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Plasma arc cutting (PAC) is an unconventional process widely used in manufacturing of heavy plate products. This work reports on the research results of machining quality of the workpiece in the plasma arc cutting on the low carbon low alloy steel. An experimental investigation of the characteristics of machining accuracy and surface integrity was carried out for basic machining parameters (cutting speed, arc current, arc voltage, plasma gas pressure, stand-off distance and nozzle diameter). The kerf geometry was determined with three accuracy parameters (top kerf width, bottom kerf width and kerf taper angle). The parameters of deviation present due to plasma curvature were defined by drag and pitch of drag line. The surface roughness was determined with two main roughness parameters through scanning the surface topography (roughness average and maximum height of the profile). The surface properties were determined over microstructure in heat affected zone (HAZ). The results show an acceptable machining quality of the PAC, so that this process is an excellent choice for fast and efficient material removal. However, the plasma arc cutting is not suitable for the final machining because of the metallurgical variations in the HAZ.
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DOI: 10.24867/ATM-2020-1-001
* Corresponding author's.e-mail: Received: 1 June 2020; Accepted: 25 June 2020
An Experimental Analysis of Cutting Quality in Plasma Arc Machining
Marin Gostimirović*, Dragan Rodić, Milenko Sekulić, Andjelko Aleksić
University of Novi Sad, Faculty of Technical Sciences, Department of Production Engineering, Trg D. Obradovica 6, 21000 Novi Sad, Serbia
Plasma arc cutting (PAC) is an unconventional process widely used in manufacturing of heavy
plate products. This work reports on the research results of machining quality of the workpiece in
the plasma arc cutting on the low carbon low alloy steel. An experimental investigation of the
characteristics of machining accuracy and surface integrity was carried out for basic machining
parameters (cutting speed, arc current, arc voltage, plasma gas pressure, stand-off distance and
nozzle diameter). The kerf geometry was determined with three accuracy parameters (top kerf
width, bottom kerf width and kerf taper angle). The parameters of deviation present due to plasma
curvature were defined by drag and pitch of drag line. The surface roughness was determined with
two main roughness parameters through scanning the surface topography (roughness average and
maximum height of the profile). The surface properties were determined over microstructure in
heat affected zone (HAZ). The results show an acceptable machining quality of the PAC, so that
this process is an excellent choice for fast and efficient material removal. However, the plasma arc
cutting is not suitable for the final machining because of the metallurgical variations in the HAZ.
Key words: plasma arc cutting; machining accuracy; surface topography; heat affected zone
Modern industrial production is characterized by the need
to satisfy consumers in terms of range, quality, prices and
delivery times of products or services. This means that
just attractive products and services can survive on the
global market, which provides consumers with more than
expected. In this context, the industrial systems of the
future must be able to adapt to the demands of the market.
In the manufacturing industries, cutting process is one of
the first stages in production of a particular component or
product [1-3]. The cutting process entails the use of
different techniques. The choice of technique depends on
the type of material to be cut, as well as size, shape and
the required level of precision of the worked part. There
are two basic cutting methods in use.
Examples of classic cutting techniques are the use of
sawing and flame cutting [4]. Sawing is a mechanical
cutting process of workpiece with circular and band
sawing machines. This method is used for smaller
sections and more precise cutting operation, but it is very
slow production method. On the other hand, Flame
Cutting (FC) is oxy-fuel gas cutting thermal process
which is used during the hard and rough work. Depending
on the application, this method is often the preferred
process because it’s much faster than mechanical
machining. The flame cutting also is very portable and
has low equipment costs. However, due to the flame heat,
the edges being cut can often form a highly defective
surface layer [5], known as a heat affected zone (HAZ).
In recent times, modern manufacturing largely conducts
cutting operations which are supported by unconventional
technologies. These processes are defined as a group of
cutting methods that remove the material by various non-
traditional techniques, not using direct contact between
the tool and the workpiece. Examples of unconventional
cutting methods are the use of water jet cutting, laser
beam cutting and plasma arc cutting. The main
advantages of unconventional technologies material
cutting processes are quality cuts and cost effective with
the ability to cope with different types materials and
geometrical configurations.
Water Jet Cutting (WJC) is a mechanical process, with or
without abrasive particles [6]. This process uses a high-
power kinetic energy of the water flow to the cutting of
the workpiece material. The process produces a precise
cut on all types of materials (metal, stone, glass, plastic,
composites, ceramic etc.), but is especially suitable for the
cutting of very hard and difficult-to-machine materials
with complex contours. In the WJC process there is no
change in mechanical and morphological properties of the
workpiece material. Therefore, this process is especially
appropriate for heat sensitive materials, because there is
no heat affected zone. A significant advantage of water jet
cutting is environmental aspect, since it does not create
hazardous waste in the form of dust or gas. Basic
disadvantage of water jet cutting is long processing time.
Laser Beam Cutting (LBC) is a thermal process involving
photon energy as a heat source [7]. The high light energy
is focusing on the surface of the workpiece, which is then
heating, melting and vaporizing. This process removes
almost all metallic or non-metallic material. The LBC
process is best suited for sheet cutting, complex profile
cutting, brittle materials machining and drilling and
perforating very small holes. The laser cutting doesn't
take long and has a high level of efficiency and accuracy.
In case of laser beam cutting, the heat affected zone and
deformation in the part are very small. Disadvantages of
the LBC are high energy consumption and maintenance
cost, the gases released during the process can be toxic
and reflective metals can't be cut using this technology.
Plasma Arc Cutting (PAC) is a thermal non-traditional
material removal process [8-10]. The PAC process uses a
focused jet of high velocity and temperature ionized gas
to melt, vaporize and remove material from the
workpiece. The plasma arc cutting is the most common
materials cutting technique for larger and more
demanding plates, profiles and pipes. Advantages of
plasma arc cutting are that any metal can be cut, process
offers fast cutting speeds, slag-free cuts and operation
with more burners. Disadvantages of the PAC process are
low quality cut and a slightly wider kerf, relatively high
power and gas consumption as well as generation of
smoke and noise during process.
The basic cutting techniques and their machining
characteristics are illustrated in Fig. 1.
In this work is presented investigation of the plasma arc
cutting from the standpoint machining characteristics of
the process. It is known that plasma arc cutting offers
very high productivity but low cut quality. In order to
enhance the cutting quality of PAC, since its
commercialization, researchers are constantly examining
ways to improve this process.
Pawar and Inamdar [11] systematized the parameters
affecting quality of plasma arc cutting from the standpoint
of dimensional accuracy and surface quality without any
further operations. The paper highlights recent results
obtained by using plasma cutting process based on
experiments and various methods that have been used for
optimisation of PAC process.
Fig. 1 The review of the basic cutting techniques
Salonitis and Vatousianos [12] conducted an experimental
research of the plasma arc cutting for assessing the quality
of the cut. The cutting quality has been monitored by
measuring the kerf width, kerf taper angle, surface
roughness and heat affected zone. The quality
characteristics were assessed by varying the processing
parameters, such as the cutting speed, workpiece
thickness, plasma power and gas pressure.
Gariboldi and Previtali [13] conducted experiment to
improve the cutting quality performed by high tolerance
plasma arc cutting. The experiment was investigated
under different process conditions like using several
cutting speed with the adoption of oxygen or nitrogen as
working and shielding gases. They found that if oxygen
was used as the plasma gas, a higher cutting speed and
better quality of kerf geometry parameters were achieved
due to the oxidation reaction.
Bini, Colosimo, Kutlu and Monno [14] revealed that
cutting speed and arc voltage affect the kerf geometry
formation mechanism. They also concluded that waviness
can be reduced by reducing the cutting speed.
Radovanovic and Madic [15] modeled plasma arc cutting
process using artificial neural networking Using this
model the cutting speed and arc current were selected
which correspond to the cut with minimal surface
Since it is still the main task of the plasma cutting to
achieve the high productivity with as good quality as
possible, in this paper special attention is directed on the
effect of machining conditions on the accuracy and
change of surface integrity. If the machining conditions
are poorly chosen, it can substantially diminish
exploitation features of the plasma arc cutting. Therefore,
in order to enable machining with a high performance, it
is necessary to investigate the effect of the PAC process
on the cut quality of the workpiece. Specifically, in this
paper specifics of the plasma arc cutting were
experimentally investigated and their influence on
material removal rate, surface topography, heat affected
zone and kerf geometry accuracy.
Plasma Arc Machining (PAM) is one of the relatively
recent nonconventional manufacturing processes. This
technique was patented by R. Gate in 1957. Initially it
was used for cutting difficult-to-machine materials and
later its application was extended to a large number of
other production operations that require high
concentrations of thermal energy: welding, sintering,
coating, depositing, heat treatment, etc [16, 17].
In physics, the term plasma describes a gas state of matter
which has been heated to a sufficiently high temperature
to become partially or completely ionized gas. Thereby,
ionized gas represents a mixture of positive and negative
ions, as well as neutral free electrons, atoms, molecules,
photons and radicals. Because of the high density of ions
and electrons, plasma is highly electrically conductive.
Temperatures in the plasma range from 10,000 to
30,000 °C.
2.1 Working principle of PAM process
The plasma arc machining is based on the high thermal
and kinetic energy of ionized gas, directed to the surface
of the workpiece. These energies lead to the development
of a very high temperature in the region of plasma impact
on the material. The temperature at the machining zone
reaches the value of 4,000 to 10,000 °C. Such a high
temperature causes intense melting and vaporizing
(combustion) of any type of workpiece material.
Afterwards, the molten material together with the eroded
particles is removed by the explosive activity of the
internal dynamic forces of the plasma channel, as well as
by a fast jet of the plasma source. Thereby, an extremely
high concentration of thermal energy leads to a number of
physical-chemical processes and phenomena in the wider
area of the workpiece surface.
How the hot gas intensively comes out of a nozzle, there is
a chance of overheating of plasma torch. A water flow is
used to surround the plasma torch to avoid its overheating.
For the process of plasma arc machining, the mechanism of
the ionization of working gas is mainly realized by heating
the gas to a very high temperature, as a result of which
ionized gas is formed. This type of ionization involves the
passage under pressure of a mixture of gases (working and
shielding gas) through the space between the anode and the
cathode, where, with power supply (DC) a strong electric
arc is maintained. In the result of this is formed an ionized
gas flowing from the nozzle in the form of a high heat
plasma. The working gases used to create plasma are argon,
helium, nitrogen, carbon dioxide or air, as well as a mixture
of these gases. Hydrogen or oxygen is used as a shielding
gas in the PAM.
The electric arc can be performed directly in a plasma
torch between the electrodes (anode and cathode) or
between the workpiece (anode) and the central electrode
(cathode). The first variant can be used for processing all
types of materials, but the intensity of the plasma is
slightly lower. In the second variant large thermal energy
is generated, which is important when machining
difficult-to-machine materials of large thickness, but it is
possible to process only electrically conductive materials.
Shown in Fig. 2 is principle of PAM process, input
parameters (workpiece, machine, plasma torch and
plasma gas) and output performance (productivity,
accuracy and surface integrity).
Fig. 2 PAM process with machining characteristics
2.2 Quality of plasma cutting
Similar to other machining processes, productivity,
accuracy and quality are the most important performance
of plasma arc cutting. In that context, it is very important
to have a good knowledge of the characteristics and
properties of the PAC process to get the best performance.
Basic characteristics of the PAC are: velocity of plasma
jet; arc current, voltage and power; gas pressure and flow
rate; and nozzle diameter and stand-off distance.
The productivity of PAC process is expressed by the
material removal rate and in this process it is defined as
the machining speed. The accuracy is defined by the
tolerances applied to the dimensions and form of the
workpiece. The quality is expressed through the surface
topography and surface properties. Thereby, the
effectiveness of the machining process determines the
productivity and the product functionality defines the
accuracy and quality.
The quality of a part is particularly significant
characteristic of the plasma arc cutting. It is generally
defined by the following properties: machining accuracy
and surface integrity. Fig. 3 is showing the PAC process
mechanism with the quality indicators.
Machining accuracy is determined by the degree of
concordance of the actual dimension and shape of the part
with the nominal geometry. The plasma arc cutting
accuracy is typically defined by kerf geometry (ISO
9013). The kerf geometry is normally expressed by top
kerf width Kt, bottom kerf width Kb and kerf taper angle
[7, 14].
Surface integrity is described by the properties of the
workpiece material, above and below the surface, after
being modified by machining or other surface generation
process. The surface integrity refers to the external
topography aspects of the surface (surface morphology
and texture surface) and the internal physical and
mechanical metallurgy aspects of the subsurface (surface
layer modification).
Fig. 3 Quality indicators of PAC process
The surface topography in plasma arc cutting is defined
by micro-geometry deviation, surface roughness and
waviness (ISO 4287). The micro-geometry deviation is
present due to plasma curvature, and defined by drag n
and pitch of drag line f. It is specificity of PAM
mechanism, because during interaction with the material
the plasma jet loses its kinetic energy and changes its
shape. Full and straight cuts are transformed into curved,
deformed or unfinished [6]. The surface roughness is
represented by different profile amplitude parameters.
Roughness average Ra, which is the arithmetic average of
the absolute values of the profile heights over the
evaluation length ln, is the primary parameter of the
surface roughness. Waviness is defined by surface
irregularities on a larger scale than the roughness. It is
determined by the waviness spacing Sw and waviness
height Wt.
The surface metallurgy in plasma arc cutting includes the
properties of the material layer, respectively study of the
nature of the microstructure, microhardness, residual
stress, crack, burn, etc [5, 18]. The metallurgical
characteristics of the material are caused by the thermal
energy, and this is called the heat affected zone (HAZ).
Experimental investigations were carried out on the 3-axis
plasma arc cutting machine type CNC Omnicut 4000 by a
manufacturer MGM from Czech Republic, Fig. 4/a. Main
technical data of the PAC machine are as follows: table
area 12000x3000 mm, working current 0 to 130 A, arc
voltage 50 to 150 V, total power consumption 1.5 kVA
max, cutting speed 20-30000 mm/min, max thickness of
the cut sheet 200 mm, positioning accuracy 0.3 mm. This
configuration provides excellent dynamic and static
properties, high stiffness of the machine carriage, high
cutting accuracy and high productivity.
Fig. 4 PAC machine (a) and RSt 37-2 steel plate after cutting (b)
In the paper, first the basic experimental tests were carried
out to assess the quality indicators for a reference level of
process parameters in plasma arc cutting. The reference
level of parameters selected as representatives are: arc
current I=80 A, arc voltage U=127 V, plasma gas pressure
p=0.5 MPa, nozzle diameter d=1.75 mm, stand-off
distance z=2 mm and impact angle
=90. The range of
the cutting speed was v=700 to 2500 mm/min. Water
cooled nozzle and air plasma / air shield combination was
used for plasma cutting operation.
Then, in the extended experiment some reference
parameters were further varied. The arc current was
chosen from the interval 50 to 100 A and the arc voltage
in the interval 121 to 133 V. The plasma gas pressure was
0.5 and 0.7 MPa, the nozzle diameter was 1.5 and 1.75
mm and the stand-off distance was 1 to 3 mm. While a
certain value was varied, the other values were held
constant at the reference level.
The basic work material used in the experiment was DIN
RSt 37-2 carbon low alloy steel (0.17% C, 1.4 % Mn,
0.05% S, and 0.05% P), tensile strength Rm=420 MPa.
RSt 37-2 is steel which contains ferrite and pearlite
microstructure, where the ferrite is much higher with
respect to the pearlite, Fig. 5. Thickness of the workpiece
was 10 mm. The cut workpiece is shown in Fig. 4/b.
The samples were cut by the PAC under certain
machining conditions. First, the parameters of the kerf
geometry (top kerf width Kt, bottom kerf width Kb and
kerf taper angle
) were measured. Then, the parameters
of the plasma jet deviation (drag n and pitch of drag line f)
were measured. The measurements were conducted using
digital caliper with accuracy to 0.001 mm, as well as by
reading the values at the photo samples recorded using
USB digital microscope with 200x magnification.
Fig. 5 Microstructure of workpiece material at magnification of 200x
Surface roughness of the workpiece in the PAC process
was estimated by measuring a set of surface parameters.
The measured parameters were roughness average Ra
(arithmetic mean deviation of the profile) and maximum
height of the profile Rt (vertical distance between the
highest and lowest points of the profile). These parameters
are the most widely used in surface roughness
measurements. The surface roughness measurements were
performed using the profilometer Mitutoyo SJ-301, Japan.
Surface properties of the specimens were assessed by
investigation of surface layer modification of the
workpiece after the plasma arc cutting. In this testing a
metallographic examination of the microstructure was
implemented, i.e. the heat affected zone (HAZ) was
evaluated. The surface metallographic identification of
the workpiece was performed with an Olympus
BHM/BH2 microscope with 1000× magnification from
Japan. For metallographic preparation was used the
equipment of the Struers, Denmark.
4. R
4.1 Basic experiment
The basic experimental investigation considered the quality
of the workpiece in the plasma arc cutting. The speed
cutting was varied for the set reference parameters.
Thereby, the machining accuracy and surface integrity
parameters of the PAC process were measured. The test on
every sample indicated a very small measuring error, which
indicates a good repeatability of the measurement results.
Fig. 6 shows the results of experimental investigation of
geometry kerf for the selected plasma cutting conditions,
specifically top kerf width Kt, bottom kerf width Kb and
kerf taper angle of both sides
L. The chosen images,
presented in the same view, show the prepared samples for
low, medium and high cutting speed. The results show that
the increase of cutting speed leads to a higher kerf taper
angle and smaller kerf width. Besides, it is evident that the
increase of cutting speed is limited by the incomplete
cutting of the material and/or the appearance of dross.
Fig. 6 Influence of the cutting speed on kerf geometry parameters
On the other hand, as shown in Fig. 7 is obtained
dependence of factors of the plasma jet deviation (drag n
and pitch of drag line f) and surface roughness parameters
(roughness average Ra and maximum height of the profile
Rt) on cutting speed in PAC process, for a reference level
of parameters. In the same figure, are shown the
experiment samples for three characteristic cutting
speeds. It can be seen that the values of the micro-
geometry deviation and surface roughness are higher
when the cutting speed increases. It is evident that the
increase of the cutting speed leads to very poor surface
topography and roughness.
Fig. 7 Influence of the cutting speed on plasma jet deviation
In this study, metallographic investigations of the surface
properties of the material show that there are heat affected
zone (HAZ) at all machining conditions of PAC.
However, the metallographic examinations showed the
uniform size of the HAZ during various cutting speeds.
Fig. 8 shows a photomicrograph of the surface layer of
the investigated RSt 37-2 carbon steel after the plasma arc
cutting, i.e. its microstructure transformation compared to
the bulk material. The analysis of the microstructure of
material revealed three characteristic layers which are: the
resolidified layer, the modified surface layer and the
interlayer. The resolidified layer is a thin zone of the
deposition of residual molten material on the surface. The
modified layer consists of the ferrite-pearlite
transformation to martensite. The interlayer shows
gradual transition of modified layer into bulk material. It
is noted that observed thickness of the total heat affected
zone is in the range of about 1mm.
Fig. 8 Photomicrograph of surface layer of carbon steel cut by PAC at
magnification of 100x
4.2 Extended experiment
In the extended experiment some additional tests were
conducted in order to provide a more complete view of
plasma arc cutting quality. The main reference parameters
were further varied, namely, arc current, arc voltage,
plasma gas pressure, stand-off distance and nozzle
diameter. Thereby, only the macro geometrical
parameters of quality were measured.
The concept of deviation of the measured value from the
nominal one is used for an evaluation of the accuracy of
the kerf geometry. Delamination factor DF is the main
geometric characteristic of the damages of the plasma arc
cutting process. The delamination factor was defined as
the ratio of top kerf width Kt to bottom kerf width Kb
during the cutting of the workpiece material (DF=Kt/Kb).
Fig. 9 shows the influence of the cutting speed on
delamination factor for two arc currents in PAC process.
The diagram shows that the increase of cutting speed
results in increased delamination factor, especially at high
speeds. Thereby, a larger arc current increases the
delamination factor too.
Fig. 9 Dependence of the delamination factor on cutting speed
Shown in Figure 10 is obtained dependence of the
delamination factor on arc voltage during two plasma gas
pressure. The diagram shows that there exists an optimal
arc voltage which results in minimum delamination
factor. It is also seen that the larger plasma gas pressure
decreases the delamination factor.
Fig. 10 Influence of the arc voltage on delamination factor
Fig. 11 shows the influence of the arc current on
delamination factor for two nozzle diameters. The
diagram shows that the increase of arc current results in
significantly reduced delamination factor, and this for
both nozzle diameters. Thereby, a smaller nozzle diameter
makes somewhat lower delamination factor.
Fig. 11 Dependence of the delamination factor on arc current
Shown in Figure 12 is obtained dependence of the
delamination factor on nozzle stand-off distance during
two cutting speeds. The diagram shows that there exists a
slight increase of the delamination factor with increase of
cutting speed. Of course, a lower cutting speed is more
4.3 Discussion
Analysis of previous experimental results revealed that
most impact on the plasma arc cutting quality has the
cutting speed. Increase of the cutting speed increases the
macro and micro geometrical parameters of quality
(parameters of the kerf geometry, parameters of the
plasma jet deviation and surface roughness parameters).
Also, the arc current has a significant effect on the
machining quality. On the other hand, the arc voltage,
plasma gas pressure, stand-off distance and nozzle
diameter have somewhat less impact on the quality.
Besides, the mentioned machining parameters have
mostly the opposite effect on the quality, which
significantly complicates control design of the plasma arc
cutting process.
Fig. 12 Influence of the stand-off distance on delamination factor
At the same time, it is important to note that there is heat
affected zone at any machining conditions of the plasma
arc cutting. The thickness of the HAZ is related to
machining conditions, but above all with the material
thickness and its thermal conductivity. Thereby, influence
of PAC machining parameters on the HAZ is almost
As previously mentioned, it is evident that the machining
quality in PAC process depends on a number of
machining parameters. Figure 13 shows the level of
variation of the most important parameters of the quality,
i.e. degree of their effect on the PAC process. The level of
variation of the plasma arc cutting parameter was
determined by using advanced statistical analysis.
Fig. 13 The level of variation of the machining parameters on the
quality of PAC process
Plasma arc cutting is a non-traditional highly productive
process widely used in plate processing made from
difficult-to-machine materials. Compared to other cutting
techniques, the PAC process achieves the fastest cutting
speed with satisfactory accuracy and surface finish.
However, the plasma arc cutting leads to intense
concentration of heat in the cutting area, which is why
heat affected zone is always present.
On the ground of experimentally measured values it can
be concluded that increasing of the cutting speed and arc
current leads to a significant deterioration of machining
quality of the PAC process. It is primarily the cut
geometry deviation, presence of the jet lag effect present
due to plasma curvature, increase of the surface roughness
and the occurrence of dross. However, the other
machining parameters have different impact on the
cutting quality, which additionally complicates setting
and guidance of the plasma arc cutting process.
The investigations show that there is a major heat affected
zone at defined machining conditions in the PAC process.
The heat affected zone is related to above all with the type
and thickness of material. The value of the HAZ is greater
for thicker non-conductive material that is cut at lower
cutting speed and larger arc current.
This paper presents a part of researching at the Project
financed by Ministry of Education, Science and
Technological Development of the Republic of Serbia.
[1] Kovac, P., Gostimirovic, M., Sekulic, M., Savkovic,
B. (2009). A review of research related to advancing
manufacturing technology. Journal of Production
Engineering, 12(1), 9-16.
[2] Sekulic, M., Kovac, P., Gostimirovic, M., Kramar, D.
(2013). Optimization of high-pressure jet assisted
turning process by Taguchi method. Advances in
Production Engineering & Management, 8(1), 5-12.,
DOI: 10.14743/apem2013.1.148.
[3] Patel, P., Nakum, B., Abhishek, K., Kumar, R.
(2018). Machining performance optimization during
plasma arc cutting of AISI D2 steel: application of
FIS, nonlinear regression and JAYA optimization
algorithm. Journal of the Brazilian Society of
Mechanical Sciences and Engineering, 40, 240, DOI:
[4] Zhou, B., Liu, Y. J., Tan, S. K. (2013). Efficient
simulation of oxygen cutting using a composite heat
source model. International Journal of Heat and Mass
Transfer 57(1), 304–311.
[5] Gostimirovic, M., Kovac, P., Sekulic, M. (2018). An
inverse optimal control problem in the electrical
discharge machining. Sadhana, 43(5), 70, DOI:
[6] Gostimirovic, M., Pucovsky, V., Sekulic, M., Rodic, D.,
Pejic, V. (2019). Evolutionary optimization of jet lag in
the abrasive water jet machining. International Journal
of Advanced Manufacturing Technology, 101(9–12),
3131-3141, DOI: 10.1007/s00170-018-3181-5.
[7] Madic, M., Radovanovic, M., Gostimirovic, M.
(2015). ANN modeling of kerf taper angle in CO2
laser cutting and optimization of cutting parameters
using Monte Carlo method. International Journal of
Industrial Engineering Computations, 6(1), 33-42,
DOI: 10.5267/j.ijiec.2014.9.003
[8] Singh, G., Akhai, S. (2015). Experimental study and
optimisation of MRR in CNC plasma arc cutting.
International Journal of Engineering Research and
Applications 5(6), 96–99.
[9] Pawar, S. S., Inamdar, K. H. (2017). Experimental
Analysis of Plasma Arc Cutting Process for SS 316 l
Plates. IOSR Journal of Mechanical and Civil
Engineering, 75-80.
[10] Naik, D. K., Maity, K. (2020). Experimental analysis
of the effect of gas flow rate and nature on plasma arc
cutting of hardox-400. Weld World 64, 345–352,
DOI: 10.1007/s40194-019-00836-8.
[11] Pawar, S. S., Inamdar, K. H. (2016). Factors affecting
quality of plasma arc cutting process: A review.
International Journal of Advanced Technology in
Engineering and Sciences, 4(12), 177–183.
[12] Salonitis, K., Vatousianos, S. (2012). Experimental
investigation of the plasma arc cutting process.
Procedia CIRP, 3(1), 287–292, DOI:
[13] Gariboldi, E., Previtali, B. (2005). High tolerance
plasma arc cutting of commercially pure titanium.
Journal of Materials Processing Technology, 160(1),
[14] Bini, R., Colosimo, B. M., Kutlu, A. E., Monno, M.
(2008). Experimental study of the features of the kerf
generated by a 200A high tolerance plasma arc
cutting system, Journal of Materials Processing
Technology, 196(1-3), 345-355.
[15] Radovanovic, M., Madic, M. (2011). Modeling the
plasma arc cutting process using ANN,
Nonconventional technologies review, 4, 43–48.
[16] Hema, P., Ganesan, R. (2020). Experimental
investigations on SS 304 alloy using plasma arc
machining. SN Applied Sciences 2, 624, DOI:
[17] Maity, K. P., Bagal, D. K. (2015). Effect of process
parameters on cut quality of stainless steel of plasma
arc cutting using hybrid approach. International
Journal of Advanced Manufacturing Technology, 78(1–
4), 161–175, DOI: 10.1007/s00170-014-6552-6.
[18] Gostimirovic, M., Sekulic, M., Kopac, J., Kovac, P.
(2011). Optimal control of workpiece thermal state in
creep-feed grinding using inverse heat conduction
analysis, Strojniški vestnik - Journal of Mechanical
Engineering, 57(10), 730-738, DOI: 10.5545/sv-
... A key feature of the process of material removal is his ability to produce vital components of complex geometry, exceptional surface finish, high dimensional accuracy, and usually from difficult-to-machine materials. It covers a wide range of material removal operations such as turning, drilling, milling, grinding and other processes [1][2][3][4]. ...
... Since the main problem of material removal process is to achieve a high-quality finish with the highest possible productivity level, special attention is focused on the optimization of the processing conditions. There is a series of works which deal with optimization of machining strategy using various techniques [3,4,27,[31][32][33]. However, although heat and temperature are parameters which directly affect the process performance, their use for the optimization is quite complex in nature. ...
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This paper reports on the results of research on thermal aspects in the process of material removal by inverse heat transfer problem. The research focuses on the identification, modeling and optimization of machining process based on the measured temperature at a particular point of the workpiece. The inverse approach determines the overall temperature distribution of the workpiece and the unknown heat flux at the tool/workpiece interface in machining. By introducing and minimizing an objective function based on the heat flux function, relationship of the heating power and duration on the surface layer of the workpiece is optimized. In this way, the most favourable machining conditions are determined in order to achieve high productivity and quality levels. The inverse optimization problem is solved by using the analytical, numerical and regularization methods. Formulation, application and analysis of the inverse optimization problem of heat transfer are shown on the example of creep-feed grinding. The creep-feed grinding process is a widely used abrasive machining process that is characterized by high thermal load of the workpiece. The results of the inverse optimization problem were verified by a series of experiments under different machining conditions. Problem inverzne optimizacije prenosa toplote kod obradnog procesa-pregled.
... While this hardness value creates a negative situation for machining processes on the surfaces, the machining process of a part prepared by laser cutting is carried out relatively easily. Drilling/editing a plasma-cut hole later with a drill is particularly demanding [14]. Considering the hardness distribution, high hardness in plasma arc cutting is seen in the region of 750-950 μm. ...
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The laser beam, plasma arc, and oxygen cutting methods are widely used in metal cutting processes. These methods are quite different from each other in terms of initial setup cost and cutting success. A powered laser beam is used in laser beam cutting, plasma is used in plasma arc cutting, flammable gas - oxygen mixture is used in the oxygen cutting method. In this study, the cutting success of these methods was investigated on tensile specimens. Microstructure, hardness (HV 0.1), surface roughness, and strengths were investigated after the cutting process. The tensile test implemented with tensile samples cut from the same material by these three methods, it was observed that the strength values of the samples changed by about 8% in tensile strength depending on the cutting process. The hardness of the cut surfaces in plasma arc cutting increased from 150 HV to 230 HV for S235JR material. For this reason, it is difficult to perform machining operations after plasma cutting. The hardness value reached after laser beam cutting is 185 HV. Plasma arc cutting is more cost-effective than laser beam cutting. 1-3° vertical inclination (conicity) occurs on the cut surface in plasma arc cutting, while this inclination almost does not occur in laser cutting. In plasma cutting benches, cutting is done with oxygen, and in cutting with oxygen, the taper is seen in a small amount.
In this study, hole tolerances were investigated by creating holes on 6061-T6 Aluminium and 100Cr6 Bearing Steel in the CNC plasma machine. Holes with diameters of 4, 6.5 and 9 mm were cut circularly in the plates of 3, 6 and 10 mm thickness. The experiments were carried out at three different cutting speeds. Delamination factor, circularity error and taper values were measured. The amounts of burrs formed as a result of circular cut were investigated. For the same plate thickness and hole diameter, as the cutting speed increased, the delamination factor did not change much, but the circularity error and taper values increased. It was observed that the difference between the inlet and outlet diameters decreased as the plate thickness increased. This reduced the circularity error and taper. As the cutting speed increased, the delamination factor, circularity error and taper values increased. As a result of the regression and variance analysis, it was seen that the most important effect on the hole quality was the cutting speed. It has also been observed that the hole quality of 100Cr6 Bearing Steel was better than 6061-T6 Aluminium alloy.
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Plasma arc machining is a well-recognized unconventional machining process widely used to machine intricate part profiles for alloys which are difficult to machine. The surface roughness, material removal rate (MRR), and kerf ratio are predominant factors which influence the performance and quality of plasma cut surfaces. The present research focusses on the effect of plasma arc cutting parameters such as arc voltage, cutting speed, standoff distance, and plasma offset on the cut quality characteristics of SS 304 alloy machined using two different types of nozzles (130 A and 200 A). The experiments were conducted according to a mixed Taguchi design of L18 orthogonal array, and grey relational analysis technique is used for optimization of the above-said cutting conditions. The experimentation on SS 304 alloy is carried out using two different nozzles and identified the best suited nozzle to cut SS 304 alloy of thickness 6 mm which produces better surface roughness and MRR characteristics. Scanning electron microscopy analysis is carried out to inspect the surface morphologies at various cutting conditions.
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The research and development in the precise and accurate machining technology of hard metals (Ferrous, non-ferrous and glass, etc) are gaining much importance in the industry for the last many years. Due to the tremendous competition and cost factor, non-conventional machining technology is becoming the first choice of engineers and technicians. In this era of advanced technological processes, the CNC plasma arc machining is gaining tremendous ground in the industry. It is much more capable of producing the best finished, high accurate machining of a very complicated non-symmetrical profile in no time. The main objective and targets of this practical experiment are based to achieve the best possible setting and parameters of operation on a CNC plasma arc machine to achieving speedy work i.e. Maximum material removal rate.
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One of the main characteristics of abrasive water jet machining (AWJM) is jet lag effect. In this case, by controlling basic machining parameters (water pressure, cutting speed, and abrasive mass flow rate), evolutionary algorithm is used for modeling and optimization of trajectory curvature in AWJM process. Based on experimental investigation, genetic programming was used as the main exploration tool for generating function of the jet lag depending on the machining conditions and as a potential way in the AWJM simulation. Judging by the output, the genetic programming yielded impressive results and has proven to be very practical for modeling of the abrasive water jet trajectory curvature. In the sequel, the optimization of AWJM process is used approximate optimal control problem which leads to the best solution for the jet lag considering the machining parameters. With this action, we can say that different access has been made to find precise dependence of AWJM process parameters with the trajectory curvature to obtain high productivity and quality results.
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Electrical discharge machining (EDM) is a thermal material removal process by means of electrical discharge. Because of the stochastic nature of the EDM process, electro-thermal energy conversion in the discharge zone is still not well understood. In this paper, an inverse optimal control problem was used for analysis and optimization of energy conversion processes in order to improve machining efficiency. Modeling and identification of a thermal process were conducted using the inverse heat transfer problem based on the known temperature within a workpiece. In addition to the temperature field, this approach allows the determination of unknown heat flux density distribution on the workpiece surface. By using the heat flux, the inverse optimal control problem based on minimizing a Tikhonov functional allows to obtain the optimal heat source parameters (discharge power and discharge duration) on the discharge energy. In this context, the concept of inverse problem allows reliable determination of the optimal discharge energy to achieve the highest possible productivity with the desired quality. The performance of prediction of the heat affected zone compared to the experimental results showed a good agreement, which confirms the validity of the inverse method compared to the reported models.
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In this paper, an attempt has been made to develop a mathematical model in order to study the relationship between laser cutting parameters such as laser power, cutting speed, assist gas pressure and focus position, and kerf taper angle obtained in CO2 laser cutting of AISI 304 stainless steel. To this aim, a single hidden layer artificial neural network (ANN) trained with gradient descent with momentum algorithm was used. To obtain an experimental database for the ANN training, laser cutting experiment was planned as per Taguchi’s L27 orthogonal array with three levels for each of the cutting parameters. Statistically assessed as adequate, ANN model was then used to investigate the effect of the laser cutting parameters on the kerf taper angle by generating 2D and 3D plots. It was observed that the kerf taper angle was highly sensitive to the selected laser cutting parameters, as well as their interactions. In addition to modeling, by applying the Monte Carlo method on the developed kerf taper angle ANN model, the near optimal laser cutting parameter settings, which minimize kerf taper angle, were determined.
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Due to intensive friction between grinding particles and workpiece material, a substantial quantity of thermal energy develops during grinding. Efficient determination of real heat loading in the surface layer of the workpiece material in grinding largely depends on the reliability of basic principles of distribution of heat sources and the character of the temperature field within the cutting zone. Therefore, this paper takes a different approach towards the identification of the thermal state of the creep-feed grinding process by using the inverse problem to approximate heat conduction. Based on a temperature measured at any point within a workpiece, this experimental and analytical method allows the determination of a complete temperature field in the workpiece surface layer as well as the unknown heat flux on the wheel/workpiece interface. In order to solve the inverse heat conduction problem, a numerical method using finite differences in implicit form was used. When the inverse heat conduction problem is transformed into an extreme case, the optimization of heat flux leads to an allowed heat loading in the surface layer of workpiece material during grinding. Given the state function and quality criterion, the control of workpiece heat loading allows the determination of optimal creep-feed grinding conditions for particular machining conditions.
This research paper exhibits an experimental investigation of plasma arc cutting of hardox-400 using different types of plasma gases. Nature and behavior of the plasma arc were studied and described the effect of plasma gas on the workpiece. The experiments were performed on 10 mm hardox-400 using CNC plasma cutting machine. The selected workpiece material has very good mechanical properties like high toughness, good bendability, and good weldability. This special abrasion resistance steel is used in part manufacturing of front loaders, buckets, barges, and various mining equipment. Four different plasma gases were chosen for this experiment, i.e., air, argon, oxygen, and nitrogen. Thermophysical properties of plasma gases, properties of generated arc, cutting performance, and energy balance are explained for different plasma gases used. The kerf shape and material removal rate (MRR) due to the generated arc were measured and analyzed the effect. This paper clarifies the potential of cutting process by varying the flow rate and chemical composition of the plasma gas.
The work focuses on assessing the optimal machining conditions which could simultaneously satisfy multiple process performance indices during machining of AISI D2 steel. The main characteristic indices that have been considered here for evaluating plasma arc machining are surface roughness and material removal rate; the corresponding machining parameters are cutting speed, gas pressure and torch height. The study proposes an integrated optimization module combining fuzzy inference system, nonlinear regression and JAYA algorithm towards optimizing correlated multi-response features during machining of AISI D2 steel. Optimum value of machining parameters found as cutting speed of 4000 m/min, gas pressure of 95 psi and torch height of 0.5 mm using aforementioned methodology. Application potential of the aforesaid integrated optimization route has been compared to that of teaching–learning based optimization (TLBO) algorithm and genetic algorithm. It has been concluded that JAYA algorithm possesses less convergence time and hence execution is faster as compared to TLBO and genetic algorithm.