengthunderdifferent vc,and(c)toolflankwearimages underdifferent cuttinglengths[112].Reproducedwithpermissionfrom
Ref.[112]fromSpringerNature.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 9
coatedtoolincreasedby32%and66%atvcvaluesof150
and200m/min,respectively,asshowninFig.5(b)[112].
The tool-wear image in Fig.5(c) [112] reveals that the
TiAlSiNcoatingcansignificantlyprolongthetoollifeof
the cutting edge. Furthermore, the TiAlSiN-coated tool
exhibits better oxidation resistance and more uniform
chips[112].
2.2HSDMofhigh-strengthsteel
The wear resistance of the workpieces determines their
service performance. Huang et al. [114] focused on the
influence of HSDM of AISI D2 (when milling high-
strengthsteel,thehigh-speedcuttingrangeisreachedata
vcof 300m/min[113])onthesurfaceintegrityandwear
resistance. After the HSDM, the wear resistance of the
machined surface was evaluated through friction and
wear tests without lubrication. The results showed that
the surface morphology, microhardness, and yield
strengthoftheworkpieceexhibitedanisotropiccharacter-
istics after friction and wear experiments. Because of
anisotropy,the wear resistance of the workpiece surface
mainlydependsontheslidingdirection.Furthermore,the
surfaceoftheworkpiecehardens.Duringtheinitialphase
ofwear(thefirst10min),thesurfacewearofHSDMwas
62%lessthanthatofCMmilling[114].
The surface quality indices include the surface
roughness, hardness, and residual stress. Zheng et al.
[115] used a CVD-coated tool (Al2O3 + TiC) for the
HSDM of AISI 4340 steel. The relationships between
cutting parameters, cutting force, and surface roughness
were discovered, and the effects of tool wear on the
cuttingforceandsurface roughness were studied. Itwas
found that the cutting force was most influenced by αp,
whereas fz had the greatest effect on the surface
roughness.Basedontheempiricalmodel,optimalcutting
parametersforsmallcuttingforceand surface roughness
were obtained when αp ranged from 0.2 to 0.4 mm, fz
rangedfrom0.03 to 0.06mm/z,vcwasselectedbetween
350–450m/min,andαerangedfrom3to4mm.Basedon
theSEMresults,thewearrateofthecoatedtoolwaslow.
By observing the effects of friction and wear, it was
found that the increase in the cutting force and surface
roughnesswassmallintheinitialandstablewearstages.
However, when the wear value exceeded 0.25 mm, the
increaseincuttingforcesuddenlyincreasedsignificantly.
The experimental results also indicated that the wear of
coated tools was mainly caused by adhesion, oxidation,
anddiffusion,accompaniedbyasmallamountofspalling
and chipping [115]. In addition, the authors studied the
influence of tool coating (TiAlN + TiN, AlTiN, and
TiN/TiCN/TiAlN) and cutting parameters on the cutting
force and surface roughness. Among these three coated
tools, the TiN/TiCN/TiAlN-coated tools were the most
suitableforthe HSDM processing ofAISI 4340. Owing
to the resultant force, the flank wear width and surface
roughness values were minimal. As the optimal cutting
parameters,valuesforαpof0.4mm, fzof0.02mm/z,αe
of2mm,andvcintherangefrom280–440m/min were
obtained [116]. In addition to the above investigations,
researchersused aTiCN-NbCcompositecoatingtoolfor
HSDM of AISI 4340 steel and found that when the
cutting parameters were within HSDM conditions, the
surfaceroughness valuechanged from0.25 to0.45 µm,
and the surface roughness was minimal at a vc of 350
m/min.Furthermore, applying the TiCN-NbC composite
coatingtoolresultedinworkhardeningof theworkpiece
surface.Theresultsshowedthatthehardnessvalueafter
processingwas1.1–1.2timesthatofthe workpiecebody
material,andthehardeninglayerdepthwas60to80µm,
as shown in Fig.6(a) [117]. The residual stresses in the
cuttingdirectionrangedfrom‒490to‒320MPa,whereas
the residual stresses in the feed direction ranged from
−600 to ‒370 MPa, as shown in Fig.6(b) [117].
Furthermore, higher fz, vc, and αe and smaller αp values
canprovidea workpiece withhigh residual compressive
stress[117].
2.3HSDMofnickel-basedalloy
Thecuttingparameterscansignificantlyaffectthecutting
force and generate tool wear. Li et al. [118] conducted
HSDM experiments on Inconel 718 workpieces with an
(Al, Ti)N-coated milling cutter (for nickel-based alloy
cutting,thehigh-speedcuttingrangewasreachedatavcof
100 m/min) [119]. The change in cutting forces was
investigatedasαp,vc,and fzvaluesincreasedfrom0.5to
2 mm, from 140 to 240 m/min, and from 0.1 to 0.18
mm/z, respectively. According to the results, the radial,
tangential,andaxialforcesincreasedwithanincreasein
fz. With increasing vc, the axial force fluctuated
significantlyandthendecreased,butthechangeinvchad
little effect on radial and tangential forces. With the
increaseinαp,irrespectiveofthechangesinfzandvc,the
values of the radial, tangential, and axial forces always
increased [118]. The above investigations demonstrate
that only an increase in vc can appropriately reduce the
cuttingforce.However,theeffectsofcuttingparameters
ontoolwear havenotbeenstudied.Thetool wearunder
differentvcisshown in Fig.7 [120,121]. Kamdanietal.
[120] used PVD-coated tools (TiN/TiAlN) to study the
influenceof vcandαe(radialcutwidth)on thetoolwear
of Inconel 718 processed by HSDM and observed that
whenvcwasintherangeof80–120m/min,thetoolwear
increasedwithanincreaseinαeandreacheditsmaximum
whenvc increased to 120 m/min. According to Fig.7(a)
[120],tool wear wasmore severe with an increasein vc
andαe.
As the above studies did not simultaneously consider
both the cutting force and tool wear mechanism in the
HSDM processing of nickel-based alloys, Zhang et al.
[122]appliedPCBNtools to the HSDM ofGH4169and
10 Front.Mech.Eng.2023,18(2):28
observed the influence of vc, fz, and αp on cutting force
and tool wear. The cutting force increased with an
increaseinαp,whereasitdecreasedwithanincreaseinvc.
Furthermore,withanincreaseinvcandfzoradecreasein
αp, flank wear gradually decreased. When vc, fz, and αp
were1065m/min, 0.12 mm/z,and0.5mm,respectively,
the corresponding cutting parameters were optimal. The
tool-wear values of the rake and flank surfaces became
moreuniformwhen vc was1065m/min.BecauseTi,Al,
and O elements were concentrated on the bond layer at
Fig. 6Microhardnessandresidualstressunderdifferentcuttingparameters:(a)microhardnessofdepthfromthemachinedsurfaceunder
different cutting parameters and (b) variation of machining surface residual stress with cutting parameters [117]. Reproduced with
permissionfromRef.[117]fromElsevier.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 11
thecuttingedge,themainwearmechanismwasadhesive
wear[122].
The above studies demonstrated the influence of
milling parameters on the cutting force and tool wear
during HSDM. However, the influence of the cutting
parameterson thesurface roughnessof coatedtools has
not been studied. Therefore, Qiao et al. [123] used a
PVD-coated (TiAlN/TiN) tool to conduct HSDM of
nickel-basedFGH97alloy.Thesurfaceroughnessof the
workpiece surface was explored within the specified
limitswhenαpchangedfrom0.1to0.3mm,vcfrom30to
210 m/min, and fz from 0.08 to 0.12 mm/z. The results
showed that the surface roughness increased with an
increasein αp and fz, but with increasing vc, the surface
roughness first increased and then decreased. The
minimumsurfaceroughnesswasobtainedforvcvaluesin
therangeof170–190m/min[123].
The cutting parameters not only affect the surface
roughness but also influence the tool wear and cutting
temperature. In addition to the cutting parameters, the
coating type also affects the surface roughness.
Molaiekiyaetal.[124]studiedthecuttingperformanceof
aSiAlON ceramictoolinthe HSDMofInconel718 and
measuredthetoollife,toolwear,andcuttingforceduring
machining. When the same volume of material was
removed, tool wear first decreased and then increased
withanincrease invc.Whenvcremainedin therangeof
900–1100m/min,the tool lifewasthelongest,asshown
in Fig.7(b) [121]. The change rule of the tool surface
temperature gradient was also explored using the FEM
under different vc conditions. During HSDM, a large
amount of cutting heat was generated on the contact
surface of the tool and chip, and the temperature was
mainly concentrated in the narrow strip of the second
deformation zone, as shown in Fig.8(a) [121]. This is
becauseoftheextremelylowthermalconductivityofthe
SiAlONceramictoolandtheshortcuttingtimewithinthe
setrangeofvc.Furthermore,whenvcwas900m/min,the
thermal softening effect was prominent, leading to a
relatively low cutting force. Based on the experimental
dataforthecuttingforce,cuttingheat,andtoolwear,the
optimal vc value was 900 m/min. By analyzing the tool
Fig. 7Toolwearunderdifferentvc:(a)toolwearunderdifferentmachiningconditions[120]and(b)experimentaftercutting21.75cm3
andflankwearoffiniteelementmethod[121].ReproducedwithpermissionsfromRefs.[120,121]fromMalaysianTribologySocietyand
SpringerNature.
12 Front.Mech.Eng.2023,18(2):28
wear under different cutting parameters of FEM, it was
found that at the same tool wear rate, compared with
ordinary cemented carbide tools, the SiAlON ceramic
toolcouldimprovethematerialremovalratefour tofive
times, as shown in Fig.8(b) [121]. In addition, the
authors used a SiAlON ceramic tool and a PVD-coated
(WC-Co)tool forHSDMprocessing.Comparedwiththe
PVD-coated tool, the SiAlON ceramic tool exhibited a
better surface roughness, as shown in Fig.9 [124].
However,theceramictoolformedaveryhardwhitelayer
withdepthsrangingfrom1to2µmonthesurfaceofthe
workpiece during HSDM. After corrosion, it remained
whiteunderametallographicmicroscope.Themaximum
residualtensilestressinHSDMprocessedwiththePVD-
Fig. 8Cuttingtemperatureandtoolwearunderdifferent cutting conditions: (a) temperature distribution under different vc conditions
and(b)toolwearwithdifferentcuttingvolumes[121].ReproducedwithpermissionfromRef.[121]fromSpringerNature.
Fig. 9Surfaceroughness corresponding todifferentcoated tools: (a)SiAlONtool and (b)physicalvapor deposition tool[124].PVD:
physicalvapordeposition.ReproducedwithpermissionfromRef.[124]fromSpringerNature.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 13
coatedtoolwas2.5times higher than that obtainedwith
CMpouringcutting,which was caused by rapidcooling
at high temperatures. Therefore, CMQL technology is
necessarytoreducethethermaldamagecausedbytoolor
workpiecesurfacesduringHSDMprocessing[124].
AlthoughMolaiekiyaetal.[124]systematicallystudied
the HSDM process of SiAlON ceramic tools, the
hardnessofthehardwhitelayerand cutting forces were
not explored under HSDM and CM conditions. To
determinethechangeinhardness,Şirinetal.[125]used
HSDM and SiAlON ceramic tools to process nickel-
based X-750 alloys. The surface roughness, cutting
temperature, cutting force, and microhardness of the
workpiece were measured in the vc range of 500–
700m/min,andthevfrangeof0.025–0.075mm/r.Itwas
found that the surface roughness increased with
increasing vc and vf. Under all cutting conditions, the
surfaceroughnesscorrespondingtoHSDMwasrelatively
large. The cutting force and temperature were 565.7 N
and 450 °C, respectively. The tool wear was small
because the tool coating provided anti-wear properties
during processing. Compared with CM pouring cutting,
HSDM can increase the hardness of the workpiece by
16.94%[125].
The above studies systematically revealed the cutting
effectoftheHSDMofnickel-basedalloyswithSiAlON
ceramic tools, but a formula for the cutting force and
cutting temperature in the cutting process has not been
established. Thus, Zha et al. [126] investigated the
HSDM process of Inconel 718 with a SiAlON ceramic
toolbasedon FEM andderivedformulas for thecutting
force and cutting temperature. Subsequently, an HSDM
experiment was performed using the specific cutting
temperaturetoverifythecuttingforceformula.Whenαp,
αe, fz, and vc reached 0.3 mm, 6 mm, 0.03 mm/z, and
527.52 m/min, respectively, the cutting force began to
decrease,indicatingthatthecuttingtemperatureexceeded
the softening temperature of Inconel 718. The experi-
ments showed that when vc was higher than 527.52
m/min, the HSDM process for Inconel 718 was easier.
The accuracy of the formula for the cutting force and
temperature was verified based on experimental results
[126].
2.4SummaryofHSDMofdifficult-to-machinemetal
materials
Based on the above investigations, the cutting speed
ranges of difficult-to-machine metal materials are
different in the HSDM process owing to the different
properties of these materials. The suitable cutting speed
range is 100–300 m/min for titanium alloy, 300–
450m/min for high-strength steel,and 500–1100 m/min
for nickel-based alloys. Titanium alloys are commonly
usedfor aircraft fuselages, while nickel-based alloys are
primarilyused for aircraftengines. However, the engine
servicelife is typically shorter thanthat of the fuselage.
Toincrease thecuttingspeedofnickel-basedalloys,itis
necessary to introduce high-performance SiAlON cera-
mic tools. In terms of the entire aircraft, the content of
titanium alloy is much higher in structural parts than in
high-strength steel landing gears. This means that
increasing the cutting speed of titanium alloy has a
greaterimpactthanincreasingthecuttingspeedofhigh-
strength steel. Based on Fig.10 and the above research
results, the cutting force and surface roughness in the
HSDMprocessaredifficultto reduce with uncoated and
ordinarycoatedtools(TiN/TiAlN,TiN/Al2O3/TiCN,and
AlTiN), and the tool wear is also severe. High-perfor-
mance tools (SiAlON ceramic tools) and composite-
coated tools (TiN/TiCN/TiAlN, TiCN-NbC) can reduce
thecuttingforce,temperature,andsurfaceroughnessand
minimize tool wear during the machining process.
However,comparedwith CM pouringcutting,the depth
of the surface-hardening layer and the residual stress of
HSDMmachiningarehigher,whichlimitstheapplication
and promotion of the HSDM machining process.
ConsideringthatthedeficiencyofHSDMprocessingcan
be eliminated by LAM, UVAM, and CMQL technolo-
gies, which have been sufficiently researched, the
subsequent work of HSDM mainly focuses on energy
field-assistedmillingtechnology.
3LAM of difficult-to-machine metal
materials
LAM is a new auxiliary processing mode for the local
softeningofworkpieces using a laserheatsource before
processing.BecauseLAMtechnology can reduceenergy
consumptionbyreducing thecuttingforce,itisa typical
greenandlow-carbon processing technology [127].This
principleisshowninFig.11(a)[128].Theincidentangle
of the laser beam (feeding simultaneously with the
milling cutter) is set to ensure that the heat source
radiated into the shear zone of the workpiece surface.
Subsequently,the optimal laserparameters (PL, dL, etc.)
and milling parameters (vc, αp, etc.) are combined to
reduce the strength and hardness of difficult-to-cut
materials.Therefore, LAM can reduce the cutting force,
prolongthe tool life, improve thematerial removal rate,
reduce the cutting energy consumption, reduce the
manufacturing cost, and optimize the workpiece surface
quality [128]. The LAM of difficult-to-machine metal
materials is divided into three classes according to the
LAM preheating temperature range, and the logical
structureisshowninFig.11(b).
For studies on LAM of high-strength steel, first, the
laserparametersandcuttingparameterswerechanged to
reduce the cutting force and improve tool rigidity.
Second,the influenceofthelaser preheatingtemperature
on the cutting force and specific cutting energy was
14 Front.Mech.Eng.2023,18(2):28
studied.Third,itwasverifiedthatLAMcouldreducethe
cuttingforcewiththehelpofFEM.CombiningtheFEM
methodandexperiments,theresearchersfoundthatLAM
couldreducethecuttingforceandsurfaceroughnessand
that the most influential parameter on the surface
roughness was the cutting speed. A comparison of the
tool wear under high and low feed conditions revealed
that LAM can significantly improve material removal
under high feed conditions. Subsequently, after the
optimization of the laser and cutting parameters, it was
verified based on slot milling experiments that LAM
couldgreatlyreducesurfaceroughnessandtoolwear.To
reducetheexperimentalworkload,aphysical-basedLAM
cuttingforcemodelisproposed,andtheaccuracyofthe
modelisverified. Furthermore, toattainanoptimallaser
preheatingeffect,atwo-stageLAMprocesswasproposed
to match the laser softening depth with the cutting
manufacturing depth. Finally, to effectively control the
range of the heat-affected zone (HAZ), the influence of
the laser preheating parameters on the HAZ size was
exploredindetail.
To study the LAM of titanium alloys, the preheating
temperature was first set to 618 °C to explore the
influence of cutting parameters on the cutting force and
microstructure of the planar workpiece. Second, the
optimal laser power for surface machining was
determinedby combining FEM with the tool inclination
angle, and its accuracy was experimentally verified.
Third, a laser-assisted fillet milling strategy was
developed, and it was found that the cutting force,
specificenergy,and surface roughness couldbereduced
ata preheating temperature of 600 °C. Furthermore, the
surface LAM strategy of the tool inclination and fillet
was integrated to reduce the cutting force and cutting
specific energy. Subsequently, the cost of single-piece
manufacturingunderLAM conditionscanbereducedby
adjusting the laser parameters to obtain a preheating
temperature of 500 °C. Finally, the laser and milling
parameters were adjusted simultaneously to reduce the
annualproductioncostsoftheenterprise.
When investigating the LAM of nickel-based alloys,
thepreheating temperature wasfirst set to800 °C using
external laser-assisted equipment, and the effects of
increasingtheLAMplaneoftheworkpieceonthecutting
force, surface roughness, and tool wear were compared.
Second, the influence of the laser power parameters on
the tool wear in plane milling was studied. Third, the
influenceofsimultaneouschangesinthelaserandcutting
parametersonthecuttingforce and surface roughness in
plane milling was explored. It was found that adjusting
onlythelaserandcuttingparametersledtoanincreasein
thesurfaceroughness.Subsequently,anewlaser-assisted
reciprocatingpreheatingprocesswasproposed,andLAM
backandforth(B&F)preheatingwasfoundtoreducethe
surfaceroughnessvalueduringplanemilling.Subsequen-
tly,contour LAM and slope LAM were proposed based
on the results of the parameter optimization and a new
process of plane milling. When comparing the cutting
Fig. 10Summaryofhigh-speeddrymillingmachinability.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 15
force,surfaceroughness, andspecificcuttingenergy,the
contourLAM had better effectsthan the slopeLAM. In
addition,theactual temperatureoftheworkpiecesurface
significantlyinfluencestheLAM manufacturing process.
The constant laser energy used in the experiment could
notprovide a stable preheating temperature. A tempera-
ture feedback control method is proposed to establish a
tool life prediction model, and its accuracy is verified.
Finally,itwasestablishedthattheheatingareawaslarger
thantheheatsourcesizeunderactualworkingconditions,
and a new space- and time-controlled laser-heating
method was proposed. The chip morphologies and
microstructuresobtained by LAM, CM, and single laser
scanning (LS) were compared in detail. Based on the
hollow tool-holder fiber system, the effect of LAM on
reducingthecuttingforceandtoolwear was verified by
changingthelaserparameters.
3.1LAMofhigh-strengthsteel
The laser parameters (PL, laser position) and cutting
parameters(vc,αp,andαe)significantlyaffectthecutting
forceand dimensional accuracy of the workpiece. Singh
andMelkote[129]conductedLAMexperimentsonH-13
steel using an ytterbium fiber laser (wavelength of
1064 nm) and a preheating temperature of 890 °C. The
results showed that under the given cutting conditions,
the laser parameters had a significant influence on the
machining process. By properly controlling the PL, dL,
andlaser position,thestrengthof theworkpiecematerial
would be reduced, which can minimize the risk of tool
failure,reduce thecuttingforce,andimprovetherigidity
ofthetool.By observing the LAM hardnessdata,itwas
found that there was a measurable HAZ on the laser-
heatedsurfaces.TheHAZareadecreasedwithincreasing
VL[129].Inaddition,itwasobservedthatαpandPLhad
a significant influence on the cutting force during the
LAMprocessandthatthesurfaceroughnesswasaffected
byPL[130].ConsideringthatPLcouldaffecttheheating
temperature, Jeon and Pfefferkorn [131] used a 200-W
(continuous wave) Nd:YAG laser (wavelength of
1064nm)forLAMprocessingexperimentson1018steel
withvariable laserheatingtemperatures.When thelaser-
assisted temperature increased from 27 to 867 °C, the
Fig. 11Laser-assistedmilling(LAM)principleandlogic:(a)LAMschematicdiagram[128]and(b)logicalstructureofLAMdifficult-
to-machine metal materials. FEM: finite element method; B&F: back and forth. Reproduced with permission from Ref. [128] from
SpringerNature.
16 Front.Mech.Eng.2023,18(2):28
averagefeedandcuttingforceswerereducedby56%and
32%,respectively.Thespecificcuttingenergydecreased
by32%[131].BecauseFEMcanreducetheexperimental
cost and support the analysis of the temperature field
distribution in the machining process, Özel and
Pfefferkorn[132]conductedLAMresearchonAISI4340
steelbasedonFEMandexperiments.AnNd:YAGlaser
(wavelengthof1064nm)wasusedintheheatingprocess.
The FEM results were analyzed using DEFORM-2D
software.Athigh vf, the cutting forceofLAM (400 °C)
wassmallerthanthatofCM[132].Caoetal.[133]found
thebestLAM process conditions for13-8stainless steel
using a 1-kW HPDL laser (wavelength range of 940–
980nm)toobtainasurfacetemperatureof550°C.First,
the temperature field distribution of the laser-beam-
preheatedworkpiece was determined based on the FEM
method. Subsequently, the Taguchi experimental design
was applied by changing vc, vf, and αp. Finally, the
optimal process parameters of LAM were established
using variance analyses. Compared with the CM, the
cutting force and surface roughness of the LAM were
reducedby20.1%and34.4%,respectively.Theresultsof
variance analyses showed that under the appropriate
LAM conditions, the cutting force was affected by αp,
whereas vc had the greatest influence on the surface
roughness[133].
Theabovestudies showed that,inadditiontothelaser
parameters, cutting parameters also have a significant
influenceontheLAMprocess. Bermingham et al. [134]
used a 2.2-kW HPDL laser (wavelength range of
940–980nm)andapreheatingtemperatureof300°Cand
conducted comparative processing experiments with or
without LAM of high-feed milling (H.F) or low-feed
milling(L.F).Basedontheaboveexperimentalvariables
in Fig.12(a) [134], they established the relationship
betweenthematerialremovalvolume and tool wear and
observed no difference in tool wear between LAM and
CM at 100 m/min H.F. However, under L.F conditions,
the tool wear of LAM and CM was quite different. For
thesametool wear,vfwas117and150 m/minforLAM
andCM, respectively,andthematerialremovalbyLAM
wasmorethandoublethatofCM.However,whenvfwas
78m/min,theremovalrateofLAMwasonly50%higher
than that of CM. Based on the mechanism of adhesive
wear and abrasive wear, it was proven that LAM
technology could effectively prolong tool life. In
addition,compared to CM, LAM canreduce the cutting
forceby33%[134].
Afteroptimizingthecuttingparameters,itis necessary
to design a variety of experiments (such as groove
milling) to reduce surface roughness and tool wear.
Meikote et al. [135] used an ytterbium fiber laser
(wavelengthof1060nm)toconductlaser-assistedgroove
millingexperiments onA2toolsteel. Theymeasuredthe
dimensional accuracy, surface roughness, and tool wear
oftheequipment.Theauthorsfoundthatthedimensional
precisionoftheworkpiecegrooveoftheLAMwascloser
tothedrawingsettingprecisionthan that of the CM. As
shown in Fig.12(b) [135], the surface roughness of the
LAM (7.5 W) was smaller than that of the CM at
different cutting lengths, and the tool wear rate of the
LAMwaslower[135].
The cutting-force prediction model can reduce the
workload of cutting experiments and accurately deter-
minethecutting force intheLAMprocess.Kumaretal.
[136] proposed a physical-based cutting force model to
predict the cutting force during the LAM process, as
shown in Fig.13(a) [136]. The contents of the model
included the thermal model of laser heating, thermal
modeloftemperature rise causedby plastic deformation
(shear) in the process of chip formation, material
strength-relatedshearanglemodel,materialflowstrength
model,millingmodel,andtooljumpmodel.Basedonthe
newmodel,thecuttingforceduringLAMprocessingwas
Fig. 12Cutting forces and grain deformation distribution: (a) tool wear under different cutting conditions [134] and (b) surface
roughnessatdifferentvc [135]. CM: conventional milling; LAM: laser-assisted milling; H.F: high-feed milling; L.F: low-feed milling.
ReproducedwithpermissionsfromRefs.[134,135]fromElsevier.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 17
predictedand verified. The PLand VL parameters ofthe
52100 bearing steel were changed using an ytterbium
fiber laser (wavelength of 1060 nm). The experimental
resultsshowedthatthecuttingforceofLAM(18W)was
smallerthan that of CM.Both the materialremoval rate
andtoollifeofLAMwerehigher[136].
The HAZ on the machined surface affects the dimen-
sionalaccuracyandserviceperformanceoftheworkpiece
afterheatingusingthelasersystem. Kadivar et al. [137]
proposedatwo-stageLAMprocesstosolvetheproblems
in which a continuous wave or short-pulse laser may
producean HAZ that may be retained on the surface of
thefinishedproduct,andtheuseofcoolantwouldleadto
a decrease in laser heating efficiency. The first stage is
basedonanultrashortpulselasertosoftentheshearzone
on the workpiece surface. In the second stage, a micro-
milling cutter is used to change the softened surface
constructed in the first stage to the final size. The
advantage of using an ultrashort pulse laser was that it
achieved control of the HAZ range in real time. The
workpiececouldbe machined to acertain softening size
bycontrollingthelaserparameters.Theworkpieceisthen
processed under different cutting conditions. Therefore,
theprocessing parameters were independent of the laser
parameters. However, the two-stage coordination can
match the laser softening depth with the cutting
manufacturing depth. The LAM of X5CrNi18-10 steel
was conducted using a Yb:YAG picosecond laser. The
laser heat parameters included PL and the distance
betweenthe laser spotand tool. Thecutting transforma-
tionparameters were vc, fz, and αe. Itwas observed that
the cutting force is affected by vc. Compared with CM,
LAMsignificantlyreducedtheaxialandtangentialforces
by70%and 50%, respectively.Regardingchip morpho-
logy,theLAMchipwassmallandthin,asshowninFig.
13(b)[137], whichalsoledtoasmallermilling forcefor
LAM. In addition, appropriate laser parameters are
essentialforachievingefficientLAMmachining.Setting
PLto10Wreducedthemachiningtemperatureby50%.
Therefore,foroptimalLAMperformanceparameters,the
laser power should be set to 10 W, and the distance
betweenthespotandthetoolshouldbe250µm[137].
Controlling the HAZ is crucial for machining
processes.Zeng etal.[138]foundthatLAMmayinduce
aworkpiecetoproduceaharmfulHAZ. Accordingly,an
HAZanalysismodelwasestablished to predict the HAZ
generated by laser heating in the LAM of AerMet100
steel.A 1-kW HPDL laser(wavelength of 915nm) was
used to verify the proposed analysis model by
transforming PL and vf. According to Fig.14 [138], the
HAZ size increased significantly with an increase in PL
(from200to 1000 W)anddecreasedwithanincreasein
vf. The temperature change in the HAZ ranged from
138.8 to 574.7 °C. The HAZ width increased with dL,
while the HAZ depth decreased because of the inverse
correlation of the dL energy concentration. Therefore,
Fig. 13Force prediction and cutting morphology: (a) laser-assisted milling (LAM) force prediction methodology [136] and
(b)comparisonofchipmorphology[137].CM:conventionalmilling.ReproducedwithpermissionsfromRefs.[136,137]fromASMEand
Elsevier.
18 Front.Mech.Eng.2023,18(2):28
consideringthat the side millingae value wassmall and
theapvaluewaslarge,itwasrecommendedtousealaser
witha smaller dL value, whereas the opposite applies to
face milling, for which a laser with a larger dL value
should be utilized. Compared with the other laser
parameters, the influence of the laser incident angle on
theHAZwas small.Furthermore,asshowninFig.14(a)
[138], the HAZ could be caused by a critical PL value
becausethePLvaluewaslessthan the critical PL value.
The absorption temperature of the workpiece did not
reach the austenite transformation temperature of the
material[138].
3.2LAMoftitaniumalloy
LAM can aid in optimizing the cutting force and
improvingthemicrostructure of planarworkpieces.Kim
and Lee [139] used a 1-kW HPDL laser (wavelength
rangeof 940–980nm)andsetthesurfacetemperatureof
theLAMworkpieceto618°C(laserpower of 80 W) to
perform comparative cutting experiments on TC4
workpieces with and without LAM processing. The
purposeofthisstudywastoassesstheinfluenceofvc,fz,
andαponcuttingforce,toolwear,andsurfaceroughness.
TheresultsshowedthatthecuttingforceoftheLAMwas
reduced by 13%–46% compared with that of the CM.
Adhesion of cracks and chips was not observed on the
tool wear surface under the SEM conditions. In all
experiments, the surface roughness and microstructure
wereimproved,asshowninFig.15[139].
In actual machining processes, titanium alloy parts
mostly possess curved surfaces, such as compressor
blades and casings of aeroengines. The optimal laser
powerfor machining curvedsurfaces can be determined
based on the tool-inclination angle. Sim and Lee [140]
workedonthe preheating andmachiningoptimizationof
thetool-pathinclinationangleintheLAMprocess.First,
FEMwasappliedforthethermalanalysisofTC4.Based
onthis, the optimalPL was determined according to the
tool-path angle. TC4 milling experiments were then
conductedusing a 1-kW HPDL laser (wavelength range
of808‒980nm,laserpowerof80W).Accordingto the
results, the preheating temperature decreased with
increasing tool-path inclination, as shown in Fig.16(a)
[140].However,whenthetoolinclinationangleexceeded
75°, the preheating temperature began to increase. The
accuracy of the simulation process was verified by the
experimentalresults. The experiments also revealed that
thecutting force in the LAM process decreasedwith an
increaseinthetool-pathinclinationangle[140].
Consideringthereductioninthestressconcentrationof
fillets, the fillet can improve the service life of the
workpiece, and the fillet strategy is widely utilized in
actualtoolpathdesign.Therefore,itisnecessarytocreate
Fig. 14Effectof differentlaserparameters onheat-affectedzone:(a) PL,(b)dL, (c)vf,and (d)laserincident angle[138].HAZ: heat-
affectedzone.ReproducedwithpermissionfromRef.[138]fromSpringerNature.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 19
a detailed LAM strategy for the tool path of the fillets.
WooandLee[141]proposedalaserenergyfield-assisted
fillet milling strategy to solve the problem in which the
laserbeamcouldnotcontinuouslyirradiatethetopofthe
workpiecewhenlaserenergyfield-assistedcornermilling
wasconductedusinganadditionalaxislasermodule.The
laser-assistedfilletmillingpathandprocessingconditions
based on the linear difference are shown in Fig.16(b)
[141].The specific implementation scheme included the
following: First, the milling origin (0, 0), the expected
filletradius(R),thenumberofcoordinatepoints,andthe
tool radius angle (αi) were determined to calculate the
coordinate tool point (Pci). The calculation formula for
thetoolcoordinatepointcanbeexpressedas
x=r×cos(180 + α)+r,r=rc+R,(1)
y=r×sin(180 + α)+r,(2)
where r represents the radius of the cutting tool, and rc
representsthesumoftheradiusofthecuttingtool.
Second, the distance (xcl) between the tool center and
the laser heat source center as well as the heat source
radius were determined, and the distance (∆xi) between
theinitialcoordinatepoint(Pli)oftheheatsourceandthe
end coordinate point (PLi) of the laser heat source was
calculated. Finally, the calculated tool coordinates and
laserheatsourcecoordinatesweretransformedintoGand
Mcodesandwereinputintothemachinetool.
After the fillet LAM strategy was completed, the
effectivecuttingdepth wasobtainedbythermalanalysis,
asshownin Fig.17 [142]. Theresponse surface method
was used to design the experiments. Finally, the
experiment was conducted using a 1-kW HPDL laser
with wavelengths ranging from 940 to 980 nm and a
preheating temperature of 600 °C. A cutting-force
predictionmodelwasestablishedbasedontheregression
analysis. Optimal manufacturing conditions for milling
TC4 are provided. The results showed that, compared
with CM, the feed force, axial force, cutting ratio, and
surface roughness of LAM were reduced by 23.7%,
20.6%,24.2%,and47%,respectively[141,142].
The LAM of curved surfaces under real operating
conditions can be determined by combining the tool-
inclinationangle with the fillet LAM strategy. Oh et al.
[143] combined a curved surface milling method with
LAMtechnologyusing a1-kWHPDLlaser(wavelength
rangeof940–980nm)anddeterminedthatthepreheating
temperature for milling TC4 material was 980 °C. The
cuttingforceand specific energyofconventionalsurface
milling and curved-surface LAM technology under
differentprocessingconditionswere assessed. Compared
with conventional surface milling, the cutting force and
Fig. 15Conventionalmillingand laser-assisted milling (LAM) machinedsurface:(a)surfaceroughness and (b) microstructure [139].
CM:conventionalmilling.ReproducedwithpermissionfromRef.[139]fromMDPI.
20 Front.Mech.Eng.2023,18(2):28
specificcuttingenergyofcurvedsurfaceLAMdecreased
by33%andby28%to41%,respectively[143].
According to Taylor’s tool-life equation, the single-
piece manufacturing cost of LAM can be quickly
obtained.Hedberg et al. [144] conducted LAM research
onTC4usinga1-kWIPGPhotonicsytterbiumfiberlaser
(wavelength of 1071 nm). Based on the heat transfer
mechanismofTC4,a temperature distributionprediction
model for LAM was established. The appropriate laser
parameters were optimized using the prediction model.
The surface quality, unit cost, and annual cost are
presented in Fig.18 [144,145]. To ensure the surface
Fig. 16Rotationangleandroundangleoflaser-assistedmilling:(a)temperaturedistributionofrotationangle[140]and(b)round-angle
laser-assistedmillingpath[141].ReproducedwithpermissionfromRefs.[140,141]fromSpringerNature.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 21
integrity and service performance of the workpiece
manufactured by LAM, the cutting force, tool wear,
microstructure(Fig.18(a)[144]),XRDstructure,surface
hardness,residualstress (Fig.18(b)[144]),andeconomy
of LAM technology were determined. According to
Taylor’stoollifeequationobtainedfromtheresultsofthe
hypothesis and experimental tests, the total costs of a
singlepiece manufactured by CM and LAM technology
underdifferentvcvalueswerecalculated,andtheresults
are shown in Fig.18(c) [144]. Compared to CM, the
cutting force, residual stress, and manufacturing cost of
LAM (preheating temperature of 500 °C) were reduced
by20%, 10%, and33%, respectively. Inaddition, LAM
extendedthetool life by64%andimprovedthematerial
removalrateby35%[144,146].
After optimizing the LAM parameters, the annual
production cost of the enterprise can be significantly
reduced.Wiedenmannet al. [147]applied LAM techno-
logytoconductexperimentsonTC4titaniumalloys.The
experiment was set up based on the central composite
design (CCD) method using a 4-kW Nd:YAG laser
(wavelength of 1064 nm) as an experimental auxiliary
tool and PL, dL, xL, αp, αe, and fz as the parameter
variables. After studying the influence of simultaneous
changesinthelaserandmillingparametersonthecutting
force, the authors found that among the selected
parameters, PL had the greatest influence on the cutting
forceinalldirections,withanoveralldecreasingtrendin
the cutting force with increasing PL. The determined
theoretical optimal value of dL was 2.65 mm [147].
Furthermore,comparedwithCM,LAMtechnologycould
reduce the cutting force, improve the material removal
rateby33%,andprolongthetool life by 19% when the
preheating temperature was 800 °C [145]. As shown in
Fig.18(d) [145], taking the milling of titanium turbine
bladesas an example, the highest economic potential of
LAM is the production of 1200 parts per year, which
couldsaveup to 10.5%ofthe manufacturing costofall
products.
3.3LAMofnickel-basedalloys
Externallaserauxiliary equipment iswidely used owing
to its convenient installation. Kong et al. [148] used an
Nd:YAGlaser(wavelengthof1064nm)andapreheating
temperature of 800 °C to conduct LAM of a planar
workpiece made of K24 nickel-based alloy. The effec-
tiveness of the LAM was explored by measuring the
cutting force, surface roughness, and tool wear at
different material removal temperatures, which could
reducethe surfaceroughnessandcutting force.Fromthe
experimental results, they discovered that the cutting
force was reduced by 30%–70%, and the life of the
coated tools was extended by 46%. By comparing
different coated tools, the authors found that the main
wearmechanismsof the toolsin the LAM processwere
adhesivewearandabrasivewear,asshownin Fig.19(a)
[148]. The TiAlN-coated tools had the highest wear
resistance at a cutting speed of 30 m/min, whereas the
TiCNcoatinghad the poorest performance.Notchescan
beobservedafterprocessingforacertaintime,asshown
inFig.19(b)[148]. Becausethetooldamagewas caused
by the high temperature in the machining process, Tian
et al. [149] proposed a transient three-dimensional
thermalmodelforLAMtoaccuratelyobtainthetempera-
turedistribution. Theaccuracyofthe modelwasverified
by measuring the surface temperature using an infrared
thermalimagerandthermocouple. The LAMexperiment
on a planar workpiece made of Inconel 718 was
conducted using a 4-kW HPDL laser (wavelength of
808 nm). Tool wear was observed by SEM, indicating
that with increasing PL, abrasive wear became more
uniform. Excessive PL leads to an increase in the tool
wear, as shown in Fig.19(c) [149]. Therefore, the
following experimental conclusion was obtained. The
verification model could provide the transient tempera-
ture distribution of the workpiece when its geometrical
shape changed during the machining process. After
adjusting PL, the laser temperature was set to 520 °C.
Under this condition, compared with CM, LAM can
Fig. 17Thermalanalysisoflaser-assistedmilling[142].ReproducedwithpermissionfromRef.[142]fromSpringerNature.
22 Front.Mech.Eng.2023,18(2):28
Fig. 18Surfacequality,unitcostandannualcost:(a)microstructure,(b)residualstress,(c)costoftheunitunderdifferentvc[144],and
(d) annual costs of produced parts [145]. CM: conventional milling; LAM: laser-assisted milling. Reproduced with permissions from
Refs.[144,145]fromSpringerNatureandElsevier.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 23
reduce the cutting force, number of chips, and surface
roughness by 40% to 50%, 50%, and 50%, respectively
[149].
A systematic understanding of the comprehensive
mechanism of the processing technology and choice of
laserparametersiscrucialforadetailedunderstandingof
theLAMprocess.KinandLee[150]performedanLAM
experiment on a planar workpiece made of Inconel 718
witha1-kWHPDLlaser(wavelength range of 940–980
nm).First, material properties (thermal conductivity and
specific heat) were obtained. The appropriate PL and
rangeofthepredictedtemperatureweredeterminedbased
Fig. 19Flank face wear at different milling conditions: (a) scanning electron microscope of coated tool at 10s with laser-assisted
milling, (b) scanning electron microscope of coated tool at 16.6 min with laser-assisted milling [148], and (c) scanning electron
microscope of the coated tool at 20 mm with laser-assisted milling under different PL [149]. Reproduced with permissions from
Refs.[148,149]fromSpringerNatureandASME.
24 Front.Mech.Eng.2023,18(2):28
on the FEM. Subsequently, LAM experiments were
conducted with different PL and αp. According to the
results, the cutting force decreased with increasing PL
irrespective of the change in αp. Compared to CM, the
cutting force of LAM decreased by 55% when the
preheating temperature was set to 900 °C (180 W), but
thesurfaceroughnessincreasedby70%[150].Second,to
eliminatethe observed negative effect ofthe increase in
surfaceroughness,anewtechnology,B&F,wasproposed
with a preheating temperature of 900 °C. In the experi-
ments, different workpiece inclination angles were
applied. The results showed that the cutting force
decreased with increasing workpiece inclination. The
levelsoftooldamageandsurfacequalitywereimproved,
as shown in Fig.20 [151]. Finally, the cutting force of
LAM (B&F) was smaller than that of LAM and CM.
Compared with CM, the surface roughness of LAM
(B&F) and LAM decreased by 34.2% and 56.8%,
respectively [151]. Based on the parameter optimization
for planar LAM and the new technology, the LAM
experiments on contour and slope non-uniform rational
B-spline(NURBS)three-dimensionalsurfacesoutperfor-
med at a set preheating temperature of 940 °C. The
cuttingforcesofcontourLAMandslopeLAMdecreased
by39.6%and 33.7%, respectively,comparedwith those
of CM. The surface roughness and cutting ratio were
reduced by 38.59% and 49.91%, respectively. It was
demonstrated that contour LAM was better than slope
LAM[152].
Thetemperatureofthe workpiece surface significantly
influences the LAM process. Wu et al. [153,154] found
that the laser preheating temperature was the most
important parameter affecting the laser heating effect.
However, a constant laser energy could not provide a
stablepreheatingtemperatureduring the cutting process.
The temperature feedback and cutting temperature are
shown in Fig.21 [153,154]. A temperature feedback
controlmethodfortheLAMprocesswasproposedbased
on the results shown in Fig.21(a) [153]. The authors
established a composite simulation model including a
preheating temperature model, temperature feedback
model, temperature difference prediction model, and
cuttingprocessmodel. Furthermore,thecuttingtempera-
turefieldandcuttingprocessweresimulatedtodetermine
differences in temperature. Subsequently, the laser-
heatingtemperaturecan be controlledbymonitoringand
adjusting. The simulation and experimental results
showed that PL was the main factor affecting the
difference between the preheating, shear zone, and
monitoring temperatures, as shown in Figs.21(b) [154]
and21(c)[154].TheLAMofInconel718wasperformed
using a 1-kW HPDL laser (wavelength of 808 nm).
Compared with CM, the main cutting forces correspon-
dingtopreheatingtemperaturesof400and700°Cwere
reducedby23%and45%,respectively[154].Comparing
the tool life of the CVD-coated tools and PVD-coated
tools, it was found that the CVD coating was more
suitable for the LAM process. The error of the tool life
prediction model was less than 15% according to the
experimental results, which verified the accuracy of the
model[153].
An optimized process can effectively heat a region
whoseareaiswiderthandLandensuretheuniformityof
thetemperaturedistributionintheheating region. Shang
et al. [155] proposed a new spatially and temporally
controlled (S&T) laser heating method, which was
characterized by laser points with oscillations along
specific trajectories and the generation of HAZs. In
contrast to the oscillating heating method proposed by
Bermingham et al. [134], the S&T method not only
provides information about the configuration of laser
heating(suchasPL, VL, and thelaserscanningpath)but
also shows the heating effect. In their study, the
correctnessofthelaserconfigurationwas mainly proven
Fig. 20Theinfluenceofworkpieceinclinationanglesoncuttingforceandtooldamage:(a)workpieceinclinationandcuttingforceand
(b)workpieceinclinationandtooldamage[151]. CM: conventional milling; LAM: laser-assisted milling. Reproduced with permission
fromRef.[151]fromSpringerNature.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 25
by forward and inverse heat conduction. Forward heat
conductioncandeterminethetemperaturedistributionin
the workpiece with a given laser beam configuration.
Reverse heat conduction was used to determine the
optimal laser system parameters. The LAM of Inconel
718 was conducted using a 10-kW HPDL laser at a
preheatingtemperatureof800°C.Theaveragevalueand
peak of the cutting force in the LAM process were
calculatedbasedonthemeasuredcutting force shown in
Fig.22(a)[155].Thepeakandaveragevaluesofthemain
cutting force were reduced by 55% and 47.8%,
respectively, after the proposed S&T controlled laser
heatingmethodwas applied. Thepeak and average feed
forces decreased by 26.3% and 26.1%, respectively,
whichreduced the cutting power by 35.4%. In addition,
comparedwith dry milling, LAM with the laser heating
methodcontrolledbyS&Treducedthesurfaceroughness
by14%[155]. Theauthorsalsoconducteda comprehen-
sivestudyontheresidualstressesandmicrostructureofa
workpieceprocessedbyLAMtechnology(laserpowerin
therangeof 1300–1500 W)andfurther studied thechip
morphologyandmicrostructureformation.Bycomparing
LAM,CM,and LS,ameltinglayerwasobserved onthe
freesurfaceofthechipsgeneratedbyLAMbycomparing
LAM, CM, and single laser scanning. The bending
phenomenon of the LS workpiece was also compared.
Thisbending effectwas noteliminated afterremoval of
the softening layer by the LAM process. These results
indicate that LAM technology is more suitable for the
machining of cylindrical parts. In addition, to further
understand the plastic strain during processing, it is
necessary to measure the intragranular local misorienta-
tion (LMO) in the chip crystal, namely, the dislocation
accumulated in the crystal during grain deformation, as
showninFig.22(b)[156].Amongtheimages,aslipband
composed of several slip planes is present in the LAM
chip. However, the CM image showed a more obvious
directional dislocation, and the LS image showed no
obvious dislocation. The results indicated that LAM
combines the advantages of reducing the cutting force
andimprovingthematerialremovalrates[156].
Built-inlaserauxiliary equipment isdifficulttoinstall,
anditslarge-scaleimplementationhashighcosts.Brecher
etal.[157]developeda2.3-kW(wavelengthof1070nm)
fiberlasersystemmovedbyanHohl ShaftKegel(HSK)
hollow shank based on Fraunhofer Institute for Produc-
tion Technology (Fraunhofer IPT), which preheated the
surface of the shear zone of an Inconel 718 workpiece
before machining to 800 °C. During the experiment, it
was necessary to change PL and measure the cutting
force. Compared with the CM, the cutting force, axial
force,feedforce,andtoolwearoftheLAMwerereduced
by60%, 60%,40%,and57.14%, respectively.Finally,it
was observed that the tool wear was the smallest when
thePLvaluewas1.54kW[157].
3.4SummaryofLAMofdifficult-to-machinemetal
materials
Based on the above investigations, the preheating
temperature ranges during LAM of difficult-to-machine
metalmaterialsaredifferentbecauseoftheirinconsistent
basic properties. The tensile strength of high-strength
steeldecreaseswhenthepreheatingtemperatureexceeds
400 °C. Because material oxidation can easily occur at
temperaturesabove600°C,thepreheatingtemperatureof
high-strength steel for effective processing ranges from
400 to 550 °C [132,133,138]. The tensile strength of
Fig. 21Temperaturefeedback andcuttingtemperature:(a)effect ofPLon cuttingtemperature,(b)effectof VLoncuttingtemperature
[154], and (c) schematic diagram of the temperature feedback system [153]. Reproduced with permission from Refs. [153,154] from
SpringerNature.
26 Front.Mech.Eng.2023,18(2):28
titanium alloys is significantly reduced at temperatures
above 600 °C, and the preheating temperature range of
titaniumalloys isbetween 500and 620°C foreffective
processing [139,141,142]. The yield strength of nickel-
based alloys decreases sharply when the temperature
exceeds650°C,andthepreheatingtemperatureofnickel-
basedalloysfor effective processing rangesfrom650 to
950°C[148,150,151].Compared with CM, althoughthe
preheating temperature range of difficult-to-machine
metalmaterialsforeffectiveprocessingisdifferent,LAM
of high-strength steel, titanium alloy, and nickel-based
alloyhasadvantages,suchasasmall cutting force, high
materialremovalrate,longtoollife, low specific cutting
energy,lowmanufacturingcost,smallchipsize,andhigh
surface quality, as shown in Fig.23. However, the
superiorityofLAMforvariousdifficult-to-machinemetal
materialshas been verified experimentally.The research
mainly focuses on the influence of the laser parameters
Fig. 22Cuttingforces and graindeformationdistribution: (a) cuttingforcesof path-optimized laser-assistedmilling(LAM) [155] and
(b) grain deformation distribution in different machining processes [156]. CM: conventional milling; LS: single laser scanning.
ReproducedwithpermissionsfromRefs.[155,156]fromElsevier.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 27
(PL,VL, dL, laser incident angle, and laserposition) and
cutting parameters (vc, vf, αp, and αe) on the effect of
machining processes and the results of the experiments.
However, some research aspects of LAM machining
processes, including real-time temperature control and
HAZ, are still worth studying. LAM processing
technologies include laser-assisted cavity milling, spiral
milling, and cycloid milling. Real-time temperature
control is critical in LAM, and it involves various
algorithms,suchasfuzzy control, proportional−integral−
Fig. 23Summaryoflaser-assistedmillingmachinability.HAZ:heat-affectedzone.
28 Front.Mech.Eng.2023,18(2):28
derivative (PID) control, and generalized predictive
control. To avoid producing HAZ during LAM,
researchers use finite element transient thermal analysis
and consider emissivity and absorptivity in the HAZ
modeltodeterminethelaserparameters.Furtherresearch
in LAM should focus on the theory and mechanism of
material removal and chip breaking using FEM and
temperature field control technology. It is essential to
monitorthetemperatureandphasetransitionoftheshear
zoneunderdifferentprocessingconditionstounderstand
the variation law of LAM of difficult-to-machine metal
materials. A real-time sensing model of temperature
change and microstructure transformation in the shear
zone can help optimize the process parameters. To
prevent HAZ from remaining on the workpiece surface,
LAM processes should be optimized using FEM chip
breaking simulation models and HAZ range. This
optimization includes laser scanning path, laser incident
angle, and temperature control times. Moreover, by
consideringtheeffectsoflaserandcuttingparameterson
various factors like cutting force, material removal rate,
toollife,cuttingspecificenergy,manufacturingcost,chip
morphology, and surface quality, prediction models can
bedevelopedusing various intelligentalgorithms.These
models can help promote the industrialization and
applicationofLAMtechnology.
4Ultrasonic energy field-assisted milling
of difficult-to-machine metal materials
UVAM is a typical intermittent cutting process that can
periodically open a cutting area [158]. By applying a
micron-level ultrasonic frequency vibration to the
workpiece or tool, f, and controlling the vibration
direction,A,thehigh-frequencyperiodicseparationofthe
workpieceandtoolinthecuttingprocessisrealized,and
the milling vibration is effectively reduced, thereby
improvingthemachinabilityofdifficult-to-machinemetal
materials. The basic principle and device of UVAM are
shown in Fig.24(a) [159,160]. Compared with CM,
UVAM can reduce the cutting force and temperature,
prolong the tool life, and optimize the quality of the
workpiece surface. Periodic separation of the workpiece
and tool produces a cutting process with variable
thickness,whichplaysaneffectiveroleinchip breaking
[161,162]. The UVAM of difficult-to-machine metal
materials can be divided into three classes according to
the applied vibration amplitude ranges; the logical
structureisshowninFig.24(b).
Forstudieson UVAMofnickel-basedalloys,first,the
one-dimensional axial workpiece vibration method was
used to analyze the influence of cutting parameters on
cuttingforce, tool wear, and surface roughness. Second,
the one-dimensional feed workpiece vibration method
was used to analyze the influence of cutting parameter
changes on the surface roughness and the suppression
effectofAvaluesonburrs.Finally,theeffectsofUVAM
onthe microstructure, hardness, fatigue life, and surface
roughnessoftheworkpiecewereanalyzedusingtheone-
dimensionalaxialtoolvibrationmethod.
RegardingtheresearchonUVAMoftitaniumalloycut
by a one-dimensional tool with axial longitudinal
vibration, first, the influence of cutting parameters on
cuttingforceandsurfaceroughnesswasanalyzed,andthe
effect of UVAM on surface roughness was compared.
Second, the influence of A value on the cutting force,
cuttingtemperature,and surface roughnesswasassessed
by increasing the vibration amplitude. Third, the
influence of cutting parameters on the cutting force,
cutting temperature, residual stress, and surface rough-
ness was analyzed based on one-dimensional tool axial
longitudinal vibration. Working at the longitudinal
vibrationofa one-dimensional workpiecefeed, first, the
influence of A values on the surface scale structure and
the surface roughness of the workpieces was analyzed
based on the formation mechanism of the surface
microstructureandthetheoreticalmodeloftheformation
process of the surface microstructure. Second, by
combining the FEM with the tool tip trajectory, the
influence of A values on the cutting force and surface
roughness was assessed. Based on research on two-
dimensionalultrasonicvibration,acuttingedgegeometry
model of a ball-end milling cutter considering two-
dimensionallongitudinaltorsionaltoolvibrationandaxial
position angle was established to analyze the change in
the UVAM cutting force and build a model of cutting
forceunderdifferentflankwear.Second,theinfluenceof
the A value on the cutting force, tool wear, and surface
roughnesswas analyzed. Becausethe tool changein the
ultrasonic vibration machining process would lead to
burrsinthe connection areaduringtheactualproduction
process, a non-tool change machining method based on
UVAM of a flat surface and a free curved surface
connectionareawasdevelopedtoreducethecuttingforce
andsurfaceroughness.
For studies on UVAM of high-strength steel,
considering one-dimensional tool axial longitudinal
vibration,theeffectsofUVAMonthecuttingforce,chip
morphology,andsurfacequalitywerecompared.Second,
theinfluencesoff,A,andthetoolangleontoolwearand
surfaceroughnesswereanalyzed.Third,theinfluenceoff
onthesurface roughnessandresidualstresswas studied.
To identify how one-dimensional workpiece axial
vibration and one-dimensional workpiece feed vibration
influencethemachiningprocess,theinfluenceofUVAM
cuttingparametersonsurfaceroughnesswasfirststudied.
Second, a UVAM cutting force model was established,
and a new method for determining the relationship
between the critical cutting speed and undeformed chip
thickness was proposed. Third, the effects of cutting
parameters and milling methods on the cutting force,
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 29
surfaceroughness,and chip morphologywereinvestiga-
ted. Finally, based on the helical milling (HM) process,
theeffectsofUVAMoncuttingforce,machiningenergy
consumption, and surface roughness were compared.
Basedontwo-dimensionalplanevibration,theeffectsoff
andAon the toolwear,surfaceroughness,instantaneous
cutting thickness, and material removal rate were
analyzed.
4.1Ultrasonicenergyfield-assistedmillingofnickel-based
alloy
The one-dimensional axial vibration method (workpiece
vibration) can reduce milling temperature and tool wear
andimprovesurfacequality.Hsuetal.[163]conducteda
UVAMexperimentona nickel-based MAR-M247alloy.
Using Taguchi’s experimental design, they studied the
effects of different tool materials, workpiece tempera-
tures, cutting parameters, and f on the machining
characteristics.TheresultsindicatedthatUVAMreduced
themilling temperature. Minimizing αp can improve the
surfacequalityandreducetheprocessingtemperatureand
flankwear[163].
By applying one-dimensional feed longitudinal vibra-
tion (workpiece vibration), the influence of cutting
parametersonthesurfaceroughnesswasstudied,andthe
burrsuppressioneffectbychangingAwasexplored.Fang
et al. [164] used an ultrasonic energy field with f =
32 kHz and A = 3 µm for milling Inconel 718. The
influenceoffz(2–6µm/z)onthesurfacequalityandburr
ofthe workpiece under CM and UVAM conditions was
studied. The authors found that UVAM effectively
improved the surface quality. The number of surface
defectsdecreasedsignificantlywithincreasingfz.Whenfz
exceeded5µm/z,theinfluenceofUVAMonthesurface
qualitywassmall,as shown in Fig.25(a) [164], whereas
the CM of the workpiece resulted in a poor surface
quality within the given range of parameters. It is well
knownthat surfacequalitycangenerallybedescribedby
surface roughness, as shown in Fig.25(b) [164]. As
shown in Fig.25(b) [164], the surface roughness values
after UVAM were smaller than those after CM
Fig. 24Ultrasonicvibration-assistedmilling (UVAM) principle and logic: (a) UVAM principle and device [159,160] and (b)logical
structure of laser-assisted milling difficult-to-machine metal materials. CM: conventional milling. Reproduced with permissions from
Refs.[159,160]fromElsevier.
30 Front.Mech.Eng.2023,18(2):28
Fig. 25Changesinsurfacemorphology,burrsizeandsurfaceroughnessunderdifferentfz:(a)bottomsurfacemorphologyand(b)burr
widthandsurfaceroughness[164].UVAM:ultrasonicvibration-assistedmilling;CM:conventionalmilling.Reproducedwithpermission
fromRef.[164]fromSpringerNature.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 31
processing. Furthermore, the surface roughness of the
UVAM-processedworkpiece decreased with an increase
infzbut increased slightly whenfzwas6µm/z[164].At
the same f value, the team also studied the changes in
Inconel718burrsatdifferentvc,fz,andA, ranging from
18.84 to 75.36 m/min, 2 to 8 µm/z, and 0 to 9 µm,
respectively.TheyobservedthatwhentheratioofAtofz
wasgreaterthan0.5,thechipbreaking effect of UVAM
changedtheshapeofthechips.CombiningtheFEMand
experimentalresults,itwasestablishedthatUVAMcould
effectively reduce the size of chips and burrs. With
increasing A, the inhibitory impact of UVAM on burrs
significantly increased, as shown in Fig.25(b) [164].
Underconditionsofsmallvc,highfz,andhighAvalues,
UVAMhadthegreatestinhibitoryeffectonburrs[165].
One-dimensional axial longitudinal vibration (tool
vibration)isanauxiliarycuttingmethodthatcanprovide
good machining surface quality. Suárez et al. [166,167]
conductedUVAMofNialloy718,settingfto39.61kHz
and A to 1.5 µm. They focused on the influence of
UVAMonsurfaceintegrity,fatigueresistance,toolwear,
and cutting force. Compared to CM, UVAM reduced
cuttingforce,improvedsurfacemicrostructure(Fig.26(a)
[166]),and increasedsurfacehardnessand fatiguelifeof
the workpiece by 3.79% and 14.74%, respectively.
However,toolwearonthebacksurfaceincreasedby10%
[166]. After further study, the authors found that the
roughness of the workpiece surface treated by UVAM
decreasedby75%comparedtothatofCM,asshownin
Fig.26(b)[167].
4.2Ultrasonicenergyfield-assistedmillingoftitanium
alloy
Variations in cutting parameters and amplitude (A) can
impactthecuttingforce,cuttingtemperature,andsurface
roughness of materials processed by UVAM with one-
dimensional axial longitudinal vibration (tool vibration).
SuandLi[168]investigatedthecuttingperformanceand
mechanismofTC4titaniumalloyinacuttingexperiment
with f and A values of 30 kHz and 6 µm, respectively.
Compared to CM, an increase in fz and αp reduced the
correspondingcuttingforceofUVAMby0.8%–42%and
5.3%–65%, respectively. The surface roughness also
decreasedby10.82%to37.97%.[168].Basedonthis,the
team also compared the surface roughness of selective
laser melting (SLM) and conventional melting (CL) of
TC4 with and without UVAM processing. Compared
with CM, UVAM reduced the surface roughness values
ofthe(SLM)TC4and(CL)TC4workpiecematerialsby
23.3% and 19.1%, respectively. Furthermore, it was
observed that UVAM could effectively improve the
surfacemorphologyof (SLM)TC4and(CL)TC4 [169],
but the influence of UVAM on cutting temperature has
notbeenstudied. Gao etal.[170]studiedtheeffectof A
(from 0 to 6 µm) on the cutting force, cutting tempera-
ture,andsurfaceroughnessofTC4workpiecematerialat
an f value of 30 kHz, as shown in Fig.27(a) [170]. In
Fig.27(b)[170],theyobservedthatboththecuttingforce
andcutting temperature decreasedwith increasing A but
onlyslightlywithincreasingcuttingtemperature.WhenA
Fig. 26Microstructure and surface roughness of conventional milling (CM) and ultrasonic vibration-assisted milling (UVAM):
(a) microstructure of processed surface [166] and (b) three-dimensional surface roughness [167]. Reproduced with permissions from
Refs.[166,167]fromSpringerNatureandElsevier.
32 Front.Mech.Eng.2023,18(2):28
increased from 0 to 6 µm, the surface roughness Sa
(average roughness) and Sq (surface root mean square
roughness)decreasedby35.1%and34.0%, respectively,
and the surface morphology became more uniform,
provingthatthe cutting performanceand surface quality
ofTC4couldbesignificantlyimprovedbyUVAM[170].
The change in cutting parameters can also affect the
formation mechanism of the residual stress and surface
microstructure.Xieetal.[171]systematicallystudiedthe
UVAMofTC18andTC4cells.First,basedonthe one-
dimensional axial longitudinal vibration (tool vibration)
whenfwassetto33.9kHz,theeffectsofAandvconthe
machining performance of the TC18 titanium alloy
specimenswerestudied.The observation andanalysisof
these effects included the use of a dynamometer,
thermometer, scanning electron microscope, X-ray
diffractometer,andthree-dimensionalsurfacetopography
instrument. The authors found that vc had significant
effects on cutting force, surface morphology, cutting
temperature,and residualstress.ComparedwithCM,the
cutting force and cutting temperature of UVAM-
processed workpieces decreased by 34.1% and 19.5%,
respectively, whereas the residual stresses and surface
roughnessincreasedby50.9%and163.88%,respectively.
Furthermore, the UVAM-processed workpiece surface
exhibited a plastic deformation zone at a certain depth,
and the deformation zone increased with increasing A
[171]. Second, the basic formation mechanism of the
surfacemicrostructureduringUVAMwasanalyzedusing
atheoreticalkinematicmodel established by theauthors,
as shown in Fig.28(a) [172]. According to Fig.28(b)
[172], a regular-scale microstructure was generated by
UVAMalongthefeeddirection.Inaddition,vc,fz,andA
would affect the machining surface morphology and
accuracyoftheworkpiecesize.Thesingle-factorUVAM
experimenton TC4 titanium alloy with one-dimensional
feed longitudinal vibration was performed at f of
22.7kHzandvarious A values (0, 1, 2,3,and5 µm) to
verify the accuracy of the theoretical model. The team
also found that with an increase in A, the surface-scale
Fig. 27Testparameterflowanddatacomparison:(a)ultrasonicvibration-assisted millingoveralltestparameterflowand(b)Aimpact
onmeasurementdata[170].ReproducedwithpermissionfromRef.[170]fromElsevier.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 33
structure gradually became uniform. The surface
roughness value first decreased and then increased with
increasingA.Frictionandwearexperimentsrevealedthat
the friction coefficient of the UVAM-processed work-
piecesurfacewas60%lowerthanthatobtainedafterCM
[172].
The change in cutting parameters can also affect the
dimensionalaccuracyoftheworkpieceandtiptrajectory.
Xu et al. [173] used the UVAM of TC4 with one-
dimensional feed longitudinal vibration (workpiece
vibration)whenf was setto19.832 kHz. Theyexplored
the influence of UVAM on the cutting force, surface
quality,andworkpiece size accuracyfor different A and
vf.ComparedtoCM,UVAMreducedthecuttingforceby
17%. Therefore, the tool life is extended, and the
dimensional accuracy of the workpiece is improved.
Furthermore, according to the SEM observations of the
surface morphology, UVAM can effectively reduce
surface defects and machining tool marks. Thus, the
surfacequality isoptimizedafterUVAM [173].Thetool
tiptrajectoryalsoaffectedthemachiningeffect.Zhuetal.
[174] worked on the application of UVAM in the
machining process of a workpiece. The vibration
direction was along the feed direction, and the entire
system was fixed to the workbench by the flange. To
achieve an excellent vibration effect of the TC4
workpiece on the transducer, the resonant block was
optimizedusingFEM,asshowninFig.29(a)[174].
Consideringitsdirecteffectonthetextureandsurface
morphology of the workpiece, the tool path must be
analyzed. The UVAM tool path is composed of tool
rotation, table feed motion, and micron-scale ultrasonic
vibration along the feed direction. In the Cartesian
coordinatesystemoftheworkpiece,thetooltiptrajectory
equationis
x=xr+xf+xv,
y=yr,
z=0.
(3)
Because the ultrasonic generator can only output
ultrasonic sine or sine signals, the ultrasonic vibration
displacementfunctioncanbeexpressedas
xv=Asin (2π f t +θ).(4)
Based on Eqs. (3) and (4), the tool path equation for
UVAMisobtainedas
{x=Rcosβ+vft+Asin (2π ft +θ),
y=Rsinβ, (5)
β
ωr
vf
Nz
zi
Nz
β=ωrt−2π(zi−1)/Nz
xr=Rcos ωrt
yr=Rsin ωrt
xf=vft
wherex,y,andz representthetipdisplacements,fandA
aretheultrasonicfrequencyandamplitude,respectively,t
isthe cutting time, θis the initialphase of thevibration
signal, R is the radius of the end mill, is the tool
rotationangle, istheangularvelocityofthespindle,
represents the feed rate of the workpiece, is the
numberoftips,and isthecuttingedge number (i = 1,
2,…, ), , , ,
and .
Accordingto Eq. (5), the tiptrajectory in UVAM can
Fig. 28Theoreticalmodeland results:(a)theoreticalmodelofthemachinedsurfaceand(b)differentAvaluesofthemachinedsurface
[172].ReproducedwithpermissionfromRef.[172]fromJournalofVibroengineering.
34 Front.Mech.Eng.2023,18(2):28
be obtained, as shown in Fig.29(b) [174]. In Fig.29(b)
[174],thetrajectoryanddynamiccuttingthicknessofthe
UVAM tip are clearly more complex than those of the
CM process. In the local amplification diagram, the
characteristics of UVAM are a wave-shaped trajectory
andaphasedifference.Basedonthetoolpathanalysisof
UVAM, UVAM experiments with f = 19.8 kHz and A
ranging from 8 to 14 µm were performed. The results
showed that compared with CM, the milling force of
UVAM and the associated surface roughness were
reducedby30% to 34.4%and20%to45%,respectively
[174].
The mechanism of two-dimensional longitudinal-
torsional ultrasonic vibration is very complicated.
Therefore, a new technology for this vibration was
proposed. The design of the geometric model of the
cuttingedgeofthe ball-end milling cutterwiththe axial
positionangleasthe main parameterwaspresented.The
authors derived the cutting force model of a ball-end
milling cutter under the condition of longitudinal-
torsional composite vibration. When f was 35.476 kHz
and A was 10 µm, in the longitudinal-torsional UVAM
experimentonTC4 titanium alloy, theradial,tangential,
andaxialforcesofUVAMwerereducedby60%,27.7%,
and 33%, respectively, compared to CM [175].
Furthermore, under UVAM conditions, the relationship
between the tool flank and cutting force was not
established. Based on the above research, a new tool
flankwearmodelthatconsidersthechip flow angle and
discretization of the cutting edge was developed. This
modelcouldpredictthechangetrendofthecuttingforce
atdifferentflankwearvaluesandoptimizetheprocessing
parameters. The UVAM experiment on TC4 was
performed with an f value of 35 kHz, A values in the
range of 0–4 µm, and spiral angles between 35°–50°.
Accordingto the experimental results, when A was 2or
3µm, the tool wear became stable as the cutting length
increased.Figure30(a)[176] shows that the helixangle,
unit cutting-edge length, friction time, and cutting
temperatureincreased.Theinfluenceofthehelixangleon
toolflankwearchangedinasimilarmanner;thatis,when
the helix angle was 35°, the increase in the wear value
was more stable than at other helix angles, as shown in
Fig.30(b)[176]. Theerrorsbetweenthepredictedmodel
and experimental results in the feed (x) and normal (y)
directions of the coordinate tool system (o-xyz) were
19.1% and 12.9%, respectively. Compared to CM, the
feed and normal cutting forces of UVAM decreased by
21.7% and 5.4%, respectively. When the cutting length
exceeded 67.5 m, the tool wear value of UVAM
decreased by 38.7% [176]. The application of two-
dimensionallongitudinal torsional vibration can produce
Fig. 29Optimizationofresonantblockandanalysis of tool tip trajectory: (a) finite element method (FEM) structure optimization of
ultrasonicvibration-assistedmilling (UVAM) system andresonantblockand (b) tool-tip motiontrajectoryinUVAMand conventional
milling(CM)process[174].Unit:mm.ReproducedwithpermissionfromRef.[174]fromElsevier.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 35
bettermachining effects on the workpiece cutting force,
tool wear, and surface roughness. Rinck et al. [177]
studiedthecuttingforce,tool life, and surface qualityof
TC4 titanium alloy by changing A (4, 6, 8, 10, and 12
µm) based on two-dimensional longitudinal-torsional
vibration when f was 32 kHz. Compared with CM, the
cuttingforce,toolwear,andsurfaceroughnessofUVAM
were reduced by 57%, 20%, and 16.7%, respectively
[177].
The tool change in the machining process of straight
and free-curved surface cutting leads to burrs in the
connectionareaduringtheactualproductionprocess.Ren
et al. [178] proposed a machining method without tool
change based on UVAM for straight and free-curved
surfaceconnectionareas.Atf=25kHzandA=5.6µm,
the processing performance of UVAM and CM was
assessedbychangingparametersvc,vf,andαp.Compared
withCM,noobviousburrswereobservedattheinterface
between the planar and free-curved surfaces after using
UVAM, so there was no need to use a tilt spindle or
transform tool. In addition, the milling force of UVAM
decreased by 20%–40%, and the surface roughness
decreasedby 44.3%.AsshowninFig.31[178],whenvc
was less than 157 m/min, UVAM led to an increase in
surface roughness. However, when vc was greater than
157m/min,thesurfaceroughnessdecreased[178].
4.3Ultrasonicenergyfield-assistedmillingof
high-strengthsteel
One-dimensional axial longitudinal vibration of the
cuttingtoolcanaffectthecuttingforce,chipmorphology,
and surface quality. Ahmed et al. [179] established an
analysis model to calculate the cutting force during the
machiningprocess,and the results are shownin Fig.32.
An AISI H13 machining experiment was conducted at
f = 40 kHz and A = 2 µm. The machining process was
evaluatedbasedon cutting force,chipmorphology,wear
rate, and surface integrity. The results showed that
comparedwith CM, UVAM had a smaller cutting force
andcouldproducemoreuniform,thin,andsmoothchips.
The surface quality of the UVAM workpiece also
improved. By observing the friction and wear
experimentaldata,itwasfoundthatthetoolwearcaused
byCMor UVAM was similar. However,further studies
showedthatUVAMcouldprolongtool life by changing
thevibrationdirection[179].
Considering one-dimensional axial longitudinal
Fig. 30Principleand test results:(a)influence principleofdifferent helical angletoolson cuttingedgelengthand (b)effectof A and
helicalangleontoolwearvalueofdifferentcuttinglengths[176].ReproducedwithpermissionfromRef.[176]fromElsevier.
36 Front.Mech.Eng.2023,18(2):28
vibration(toolvibration),thevaluesoff, A, and the tool
angle can affect tool wear and surface roughness. Tsai
etal.[180]studiedtheeffectsoff(25and50kHz),A(0,
2.2,and3.68µm),toolrakeangles(6°and−6°),andtool
helix angles (25°, 35°, and 45°) on tool wear and
machined surface quality using AISI 420 processed by
UVAM.Theexperimentalresultsshowed that compared
withCM, the machined surfaceafter UVAM processing
was more uniform when f was 25 or 50 kHz. The
machining tool mark became shallow with increasing f.
WithincreasingA,theroughnessofthemachinedsurface
firstdecreasedandthenincreased.Thesurfaceroughness
afterUVAMwassmallest when the toolrakeangle was
6°. The surface quality was improved by increasing the
Fig. 31Three-dimensionalmorphologyofultrasonicvibration-assistedmilling(UVAM)andconventionalmilling(CM)machinedsurfaces:
(a) CM at vc = 125.6 m/min, (b) UVAM at vc = 125.6 m/min, (c) CM at vc = 157 m/min, and (d) UVAM at vc = 157 m/min [178].
ReproducedwithpermissionfromRef.[178]fromSpringerNature.
Fig. 32Ultrasonic vibration-assisted milling (UVAM) and conventional milling (CM) analysis model of cutting force [179].
ReproducedwithpermissionfromRef.[179]fromTaylor&Francis.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 37
UVAM helix angle, as shown in Fig.33(a) [180].
MaurottoandWickramarachchi[181]conductedUVAM
ofAISI316Lwhilevaryingthevalueoff(0,20,40,and
60kHz).Theyexploredtheinfluenceofdifferentfvalues
onthesurfaceroughnessandresidualstress.Accordingto
the results, the surface roughness increased slowly with
increasing f, and the surface quality worsened. In
addition, the residual stress was compressive when the
parametersremainedwithinagivenrange.Theminimum
compressivestress was obtainedwhen f was 40 kHz,as
showninFig.33(b)[181].
Scholars have already considered the simultaneous
influence of the axial vibration and feed vibration of
workpieces during the machining process. Razfar et al.
[182] studied the UVAM of high-strength steel. First, a
UVAM experiment was conducted on AISI 1020 steel
based on one-dimensional axial longitudinal vibration
(workpiecevibration) when f wasset to 20kHz and the
power was 250 W. Then, the effects of vc, fz, αp, and
ultrasonic treatment on the surface roughness were
investigated, and the results showed that the surface
roughness of CM and UVAM exhibited similar curves
andincreasedwithincreasingfzandvc.ComparedtoCM,
theaveragesurfaceroughnessafterUVAM increased by
12.9%[182].Second,basedonthesamevibrationmode,
apowerof220 W was usedtoconduct UVAM of AISI
304steel. Subsequently, the influence of UVAM on the
cuttingforceinthreedirectionswastested.Itwasfound
that under UVAM conditions, the cutting forces were
reducedin all three directions[183]. Finally, thecutting
forceinUVAMwas described inamathematicalmodel.
The authors proposed a new relationship between the
critical cutting speed and thickness of the undeformed
chips.Accordingtotheanalyticalrelationship,thecutting
force in the UVAM had different amplitudes. CM and
UVAM experiments based on longitudinal vibration
Fig. 33Ultrasonicvibration-assistedmilling(UVAM)andconventionalmilling(CM)surfacequality:(a)influenceoffandhelixangle
ontheprocessedsurface[180]and(b)effectoffzandfonsurfaceroughnessandresidualstress[181].Reproducedwithpermissionsfrom
Refs.[180,181]fromMDPIandElsevier.
38 Front.Mech.Eng.2023,18(2):28
(workpiecevibration)inaone-dimensionalfeeddirection
wereconductedatf=23kHzand A = 20 µm, and their
cutting force and workpiece surface roughness were
compared. UVAM of X20Cr13 stainless steel was first
performed,andtheeffectsofvc,vf,andmillingmethods
on chip formation and workpiece surface quality were
analyzed. The UVAM and CM chip morphologies and
tool wear are shown in Fig.34 [184,185]. The
experimental results showed that UVAM could produce
thinner and smaller chips, as shown in Fig.34(a) [184],
andthemachinedsurfacewassmoother.Comparedwith
CM, UVAM chips had larger curvatures and smaller
sizes.Withanincreaseinvf,thechipcurvaturedecreased
[184]. Furthermore, side milling of AISI 420 stainless
steel was performed. Subsequently, the effects of vc, vf,
and milling methods on the cutting force and surface
roughnesswere studied, indicating that the cutting force
in UVAM was smaller than that in CM. Moreover,
depending on the cutting conditions, the surface
roughnessof the workpiece in UVAM can be improved
Fig. 34Ultrasonic vibration-assisted milling (UVAM) and conventional milling (CM) chip morphology and tool wear: (a) chip
morphology under different vc [184] and (b) tool wear [185]. Reproduced with permissions from Refs. [184,185] from ASME and
Elsevier.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 39
compared with that obtained by CM. Further research
showedthatwhenvfwassmall,theinfluenceofUVAM
reverse milling on the cutting force was more obvious.
However, when vf was large, the influence of UVAM
forward milling was more pronounced. Under the
conditions of low vf, high vc, and the reverse milling
process, the effect of UVAM on the surface roughness
wasmoreevident[186].
Theone-dimensionalaxiallongitudinalvibration(work-
piecevibration)based on theHM process can affectthe
cuttingforce,machiningenergyconsumption,andsurface
roughness. Rao et al. [187] conducted UVAM of AISI
1020steelusinganfvalueof20 kHz and an A value of
5 µm. HM was used to improve the energy efficiency.
The energy consumption of the feed rate in three
directions, that is, the chip-size prediction model, was
theoreticallyestablished.Itwas found thatUVAMhada
significant intrinsic effect on chip morphology, cutting
force, and machining energy consumption. Compared
with the CM, the one-dimensional axial longitudinal
vibrationreducedtheaxialforce,radialforce,andcutting
energy consumption by 47%, 14%, and 34%, respec-
tively.Axiallongitudinalvibrationscanreducemanufac-
turingcosts.Theresultsof the prediction model werein
good agreement with the experimental results, with
average errors in cutting energy consumption, chip
length, and chip width of 4.36%, 2.51%, and 3.92%,
respectively [187]. This confirms the accuracy of the
model. Considering the difference between two-
dimensional plane vibration and one-dimensional axial
longitudinal vibration, Ding et al. [185] performed
UVAM of X46Cr13 stainless steel based on two-
dimensional plane vibration under different ultrasonic f
and A. Compared with CM, the surface roughness after
UVAM decreased by 28.3%. The tool wear of UVAM
decreasedby5%–20%,asshowninFig.34(b)[185].The
chipwasthinandsmall,andthetoollifewasprolonged
[185].TheauthorsalsoconductedanFEManalysisofthe
tool-tip trajectory using different vibration parameters
and proposed a calculation model of the chip thickness.
This model can accurately calculate the instantaneous
chipthickness.Researchersverifiedthecorrectnessofthe
model based on experimental process data [188] and
improvedthematerialremovalrate.
4.4Summaryofultrasonicenergyfield-assistedmillingof
difficult-to-machinemetalmaterials
Based on the above investigations, the ranges of
amplitudevaluesappliedinUVAMaredifferentbecause
oftheinconsistentbasicpropertiesofdifficult-to-machine
metalmaterials.Theamplituderangesofthenickel-based
alloy,titanium alloy,andhigh-strengthsteelare0–9µm,
0–14µm,and0–20µm,respectively.Theamplitudewas
consistent with the machinability of the three materials.
Combiningtheabovefindings,theoverallstructureofthe
UVAM machinability is summarized in Fig.35. By
controlling the vibration direction of UVAM, f, A, and
different processing parameters, the change rules of the
cutting force, surface morphology, surface roughness,
residualstress,chipmorphology,andtoolwearduringthe
workpiece machining process were explored. Based on
theexperimentaldata,itisconcludedthattheadvantages
of UVAM and LAM for difficult-to-machine materials
aresimilar.However,thetrajectoryoftheUVAMtooltip
anddynamiccuttingthickness were different from those
of the CM. Based on this, a calculation process for the
UVAM wave trajectory is developed. Furthermore,
consideringthe plastic deformation zone of UVAM, the
microstructure theory and the FEM model of the
machined surface were established. In addition, a new
tool flank wear model was developed based on the tool
angle to predict the surface roughness and tool wear of
UVAM-processed workpieces. Compared to CM, the
chipmorphologyandthickness of the UVAM-processed
materialschanged significantly. Toaccurately determine
the instantaneous chip morphology after UVAM, a chip
thickness model was developed using calculation and
FEM. The accuracy of each model was verified
experimentally. To improve the energy utilization rate,
UVAMandHM processes were used toconduct cutting
experiments on difficult-to-machine metal materials,
which effectively reduced the manufacturing cost.
Furthermore,basedon ultrasonicandcuttingparameters,
a prediction model showing the influence of the
instantaneous change in chip thickness on the cutting
force, surface morphology, surface roughness, residual
stress, chip morphology, and tool wear must be
established to promote the development of UVAM
technology.
5CMQLAM of difficult-to-machine metal
materials
CMQLAM is a new green machining technology that
combines the application of a cold medium, micro-
lubrication,andmilling.Inthisprocess,aliquid/gaseous
mediumissprayedintotheshearzoneinaccordancewith
the jet form, which can replace the traditional cutting
fluid to lubricate and cool the machining contact zone
[77]. The workflow and functions of the CMQLAM
systemareshownin Fig.36(a) [189].Theprincipleisto
combine a cold medium with atomizing oil mist and
water mist before reaching the nozzle, and then to cool
the shear zone through the nozzle. The water mist
vaporizesandabsorbsheat,whiletheoilmistispresentat
the contact surface between the workpiece and the tool,
reducingthe friction coefficientand heat generation due
tofriction.Thecoldmediumalsoreducestheviscosityof
the chips, which can achieve an excellent effect when
combined with micro-lubrication. Considering that
40 Front.Mech.Eng.2023,18(2):28
cuttingoil is usedin very small amounts inCMQLAM,
anoilfilmboundarylubricationisestablished,as shown
inFig.36(b)[189].
Duringnozzleoperation,theamountofoilattachedto
the machined surface increases, and the film thickness
graduallyincreases,asindicated by pointAinFig.36(b)
[189]. As CMQLAM continues, more lubricating oil is
gradually added to the low-lying surface of the shear
zone, as shown by point B. With increased amounts of
nozzleoilandprolongedinjectiontimes,thesurfacefilm
consistsofpeaksandvalleysduetofurtheradsorptionof
lubricating oil, as indicated by point C. When the oil
amount does not exceed point A, the amount of oil is
smallandtheoil film is thin, resultingindryfriction as
the tool directly contacts the peak of the workpiece.
WhentheoilamountisbetweenpointsAandC,onlythe
friction between the tool and the peak of the workpiece
occurs,resultinginaconstantfrictioncoefficient.Atthis
stage, the oil amount has little effect on the machined
surface. When the oil film at the top of the peak is
Fig. 35Summaryofultrasonicvibration-assistedmilling(UVAM)machinability.FEM:finiteelementmethod.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 41
damaged, the oil amount at point B can rapidly flow to
thetopofthepeakwithitsownfreeenergytorestorethe
original boundary lubrication state. However, when the
oil content exceeds point C, the stability of the friction
coefficient cannot be guaranteed [189]. Therefore, it is
important to control the CMQLAM lubrication parame-
ters carefully. CMQLAM of difficult-to-machine metal
materials is divided into three classes according to the
lubricationrangeofCMQLAM,asshowninFig.36(c).
Regarding the investigations on CMQLAM of nickel-
based alloys, based on a CO2 + MQL CMQL environ-
ment, first, different diameters of CO2 outlets were
compared, and numerical computational fluid dynamics
(CFD) simulations were performed to obtain the best
injection flow rate and nozzle diameter. Second, the
effectsofthefivecoolingandlubricationmethodsonthe
tool life were compared. Third, the effects of different
cooling and lubrication methods on machining tempera-
ture,cuttingspecificenergy,surfaceroughness,microhard-
ness,andresidualstresswereassessed.Then,theeffects
ofthefivecoolingandlubricationmethodsonthesurface
structure, surface morphology, and surface roughness
were compared. Based on an LN2 + MQL CMQL
environment, the effects of the three cooling and
lubrication methods on the surface roughness and tool
wearwere compared, and the effects of the toolcoating
and cooling lubrication conditions on the cutting force,
tool wear, surface roughness, and cutting temperature
were investigated. Based on a CA + MQL CMQL
environment,thecuttingforceandtoollifeunderdryand
CMQLconditionswerecompared.
TostudytheCMQLAMoftitaniumalloys,theeffects
of five micro-lubrication technologies and cutting speed
changesontoolwear,cuttingtemperature, cutting force,
andsurface roughness were analyzed based on a CO2 +
MQL CMQL environment. Under these conditions, the
cutting force was the lowest, the surface roughness was
the smallest, and optimal surface quality was obtained.
The cutting parameters and four green conditions were
varied to study their influence on cutting force, cutting
temperature,surface morphology,andsurfaceroughness.
SCCO2-OoWMQL had the best effect. Based on an
Fig. 36Cryogenicminimumquantitylubricationenergyfield-assistedmillingsystem(CMQLAM),lubricationmechanism and logic:
(a)CMQLAMsystem,(b)workpiecesurfaceboundarylubrication[189],and(c) logical structure of laser-assisted milling difficult-to-
machine metal materials. CA: cold air; MQL: minimum quantity lubrication. Reproducedwith permissionfromRef.[189]from
MechanicalScienceandTechnologyforAerospaceEngineering.
42 Front.Mech.Eng.2023,18(2):28
LN2 + MQL CMQL environment, the cutting force and
tool wear in a CMQLAM machining process were
analyzed,andtheeffectsofCMQLAMmachiningontool
life, surface roughness, cutting force, and productivity
were studied. In the CA + MQL CMQL environment,
CMQLAMsignificantlyreduced flankwear.Anewtype
of mixed nozzle capable of simultaneously injecting oil
mistandcryogenic gaswasdesigned.TheCoandaeffect
under different inlet flow rates, friction heat, and tool
wearusingconventionalandnewnozzleswerecompared.
The cutting force, tool wear, cutting temperature, and
manufacturing costs under CMQLAM conditions were
analyzed.
Regarding the studies on CMQLAM of high-strength
steel,theeffectsof four coolingandlubricationmethods
on the cutting force, cutting temperature, and tool wear
were compared in a CO2 + MQL CMQL environment.
Furthermore,theinfluenceofthenewCMQLmethodson
the cutting force, tool life, and surface roughness was
analyzed.Subsequently,the effects ofcuttingparameters
and cooling lubrication on tool life, material removal,
surface roughness, and residual stress were assessed.
Finally, the effects of the cutting speed and cooling
lubrication on the surface roughness, chip morphology,
flank wear, and cutting temperature were investigated.
Based on a CA + MQL CMQL environment, the
influence of cutting parameters on the cutting force and
temperaturewasanalyzedbysimulation,andaprediction
model was established. Experiments were conducted to
verifytheaccuracyoftheproposedmodel.Comparedto
dry milling, CMQL can reduce the cutting force and
cuttingtemperature. The influence of cuttingparameters
onthewhitelayerwasalsoanalyzed. Theeffectofthree
internalcooling channels on cutting forceand tool wear
wasinvestigatedwiththeresultthattheCMQLAMeffect
ofa double straight channel (DSC)internal cooling tool
wasthebest.
5.1CMQLAMofnickel-basedalloy
Theoptimalinjectionflowrate,nozzlediameter,andtool
life can be obtained in a CO2 + MQL CMQL environ-
ment. CMQLAM demonstrates good cooling and
lubrication effects. Pereira et al. [190] conducted
numericalandexperimentalanalyses of theCO2+MQL
CMQLAM. First, a CFD numerical simulation of CO2
outletswithdifferentdiameterswasconducted.Basedon
theCMQLenergyfieldwithaCO2pressureof14bar(1
bar=105Pa)andanMQLflowrateof100mL/h,Inconel
718 was processed via assisted milling, and the optimal
CO2injectionvelocityandoutletdiameterwere325m/s
and1.5mm,respectively.Theteamcomparedtheeffects
ofdrying,pouring,CO2,MQL,andCO2+MQLcooling
and lubrication methods on cutting. Different nozzle
diameters, cutting temperatures, and specific cutting
energiesareshowninFig.37[190,191].Comparedwith
CM pouring machining, the tool life of dry milling was
shortenedby53.3%. When only CO2or MQL was used
to assist milling, the tool life increased by 67.7% and
84.2%, respectively. CMQLAM could increase the tool
life to 93.5% and reduce the cutting oil by 90%, which
proved that CMQLAM could be applied in practical
engineering[190,192],asshowninFig.37(a)[190].
Theeffectsofdifferentcoolingandlubricationmethods
on the machining temperature, specific cutting energy,
surface roughness, microhardness, and residual stress
were compared in a CO2 + MQL CMQL environment.
Rossetal.[191]foundthatMQL and cryogenic cooling
can replace the CM cutting fluid; however, the cooling
andlubricationcharacteristicsofCO2+MQLCMQLAM
were not explored under high-speed cutting conditions.
They compared the processing effects of Nimonic 80A
underCO2,MQL, and CMQL conditionsandconducted
in-depth research on the processing temperature, energy
consumption,surface,andsubsurface.AtaCO2 pressure
of2.5barandMQLflowrateof60mL/h,theprocessing
temperature and specific cutting energy under CMQL
conditions ranged between 34%‒53% and between
17%‒19%,respectively,andwerereducedcomparedwith
MQL,as shown inFig.37(b) [191]. In addition, CMQL
decreased the grain size by reducing the friction at the
cutting point, thereby increasing the surface fatigue
strengthoftheworkpieceand providing the best cooling
effectduringprocessing,whichshowedthesuperiorityof
CMQL, as shown in Fig.38(a) [191]. The team also
conductedastudytoanalyzetheeffectsofCMpouring,
MQL, CO2, and CMQL on cutting temperature, surface
roughness,toolwear,microhardness,andresidualstress.
Theresultsshowedthat,comparedtoCMpouring,MQL,
and CO2, the processing temperature was reduced by
41%–53%, 29%–46%, and 17%–23%, respectively,
under CMQL conditions. The surface roughness also
decreased by 42%–54%, 34%–45%, and 19%–29%,
respectively. The tool wear was reduced by 48%–71%,
42%–56%,and22%–40%,respectively.Furthermore,the
surface microhardness increased by 9.57%, 9.13%, and
4.87%,respectively.WhencomparedtoCMpouring,the
residual compressive stress obtained by CMQL
processing increased by 25.18%. It was verified that
CMQLhastheadvantages of a lowcuttingtemperature,
high residual compressive stress, microhardness, and
goodsurfacequality,asshowninFig.38(b)[193].
Theeffectsoffive cooling and lubricationmethodson
the surface microstructure, morphology, and roughness
were compared in a CO2 + MQL CMQL environment.
Milling of Inconel 718 was conducted by Sterle et al.
[194]Theeffectsofdrying,CMpouring,LCO2,LCO2+
MQL (oil), and LCO2 + MQL (MoS2) cooling and
lubrication methods on the surface smoothness,
roughness,surfacemorphology,andmicrostructurewere
compared.The LCO2 pressure and MQL flow rate were
12 kg/h and 120 mL/h, respectively. The experimental
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 43
results showed that the surface finish under LCO2
treatment was close to that obtained with dry cutting.
Compared with LCO2 + MQL (oil), the surface
smoothness obtained by LCO2 + MQL (MoS2) was
improved,andtheMoS2 particles were easier to remove
after milling. Compared with CM casting milling, the
application of LCO2 + MQL (MoS2) resulted in lower
surfaceroughness,bettersurfacemorphology,andamore
uniformsurfacemicrostructure[194].
Inaddition toCO2+MQL,LN2+MQLalsocaused a
reduction in tool wear and surface roughness. Shokrani
etal.[195]foundthatMQL,LN2,andCMQLprocessing
were effective cooling lubrication technologies for
improvingthemachinabilityofdifficult-to-machinemetal
Fig. 37Different nozzle diameters, cutting temperatures, and specific cutting energies: (a) experimental results of different nozzle
diameteroutlets[190],and(b)effectsofgreenlubricationandcuttingparametersoncuttingtemperatureandspecificcuttingenergy[191].
MQL:minimumquantitylubrication.ReproducedwithpermissionsfromRefs.[190,191]fromSpringerNatureandElsevier.
44 Front.Mech.Eng.2023,18(2):28
Fig. 38Grain size distribution and scanning electron microscope: (a) effect of green lubrication on grain size distribution [191] and
(b) scanning electron microscope images of different green lubricants [193]. CM: conventional milling; MQL: minimum quantity
lubrication.ReproducedwithpermissionsfromRefs.[191,193]fromElsevier.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 45
materials. Therefore, groove milling experiments were
performed on Inconel 718 using the MQL, LN2, and
CMQL cooling and lubrication methods at an LN2
pressure of 1.2 bar and an MQL flow rate of 60 mL/h.
Compared with MQL, CMQL increased the tool life by
200% and reduced the surface roughness of the groove
bottom surface by 18% and that of the groove side
surface by 5% [195]. Based on the above experiments,
theteamchangedtheLN2pressureto1barandtheMQL
flow rate to 70 mL/h and conducted comparative
experiments under CM pouring cooling lubrication
conditions. The results showed that compared with CM
pouringcutting,CMQLcouldincrease tool life by 77%.
The surface roughness values of the side and bottom of
themachinedpartswerelessthan0.4µm.Bymonitoring
theenergyconsumptionofthemachinetool,itwasfound
that the energy consumption increased with tool wear.
Thesestudies clearly demonstrate thatthe application of
CMQLAMtoInconel718isfeasible[196].
Thecombination of toolcoating and greenlubrication
conditions will have a better effect on the machining
process. Şirin et al. [197] conducted an experimental
studyon theInconelX750alloyandexploredtheeffects
of tool coating (no coating, low-temperature treatment,
and TiAlN coating) and green lubrication conditions
(LN2, MQL, and CMQL) on tool wear, surface rough-
ness, surface morphology, cutting force, and cutting
temperature. Using an LN2 pressure of 15 bar and an
MQL flow rate of 50 mL/h, the authors showed that
althoughthehardnessofthetoolincreasedby7.36%after
low-temperaturetreatment, the tool life decreased in the
following order: TiAlN coating, low-temperature treat-
ment,andnocoating.ComparedwiththeuseofLN2,the
toolwearoftheuncoatedtoolwaslowerwhenapplying
MQL and CMQL; for the coated tool, the tool wear
decreasedby 63.8% and 70.1%, respectively. Compared
withtheuncoatedtool,thesurfaceroughnessofthetool
subjected to low-temperature treatment and the coated
tool was reduced by 2.72% and 6.22%, respectively,
whilethecuttingforcedecreasedby4.81%and7.11%,as
shown in Fig.39 [197]. Compared to the application of
LN2, the surface roughness values obtained with MQL
and CMQL decreased by 4.81% and 18.52%, respec-
tively. Under green lubrication conditions, compared to
LN2, the cutting forces using MQL and CMQL were
reducedby7.1%and10.76%,respectively,forthecoated
tool. Compared with the noncoated tools, the cutting
temperature of the coated tools decreased by 5.75%.
Fig. 39Differentgreen coolinglubricationandtool machiningsurfaces:(a) uncoatedtoolliquid nitrogen,(b)uncoated toolminimum
quantity lubrication (MQL), (c) uncoated tool cryogenic MQL (CMQL), (d) low-temperature treatment tool LN2, (e) low-temperature
treatmenttoolMQL,(f)low-temperaturetreatmenttoolCMQL,(g)TiAlN-coatedtool LN2,(h) TiAlN-coatedtoolMQL,and(i)TiAlN-
coatedtoolCMQL[197].ReproducedwithpermissionfromRef.[197]fromElsevier.
46 Front.Mech.Eng.2023,18(2):28
Compared to LN2, the cutting temperature decreased by
30.31%underCMQLcoolingand lubrication conditions
[197].
CA + MQL can prolong the tool life and reduce the
cuttingforce.Zhangetal.[198]studied the influence of
differentcuttingconditionsontoollifeandcuttingforce
changes during the machining of Inconel 718. In the
CMQLAMprocess,theCApressurewas1.5bar,andthe
MQL flow rate was 8 mL/h. Under dry milling and
CMQL conditions, flank wear and cutting edge fracture
werefoundtobethemainfactors leadingtotoolfailure.
Compared with dry milling, CMQL reduced the cutting
force, increased the tool life by a factor of 1.57, and
significantly improved the machinability of Inconel 718
[198].
5.2CMQLAMoftitaniumalloy
A minimal cutting force and surface roughness were
observed in the CO2 + MQL CMQLAM process.
Bagherzadeh et al. [199] studied the effects of MQL,
CO2,LN2,CO2 + MQL, andLN2+ MQL on toolwear,
cuttingtemperature,cuttingforce,andsurfaceroughness
in the machining process of TC4 at different cutting
speeds.The CO2andLN2pressuresandMQLflow rates
were set to 10.8 kg/h, 36, and 90 mL/h, respectively.
When comparing the tool wear under different cooling
lubricationconditionsatvc=60m/min,applyingCO2+
MQLresultedina31.8%lowertoolwearthanusingCO2
alone, while that under LN2 + MQL conditions was
59.6% lower than when using only LN2, and the
minimum tool wear could be obtained when applying
MQL only, as shown in Fig.40(a) [199]. When vc was
120m/min,thetoolwearobtainedusingCO2,LN2,CO2+
MQL, and LN2 + MQL decreased by 35.4%, 29.6%,
38.9%,and53.6%,respectively.Theminimumtoolwear
canbeachievedunderLN2+MQLconditions,asshown
inFig.40(b)[199]. The cutting force atvc = 120 m/min
undercoolingconditions (CO2 orLN2)alonewashigher
thanthatunderMQLconditions,whereasboththecutting
force and surface roughness were assumed to be the
lowest values when applying CMQLAM (CO2 + MQL)
[199].
Optimal surface quality can be obtained in a CO2 +
MQLCMQLenvironment.Hanenkampet al. [200] used
aCMQLenergyfield(CO2+MQL)withaCO2pressure
of 10 kg/h and an MQL flow rate of 60 mL/h for the
assisted milling of TC4. The research showed that
comparedwithCMgating cutting, thesurfaceroughness
values under CO2 and MQL conditions increased by
11.0% and 82.5%, respectively. When applying
CMQLAM,the surface roughness was the smallest, and
thesurfacequalitywasimproved[200].
The best results were obtained under SCCO2-
OoWMQLconditions.Caietal.[201]studiedthemilling
ofTC4infourgreenenvironments:drycutting,SCCO2,
SCCO2-WMQL, and SCCO2-OoWMQL. They analyzed
the effects of vc, fz, αe, and green lubrication on the
cutting force, temperature, surface morphology, and
surface roughness. In the experiments, the SCCO2
pressure and MQL flow rate were set to 7.5 bar and
50 mL/h, respectively. Irrespective of the green lubrica-
tion environment, when vc increased from 20 to
60m/min,theaveragecuttingforceincreasedby273.6%.
Under the SCCO2-OoWMQL condition, owing to its
excellent cooling lubrication, chip removal, and chip
breaking performance, the friction coefficient of the
contact surface between the tool and workpiece was
reduced,resulting in a lower cutting force. Furthermore,
owingtotheforcedconvectionheattransfer,vaporization
heat absorption, and promotion of chip removal and
lubricationofOoWMQLparticlesbySCCO2,thecutting
temperature and surface smoothness were optimal, as
shown in Fig.41(a) [201]. The cutting temperature
increased with an increase in vc, fz, and αe, whereas the
surfaceroughnessincreased with increasing vcandfz, as
shown in Fig.41(b) [201]. Under the action of SCCO2,
owing to the increase in material strength and hardness,
thefrictionatthetoolandworkpieceinterfacedecreased,
andthecuttingforceincreased,rangingfrom8%to64%.
Thiswouldresultinpoorprocessingperformance[201].
In an LN2 + MQL CMQL environment, the influence
of cutting parameters on the cutting force, tool wear,
surface roughness, and productivity was analyzed.
Suhaimietal.[202]appliedassistedmillingtoTC4with
aCMQLenergyfield (LN2 + MQL) using 2.5‒3barair
pressureandanMQLflowrateof180mL/h.Compared
to CM pouring cutting, the cutting force and tool wear
obtainedbyCMQLAM were reducedby54% and 90%,
respectively[202].Theteamalsoexploredtheprocessing
mechanismofCMQLAMandfoundthatusingonlyLN2
for processing led to strong adhesive wear of the tool.
Through the detection of the cutting force, it was
determined that the point where the cutting force
decreases to 0 N was the blade fracture point [203]. To
explore the influence of multiple parameters on
CMQLAMprocessing,Shokraniet al. [204], based ona
full-factor experimental design, combined the CMQL
energyfield (LN2+ MQL)with anLN2 pressureof 1.5
barandanMQLflowrateof70mL/hforassistedmilling
of TC4. It was found that compared with CM pouring,
CMQLAMincreasedthetoollifeby a factor of 30. The
effective cooling and lubrication characteristics of
CMQLAM control tool wear and adhesion rates. When
only LN2 was used to cool the workpiece surface, the
hardnessofthematerialandtheplasticdeformationofthe
cuttingedgeincreased,therebypromotingadhesivewear.
When vc was high, CMQLAM exhibited excellent
cooling and lubrication performance, which reduced the
frictionforceandtoolwear,asshowninFig.42(a)[204],
stabilizedthesurfaceroughnessat0.2µm,andincreased
productivity by 50%. To study the tool life under
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 47
Fig. 42Toollifeandmicroscopicimagesunderdifferentcuttingconditions:(a)microscopicimagesofthecuttingedgeattheendoftool
lifeand(b)toollifemeasurementandpredictionresults[204].ReproducedwithpermissionfromRef.[204]fromElsevier.
50 Front.Mech.Eng.2023,18(2):28
different milling conditions, the tool life under multi-
parameter conditions was modeled and predicted, as
showninFig.42(b)[204].
Comparedwithothercryogenicmedia,theuseofCAis
relatedtoahighereconomicvalue, and CA + MQL can
significantlyreduceflankwear.Therefore,Suetal.[205]
employed TC4 in high-speed end milling experiments
andcomparedtheeffectsofdry,CA,andCMQLcooling
and lubrication methods on the cutting temperature and
toolwear.TheCApressureandMQL flowratewereset
to6bar and90mL/h,respectively.It wasfoundthatthe
measuredtemperaturevalues of theshearzoneincreased
in the order of CMQL, CA, and dry milling. The flank
wear when using CA was almost the same as that
obtained with dry milling, whereas the flank wear
observed when applying CMQL was significantly
reduced[205].
After the CMQL and milling parameters were deter-
mined, the atomizing nozzle structure of CMQL had a
directimpactonthemachiningprocess.Songetal.[206]
foundthatwhenMQLandcryogenicgaswereappliedon
bothsidesofthetool,theoilmistcouldnotpenetratethe
shear zone owing to the low injection pressure of the
cryogenic gas. Therefore, it is necessary to design a
hybridnozzlethatcansimultaneouslyinject oil mist and
cryogenic gases. Based on the Coanda effect and CFD
software analysis, the Coanda effect of the nozzle was
testedat differentinletflowrates,asshowninFig.43(a)
[206]. It can be observed by CFD that flow separation
occurs earlier at lower flow velocities. Therefore, the
flow parameters should be controlled to achieve ideal
cooling and lubrication effects after nozzle design. To
evaluate the performance of the nozzle, combined with
CA(pressureof 5 bar) and CO2gas (pressure of 8 bar),
TC4wasprocessedusingthedesignednozzle(MQLflow
rate of 19.8 mL/h) and conventional nozzle (MQL flow
rate of 54.9 mL/h). According to the results, low-tem-
perature micro-lubrication energy field-assisted milling
with the designed nozzle can reduce the friction heat in
the processing area, tool wear, and the minimum
Fig. 43Nozzlestructureandtoolwear:(a)nozzleCoandaeffect[206]and(b)influenceofgreenlubricationandcuttingvolumeontool
wear[207].ReproducedwithpermissionsfromRefs.[206,207]fromSpringerNature.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 51
temperatureofthecuttingzoneto310°C[206].Forthe
milling of TC4, the team also compared the cooling
lubrication performance of CMQL, dry conditions, CA,
andMQLwithaCO2pressureof4barandanMQLflow
rateof19.8mL/h.Theresultsshowedthatunderthesame
flow rate, CMQL reduced the cutting force, tool wear,
andcutting temperature by 23%, as shown inFig.43(b)
[207]. In addition, an economic analysis proved that
CMQLischeaperthanconventionalmethods[207].
5.3CMQLAMofhigh-strengthsteel
The new CMQL method can achieve better machining
effects. Mulyana et al. [94] conducted a milling
experimentonHTCSsteeland studied the effects ofdry
milling, MQL, SCCO2 and CMQL (SCCO2 + MQL)
conditions on the cutting force, temperature, and tool
wear. The pressure of SCCO2 was set to 4 bar, and the
flow rate of the MQL was 160 mL/h. Compared to dry
milling, the cutting force and cutting temperature under
CMQL conditions were reduced by 60% and 55%,
respectively. Compared with dry milling, MQL, and
SCCO2,thetoollife increased by 150%,87%,and22%,
respectively,whenusingCMQL.Overall,CMQLwasthe
best choice for reducing tool wear and prolonging tool
life, which could significantly improve the processing
efficiency [94]. In addition to the common CMQL
method (SCCO2 + MQL), Yuan et al. [208] proposed a
new CMQL (SCCO2-OoW) cooling and lubrication
system for milling 316L stainless steel. The effects of
SCCO2, OoW (oil-on-water), common CMQL, and new
CMQL on the cutting force, tool life, and surface
roughness were compared and analyzed. The SCCO2
pressure and MQL flow rate were set to 0.12 kg/h and
20 mL/h, respectively. The experimental results showed
thatcompared with common CMQL, SCCO2, and OoW
conditions, the application of the new CMQL method
maintainedalowercuttingforceand stable cutting force
variation throughout the cutting process. The tool life
decreasedinthe order ofthenewCMQLprocess,OoW,
ordinary CMQL, and SCCO2. When vc was 90 m/min,
comparedtoSCCO2andOoW,thesurfaceroughnessof
the new CMQL method decreased slightly. Compared
with SCCO2, the surface roughness of the workpieces
processed under OoW and CMQL conditions decreased
by25%and23%, respectively, when vc was120m/min.
Atavcof150m/min,thesurfaceroughnessofOoWand
CMQL was reduced by 39% and 32%, respectively,
compared with SCCO2, which proved that the new
CMQLmethodhadthebestmillingeffect[208].
The green lubrication parameters and cutting parame-
ters have a strong influence on machining. Wika et al.
[209] applied CM pouring and the CMQL (SCCO2 +
MQL) cooling lubrication mode at different vc and fz in
the milling of 304L stainless steel using an SCCO2
pressure of 6 bar and an MQL flow rate of 60 mL/h.
Compared with CM pouring cutting, the use of CMQL
resultedinthelongesttoollife,withanincreaseof324%
when vc and fz were 215 m/min and 0.5 mm/z, respec-
tively.TheCMQLmaterialremovalincreasedby158%.
Althoughthesurfaceroughnessdecreasedwithincreasing
fz,itincreasedwithincreasingvc.By using a high fz and
low vc, the surface roughness can be reduced by 30%.
UndertheconditionsofCMpouringandCMQL, tensile
residual stress was produced on the workpiece surface.
Whencombiningexperimentaldata,theauthors found fz
tobethemainfactoraffectingresidualstress,asshownin
Fig.44[209].
The above research shows that CMQLAM can
effectively prolong tool life when the vc value is high.
Basedonthis,ManimaranandNimelSwornaRoss[210]
studiedthe influence of vc inthe range of 45–75 m/min
on the cutting performance of AISI H13 steel at a
constantαp. Theeffectsofdrymilling,CMpouring,and
CMQL conditions on the surface roughness, chip
morphology, flank wear, and cutting temperature were
tested.TheCO2pressurewas2.5bar,andtheMQLflow
ratewas60 mL/h.Theresultsshowedthatunder CMQL
machining conditions, the cutting forces in the three
directions were reduced by 12%–16%, 11%–14%, and
12%–13% compared to dry milling. When compared to
the CM pouring process, the cutting forces were also
reduced by 6%–8%, 5%–7.5%, and 6.5%–8%,
respectively. Moreover, the application of CMQL
reducedthe cutting temperature by 52%–53% compared
to dry milling, and by 38%–41% compared to CM
pouring. Tool wear was also reduced by 50%–57%
comparedtodrymilling,andby14%–23%comparedto
CMpouring.Theaveragesurfaceroughnessdecreasedby
65%–71%and33%–41%,respectively. Additionally, the
machining hardness of CMQL was 6% and 2% higher
than those obtained by dry milling and CM pouring,
respectively. Compared with dry conditions and CM
pouringconditions,theuseofCMQLresultedinabetter
chip-breakingperformance,asshowninFig.45(a)[210].
Thecuttingforceandtemperatureaccompanytheentire
process. Zhang et al. [211] analyzed the influence of
CMQL on the cutting force and temperature during the
high-speedmillingof 300M steel. First,theinfluence of
cutting parameters on the cutting force and temperature
was investigated. The model was established using a
simulation and a prediction algorithm. Then, by single-
factorexperiments,withaCApressurerangeof6‒10bar
and an MQL flow rate of 265 mL/h, the variations in
cuttingforceandtemperaturewiththecuttingparameters
vc, fz, αp, and αe were studied under dry milling and
CMQL conditions, as shown in Fig.45(b) [211].
Comparedwith dry milling, the CMQLmethod resulted
in better lubrication and cooling effects, which could
effectivelyreducethecuttingforceandtemperatureinthe
shear zone. Based on this, the authors verified the
accuracy of the prediction model and provided a
52 Front.Mech.Eng.2023,18(2):28
theoretical and experimental basis for the subsequent
application of CMQL [211]. Furthermore, the team
performedmillingexperimentson300Msteelunderdry,
CA, water mist cooling, oil mist friction reduction, and
CMQLlubricationconditionsusingaCApressureof4.8
bar and an MQL flow rate of 150 mL/h. Through the
resultsofsingle-factorandorthogonalexperiments,itwas
foundthat, compared with other cooling and lubrication
conditions,CMQLcuttingconditionscouldobtainlower
cuttingforcesandbettersurfacesmoothness[212].
The white layer affects the service performance of
workpieces. Zhang et al. [213] studied the influence of
toolwearontheformationofawhitelayerindrymilling
andCMQLAMofH13steelat a CA pressure of 1.5bar
andMQLflowrate of 20mL/h.Theresultsshowedthat
CMQLAM could increase tool life by a factor of 1.78
comparedwithdrymilling.Furthermore,theformationof
thewhitelayerwasrelatedtotoolwear.Thethicknessof
the white layer increased with increasing tool wear.
According to the experimental results, the white layer
couldbepartiallyorcompletelyeliminatedunderCMQL
conditions by optimizing the parameters, as shown in
Fig.46(a)[213].This indicates that CMQL canimprove
the surface integrity [213]. The authors also conducted
side-milling experiments on H13 steel. Under CMQL
conditions using a CA pressure of 2 bar and an MQL
flowrateof 15 to 20 mL/h,the effects of three typesof
internal cooling tools, namely, double helix channel
(DHC), single straight channel (SSC), and DSC, on the
cutting force and tool wear were analyzed. Flank wear
andfracturewere found tobe the main factorsaffecting
toollife.The cutting force increasedwith an increase in
tool wear. Comparing the tool wear of three internal
coolingtools under CMQL conditions(Fig.46(b) [214])
revealed that the DSC tool achieved an effective
reduction in tool wear and a life 1.59 times longer than
that of the DHC tool, indicating that the DSC tool was
better than the DHC tool. From the perspective of
environmentalprotectionandeconomy,CMQLAMusing
a DSC internal cooling tool had the best effect on
machining[214].
5.4SummaryofCMQLAMofdifficult-to-machinemetal
materials
Based on the research presented above, the flow rate
range of MQL used in CM with CMQLAM varies
according to the basic properties of the difficult-to-
machinemetalmaterials beingused.TheMQLflowrate
ranges for nickel-based alloy, titanium alloy, and high-
strength steel are 8–120 mL/h, 19.8–180 mL/h, and
15–256 mL/h, respectively. These values are consistent
withthemachinabilityofthethreematerials.Insummary,
CMQLAM of difficult-to-machine metal materials is
depictedinFig.47.ComparedtoCMcastingcutting,the
types of low-temperature medium, gas pressure, MQL
flow rate, atomizing nozzle type, coating tool type, and
cutting parameters all affect the machining results. The
advantagesof CMQLAMincludelowcuttingforce,high
materialremovalrate,longtoollife, low cutting specific
energy, low cutting temperature, low manufacturing
costs,smallchipsize,andhighsurfacequality.However,
Fig. 44Average residual stresses corresponding to different fz and vc: (a) conventional milling 0° residual stresses, (b) conventional
milling 90° residual stresses, (c) cryogenic minimum quantity lubrication 0° residual stresses, and (d) cryogenic minimum quantity
lubrication90°residualstresses[209].ReproducedwithpermissionfromRef.[209]fromElsevier.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 53
Fig. 45Chipmorphology,cutting force, and cuttingtemperature:(a)chip morphology under differentlubricationenvironments[210]
and (b) influence of cutting parameters on cutting force and cutting temperature [211]. CM: conventional milling; CMQL: cryogenic
minimumquantitylubrication.ReproducedwithpermissionsfromRefs.[210,211]fromASTMandSpringerNature.
54 Front.Mech.Eng.2023,18(2):28
there is currently no model available to obtain optimal
parameters,andtheFEMmodelofthemachiningprocess
during cooling and lubrication and the predictive
optimization algorithm model still require further
research. Additionally, a normative guidance theory has
not been developed for the lubrication mechanism of
CMQLAM, and optimal processing parameters of
CMQLAM have not been defined. In the future, it is
necessary to design an intelligent matching system or
database to establish a quantitative correspondence
between the evaluation index level and the cooling
medium parameters, to realize the most effective
combinationof lubricatingoiltypesandprocessparame-
ters under different processing conditions. Moreover, an
intelligent nozzle and a multi-parameter coordinated
control system that can automatically adjust the space
attitude should be designed to guide the practical
production environment for the purpose of accurately
transportingtheCMQLfluidtothecuttingzone.
6Conclusions
The discussed shortcomings, such as the large removal
rate of titanium alloy, nickel-based alloy, high-strength
steel, and other difficult-to-machine metal materials, the
high energy consumption of machine tools, large tool
consumption, low processing efficiency, large emissions
of cutting oil mist and waste liquid, environmental
pollution and health hazards, and the dependence on
importedhigh-endtools andcuttingoil,seriouslyrestrict
the green low-carbon and independent and controllable
development of the manufacturing industry. With the
increasingdemandtoaddresstheissuesof‘carbonpeak’,
‘carbon neutralization’, and ‘manufacturing power’, the
concept of green manufacturing is becoming more
importantandwillhaveaprofoundimpactonthefuture
development of the global manufacturing industry. It is,
therefore, crucial to explore and address the limitations
and defects of energy-field-assisted green processing
technology for difficult-to-machine metal materials, and
toprovideinnovativeprocessingmethodsforglobalhigh-
endmanufacturing.
(1) Energy field-assisted machining mechanisms for
difficult-to-machinemetalmaterials
TheuseofLAM,UVAM,andCMQLAMtechnologies
toprocesstitanium alloys, nickel-basedalloys,andhigh-
strength steel can reduce the cutting force, improve the
material removal rate, prolong the tool life, reduce the
cutting specific energy, reduce manufacturing costs,
decrease chip size, and improve surface quality.
However, their processing mechanisms differ from one
another. LAM softens the shear zone using the laser
system before machining. UVAM applies ultrasonic
frequencyvibrationtotheworkpieceortool basedonan
ultrasonic system, which realizes a high-frequency
periodic separation of the workpiece and tool in the
cutting process. CMQLAM uses a jet device to spray a
liquid/gaseousmediuminto theshearzonedependingon
thejetform,which can replace theCMcutting fluid for
lubrication and cool the machining contact zone.
ComparedwiththeCM,theLAMhasagreaterinfluence
Fig. 46Subsurfaceandchannelstructures:(a)whitelayer[213]and(b)threechannelstructuresofinternalcoolingmillingtools[214].
ReproducedwithpermissionsfromRefs.[213,214]fromSAGEandSpringerNature.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 55
onthecuttingforce,anditslimitvaluecanbereducedby
70%. UVAM has the greatest effect on chips, making
them thin and small. CMQLAM has the greatest
influenceonthetoollifeandcuttingtemperature,andits
limit values can be reduced by 157% and 60%,
respectively.
(2) Energy field-assisted machining methods for
difficult-to-machinemetalmaterials
Fig. 47Summaryofcryogenicminimumquantitylubricationenergyfield-assistedmilling(CMQLAM)machinability.
56 Front.Mech.Eng.2023,18(2):28
Currently, the use of titanium alloys, nickel-based
alloys, and high-strength steel is increasing. Traditional
processing methods cause severe tool wear, low proce-
ssing efficiency, and poor surface integrity. Therefore,
new processing methods are required for this purpose.
FortheLAMprocess,thispapersystematicallyillustrates
the influence of laser and cutting parameters on the
cutting force, material removal rate, tool life, cutting
specific energy, manufacturing cost, chip morphology,
and surface quality. To improve the data-driven proce-
ssingeffect,anintelligentalgorithmshouldbeestablished
topredicttheinfluenceofthelaserandcuttingparameters
onthecorrespondingparameters.FortheUVAMprocess,
inadditiontoexploringtheeffects of ultrasonic parame-
ters, cutting parameters, and vibration direction changes
oncuttingforce,surface morphology, surfaceroughness,
residual stress, chip morphology, and tool wear, a
predictionmodeloftheinfluenceofinstantaneouscutting
thicknesschange on the corresponding result parameters
should be developed based on ultrasonic and cutting
parameters. For the CMQLAM process, after exploring
the effects of air pressure, flow rate, and cutting para-
meters on cutting force, material removal rate, tool life,
cutting specific energy, cutting temperature, manufactu-
ringcost,chipsize,andsurfacequality,itisnecessaryto
establish a CMQLAM specification guidance theory to
definetheoptimalprocessingparameters.
(3) Difficulties in energy field-assisted machining of
difficult-to-machinemetalmaterials
A laser energy field can soften a material before
machining.Anultrasonicenergy field canimprovechip-
breaking ability. The CMQL energy field can reduce
cutting fluid emissions and realize green machining.
However, there are still difficulties restricting the
applicationanddevelopmentofenergyfields,suchasthe
longprocessingcycleofLAM,littleeffectofUVAMon
reducingthetemperature of theshear zone, and residual
oil on the surface of the CMQLAM-processed
workpieces. Therefore, the engineering application and
development of energy field-assisted HSDM green
machining technology requires combined global efforts.
This review provides feasible ideas for realizing multi-
energyfieldcollaborativegreenmachiningofdifficult-to-
machinemetalmaterialsinthefuture.
7Prospects
Difficult-to-machinemetalmaterialswillremainaglobal
research hotspot in the future. However, there are still
somelimitationstotheefficientandprecisemachiningof
difficult-to-machine metal materials. The above syste-
matic summary shows that future research directions of
energy field-assisted green machining technology for
HSDMmaymainlyfocusonthefollowingpoints:
(1)Fortoolcoatingswithdifferentapplicationrequire-
ments, the elemental composition and thickness of
coatings should be explored with three processing
scenarios: rough machining, semi-finishing, and
finishing.Thus, the optimumworking conditions canbe
appliedto thevariousprocessingmethodsofdifficult-to-
machinemetalmaterials,whichcanprolongthetoollife
intheenergyfield-assistedHSDMprocess.
(2)Itisnecessary to utilize multi-energyfieldsynergy
toassist the manufacturingof difficult-to-machine metal
materials, and cutting force, vibration, and temperature
sensingtechnologycanbeusedassignalinputsourcesto
controlthe ultrasonicandCMQLparametersinrealtime
under different processing conditions, which can realize
the adaptive intelligent control of difficult-to-machine
metalmaterialsinlarge-scalemanufacturing.
(3)Toaddresstheproblemofhighcarbonemissionsin
themachiningprocess,amulti-energyfieldcollaborative
and multi-dimensional carbon-efficient concept for
HSDM is proposed, which considers both efficient
material removal and surface quality assurance and
realizes green intelligent machining using multi-energy
fieldsatalowtotalenergyconsumptionoftheprocess.
Nomenclature
Abbreviations
B&F Back-and-forth
CA Coldair
CCD Centralcompositedesign
CFD Computationalfluiddynamics
CL Conventionalmelting
CM Conventionalmilling
CMQL Cryogenicminimumquantitylubrication
CMQLAM Cryogenic minimum quantity lubrication energy field-
assistedmilling
CVD Chemicalvapordeposition
DHC Doublehelixchannel
DSC Doublestraightchannel
FEM Finiteelementmethod
HAZ heat-affectedzone
H.F Highfeedmilling
HM Helicalmilling
HPDL High-powersemiconductorlaser
HSDM High-speeddrymilling
LAM Laser-assistedmilling
LCO2Liquidcarbondioxide
L.F Lowfeedmilling
LMO Localmisorientation
LS Singlelaserscanning
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 57
MQL Minimumquantitylubrication
Nd:YAG Neodymium-dopedyttriumaluminumgarnet
NMQL Nanofluidminimumquantitylubrication
NURBS Non-uniformrationalB-spline
OoW Oil-on-water
PCBN Polycrystallinecubicboronnitride
PVD Physicalvapordeposition
SCCO2Supercriticalcarbondioxide
SEM Scanningelectronmicroscope
SLM Selectivelasermelting
SSC Singlestraightchannel
S&T Spatialandtemporal
TAM Thermal-assistedmachining
TC4 Ti–6Al–4V
UVAM Ultrasonicvibration-assistedmilling
XRD X-raydiffraction
Variables
AVibrationamplitude
dLHeatsourcesize
fVibrationfrequency
fzFeedpertooth
NzNumberoftips
PciCoordinatetoolpoint
PliInitialcoordinatepoint
PLLaserpower
PLiEndcoordinatepoint
rRadiusofthecuttingtool
rcSumoftheradiusofthecuttingtool
RExpectedfilletradius
Sa Averageroughness
Sq Surfacerootmeansquareroughness
tCuttingtime
vcCuttingspeed
vfFeedspeed
VLLaserscanningspeed
x,y,zTipdisplacements
xcl Distance between the tool center and the laser heat source
center
xLDistancebetweenspotandtool
ωrAngularvelocityofthespindle
αiToolradiusangle
αpAxialcuttingdepth
αeRadialcutwidth
βToolrotationangle
θInitialphaseofthevibrationsignal
∆xiDistance between the initial coordinate point of the heat
sourceandtheendcoordinatepoint
AcknowledgementsThisworkwassupportedbytheNational KeyR&D
Program of China (Grant No. 2020YFB2010500). The authors gratefully
acknowledgethereviewersandeditorsfortheirinsightfulcomments.
Conflict of InterestThe authors declare that they have no conflict of
interest.
Open AccessThis article is licensed under a Creative Commons
Attribution 4.0 International License, which permits use, sharing,
adaptation,distribution,andreproductioninany mediumor formatas long
asappropriate creditisgiven tothe originalauthor(s)and source,alinkto
the Creative Commons license is provided, and the changes made are
indicated.
Theimagesorotherthird-partymaterialinthisarticleareincludedinthe
article’sCreativeCommonslicense,unlessindicated otherwise in a credit
line to the material. If material is not included in the article’s Creative
Commons license and your intended use is not permitted by statutory
regulationorexceedsthepermitteduse,youwillneedtoobtainpermission
directlyfromthecopyrightholder.
Visit http://creativecommons.org/licenses/by/4.0/ to view a copy of this
license.
References
Inasaki I. Grinding of hard and brittle materials. CIRP Annals,
1987,36(2):463–471
1.
DudzinskiD,DevillezA,MoufkiA,LarrouquèreD,ZerroukiV,
VigneauJ.Areviewofdevelopmentstowardsdryandhighspeed
machiningofInconel718alloy.InternationalJournalofMachine
ToolsandManufacture,2004,44(4):439–456
2.
BowdenD, Krysiak Y, Palatinus L, Tsivoulas D, Plana-Ruiz S,
Sarakinou E, Kolb U, Stewart D, Preuss M. A high-strength
silicidephaseinastainlesssteelalloydesignedforwear-resistant
applications.NatureCommunications,2018,9(1):1374
3.
ZhaoW,Wang S Z, LiL,YangYF. Evaluation of cuttingtool
performanceof end millsfortitanium alloycomponents.Journal
of South China University of Technology (Natural Science
Edition),2015,43(9):121–126(inChinese)
4.
Li F. Wear of grinding wheels in high efficiency grinding of
nickel-basedsuperalloy.ThesisfortheMaster’sDegree.Nanjing:
Nanjing University of Aeronautics and Astronautics, 2012 (in
Chinese)
5.
ZhangXL.Investigationofmechanismin highspeedmachining
of40CrNi2Si2MoVAultrahighstrengthprocess.Thesisfor the
Master’s Degree. Harbin: Harbin University of Science and
Technology,2016(inChinese)
6.
He G H, Wu M Y, Li L X, Zou L L, Cheng C. Study on the
formationmechanismofphasetransformationandtheinfluencing
factors of cutting layer of the typical titanium alloy. Journal of
MechanicalEngineering,2018,54(17):133–141(inChinese)
7.
Ding W F, Miao Q, Li B K, Xu J H. Review on grinding
technology of nickel-based superalloys used for aero-engine.
Journal of Mechanical Engineering, 2019, 55(1): 189–215 (in
8.
58 Front.Mech.Eng.2023,18(2):28
Chinese)
Lin S. Modeling and experimental investigation on workpiece
temperature field for turn-milling of high strength steel.
Dissertation for the Doctoral Degree. Wuhan: Huazhong
UniversityofScienceandTechnology,2014(inChinese)
9.
HeGH,LiuXL,WuCH,ZhangSQ,ZouLL,LiDJ.Studyon
the negative chamfered edge and its influence on the indexable
cutting insert’s lifetime and its strengthening mechanism. The
International Journal of Advanced Manufacturing Technology,
2016,84(5–8):1229–1237
10.
LiuLJ,LvM,WuWG,ZhuXJ.Experimentalstudyonthechip
morphology in high speed milling Ti–6Al–4V alloy. Journal of
MechanicalEngineering,2015,51(3):196–205(inChinese)
11.
Ren J X, Hua D A. Principle of Grinding. Beijing: Electronic
IndustryPress,2011(inChinese)
12.
PutzM,CardoneM,DixM,Wertheim R.Analysisofworkpiece
thermalbehaviourincut-offgrindingofhigh-strengthsteelbars
to control quality and efficiency. CIRP Annals, 2019, 68(1):
325–328
13.
Kim S W, Lee D W, Kang M C, Kim J S. Evaluation of
machinability by cutting environments in high-speed milling of
difficult-to-cut materials. Journal of Materials Processing
Technology,2001,111(1–3):256–260
14.
KoshyP,DewesRC,AspinwallDK. Highspeedendmillingof
hardened AISI D2 Tool Steel (~58HRC). Journal of Materials
ProcessingTechnology,2002,127(2):266–273
15.
LongZH,Wang X B, Wang H C. Factorial study onnonlinear
characteristics of difficult-to-cut materials in high-speed cutting
process.JournalofMechanical Engineering, 2006, 42(1): 30–34
(inChinese)
16.
LiuGL,ZouB,HuangCZ,Wang XY,WangJ,LiuZQ.Tool
damageanditseffectonthemachinedsurfaceroughnessinhigh-
speed face milling the 17-4PH stainless steel. The International
Journalof Advanced ManufacturingTechnology,2016,83(1–4):
257–264
17.
MarusichT D,OrtizM. Modellingandsimulationofhigh-speed
machining. International Journal for Numerical Methods in
Engineering,1995,38(21):3675–3694
18.
UmbrelloD.Finite element simulation ofconventionalandhigh
speed machining of Ti6Al4V alloy. Journal of Materials
ProcessingTechnology,2008,196(1–3):79–87
19.
ChenG, Ren C Z, Yang X Y, Jin X M, Guo T. Finite element
simulation of high-speed machining of titanium alloy
(Ti–6Al–4V) based on ductile failure model. The International
JournalofAdvancedManufacturingTechnology,2011,56(9–12):
1027–1038
20.
Gong Q H, Sun C, Wang W. High speed and high efficiency
machiningresearchoftitaniumalloyaircraftstructurepartandits
application. Aeronautical Manufacturing Technology, 2016, (7):
26–32(inChinese)
21.
LiuMZ,LiCH,CaoHJ,ZhangS,ChenY,LiuB,ZhangNQ,
Zhou Z M. Research progresses and applications of CMQL
machining technology. China Mechanical Engineering, 2022,
33(5):529–550(inChinese)
22.
Baumeister K J, Simon F F. Leidenfrost temperature—its
correlationfor liquid metals,cryogens,hydrocarbons,and water.
23.
ASMEJournalofHeatandMassTransfer,1973,95(2):166–173
HuDH,Qiu H,Li Q.Studyonbubbledynamicsinsidedroplets
underlocalboiling.JournalofEngineeringThermophysics,2021,
42(4):1026–1031(inChinese)
24.
RaoP N,SrikantR R.Sustainablemachining utilizingvegetable
oil based nanofluids. In: Proceedings of 2015 International
Conference on Smart Technologies and Management for
Computing, Communication, Controls, Energy and Materials.
Avadi:IEEE,2015,664‒672
25.
AdlerDP,HiiWWS,MichalekDJ,SutherlandJW.Examining
the role of cutting fluids in machining and efforts to address
associated environmental/health concerns. Machining Science
andTechnology,2006,10(1):23–58
26.
Anton S, Andreas S, Friedrich B. Heat dissipation in turning
operations by means of internal cooling. Procedia Engineering,
2015,100:1116–1123
27.
Pusavec F, Kramar D, Krajnik P, Kopac J. Transitioning to
sustainable production—part II: evaluation of sustainable
machining technologies. Journal of Cleaner Production, 2010,
18(12):1211–1221
28.
SankaranarayananR, Rajesh JHN, Senthil KJ,Krolczyk G M.
Acomprehensivereviewonresearchdevelopmentsofvegetable-
oil based cutting fluids for sustainable machining challenges.
JournalofManufacturingProcesses,2021,67:286–313
29.
YangX,CaoHJ,ChenYP,ZhangCL,ZhouL.Wholeprocess
cuttingheattransfermodelforhigh-speeddryhobbing.Journalof
MechanicalEngineering,2015,51(19):189–196
30.
Chen Y P, Cao H J, Yang X. Research on load distribution
characteristic on the cutting edge in high-speed gear hobbing
process. Journal of Mechanical Engineering, 2017, 53(15):
181–187
31.
Zhang H, Dang J Q, Ming W W, Xu X W, Chen M, An Q L.
Cutting responses of additive manufactured Ti6Al4V with solid
ceramic tool under dry high-speed milling processes. Ceramics
International,2020,46(10):14536–14547
32.
Salahshoor M, Guo Y B. Cutting mechanics in high speed dry
machiningofbiomedicalmagnesium–calciumalloyusinginternal
statevariable plasticity model. International Journal of Machine
ToolsandManufacture,2011,51(78):579–590
33.
Yang X, Cao H J, Du Y B, Xu L, Chen Y P. Regulation and
control method for tool temperature in high-speed dry cutting
processes based on specific cutting energy. China Mechanical
Engineering,2018,29(21):2559–2564(inChinese)
34.
Liu G L. High-speed machinability evaluation method of
difficult-to-machinematerialforfatigueandcorrosionresistance.
DissertationfortheDoctoralDegree.Jinan:ShandongUniversity,
2019(inChinese)
35.
Li B J. Research on exergy efficiency model and coordinative
optimizationmethodofspindlesystemofhigh-speeddryhobbing
machine tool. Dissertation for the Doctoral Degree. Chongqing:
ChongqingUniversity,2019(inChinese)
36.
LuL,WangQM,ChenBZ,AoYC,YuDH,WangCY,WuS
H,KimKH.MicrostructureandcuttingperformanceofCrTiAlN
coating for high-speed dry milling. Transactions of Nonferrous
MetalsSocietyofChina,2014,24(6):1800–1806
37.
Li X G. Study on green manufacturing operation model and its38.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 59
mainlinesinmachinetoolindustry.DissertationfortheDoctoral
Degree.Chongqing:ChongqingUniversity,2012(inChinese)
Yang X. Transfer characteristics and quantification analysis
method of the cutting heat in high-speed dry hobbing.
Dissertation for the Doctoral Degree. Chongqing: Chongqing
University,2017(inChinese)
39.
Li C H, Li J Y, Wang S, Zhang Q. Modeling and numerical
simulationof thegrinding temperaturefieldwithnanoparticlejet
ofMQL.AdvancesinMechanicalEngineering,2013,5:986984
40.
Arunachalam R, Mannan M A. Machinability of nickel-based
high temperature alloys. Machining Science and Technology,
2000,4(1):127–168
41.
Song H W. Research on cutting mechanism of laser assisted
machiningforfused silica withexperiments.Dissertation for the
Doctoral Degree. Wuhan: Huazhong University of Science and
Technology,2019(inChinese)
42.
Lajis M A, Amin A K M N, Karim A N M, Radzi H C D M,
GintaTL. HotMachiningofhardenedsteelswithcoatedcarbide
inserts.American Journal of Engineering and Applied Sciences,
2009,2(2):421–427
43.
Rajagopal S, Plankenhorn D J, Hill V L. Machining aerospace
alloys with the aid of a 15 kW laser. Journal of Applied
Metalworking,1982,2(3):170–184
44.
Kim K S, Lee C M. A fundamental study on the prediction of
preheating temperature of silicon nitride ceramics by using
HPDL. Applied Mechanics and Materials, 2012, 229–231:
287–291
45.
Özler L, İnan A, Özel C. Theoretical and experimental
determination of tool life in hot machining of austenitic
manganese steel. International Journal of Machine Tools and
Manufacture,2001,41(2):163–172
46.
Tosun N, Özler L. A study of tool life in hot machining using
artificialneuralnetworksandregressionanalysismethod.Journal
ofMaterialsProcessingTechnology,2002,124(1–2):99–104
47.
DingHT,ShinYC.Improvingmachinabilityofhighchromium
wear-resistantmaterials via laser-assisted machining. Machining
ScienceandTechnology,2013,17(2):246–269
48.
Anderson M, Patwa R, Shin Y C. Laser-assisted machining of
Inconel718 with an economic analysis. International Journal of
MachineToolsandManufacture,2006,46(14):1879–1891
49.
DingHT,Shin YC. Improvementofmachinabilityofwaspaloy
via laser-assisted machining. The International Journal of
AdvancedManufacturingTechnology,2013,64(1–4):475–486
50.
Suthar K J, Patten J, Dong L, Abdel-Aal H. Estimation of
temperature distribution in silicon during micro laser assisted
machining. In: Proceedings of the ASME 2008 International
Manufacturing Science and Engineering Conference. Evanston:
ASME,2008,301–309
51.
SunS,BrandtM,DarguschMS.Thermallyenhancedmachining
ofhard-to-machinematerials—areview. International Journal of
MachineToolsandManufacture,2010,50(8):663–680
52.
Germain G, Dal Santo P, Lebrun J L. Comprehension of chip
formation in laser assisted machining. International Journal of
MachineToolsandManufacture,2011,51(3):230–238
53.
SongP P.Keyfundamentalresearchon laserassistedmachining
ofsiliconnitride ceramics. DissertationfortheDoctoralDegree.
54.
Zibo:ShandongUniversityofTechnology,2020
Fang S X, Zhao H L, Zhang Q J. The application status and
developmenttrends of ultrasonic machining technology. Journal
ofMechanicalEngineering,2017,53(19):22–32
55.
Cao F G. Ultrasonic Machining. Beijing: Chemical Industry
Press,2014(inChinese)
56.
Zhang X Y, Lu Z H, Peng Z L, Zhang D Y. High quality and
efficientultrasonicvibrationcuttingoftitaniumalloys.Journalof
MechanicalEngineering,2021,57(5):133–147
57.
YılmazB,KarabulutŞ, Güllü A. A review of thechipbreaking
methods for continuous chips in turning. Journal of
ManufacturingProcesses,2020,49:50–69
58.
MaL J, Liu G J, Wang G C. Study on mechanism of breaking
chip of axial vibration drilling. Chinese Machinery Design and
Manufacture,2009,(2):228–230(inChinese)
59.
NiCB,ZhuL D,NingJS,YangZC,LiuC F.Researchonthe
characteristics of cutting force signal and chip in ultrasonic
vibration-assisted milling of titanium alloys. Journal of
MechanicalEngineering,2019,55(7):207–216(inChinese)
60.
Verma G C, Pandey P M, Dixit U S. Estimation of workpiece-
temperature during ultrasonic-vibration assisted milling
considering acoustic softening. International Journal of
MechanicalSciences,2018,140:547–556
61.
XuXX,MoYL,LiuCS,ZhaoB.DrillingforceofSiCparticle
reinforcedaluminum-matrixcompositeswithultrasonicvibration.
KeyEngineeringMaterials,2009,416(21):243–247
62.
ZhangL B,Wang LJ,LiuXY, ZhaoHW,WangX, LuoHY.
Mechanical model for predicting thrust and torque in vibration
drilling fibre-reinforced composite materials. International
Journal of Machine Tools and Manufacture, 2001, 41(5):
641–657
63.
ZhaoB,ChenF,TongJL.Theoreticalandexperimentalresearch
on material removal rate under ultrasonic grinding. Journal of
HenanPolytechnicUniversity,2013,32(3):302–307
64.
Kaynak Y, Gharibi A, Yilmaz U, Köklü U, Aslantaş K. A
comparison of flood cooling, minimum quantity lubrication and
high pressure coolant on machining and surface integrity of
titanium Ti-5553 alloy. Journal of Manufacturing Processes,
2018,34:503–512
65.
YanP,RongYM,WangXB,ZhuJY,JiaoL,LiangZQ.Effect
ofcutting fluid on precision machined surface integrity of heat-
resistant stainless steel. Proceedings of the Institution of
Mechanical Engineers, Part B: Journal of Engineering
Manufacture,2018,232(9):1535–1548
66.
Pecat O, Brinksmeier E. Tool wear analyses in low frequency
vibration assisted drilling of CFRP/Ti6Al4V stack material.
ProcediaCIRP,2014,14:142–147
67.
AdithanM. Toolwearstudiesin ultrasonicdrilling.Wear, 1974,
29(1):81–93
68.
Wang D Z, Wu S J, Lin J P, Guo G Q, Wang P. Research on
ultrasonicelliptical vibrationmicro-cuttingInconel718based on
minimum quantity lubrication. Journal of Mechanical
Engineering,2021,57(9):264–272(inChinese)
69.
Verma G C, Pandey P M, Dixit U S. Modeling of static
machining force in axial ultrasonic-vibration assisted milling
considering acoustic softening. International Journal of
70.
60 Front.Mech.Eng.2023,18(2):28
MechanicalSciences,2018,136:1–6
CaoY,YinJF,DingWF,XuJH.Aluminaabrasivewheelwear
inultrasonicvibration-assistedcreep-feedgrindingofInconel718
nickel-based superalloy. Journal of Materials Processing
Technology,2021,297:117241
71.
KlockeF,EisenblätterG.Drycutting.CIRPAnnals,1997,46(2):
519–526
72.
YangJZ,WangCY,YuanYH,YuanSM,WangXB,LangC
L,LiWQ.State-of-the-art onMQLsynergistictechnologiesand
their applications. China Mechanical Engineering, 2022, 33(5):
506–528(inChinese)
73.
Race A, Zwierzak I, Secker J, Walsh J, Carrell J, Slatter T,
Maurotto A. Environmentally sustainable cooling strategies in
milling of SA516: effects on surface integrity of dry, flood and
MQL machining. Journal of Cleaner Production, 2021, 288:
125580
74.
Gaitonde V N, Karnik R S, Davim J P. Minimum Quantity
LubricationinMachining.JohnWiley&Sons,Inc.,2013
75.
Höhn B R, Michaelis K. Influence of oil temperature on gear
failures.TribologyInternational,2004,37(2):103–109
76.
Yuan S M, Han W L, Zhu G Y, Hou X B, Wang L. Recent
progress on the efficiency increasing methods of minimum
quantity lubrication technology in green cutting. Journal of
MechanicalEngineering,2019,55(5):175–185(inChinese)
77.
Weinert K, Inasaki I, Sutherland J W, Wakabayashi T. Dry
machining and minimum quantity lubrication. CIRP Annals,
2004,53(2):511–537
78.
Shao Y M, Fergani O, Li B Z, Liang S Y. Residual stress
modeling in minimum quantity lubrication grinding. The
International Journal of Advanced Manufacturing Technology,
2016,83(5–8):743–751
79.
HanCC.Researchonsinglecrystal diamondturningtechnology
oftitaniumalloyundernanofluidsminimumquantitylubrication.
Dissertationforthe Doctoral Degree.Harbin:Harbin Institute of
Technology,2019(inChinese)
80.
Zhang Y B. Grinding mechanism,force prediction model and
experimental validation of vegetable oil based nanofluids
minimum quantity lubrication. Dissertation for the Doctoral
Degree. Qingdao: Qingdao University of Technology, 2018 (in
Chinese)
81.
Yıldırım Ç V. Experimental comparison of the performance of
nanofluids, cryogenic and hybrid cooling in turning of Inconel
625.TribologyInternational,2019,137:366–378
82.
Yıldırım Ç V, Sarıkaya M, Kıvak T, Şirin Ş. The effect of
addition of hBN nanoparticles to nanofluid-MQL on tool wear
patterns, tool life, roughness and temperature in turning of Ni-
basedInconel625.TribologyInternational,2019,134:443–456
83.
Singh T, Dureja J S, Dogra M, Bhatti M S. Machining
performance investigation of AISI 304 austenitic stainless steel
under different turning environments. International Journal of
Automotive and Mechanical Engineering, 2018, 15(4):
5837–5862
84.
AnandN, KumarAS, PaulS.Effectof cuttingfluidsapplied in
MQCL mode on machinability of Ti–6Al–4V. Journal of
ManufacturingProcesses,2019,43:154–163
85.
DasA,PatelSK,DasSR.Performancecomparisonofvegetable86.
oilbasednanofluids towards machinabilityimprovementinhard
turning of HSLA steel using minimum quantity lubrication.
Mechanics&Industry,2019,20(5):506–526
SaidZ,GuptaM,HegabH,AroraN,KhanAM,JamilM,Bellos
E. A comprehensive review on minimum quantity lubrication
(MQL) in machining processes using nano-cutting fluids. The
International Journal of Advanced Manufacturing Technology,
2019,105(5–6):2057–2086
87.
RoushanA, RaoUS,Patra K,SahooP. Performanceevaluation
oftoolcoatingsandnanofluidMQLonthemicro-machinability
of Ti–6Al–4V. Journal of Manufacturing Processes, 2022, 73:
595–610
88.
Kaynak Y. Evaluation of machining performance in cryogenic
machining of Inconel 718 and comparison with dry and MQL
machining.TheInternationalJournalofAdvancedManufacturing
Technology,2014,72(5–8):919–933
89.
Ni J, Cui Z, Wu C, Sun J B, Zhou J H. Evaluation of MQL
broaching AISI 1045 steel with sesame oil containing nano-
particlesunderbestconcentration.JournalofCleanerProduction,
2021,320:128888
90.
GaoDQ,ZengXJ,HeNR,JiaJH,GaoSS.Applicationoflow
temperature cutting technology in the processing of difficult
materials. Manufacturing Technology and Machine Tool,
2020(6),39–43
91.
ShokraniA,DhokiaV,NewmanST.Investigationoftheeffects
ofcryogenicmachining on surfaceintegrityinCNC end milling
of Ti–6Al–4V titanium alloy. Journal of Manufacturing
Processes,2016,21:172–179
92.
FernándezD,SandáA,BengoetxeaI.Cryogenicmilling:studyof
theeffectofCO2cooling on tool wear when machining Inconel
718,GradeEAINsteelandGammaTiAl.Lubricants,2019,7(1):
10
93.
Mulyana T, Rahim E A, Md Yahaya S N. The influence of
cryogenic supercritical carbon dioxide cooling on tool wear
during machining high thermal conductivity steel. Journal of
CleanerProduction,2017,164:950–962
94.
Jozić S, Bajić D, Celent L. Application of compressed cold air
cooling: achieving multiple performance characteristics in end
milling process. Journal of Cleaner Production, 2015, 100:
325–332
95.
Chaabani S, Arrazola P J, Ayed Y, Madariaga A, Tidu A,
Germain G. Comparison between cryogenic coolants effect on
tool wear and surface integrity in finishing turning of Inconel
718. Journal of Materials Processing Technology, 2020, 285:
116780
96.
KhanAM,AnwarS,JamilM,NasrMM,GuptaMK,SalehM,
Ahmad S, Mia M. Energy, environmental, economic, and
technological analysis of Al-GnP nanofluid-and cryogenic LN2-
assistedsustainablemachiningofTi–6Al–4Valloy.Metals,2021,
11(1):88
97.
KhanAM,ZhaoW,LiL,AlkahtaniM,HasnainS,JamilM,He
N. Assessment of cumulative energy demand, production cost,
and CO2 emission from hybrid CryoMQL assisted machining.
JournalofCleanerProduction,2021,292:125952
98.
LiuMZ,LiCH,ZhangYB,An QL, YangM, GaoT,MaoC,
LiuB, CaoHJ, XuXF, SaidZ,Debnath S,JamilM, AliHM,
99.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 61
Sharma S. Cryogenic minimum quantity lubrication machining:
from mechanism to application. Frontiers of Mechanical
Engineering,2021,16(4):649–697
De Chiffre L, Andreasen J L, Lagerberg S, Thesken I B.
Performance testing of cryogenic CO2 as cutting fluid in
parting/grooving and threading austenitic stainless steel. CIRP
Annals,2007,56(1):101–104
100.
ChenB, XiongFX,TangH Q,HeL, HuSS.Effectof cooling
methodonsmalldiameterblind-holedrillingofnewβ-typedental
Ti-Zr-Nb alloy. Journal of Manufacturing Processes, 2020, 59:
421–431
101.
Damir A, Shi B, Attia M H. Flow characteristics of optimized
hybrid cryogenic-minimum quantity lubrication cooling in
machining of aerospace materials. CIRP Annals, 2019, 68(1):
77–80
102.
Schulz H, Moriwaki T. High-speed machining. CIRP Annals,
1992,41(2):637–643
103.
KrishnarajV,SamsudeensadhamS,SindhumathiR,KuppanP.A
study on high-speed end milling of titanium alloy. Procedia
Engineering,2014,97:251–257
104.
GintingA,NouariM.Experimentalandnumericalstudiesonthe
performanceof alloyed carbide tool in dry milling of aerospace
material. International Journal of Machine Tools and
Manufacture,2006,46(7–8):758–768
105.
LiA H,Zhao J,LuoHB,Pei ZQ,WangZM. Progressivetool
failureinhigh-speeddrymilling ofTi–6Al–4Valloywithcoated
carbide tools. The International Journal of Advanced
ManufacturingTechnology,2012,58(5–8):465–478
106.
LiAH,ZhaoJ,LuoHB,ZhengW.Machinedsurfaceanalysisin
high-speed dry milling of Ti–6Al–4V alloy with coated carbide
inserts.AdvancedMaterialsResearch,2011,325:412–417
107.
LiA H, Zhao J, Zhou Y H, ChenX X, Wang D. Experimental
investigationonchipmorphologiesinhigh-speeddrymillingof
titaniumalloyTi–6Al–4V.TheInternationalJournalofAdvanced
ManufacturingTechnology,2012,62(9–12):933–942
108.
Safari H, Sharif S, Izman S, Jafari H. Surface integrity
characterization in high-speed dry end milling of Ti–6Al–4V
titanium alloy. The International Journal of Advanced
ManufacturingTechnology,2015,78(1–4):651–657
109.
SharifS,SafariH, Izman S, Kurniawan D. Effectofhigh-speed
dry end milling on surface roughness and cutting forces of
Ti–6Al–4V ELI. Applied Mechanics and Materials, 2014, 493:
546–551
110.
Niu Q L, Chen M, Ming W W, An Q L. Evaluation of the
performance of coated carbide tools in face milling TC6 alloy
under dry condition. The International Journal of Advanced
ManufacturingTechnology,2013,64(5–8):623–631
111.
Liu J, Zhu S S, Deng X, Liu J Y, Wang Z P, Qu Z. Cutting
performance and wear behavior of AlTiN- and TiAlSiN-coated
carbidetoolsduringdrymillingofTi–6Al–4V.ActaMetallurgica
Sinica,2020,33(3):459–470
112.
Zhou J. Research on correlation technique and mechanism of
high-speedcuttingNi-basedsuperalloy GH4169.Dissertation for
the Doctoral Degree. Harbin: Harbin Institute of Technology,
2012(inChinese)
113.
HuangWM, Zhao J,WangSY. Necessity of multidimensional114.
evaluationof the high-speedball-endmilledsurface ofhardened
AISI D2 steel from a wear resistance perspective. The
International Journal of Advanced Manufacturing Technology,
2019,103(9–12):4085–4093
Zheng G M, Cheng X, Li L, Xu R F, Tian Y B. Experimental
investigationofcuttingforce,surfaceroughnessandtoolwearin
high-speeddrymillingofAISI4340steel.JournalofMechanical
ScienceandTechnology,2019,33(1):341–349
115.
Li Y, Zheng G M, Zhang X, Cheng X, Yang X H, Xu R F.
Cutting force, tool wear and surface roughness in high-speed
milling of high-strength steel with coated tools. Journal of
MechanicalScienceandTechnology,2019,33(11):5393–5398
116.
Zheng G M, Cheng X, Dong Y J, Liu H B, Yu Y Z. Surface
integrity evaluation of high-strength steel with a TiCN-NbC
compositecoated tool by dry milling. Measurement, 2020, 166:
108204
117.
Li H Z, Wang J. A study of cutting forces in high-speed dry
millingofInconel718.AdvancedMaterialsResearch,2012,500:
105–110
118.
Zhao B. Study on fabrication and properties of ceramic cutting
tools for high-speed machining nickel-based superalloys.
DissertationfortheDoctoralDegree.Jinan:ShandongUniversity,
2018(inChinese)
119.
KamdaniK, HasanS,Ashaary AFI A,LajisM A,RahimEA.
Studyontool wear andwearmechanismsof end millingnickel-
basedalloy.JurnalTribologi,2019,21:82–92
120.
MolaiekiyaF,StolfP,Paiva J M, Bose B, Goldsmith J, Gey C,
EnginS,Fox-Rabinovich G, Veldhuis S C. Influenceofprocess
parametersonthecuttingperformance of SiAlON ceramic tools
duringhigh-speeddryface millingofhardenedInconel718.The
International Journal of Advanced Manufacturing Technology,
2019,105(1–4):1083–1098
121.
ZhangYL,Sun JF, ShenX,ChenWY.Performanceof PCBN
tools in high-speed milling nickel-based superalloy. Materials
ResearchInnovations,2015,19(sup1):S1-118–S1-125
122.
Qiao Y, Fu X L, Yang X F. An experimental research of dry
milling powder metallurgy nickel-based superalloy with coated
carbidetools.AdvancedMaterialsResearch,2012,500:38–43
123.
Molaiekiya F, Aliakbari Khoei A, Aramesh M, Veldhuis S C.
Machined surface integrity of Inconel 718 in high-speed dry
millingusingSiAlONceramictools.TheInternationalJournalof
Advanced Manufacturing Technology, 2021, 112(7–8):
1941–1950
124.
Şirin Ş, Sarıkaya M, Yıldırım Ç V, Kıvak T. Machinability
performanceof nickelalloyX-750with SiAlONceramiccutting
toolunderdry,MQLand hBNmixednanofluid-MQL.Tribology
International,2021,153:106673
125.
ZhaJ,YuanZL,ZhangHC,LiYP,ChenYL.Nickel-based
alloy dry milling process induced material softening effect.
Materials,2020,13(17):3758
126.
LeeCM, Kim D H, Baek J T, Kim E J. Laser assisted milling
device: a review. International Journal of Precision Engineering
andManufacturing-GreenTechnology,2016,3(2):199–208
127.
Zeng H H. Research on the mechanism and surface integrity in
laser-assisted milling of AerMet100 steel. Dissertation for the
Doctoral Degree. Wuhan: Huazhong University of Science and
128.
62 Front.Mech.Eng.2023,18(2):28
Technology,2019(inChinese)
Singh R, Melkote S N. Hybrid laser-assisted mechanical
micromachining(LAMM)processforhard-to-machine materials.
JournalofLaserMicroNanoengineering,2007,2(2):156–161
129.
Singh R, Melkote S N. Experimental characterization of laser-
assisted mechanical micromachining (LAMM) process. In:
Proceedings of the ASME 2005 International Mechanical
Engineering Congress and Exposition. Orlando: ASME, 2005,
957–964
130.
JeonYH,PfefferkornF.Effectoflaserpreheatingtheworkpiece
onmicroendmillingofmetals.JournalofManufacturingScience
andEngineering,2008,130(1):011004
131.
Özel T, Pfefferkorn F. Pulsed laser assisted micromilling for
die/mold manufacturing. In: Proceedings of the ASME 2007
International Manufacturing Science and Engineering
Conference.Atlanta:ASME,2007,337–342
132.
Cao X F, Woo W S, Lee C M. A study on the laser-assisted
milling of 13-8 stainless steel for optimal machining. Optics &
LaserTechnology,2020,132:106473
133.
Bermingham M J, Kent D, Dargusch M S. Dargusch. A new
understandingofthewear processesduringlaserassistedmilling
17-4precipitationhardenedstainlesssteel.Wear,2015,328–329:
518–530
134.
Meikote S, Kumar M, Hashimoto F, Lahoti G. Laser assisted
micro-millingofhard-to-machine materials. CIRPAnnals,2009,
58(1):45–48
135.
KumarM,Chang CJ,MelkoteSN,RoshanJosephV.Modeling
andanalysisofforces in laser assisted micro milling. Journal of
ManufacturingScienceandEngineering,2013,135(4):041018
136.
KadivarM,AzrhoushangB,Zahedi A, Müller C. Laser-assisted
micro-milling of austenitic stainless steel X5CrNi18-10. Journal
ofManufacturingProcesses,2019,48:174–184
137.
Zeng H H, Yan R, Wang W, Zhang H, Yan J N, Peng F Y.
Analytical modeling of the heat-affected zone in laser-assisted
milling of AerMet100 steel. The International Journal of
Advanced Manufacturing Technology, 2020, 109(9–12):
2481–2490
138.
KimDH,LeeC M.Experimentalinvestigationonmachinability
of titanium alloy by laser-assisted end milling. Metals, 2021,
11(10):1552
139.
Sim M S, Lee C M. Determination of optimal laser power
according to the tool path inclination angle of a titanium alloy
workpieceinlaser-assistedmachining.TheInternationalJournal
of Advanced Manufacturing Technology, 2016, 83(9–12):
1717–1724
140.
Woo W S, Lee C M. A study on the optimum machining
conditionsand energyefficiencyofalaser-assisted filletmilling.
International Journal of Precision Engineering and
Manufacturing-GreenTechnology,2018,5(5):593–604
141.
WooWS,LeeCM.Laser-assistedmillingofturbinebladeusing
five-axis hybrid machine tool with laser module. International
Journal of Precision Engineering and Manufacturing-Green
Technology,2021,8(3):783–793
142.
Oh N S, Woo W S, Lee C M. A study on the machining
characteristics and energy efficiency of Ti–6Al–4V in laser-
assisted trochoidal milling. International Journal of Precision
143.
Engineering and Manufacturing-Green Technology, 2018, 5(1):
37–45
Hedberg G K, Shin Y C, Xu L. Laser-assisted milling of
Ti–6Al–4V with the consideration of surface integrity. The
International Journal of Advanced Manufacturing Technology,
2015,79(9–12):1645–1658
144.
Wiedenmann R, Zaeh M F. Laser-assisted milling—process
modeling and experimental validation. CIRP Journal of
ManufacturingScienceandTechnology,2015,8:70–77
145.
Hedberg G K, Shin Y C. Laser assisted milling of Ti–6Al–4V
ELI with the analysis of surface integrity and its economics.
Lasers in Manufacturing and Materials Processing, 2015, 2(3):
164–185
146.
Wiedenmann R, Liebl S, Zaeh M F. Influencing factors and
workpiece’s microstructure in laser-assisted milling of titanium.
PhysicsProcedia,2012,39:265–276
147.
Kong X J, Yang L J, Zhang H Z, Zhou K, Wang Y. Cutting
performance and coated tool wear mechanisms in laser-assisted
millingK24nickel-basedsuperalloy.TheInternationalJournalof
Advanced Manufacturing Technology, 2015, 77(9–12):
2151–2163
148.
Tian Y G, Wu B X, Anderson M, Shin Y C. Laser-assisted
milling of silicon nitride ceramics and Inconel 718. Journal of
ManufacturingScienceandEngineering,2008,130(3):031013
149.
KimT W,LeeCM.Determination ofthemachiningparameters
of nickel-based alloys by high-power diode laser. International
JournalofPrecisionEngineeringandManufacturing,2015,16(2):
309–314
150.
KimDH,LeeCM.Astudyonthelaser-assistedball-endmilling
of difficult-to-cut materials using a new back-and-forth
preheating method. The International Journal of Advanced
ManufacturingTechnology,2016,85(5–8):1825–1834
151.
KimEJ,LeeCM. A study on the machining characteristics of
curvedworkpieceusinglaser-assisted milling with different tool
pathsinInconel718.Metals,2018,8(11):968
152.
Wu X F, Zhu W B, Chen J F. Tool wear mechanisms in laser-
assisted milling of nickel-based superalloys. Journal of the
BrazilianSocietyofMechanicalSciencesandEngineering,2021,
43(3):151
153.
WuXF,ChenJF. Thetemperature processanalysis andcontrol
on laser-assisted milling of nickel-based superalloy. The
International Journal of Advanced Manufacturing Technology,
2018,98(1–4):223–235
154.
ShangZD, Liao Z R, SarasuaJA,BillinghamJ, Axinte D. On
modelling of laser assisted machining: forward and inverse
problems for heat placement control. International Journal of
MachineToolsandManufacture,2019,138:36–50
155.
XuDD,LiaoZR,AxinteD,SarasuaJA,M’SaoubiR,Wretland
A.Investigationofsurfaceintegrityinlaser-assistedmachiningof
nickelbasedsuperalloy.Materials&Design,2020,194:108851
156.
Brecher C, Emonts M, Rosen C J, Hermani J P. Laser-assisted
milling of advanced materials. Physics Procedia, 2011, 12:
599–606
157.
Zhang X Y, Lu Z H, Peng Z L, Zhang D Y. High quality and
efficientultrasonicvibrationcuttingoftitaniumalloys.Journalof
MechanicalEngineering,2021,57(5):133–147(inChinese)
158.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 63
XueF,ZhengK,LiaoWH,ShuJ,DongS.Investigationonfiber
fracture mechanism of C/SiC composites by rotary ultrasonic
milling.InternationalJournalofMechanicalSciences,2021,191:
106054
159.
ChenWQ,ZhengL,XieWK,YangK,HuoDH.Modellingand
experimental investigation on textured surface generation in
vibration-assistedmicro-milling.Journalof Materials Processing
Technology,2019,266:339–350
160.
ZhangXY,ZhangDY,Sui H,JiangXG.Influenceofdepthof
cut on elliptical ultrasonic vibration cutting mechanism. ACTA
AeronauticaetAstronauticaSinica,2017,38(4):420567
161.
LvDS,Xu J H, Ding W F, Fu Y C,YangCY,SuHH. Tool
wear in milling Ti40 burn-resistant titanium alloy using
pneumatic mist jet impinging cooling. Journal of Materials
ProcessingTechnology,2016,229:641–650
162.
HsuCY,Huang C K, Wu C Y. Milling of MAR-M247nickel-
basedsuperalloywithhightemperatureandultrasonicaiding.The
International Journal of Advanced Manufacturing Technology,
2007,34(9–10):857–866
163.
Fang B, Yuan Z H, Li D P, Gao L Y. Effect of ultrasonic
vibration on finished quality in ultrasonic vibration assisted
micromilling of Inconel 718. Chinese Journal of Aeronautics,
2021,34(6):209–219
164.
Yuan Z H, Fang B, Zhang Y B, Wang F. Effect of cutting
parameters on chips and burrs formation with traditional
micromillingandultrasonicvibrationassistedmicromilling.The
International Journal of Advanced Manufacturing Technology,
2022,119(3–4):2615–2628
165.
Suárez A, Veiga F, de Lacalle L N L, Polvorosa R, Lutze S,
Wretland A. Effects of ultrasonics-assisted face milling on
surface integrity and fatigue life of Ni-alloy 718. Journal of
Materials Engineering and Performance, 2016, 25(11):
5076–5086
166.
Suárez A, Veiga F, Polvorosa R, Artaza T, Holmberg J, de
LacalleLNL,WretlandA.Surfaceintegrityandfatigueofnon-
conventional machined alloy 718. Journal of Manufacturing
Processes,2019,48:44–50
167.
SuYS,LiL.Aninvestigationof cuttingperformanceandaction
mechanism in ultrasonic vibration-assisted milling of Ti6Al4V
usingaPCDtool.Micromachines,2021,12(11):1319
168.
SuY S,LiL.Surface integrityofultrasonic-assisted drymilling
of SLM Ti6Al4V using polycrystalline diamond tool. The
International Journal of Advanced Manufacturing Technology,
2022,119(9–10):5947–5956
169.
Gao H H, Ma B J, Zhu Y P, Yang H. Enhancement of
machinabilityand surface quality of Ti–6Al–4V by longitudinal
ultrasonic vibration-assisted milling under dry conditions.
Measurement,2022,187:110324
170.
XieWB,WangXK,LiuEB,WangJ,TangXB,LiGX,Zhang
J,YangLQ,ChaiYB,Zhao B. Research on cutting force and
surfaceintegrityofTC18titaniumalloybylongitudinalultrasonic
vibrationassistedmilling.TheInternationalJournalofAdvanced
ManufacturingTechnology,2022,119(7–8):4745–4755
171.
Zhang C Y, Zhao B, Zhao C Y. Effect of ultrasonic vibration-
assisted face milling on the surface microstructure and
tribologicalproperties.Journalof Vibroengineering,2022, 24(1):
1–17
172.
Xu L H, Na H B, Han G C. Machinablity improvement with173.
ultrasonic vibration-assisted micro-milling. Advances in
MechanicalEngineering,2018,10(12):1687814018812531
ZhuLD,NiCB,YangZC,LiuCF.Investigationsofmicro-
texturedsurfacegenerationmechanismandtribologicalproperties
in ultrasonic vibration-assisted milling of Ti–6Al–4V. Precision
Engineering,2019,57:229–243
174.
Wang X B, Jiao F, Zhao C Y, Zhao B. Modeling and
experimental analysis of cutting force in longitudinal‒torsional
ultrasonic-assisted milling of titanium. Advances in Mechanical
Engineering,2019,11(4):1687814019835107
175.
GaoGF,XiaZW, Su T T, Xiang D H, Zhao B. Cutting force
model of longitudinal‒torsional ultrasonic-assisted milling
Ti–6Al–4V based on tool flank wear. Journal of Materials
ProcessingTechnology,2021,291:117042
176.
Rinck P M, Gueray A, Kleinwort R, Zaeh M F. Experimental
investigationsonlongitudinal‒torsionalvibration-assistedmilling
of Ti–6Al–4V. The International Journal of Advanced
ManufacturingTechnology,2020,108(11–12):3607–3618
177.
RenWF,XuJK, Lin J Q, Yu Z J, Yu P, Lian Z X, Yu H D.
Research on homogenization and surface morphology of
Ti–6Al–4V alloy by longitudinal‒torsional coupled ultrasonic
vibrationball-endmilling.TheInternationalJournalofAdvanced
ManufacturingTechnology,2019,104(1–4):301–313
178.
Ahmed F, Ko T J, Kurniawan R, Kwack Y. Machinability
analysis of difficult-to-cut material during ultrasonic vibration-
assistedballendmilling.MaterialsandManufacturingProcesses,
2021,36(15):1734–1745
179.
TsaiMY,ChangCT,HoJK.Themachiningofhardmoldsteel
byultrasonicassistedendmilling.AppliedSciences,2016,6(11):
373
180.
MaurottoA, Wickramarachchi C T. Experimental investigations
on effects of frequency in ultrasonically-assisted end-milling of
AISI316L:afeasibilitystudy.Ultrasonics,2016,65:113–120
181.
RazfarM R,SarviP, ZarchiMMA.Experimental investigation
of the surface roughness in ultrasonic-assisted milling.
Proceedings of the Institution of Mechanical Engineers, Part B:
JournalofEngineeringManufacture,2011,225(9):1615–1620
182.
SarviHampa P, Razfar M R, Malaki M, Maleki A. The role of
dry aero-acoustical lubrication and material softening in
ultrasonicallyassistedmilling of difficult-to-cut AISI 304steels.
TransactionsoftheIndianInstituteofMetals,2015,68(1):43–49
183.
AbootorabiZarchiMM,RazfarMR,AbdullahA.Experimental
investigation of chip formation and surface topology in
ultrasonic-assisted milling of X20Cr13 stainless steel. In:
Proceedings of the ASME 2013 International Manufacturing
Science and Engineering Conference collocated with the 41st
North American Manufacturing Research Conference. Madison:
ASAM,2013,V001T01A042
184.
DingH,IbrahimR,ChengK,ChenSJ.Experimentalstudyon
machinability improvement of hardened tool steel using two
dimensional vibration-assisted micro-end-milling. International
Journal of Machine Tools and Manufacture, 2010, 50(12):
1115–1118
185.
AbootorabiZarchiMM, Razfar M R, Abdullah A. Influence of
ultrasonicvibrationsonside milling of AISI 420 stainless steel.
The International Journal of Advanced Manufacturing
Technology,2013,66(1–4):83–89
186.
Rao K V, Prasad V U S V, Ben B S. A comparative study on187.
64 Front.Mech.Eng.2023,18(2):28
cutting forces and power consumption in plain and ultrasonic
vibration helical milling of AISI 1020 steel. Proceedings of the
Institution of Mechanical Engineers, Part B: Journal of
EngineeringManufacture,2022,236(13):1726–1737
DingH, ChenSJ,ChengK. Twodimensionalvibration-assisted
micro-milling:kinematicssimulation,chipthicknesscomputation
and analysis. Advanced Materials Research, 2010, 97‒101:
2779–2784
188.
Qi B Y, He N, Li L, Zhao W, Bian R. Cryogenic minimum
quantity lubrication technology and its action mechanism.
MechanicalScience and TechnologyforAerospace Engineering,
2010,29(6):826–831,835(inChinese)
189.
PereiraO, Rodríguez A,BarreiroJ,Fernández-Abia AI,López-
de-Lacalle L N. Nozzle design for combined use of MQL and
cryogenic gas in machining. International Journal of Precision
Engineering and Manufacturing-Green Technology, 2017, 4(1):
87–95
190.
RossNS,GopinathC,NagarajanS,GuptaMK,ShanmugamR,
Kumar M S, Boy M, Korkmaz M E. Impact of hybrid cooling
approachon millingandsurfacemorphologicalcharacteristics of
Nimonic 80A alloy. Journal of Manufacturing Processes, 2022,
73:428–439
191.
PereiraO,CatalàP,RodríguezA,OstraT,VivancosJ,RiveroA,
López-de-Lacalle L N. The use of hybrid CO2 + MQL in
machiningoperations.ProcediaEngineering,2015,132:492–499
192.
NimelSworna Ross K, Manimaran G, Anwar S, Rahman M A,
KorkmazME, Gupta M K, Alfaify A, Mia M. Investigation of
surface modification and tool wear on milling Nimonic 80A
under hybrid lubrication. Tribology International, 2021, 155:
106762
193.
Sterle L, Mallipeddi D, Krajnik P, Pušavec F. The influence of
single-channelliquidCO2andMQL deliveryonsurfaceintegrity
inmachiningofInconel718.ProcediaCIRP,2020,87:164–169
194.
Shokrani A, Dhokia V, Newman S T. Hybrid cooling and
lubricating technology for CNC milling of Inconel 718 nickel
alloy.ProcediaManufacturing,2017,11:625–632
195.
Shokrani A, Newman S T. Hybrid cooling and lubricating
technologyforCNCmillingofInconel718nickelalloy.Procedia
CIRP,2018,77:215–218
196.
Şirin S, Yıldırım Ç V, Kıvak T, Sarıkaya M. Performance of
cryogenically treated carbide inserts under sustainable cryo-
lubrication assisted milling of Inconel X750 alloy. Sustainable
MaterialsandTechnologies,2021,29:e00314
197.
ZhangS, Li JF,Wang YW.Toollife andcuttingforces in end
milling Inconel 718 under dry and minimum quantity cooling
lubrication cutting conditions. Journal of Cleaner Production,
2012,32:81–87
198.
BagherzadehA,KuramE, Budak E. Experimental evaluation of
eco-friendly hybrid cooling methods in slot milling of titanium
alloy.JournalofCleanerProduction,2021,289:125817
199.
Hanenkamp N, Amon S, Gross D. Hybrid supply system for
conventional and CO2/MQL-based cryogenic cooling. Procedia
CIRP,2018,77:219–222
200.
Cai C Y, Liang X, An Q L, Tao Z R, Ming W W, Chen M.
Cooling/lubrication performance of dry and supercritical CO2-
based minimum quantity lubrication in peripheral milling
Ti–6Al–4V. International Journal of Precision Engineering and
201.
Manufacturing-GreenTechnology,2021,8(2):405–421
SuhaimiMA,YangGD,ParkKH,HisamMJ,SharifS,KimD
W. Effect of cryogenic machining for titanium alloy based on
indirect, internal and external spray system. Procedia
Manufacturing,2018,17:158–165
202.
ParkKH,YangGD,SuhaimiMA,LeeD Y,Kim TG,KimD
W, Lee S W. The effect of cryogenic cooling and minimum
quantitylubrication onendmillingoftitanium alloyTi–6Al–4V.
Journal of Mechanical Science and Technology, 2015, 29(12):
5121–5126
203.
ShokraniA,Al-SamarraiI,NewmanST.HybridcryogenicMQL
forimprovingtoollifeinmachiningofTi–6Al–4Vtitaniumalloy.
JournalofManufacturingProcesses,2019,43:229–243
204.
Su Y, He N, Li L. Effect of cryogenic minimum quantity
lubrication (CMQL) on cutting temperature and tool wear in
high-speed end milling of titanium alloys. Applied Mechanics
andMaterials,2010,34–35:1816–1821
205.
SongKH,LimDW, ParkJ Y,Ha SJ,YoonGS.Investigation
oninfluence ofhybrid nozzleofCryoMQLontool wear,cutting
force,andcuttingtemperature in milling of titanium alloys. The
International Journal of Advanced Manufacturing Technology,
2020,110(7–8):2093–2103
206.
Ha S J, Kim D W, Kim J H, Park J Y, Song K H. Economic
evaluation and machining performance in Ti–6Al–4V titanium
alloymillingbyintegratedCO2&MQLinjectionsystem.Journal
ofMechanicalScienceandTechnology,2021,35(9):4135–4142
207.
Yuan Y H, Wang C Y, Yang J Z, Zheng L J, Xiong W Q.
Performanceofsupercritical carbon dioxide(scCO2)mixedwith
oil-on-water (OoW) cooling in high-speed milling of 316L
stainlesssteel.ProcediaCIRP,2018,77:391–396
208.
WikaK K, Litwa P, Hitchens C. Impact of supercritical carbon
dioxidecoolingwith minimum quantitylubricationontool wear
andsurfaceintegrityin the milling of AISI 304L stainless steel.
Wear,2019,426–427:1691–1701
209.
ManimaranG,Nimel Sworna Ross K.SurfacebehaviorofAISI
H13 alloy steel machining under environmentally friendly
cryogenic MQL with PVD-coated tool. Journal of Testing and
Evaluation,2020,48(4):3269–3280
210.
ZhangHP,ZhangQY,RenY,ShayT,LiuGL.Simulationand
experiments on cutting forces and cutting temperature in high
speed milling of 300M steel under CMQL and dry conditions.
International Journal of Precision Engineering and
Manufacturing,2018,19(8):1245–1251
211.
Zhang H P, Ding C L, Shi R X, Liu R H. Optimization of
technologicalparametersandapplication conditionsof CMQLin
high-speed milling 300M steel. Integrated Ferroelectrics, 2021,
217(1):141–153
212.
ZhangS,LiJF,LvHG.Toolwearandformationmechanismof
white layer when hard milling H13 steel under different
cooling/lubrication conditions. Advances in Mechanical
Engineering,2014,6:949308
213.
Zhang C L, Zhang S, Yan X F, Zhang Q. Effects of internal
coolingchannelstructuresoncuttingforces and tool life in side
milling of H13 steel under cryogenic minimum quantity
lubrication condition. The International Journal of Advanced
ManufacturingTechnology,2016,83(5–8):975–984
214.
JinZHANGetal.Energyfield-assistedhigh-speeddrymillingofdifficult-to-machinematerials 65
