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WEDM of AA6061: an insight investigation of axial and lateral dimensional errors
Abstract
Geometrical machining errors in terms of overcut and/or undercut are the inherent problems associated with wire-cut electric discharge machining (EDM) process. Such errors are ultimately transformed into compromised dimensional accuracy of the machined part. The magnitude of the said errors is presumed the same in both the cutting orientation of work part. However, practically there exists variations along both the cutting orientations, i.e. axial and lateral. Moreover, not only the lateral and axial dimensions are different from the designed dimensions but also a noticeable difference in errors magnitude is observed along both the cutting directions. Variation in kerf along different edges of the machined profile also plays a pivotal role in error amplification. Such difference in geometrical dimensions seriously matters in high-precision applications. Therefore, the present research examines the impact of seven control parameters for minimizing the magnitude of kerf width, axial and lateral dimensional errors. Al-alloy 6061 is taken as a substrate because of its wide use in precision-oriented applications. Parametric effects are thoroughly analyzed through statistical tests and SEM-based analysis. Results revealed that the use of optimal settings yields a reduction of 13.5%, 49%, and 27% in the magnitudes of kerf width, axial, and lateral dimensional errors, respectively.
... Therefore, study on dimensional accuracy becomes vital for high precision related applications and the potential of dimensional accuracy should be minimal. [1] Aluminium (Al) 6061 alloy a lightweight and low density material is demanding materials for variety of components in the areas of industrial applications namely automotive, defense and aerospace industries. This is by the virtue of enchiting properties such as high thermal conductivity, good machinability, high ductility and better corrosion resistance. ...
... At past, EDM was mainly utilized in dies and molds industry; however, at present scenarios, it is also used in machining of parts in automobile, surgical and aviation sectors. Ishfaq et al. 1 , Pramanik et al. 2 , Arooj et al. 3 , Niamat et al. 8 and Kuo et al. 9 have machined Al6061 alloy with EDM process to study the influence on surface integrity (surface roughness, recast layer, surface morphology) and machining rate. However, micro-cracks, lower productivity rate, voids, higher recast layer and poor surface quality, are some of the issues raised by the researcher which limits the application of EDM process at broader manufacturing scale in industries. ...
... However, micro-cracks, lower productivity rate, voids, higher recast layer and poor surface quality, are some of the issues raised by the researcher which limits the application of EDM process at broader manufacturing scale in industries. [1][2][3]8] Over period of time modifications and advancement in EDM process were considered by researchers with integration with other processes and addition of additives in dielectric. Thus, for improving the process stability and above-mentioned problems faced by EDM, researchers have use ultrasonic vibration to workpiece, orbital motion for tool, powder as additives to mixed to dielectric, external magnetic field and effective flushing system in EDM process. ...
Magnetic field assisted powder mixed electrical discharge machining (MFAPM-EDM) process is a hybrid process machining process which improves the machining characteristics and stability of process using assistive magnetic field and dielectric admixed powder. In this article, study on overcut has been performed on MFAPM-EDM machined Aluminium 6061 alloy. Discharge current, powder concentration, pulse on duration, pulse off duration, and magnetic field strength as process parameters have been varied during experimentation. Box Behnken design approach was employed for experimental design to carry out the experiments. Suitable Semi-empirical model was formulated using dimensional analysis for predicting the overcut. The empirical model developed was also compared with RSM model and was found better in predicting the response. Optimum process parameters for minimal overcut was conducted desirability function approach of RSM. Experimental results divulged discharge current as the most important parameters for overcut as compared to other process parameters on account of higher F-value. Confirmatory experiments revealed good correlation between optimum and experimental results.
... Therefore, the requirement of AMCs in aforesaid applications rules out the use of conventional means and make non-conventional cutting techniques preferable in the context of geometrical accuracy of the processed part. [6] Amongst the advanced non-traditional cutting processes, WEDM is considered as a potential claimant to machine complex and intrinsic shapes with considerable focus on dimensional accuracy. [7] Moreover, geometrically accurate shapes produced on the Aluminum matrix are required for appropriate functionality and have extensive applications in the automotive and aeronautical sectors. ...
... Earlier, it is generally supposed that the effect of cutting orientation is the same on the overall shape being machined, which is deemed not to be. [6] Similarly, the effects of wire cutting realized at the top and bottom faces of the targeted workpart are often assumed to be equal unless the assembly gets shifted in micron. The effects on both faces may cause the angular error at machined parts' corners. ...
... As the material has proven specialized applications that require highly precise and geometrically accurate parts. [6] Therefore, WEDM is employed for its potentiality to cut complex and geometrically tolerable parts. The process uses a thermoelectrical phenomenon between a continuous wire electrode and workpiece. ...
Al-matrix composites specifically Al6061-7.5%SiC which holds promising mechanical properties, is a potential candidate in aeronautical industry. Though the reinforcement of SiC in Al-substrate has appreciably enhanced the mechanical characteristics, but it complicates its machining as the composite bears excellent hardness and strength. Moreover, its intended applications require the formation of intricate profiles. Therefore, the processing/machining of such composite is challenging. Wire electric discharge machining (WEDM) is an appreciable choice for Al6061-7.5%SiC machining. However, intrinsic issues of WEDM, i.e., wire vibrations and lag have resulted in a compromised dimensional accuracy of machined part. Furthermore, realization of similar errors’ magnitude in both the cutting orientations (axial; EXD and lateral; EYD) is difficult because of the presence of SiC-reinforcement which is a stimulus for wire disturbances. Similarly, this reinforcement influences corner accuracy and makes it’s tedious to attain same corner errors at both faces (top; AETOP and bottom; AEBOT). These accuracy issues have not been discussed yet which is primarily done herein using response surface methodology. Statistical, optical, and SEM analyses are performed for detailed understanding of the parametric effects. The minimum error values achieved are 0.01 mm, 0.105 mm, 0.249° and 0.475° in case of EXD, EYD, AETOP and AEBOT
respectively.
... It was also concluded that the coupled magnetic mechanical model holds high reliability and feasibility to improve the corner accuracy. Ishfaq et al. [3] studied the effect of seven different control factors on lateral, and dimensional errors, and kerf width (KW) in WEDM of Al 6061. It was inferred that the vibrational frequency of the electrode wire is the main cause of lateral dimensional errors. ...
... The effect of seven key control variables namely; Open voltage, wire tension, pulse on time, pulse off time, servo voltage, wire feed, and flushing pressure have been thoroughly examined on the corner accuracy (top and bottom), roughness, and material removal rate. The selection of the said control variables was based on the detailed literature review [3,[22][23][24][25][26][27][28]. Moreover, preliminary trial were also conducted before the actual experimentation to define the parametric levels. ...
Aluminum and its alloys specifically Al6061 bear numerous applications in aerospace and marine etc. where dimensional accuracy is of utmost importance which favors the use of wire electric discharge machining (WEDM). However, the achievement of a similar level of dimensional consistency in terms of corner deviation at both upper and the lower face of the workpiece is challenging. The issues of wire lag and wire vibrations are the prime stimuli for provoking the said corner errors, but their influence is notably different at both the faces of the cut specimen. Essentially similar level of corner accuracy is deemed necessary at upper and lower face of the cut specimen for its accurate functionality in its end application. This aspect has not been explicitly studied so far during WEDM of Al6061 alloy which is primarily investigated in this research. Moreover, the aspect of corner accuracy has not been discussed considering the material removal rate and surface roughness to iterate an optimal setting that yields dimensionally consistent product at optimized material removal rate and surface quality which is done herein. Seven WEDM process variables have been selected to envisage their impact on the selected responses under L27 Taguchi’s design. Experimental findings revealed that corner errors realized at top and bottom faces are markedly different. Angular error at the top face is significantly influenced by Wire tension, off-time, and flushing pressure with percentage contributions of 25.5%, 12%, and 15.6% respectively. Whereas, the angular error at bottom is mainly influenced by open voltage, on time, wire feed, and flushing pressure with percentage contribution of 28.5%, 15.3%, 13.2%, and 10.7% correspondingly. In case of surface finish and material removal rate, pulse longevity is the prime control variable with contribution of 51% and 88% respectively. Greater magnitude of wire tension is observed to cause the taperness in the wire electrode that yields higher corner error at the top face. Corner errors at both the faces i.e. top and bottom are reduced at greater value of open voltages. Scanning electron microscopy analysis depicts that the crater depth and its width, material melting, vaporization, and redeposit on the machined surface are increased by increasing spark duration and subsequently poor surface finish is achieved. An optimal parametric combination for simultaneous optimization of the conflicting responses has been proposed using weighted signal-to-noise ratio. The adequacy of the developed optimal combination has also been validated via confirmation trials.
... Dimensional accuracy is a mandatory requirement to achieve correct functionality of finished product(s) [57]. It is reported in the literature that traditional dielectrics give high D d values [58]. For that purpose, vegetable oils have been selected in this study to check if EDM processing of Inconel 600 with natural dielectrics may fabricate parts with tight tolerances. ...
Inconel 600 is widely used in aeronautical and aerospace industry owing to its excellent mechanical, wear and corrosion characteristics. This high strength alloy requires a special machining environment which justifies the use of Electric Discharge Machining (EDM). However, low cutting rate, which accounts for the productivity aspect, and emission of toxic fumes generated by thermal breakdown of kerosene dielectric currently limit the use of EDM. Moreover, since EDM is an energy intensive machining process, industry has a stringent emphasis to make this process sustainable and eco-friendly. In this context, the potentiality of six bio-degradable dielectrics was comprehensively investigated here for the first time ever to achieve cleaner and sustainable production of Inconel 600. Each biodegradable dielectric was coupled to four electrode materials to find the best tool-dielectric combinations for the EDM processing of this Ni-based super alloy. The responses were defined considering the three key ingredients of sustainability: i.e. productivity (assessed in terms of material removal rate and tool wear ratio), quality (expressed in terms of surface finish and dimensional deviation) and power consumption (expressed in terms of specific energy consumption). Experimentation was performed with a full factorial design taking dielectric type and electrode material as input variables. The EDM configuration including amla oil as dielectric and brass electrode was the best in terms of maximum MRR (19.8 mm3/min), 560% better than the standard EDM configuration including the same brass tool and kerosene dielectric. The lowest surface roughness SR (quality aspect) was obtained by the EDM configuration including a brass electrode and the sunflower oil dielectric: surface quality improved by 30.6% with respect to standard EDM using the same electrode and kerosene dielectric. Considering the specific energy consumption, the EDM setup with brass electrode and amla oil dielectric was 6.6 times more efficient than standard EDM with the same electrode and kerosene dielectric. The combination of coconut dielectric and Cu electrode results in a 5.4 times lower tool wear ratio than the traditional dielectric. In terms of achieving a better dimensional control, graphite electrode is a preferred choice against olive oil dielectric. Based on the measured values for EDM responses, it was revealed that relative percentage of carbon dioxide emissions reduces by 83.95% if amla oil is used in comparison to the CO2 emissions noted for standard kerosene oil considering brass as electrode. Finally, an optimal combination of the best biodegradable dielectric fluid and electrode material to satisfy all performance indicators was proposed through MOGA technique. Experimental data were properly fitted by using artificial neural networks. The EDM setup with copper electrode and amla oil dielectric achieved the best global performance with respect to all responses.
... Further, Pramanik et al. [26,27] optimized the value of various input parameters of WEDM for AA6061 to obtain the outcome response such as MRR, kerf width and SR by adopting optimization methods. In addition, Ishfaq et al. [28,29] investigated the impact of several control variables of WEDM for AA 6061 for dimensional accuracy issues by adopting statistical techniques and SEM. The results show that corner errors at the top and bottom together with MRR and SR are highly affected by the parameters and pulse variations. ...
Wire-electric discharge machining offers a number of benefits in comparison to traditional manufacturing processes likewise, no obvious mechanical cutting traces also hard and rigid materials can be processed perfectly in WEDM. Since, aluminum alloys are used in aerospace, shipbuilding, breathing gas cylinders for scuba diving, surgical components and automotive industry for their high-strength-to-weight ratio, accurate shapes and dimensions. Through this method, complicated structures made of aluminum alloy are produced in a single setup with incredibly tight tolerances. The present investigation explores WEDM for AA6061 to optimize different process variables for attaining performance measures in terms of maximum MRR and minimum SR. Taguchi’s L18 OA matrix, S/N ratio, ANOVA and Grey Relational Analysis were employed to optimize SR and MRR. It has been noted from ANOVA that pulse on time and peak current are the most influential aspects for MRR and SR with their contributions of 13.33% and 16.25% respectively. Further, the best possible considered parameters setting has been established by applying GRA for MRR and SR are, pulse on time-50µs, pulse off time-13µs and peak current-4 amp.
... It is worthy to state that geometric accuracy plays a vital duty in ensuring the accurate functionality of the machined specimen [19]. It has already been reported that the use of traditional dielectric(s) yield significant dimensional variations during EDM [20]. Therefore, vegetable oils, as mentioned before, have been practiced instead of kerosene oil to produce components with tight tolerances. ...
Inconel 600 is a Ni-based superalloy having exclusive properties like high strength and stability in harsh conditions. However, its accurate machining is challenging via conventional cutting methodologies. As a result, the use of electric discharge machining is common in cutting Inconel 600 precisely. But the intrinsic issue of overcut associated with traditional EDM limits its appreciation in cutting Ni-based alloy. Moreover, conventional dielectric oil used in EDM releases hazardous fumes and gases that put the operator’s health at risk. Therefore, in this study, six different biodegradable dielectrics have been investigated for their potential in controlling the dimensional overcut, which have yet to be evaluated thoroughly. The performance of biodegradable dielectrics (canola, amla, olive, sunflower, coconut, and mustard oil) against four types of electrode materials has been evaluated using full factorial design in the EDM of Inconel 600. Experimental findings are analyzed with statistical tests and optical/scanning electron microscopic evidence. The experimental results indicated that canola dielectric yield the smallest dimensional overcut. However, combination of sunflower oil and copper electrode proved as second premier case to reduce the overcut. Compared to the conventionally used kerosene oil, the biodegradable dielectrics (canola and sunflower) display a 63% and 1.2-folds reduction in overcut.
... 1,2 Sticking of Aluminium chips to tool, burr buildup on cutting edge, tool tip failure and localization of shear stress are some of the issues observed by researchers on traditional machining of Al6061 alloy. [3][4][5][6] Thus, non-traditional machining process (Abrasive water jet, electric discharge machining, etc.) aimed to machine Al6061 alloy for mitigating the problems face in traditional machining. Among the non-traditional machining process, electrical discharge machining (EDM) has gained significantly use on machining complex contours on the materials regardless of materials hardness to get required precision and dimensional accuracy. ...
Magnetic field assisted powder mixed electrical discharge machining (MFAPM-EDM) is a variant of EDM process where magnetic field coupled with electric field is used with addition of fine powder in dielectric to improve the surface quality, machining rate and stability of the process. Aluminium 6061 alloy as workpiece was selected due to growing use in aviation, automotive, naval industries. In this present work, parametric study and optimization was carried out on MFAPM-EDM machined Aluminium 6061 alloy. In this study, process parameters such as discharge current (I P), spark duration (PON), pause duration (POFF), concentration of powder (CP) and magnetic field (MF) were considered to analyze the effect on material erosion rate (MER) and electrode wear rate (EWR). Box Behnken design approach based on response surface methodology (RSM) was utilized for performing the experiments. Quadratic model to predict the MER and EWR were developed using response surface methodology. Discharge current has most significant effect of 50.176% and 36.36% on MER and EWR, respectively among all others process parameters. Teacher-learning-based optimization (TLBO) was employed for determining the optimal process parameters for maximum MER and minimal EWR. The results obtained with TLBO was compared with well-known optimization methods such as genetic algorithm (GA) and desirability function of RSM. Minimum EWR (0.1021 mm 3 /min) and maximum MER (30.4687 mm 3 /min) obtained using TLBO algorithm for optimized process parameters was found to better as compared to GA and desirability function.
Inconel 718, a rich nickel content alloy, has been widely adopted for high-temperature applications across industries. A recently explored non-conventional machining method, wire electrical discharge machining (WEDM), is suitable for machining these alloys. However, the dimensional inaccuracy, high consumption of wire tool electrodes and poor surface quality affects precision and productivity. This study aimed to investigate the effect of employing different wire diameters in WEDM and influence on performance characteristics such as the dimensional deviation, overcut, wire consumption, surface roughness, recast layer thickness, micro hardness, microstructural and metallurgical changes. For small wire diameters compared to large wire diameters, a significant reduction in the dimensional deviation and overcut is incurred. With average-sized craters, a surface machined using a small-diameter wire showed enhancement, decreased changes in micro-hardness, and lower recast layer thickness than a surface machined using a large-diameter wire. For the prediction of surface roughness, a model was developed considering wire diameter. In addition, wire consumption for smaller wire diameters is reduced, encouraging cost-efficiency, and solving problems with waste disposal. The Inclusion of smaller-diameter wires in WEDM has increased the precision with productivity, promoted reduction in the wire and workpiece waste, and has a lower environmental impact.
Ti-6Al-4V is considered a challenging material in terms of accurate machining. Therefore, electric discharge machining (EDM) is commonly engaged, but its low cutting rate depreciates its use. This issue is resolved if graphene nanoparticles are mixed in the dielectric. However, the control over the sparking phenomenon reduces because of the dispersion of graphene particles. Subsequently, the machined profile’s geometric accuracy is compromised. Furthermore, the presence of nanographene induces different sparks along axial and radial cutting orientations. This aspect has not been comprehensively examined yet and dedicatedly targeted in this study to improve the quality of EDM process for Ti-6Al-4V. A total of 18 experiments were conducted under Taguchi’s L18 design considering six parameters namely, electrode type, polarity, flushing time, spark voltage, pulse time ratio, and discharge current. The aluminum electrode proved to be the best choice to reduce the errors in both the cutting orientations. Despite the other parametric settings, negative tool polarity yields lower values of axial (ADE) and radial errors (RDE). The developed optimal settings ensure 4.4- and 6.3-times reduction in RDE and ADE, respectively. In comparison to kerosene, graphene-based dielectric yields 10.2% and 19.4% reduction in RDE and ADE, respectively.
Wire Electrical-Discharge-Machining (WEDM) is a well-known unconventional machining process to produce intricate shapes. However, obtaining a satisfactory WEDM cutting performance is indeed a challenging task during precision cutting. Hence, this investigation aims to attempt a favorable machining parameter setting in order to corner-cutting during WEDM for In-718. Here, machining performance characteristics have been considered based on corner deviation (CD) along with Material Removal Rate (MRR) and surface roughness (SR). Taguchi’s experiment design technique (L16) has been considered to run the experiments. The controllable process parameters are considered as Spark-on-time (Son), flushing-pressure (Fp), wire-tension (Tw), and discharge-current (Id). The aforesaid machining performance characteristics have been achieved through the two most popular wire electrodes, i.e., Zinc-coated brass electrode (Zn-BE) and Brass Wire Electrode (BWE), and compared the results. The comparison of performances by the wire electrodes on CD, MRR, and SR varied from 0.0286 mm to 0.0844 mm, 0.0045 g/min to 0.0214 g/min and 3.12 µm to 4.80 µm for BWE and 0.0218 mm to 0.0783 mm, 0.0090 g/min to 0.0342 g/min and 2.58 µm to 4.40 µm for Zn-BE respectively. However, machining with Zn-WE yields reduced CD, SR, and increased MRR value and shows less defect on the WEDMed surfaces than its counterpart. The present study developed the mathematical model based on non-linear regression for correlating the machining parameters with the machining responses. The next step of this study is that a unique optimization strategy, namely grey relation analysis (GRA) integrated with Teaching Learning-Based Optimization (TLBO), has been implemented for achieving optimal parametric setting. The satisfactory machining setting obtained from GRA-TLBO has been compared with GRA-JAYA and GRA-genetic algorithm (GA). The proposed methodology appears more fruitful in terms of computational time and effort.
Aluminum base alloys used in aeronautical applications is machined using WEDM to machine complex profiles with good accuracy and minimum taperness. This present investigation explores wire cut EDM machine tool usage for optimization process variables of Aluminium-6061 alloy. A Sequence of experiments are developed to research the process parameters, effects such a pulse on time—TON, wire feed rate—WFR, pulse off time—TOFF and servo voltage control—SVC on dimensional deviation—DD, Taperness, wire wear rate—WWR and metal removal rate—MRR. Trial runs on Al-6061 are conducted by taguchi design of experiments, a regression equation is developed. Genetic algorithm optimization technique is applied to yield global optimum results for optimizing process variables. Finally, comparison done across experimental results to predicted values for effectiveness 95% of confidence level was obtained. The optimum levels for getting minimum taperness is identified for square geometry are pulse on time—103 µs, pulse off time—59.99 µs, wire feed rate—6.45 mm/min and control of speed—92.52%. For circular geometry the identifications are pulse on time—103 µs, pulse off time—59.99 µs, wire feed rate—7.88 mm/min and control of speed—42.34% for optimum response. The optical microscope conformation test has obtained with satisfactory.
In this paper, the hydrophobic polymer surface with regular and controllable micro-textured structures was effectively and rapidly fabricated by micro-injection molding using a novel micro-textured mold machined by wire electrical discharge machining (WEDM). The phase constitutions of smooth and micro-textured mold surfaces were compared along with machined surface roughness of molds. The surface topographies of micro-textured molds and micro-injection molded polymers were characterized. The machining accuracy of WEDM for micro-textured mold and the replication rate of micro-injection molding for micro-textured polymer were calculated and analyzed. The wetting behaviors of smooth and micro-textured polymer surface were investigated together with the static contact angle and contact angle evolution versus time. The experimental results show that the maximum contact angle on the micro-textured polymer surface can reach to 127.5°, which was improved by about 71.6% compared with smooth polymer surface. It is shown that the highest machining accuracy of mold and the maximum replication rate of micro-injection molding can reach to 0.153% and 99.455%, respectively.
Wire electro-discharge machining (WEDM) is a widely used machining process for machining of difficult to cut materials, which are used in precision profile applications like dies, metal stampings, and gas turbine parts. In the present research work, a new slant type taper fixture was used to obtain angular machining of triangular shape slots of sides 1mm, 3mm and 5mm machined both in 0° and 30° as slant angles on Hastelloy X. The corner radius and corner errors were investigated for different machining parameters like corner dwell time (CDT), offset distance (WO), wire guide distance (WGD) and cutting speed override (CSO) using L16 orthogonal array for both the slant angles. SEM micrographs indicated that corners were with lower radii at 30° than in 0° slant profiles, at lowest and highest cutting speeds. The main effects plot showed that the corner radius increases with the increase in wire offset and wire guide distance parameters. The increase in corner dwell time has an adverse effect on the corner radius. The triangles were machined at different cutting speeds from 0.47 to 1.51 mm/min with various parameters; it was observed that as the corner radius decreases the corner error also reduces. However, the corner radius and corner error can be minimized by selecting an optimized cutting parameter.
The paper deals with the experimental study of laser beam micromachining of the powder metallurgy processed Ti compacts applying the industrial grade fibre nanosecond laser operating at the wavelength of 1064 nm. The influence of the laser energy density on the surface roughness, surface morphology and surface elements composition was investigated and evaluated by means of surface roughness measurement, scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDS) and X-ray diffraction (XRD) analysis. The different laser treatment parameters resulted in the surfaces of very different characteristics of the newly developed biocompatible material prepared by advanced low temperature technology of hydride dehydride (HDH) titanium powder compactation. The results indicate that the laser pulse energy has remarkable effects on the machined surface characteristics which are discussed from the point of view of application in dental implantology.
Clad composites have emerged as a suitable choice to augment the industrial needs due to having a combination of different properties. The accurate cutting is challenging due to the heterogeneous nature of the composite. Conventionally, thermal cutting (plasma/gas) techniques are commonly employed which provide poor cut quality, deeper heat affected zones and demand additional finishing operations. Therefore, this research evaluates the potential of abrasive water jet cutting (AWJC) as a proficient substitute for the cutting of stainless-clad-steel composite in terms of surface quality. However, it is difficult to produce a similar level of surface finish at both the layers because the constituent layers have different mechanical properties. The effect and significance of four important AWJC parameters on cut quality are examined through statistical analyses. Optical and scanning electron microscopic analyses are further provided as evidence of the reported results. Optimal settings are also developed using a weighted signal-to-noise ratio technique which can provide minimal roughness at each layer. Moreover, using the optimal settings, a similar level of surface finish has been achieved for both the layers with a difference of just 0.03 µm between the constituent layers.
Stainless steel (SS 304) is commonly employed in industrial applications due to its considerable corrosion resistance, thermal resistance, and ductility. Most of its intended applications require the formation of complex profiles, which justify the use of wire electrical discharge machining (WEDM). However, its high thermal resistance imposes a limitation on acquiring adequate surface topography because of the high surface tension of the melt pool, which leads to the formation of spherical modules; ultimately, this compromises the surface quality. Furthermore, the stochastic nature of the process makes it difficult to optimize its performance, especially if more than one conflicting response is involved, such as high cutting speed with low surface roughness and kerf width. Therefore, this study aimed to comprehensively investigate the interaction of SS 304 and WEDM, with a prior focus on simultaneously optimizing all the conflicting responses using the Taguchi-based grey relational approach. Analysis of variance (ANOVA) revealed that the current was the most significant parameter for cutting speed and kerf, whereas roughness, voltage (45%), drum speed (25.8%), and nozzle offset distance (~21%) were major contributing factors. SEM micrographs showed that optimal settings not only ensured simultaneous optimization of the conflicting responses but also reduced the number and size of spherical modules.
Ecological manageability in manufacturing these days is a dire and exceptional issue and the principle concerns are identified with increasingly proficient utilization of energy and materials. Recycling can save a large amount greenhouse gas emissions, particularly in the case of aluminum. The parameter on the innovative technique on the direct recycling was investigated by employing design of experiments, via hot press forging process (DR-HPF). Thus, reutilizing of aluminum chips AA6061 with full factorial 32 design of experiment comprising a variety of working temperature and holding time were employed. Central composite design (CCD) was applied to outline the experiments towards evaluating the influences of the hot press forging parameters to the three responses; ultimate tensile strength (UTS), elongation to failure (ETF), and global warming potential (GWP). In conjunction with this, the environmental impacts associated with DR-HPF process are evaluated alongside the resultant conventional recycling (CR) by using re-melting route as indication. Experimental measurements, literature analysis and industrial data were merged to acquire the analysis of aluminum recycling life cycle. Clear conclusions were successfully drawn through the attained results on the outlook proposed by solid state direct recycling for the purpose of reducing the environmental effects by taking material and energy conservation as one of the most essential impacting factor. The global warming potential of a DR-HPF route gives a significant environmental impact where it is reduced up to 69.2% in comparison to the conventional (melting) routes.
ABSTRACT
In wire electrical discharge machining (WEDM) process, to the machine, sharp corner without error is an
extremely challenging issue which is vital for precision machining. Owing to the presence of huge wire
deflection, the accuracy of the machined corner is undesirably affected. The aim of this study is to
explore the effect of process parameters namely, spark on time, spark off time, wire tension, wire feed
rate, and spark gap voltage on corner error for acute angle (60°), right angle (90°) and obtuse angle
(120°) triangular profiles during WEDM of Ni50.89Ti49.11 shape memory alloy (SMA). Owing to the effect of
discharge concentration, corner error for acute angle profile is predominantly affected by spark on time,
spark off time, and spark gap voltage. Wire tension was the most influencing parameter for corner error
of obtuse and right angle profile due to the effect of wire deflection and wire vibration, whereas wire
feed rate has trivial effect for all type of profile. In order to reduce the corner error, pulse modification
technique was utilized. At low pulse parameters, corner error for 60°, 90°, and 120° profile was reduced
by 43.38%, 31.12%, and 29.04%, respectively, as compared to high pulse parameters.
Wire electric discharge machining (WEDM) is one of the most important non-traditional manufacturing methods and widely utilized in aerospace and tooling industry. However, the lack of the accurate numerical description of the WEDM process impedes a better understanding of the WEDM process and its machining mechanism. Since the vibration of the wire significantly affects the discharge location and the temperature distribution of the workpiece, the thermophysical model of the WEDM is much more complex than that of the EDM. In this paper, based on the classical thermal model of the EDM, a novel finite element method (FEM) model of WEDM considering the three dimensional wire vibration was proposed to simulate the machining process and verified by a series of WEDM experiments. Eventually, the effects of the wire vibration on the material removal rate and recast layer thickness were investigated quantitatively by analyzing the simulation results of this new thermophysical model and corresponding experimental results.
Aluminum alloy AA 6061-T651 and 5A06-H112 rolled plates were successfully welded by friction stir welding (FSW) at three rotation speeds of 600, 900, and 1200 rpm with two transverse speeds of 100 and 150 mm/min. Mechanical properties and strain field evolution of FSW AA 6061-AA 5A06 were characterized by the uniaxial tension and digital image correlation (DIC) tests. Furthermore, the hardness distribution map of whole cross section was obtained via the nanoindentation method with 700 indents. Both DIC and nanoindentation results reveal that the heat-affected zone (HAZ) of AA 6061 alloy is the softest area in the weldment, and the fracture happens in this region. The microstructure evolution characterized by electron-backscatter diffraction (EBSD) indicates that the continuous dynamic recrystallization is the primary grain structure evolution in the stirring zone, and the grain refinement helps improve the mechanical properties. Analyses of the micro- and macrofeatures of the fracture surfaces via scanning electron microscopy (SEM) and optical microscope suggest that the increasing of heat input could enlarge the size of HAZ and reduce the slant angle of HAZ and thus lead the fracture angle to decrease and cause the dimples change from inclined ones to normal ones.
Owing to the desirable properties of vegetable oils as cutting fluids, an attempt is made to explore the potentiality of plentifully available vegetable oils as a cutting fluid for turning AA 6061. Two nonedible vegetable oils, Jatropha and Pongamia, in their chemically modified (epoxidized) versions are used as straight cutting fluids. Cutting fluids are introduced to the machining zone with the aid of Minimal Quantity Lubrication (MQL) method. Taguchi’s technique of orthogonal arrays is used to develop an effective design of experiments. The results obtained under epoxidized versions of Jatropha and Pongamia oils are compared with the results of mineral oil in terms of cutting forces and surface roughness. Experimental observations and statistical analysis show that, compared to mineral oil, the modified versions of vegetable oil-based cutting fluids are more effective in reducing the cutting forces and increasing surface finish. It is also observed that the modified Pongamia oil showed lesser flank wear compared to the other two tested oils.
This paper presents the experimental investigation on wire electrical discharge machining (WEDM) of aluminum alloy 5083 (AA5083), an exotic material widely used for cryogenic applications. In this work, an attempt has been made primarily to examine the influence of number of trim cuts on WEDM for the following responses: cutting speed, surface roughness, corner error and dimensional shift. AA5083 is one of the predominant materials used in cryogenic applications. It is inevitable to comprise the inherent property and surface quality of the material in cryogenic conditions. Hence, it is identified that cutting AA5083 in WEDM is a potential process. Taguchi methodology has been used for conducting the experiments. The present work has been focused on satisfying the customer needs and demands of acquiring the expected surface quality with maximum productivity. Experimental results proved that the rough cut followed with one optimal trim cut produces maximum cutting speed with good surface quality. Besides, an expression has been derived for calculating average cutting speed and effective cutting speed in trim cuts. Furthermore, the surface integrity of the rough cut and trim cut is compared and discussed with the SEM micrographs.
Friction stir welding (FSW) is the most popular and efficient method of solid state joining for similar as well as dissimilar metals and alloys. It is mostly used in applications for aerospace, rail, automotive and marine industries. Many researchers are currently working with different perspectives on this FSW process for various combinations of materials. The general input process parameters are the thickness of the plate, axial load, rotational speed, welding speed and tilt angle. The output parameters are joint hardness, % of elongation, impact and yield strengths. Genetic programming (GP) is a relatively new method of evolutionary computing with the principal advantage of this approach being to evaluate efficacious predictive mathematical models or equations without any prior assumption regarding the possible form of the functional relationship. This paper both defines and illustrates how GP can be applied to the FSW process to derive precise relationships between the output and input parameters in order to obtain a generalized prediction model. A GP model will assist engineers in quantifying the performance of FSW, and the results from this study can then be utilized to estimate future requirements based on the historical data to provide a robust solution. The obtained results from the GP models showed good agreement with experimental and target data at an average prediction error of 0.72%.
In recent years, Wire-Electrical Discharge Machining (WEDM) has gained popularity in industry due to its capability to generate complicated shapes in exotic materials, irrespective of their hardness. Conventional machining of Nimonic C-263 super alloy is an extremely difficult and costly process due to its high hardness and tool wear rate. The present research work investigates the influence of the WEDM process parameters on different performance measures during machining of Nimonic C-263 super alloy. Mathematical model for all four important performance measures, namely, cutting rate, surface roughness, spark gap and wire wear ratio, was developed and the responses were used for studying the inter-relationship between performance measures and process parameters. The optimal settings of operating conditions were predicted using desirability function. The effectiveness of multi-cut strategy was also investigated in the paper.
This article presents a systematic approach for modeling and analysis of machining characteristics of Micro-Wire Electric Discharge Machining (Micro-WEDM) process using the Response Surface Methodology (RSM). The effect of various input parameters, such as voltage, capacitance, and feed rate on machining, performance of material removal rate (MRR), kerf width (KW), and surface roughness (SR) was investigated. Experimental work was carried out on Aluminum Matrix Composite (A413-9% B4C) with zinc coated copper wire using RSM with central composite design (CCD). The second order mathematical modeling and analysis of variance (ANOVA) were performed to optimize the machining parameters. It has been found out that main and interaction effects are significant on the machining performance. The optimized values of MMR, KW, and SR parameters were found to be 0.259943 mm3/min, 87 µm, and 0.97 µm, respectively.
The experimental research presented in this paper deals with the concurrent optimisation of the responses namely cutting speed, surface roughness and corner inaccuracy during wire electrical discharge machining (WEDM) of aluminium 5083 alloy. The aluminium 5083 is magnesium-based aluminium alloy predominantly used in marine, cryogenic and aerospace applications. The conventional means of processing of 5083 AA is difficult as it exhibits poor machinability and average workability in the context of producing intricate shapes with very high precision and accuracy. WEDM is one of the lucrative machining techniques to process this alloy. Experiments have been performed based on L-18 orthogonal array with pulse on time, pulse off time, peak current, wire tension, servo feed setting and corner angle as control factors. ANOVA was performed to find the significance of the factors considered. Taguchi's additive model was used for prediction. Later, the responses were concurrently optimised based on Pareto optimality approach and a technology table has been tailored for handy use.
Functional performance of a gear during its service life depends on its manufacturing quality which is decided by the amount of deviations in the gear geometry. Most of the conventional miniature gear manufacturing processes (i.e. stamping, hobbing, powder-metallurgy, extrusion, die-casting) are unable to meet the very high quality requirements of miniature gears used in highly precise and sophisticated equipments such as devices used in MEMS, NEMS and timer mechanisms, robots, micro-motors, micro-pumps etc. Present work was undertaken to explore the use of wire electrical discharge machining (WEDM) as a superior alternative miniature gear manufacturing process. This paper reports on the deviations in macro-geometry (i.e. span, tooth thickness, dimensions over two-balls) and micro-geometry (single pitch deviation, runout, and surface finish) of WEDMed miniature external spur gears (having 9.8 mm outside diameter with 12 teeth) made of brass. The best quality WEDMed miniature gear had very less macro-geometry and micro-geometry deviations and belongs to American Gear Manufacturers Association (AGMA) quality range 8-11. The average surface roughness and maximum surface roughness were 1 µm and 6.4 µm respectively. The SEM images indicate tooth surfaces free from surface defects. Attempt was made to find the probable causes of deviations in geometry of WEDMed miniature gears. Comparative study of the WEDMed miniature gear with the hobbed gear was also done. The findings of the present work prove that using appropriate process parameters WEDM can manufacture superior quality miniature gears than by any conventional process.
The raw and modified versions of two nonedible vegetable oils, Pongam (Pogammia pinnata) and Jatropha (Jatropha curcas), and a commercially available branded mineral oil are used as straight cutting fluids for turning AA 6061 to assess cutting forces. Minimum quantity lubrication is utilized for the supply of cutting fluids. Cutting and thrust forces are measured. Cutting power is determined for various cutting speeds, depths of cut, and feed rates. Also, drilling is performed on the material to understand the material removal rate (MRR) under these oils. The performances of vegetable oils are compared to mineral oil. A noticeable reduction in cutting forces is observed under the Jatropha family of oils compared to mineral oil. Further, better material removal rate is seen under both the vegetable oils and their versions compared to under petroleum oil for the range of thrust forces.
Wire cut electrical discharge machining was identified as a good alternative to conventional machining for machining super alloys that possess low machinability. In the present work, effect of wire tension along with current, pulse on time, and pulse off time on the performance characteristics such as spark gap, surface roughness, amplitude of wire vibration, and cutting rate were studied in wire cut electrical discharge machining of Inconel 718 metal. Experiments were conducted at five levels of the process parameters as per orthogonal array of L25 and their results were collected. These experimental results were analyzed and the interaction effect of wire tension along with current, pulse on time, and pulse off time on performance characteristics was studied using analysis of variance. Response models were developed for the four responses in terms of process parameters and the accuracy of such models was tested. In addition to the above studies, effect of the wire displacement on the kerf size, cutting rate was studied. Spark energy was also estimated for all the experiments and its effect on the performance characteristics was studied. The response models developed in this study were able to predict the experimental results i.e. amplitude of wire vibration, surface roughness, cutting rate, and spark gap with an accuracy of R² values of 1.0, 0.96, 0.88, and 0.99, respectively. Interaction effect of current and wire tension was found to have the most significant effect on the amplitude of cutter vibration and surface roughness.
Wire electrical discharge machining (WEDM) is a demanding high-precision process for machining of hard-to-machine materials. The main issue is manufacturing errors in shape and radius of small arcs generation. In this paper, a novel model about spark variable gap sizes and nonuniform spark distribution around the wire on arced path machining is first theoretically developed using spark angle domain and WEDM dynamic analysis. Applying spark-force distributed around the wire and resulting wire deflection are estimated by the WEDM conditions influenced by plasma channel specifications, discharge frequency, wire guide clearance, wire tension, and arc radius. Total theoretical arced machining errors including wire deflection and spark gap size variation around the wire interface are calculated based on the proposed model. In addition, machining errors of straight and small arced paths are experimentally analyzed under variation of WEDM influential parameters including discharge frequency, arced path radius (150, 300 and 450 μm), and wire tension through the statistical full factorial. Comparison of the results for different sets of variable parameters shows that the theoretical values of the arced machining errors can be consistent with the experimental one by a coefficient which depends on the machining conditions and the WED machine type. Finally, based on the theoretical and experimental results, a theoretical algorithm and an operational method with mean accuracy of 84.8% are proposed for predicting and compensating the errors of WEDM on the arced paths. Findings of this research can be used in high-accurate WEDM applications and industries.
Wire electric discharge machining has become one of the popular machining processes used for generating complex geometry on electrically conductive materials. Due to its complex behaviour, a correlation between parameters and machining characteristics has been established by a neural network model. This study also recommends an optimal setting of process parameters with an aim to improve machining performance, which is achieved by using Jaya algorithm. Experiments were conducted on maraging steel 300 using silver coated brass wire to study the effects of process parameters (pulse on time, pulse off time, peak current, and servo voltage and wire tension) on the performance characteristics such as root mean square roughness, cutting speed, and kerf width. From the study, it is revealed that pulse on time is the predominant factor that mostly influences the machining characteristics. According to the analysis of results, the most suitable parametric combinations which obtained from Jaya algorithm offer the best performance characteristics.
Machining of metal matrix composites (MMCs) reinforced with low density waste by-product particulates using non-conventional processes is relatively new in the field of material science. However, more attentation has been paid for investigations on non-traditional machining of such MMCs currently as the conventional machining may generate additional complexity. The Present study investigates the wire electro-discharge machining behaviour of compo-casted cenosphere reinforced AA6061 alloys. Cu60Zn40 coated copper wire were used as electrodes materials. The investigation demonstrates that melting and vaporisation are the dominant machining mechanisms. The weight fraction of cenosphere was observed to be the most substantial process variable that affecting the cutting rate, on-time and the wire speed of tool were the next in the order of importance. The presence of nonconductive cenosphere particles along with thermal degradation of the AMCs leads to degrading processed machined surface quality. The issues related to wire breakage and poor quality of the machined surface, Surface finish and dimensional accuracy are described in details.
Electric discharge machining has been established as an effective alternative process to conventional material removal processes for machining reinforced metal matrix composites. Wire cut electric discharge machining holes were produced in a metal matrix composite (10 vol% of SiC in Al6061), which were then investigated to determine the machinability of the material using this process. It was observed that the input factors such as the size of reinforced particles, wire tension and pulse-on time significantly affect diameter error, circularity and surface roughness. Pulse-on time, the interaction between pulse-on time and wire tension contribute to the maximum diameter error. The wire tension is the most significant factor to circularity, which is followed by the interaction between pulse-on time. In particular, wire tension with low and high tensions results in poor circularity. It has been found that there are more surface defects encountered when particle sizes are smaller, and circularity is improved when particles are in a medium size. In addition, the surface defect is reduced as the particles increase the melting resistance of the surface. The higher pulse-on time leads
to higher heat and more time to degrade the surface. Therefore, low pulse-on time and wire tension gave better surface finish.
Wire electrical discharge machining (WEDM) is one of the promising methods to produce precision dies and machine tools. In the present work, die corner accuracy achievable through trim cutting operation has been analyzed in the presence of a higher wire lag arising due to the higher workpiece thickness, acute corner angle, and higher flushing nozzle height. The influence of the corner error (uncut area left between the actual profile and the desired profile) generated in the first cut (rough cut) on the considered responses, namely volume removal rate, corner accuracy, surface roughness, and dimensional shift, has been analyzed by setting three different parameters during the first cut of the trim cutting operation. It is established that the trim cutting operation is a superior strategy for improving die corner accuracy than the pulse parameter modification strategy. Nevertheless, the high pulse parameter setting in rough cut was preferred for achieving greater productivity while the low pulse parameter setting in rough cut was chosen to achieve better corner accuracy at the cost of lower productivity.
WEDM wire-cutting processing is a special machining method using pulse discharge happenns between electrodes and workpieces. This paper have analyzed and compared the two working modes of high-speed wire-EDM machine and low-speed wire-EDM machine. For the holes or slots distributed in mould device should be machined by WEDM method and could meet technical regulation. If all the holes or slots with higher accuracy requirement are machined in one process, the form accuracy and positional accuracy mighty be achieved. The paper compared two machining methods for the special holes with experiment. The result indicates that the improved process can greatly improve the machining accuracy and this method can be used in WEDM-HS and WEDM-LS process.
Wire-cut Electro Discharge Machining (WEDM) is a special form of conventional EDM process in which electrode is a continuously moving conductive wire. The present study aims at determining parametric influence and optimum process parameters of Wire-EDM using Taguchi’s Technique and Genetic algorithm. The variation of the performance parameters with machining parameters was mathematically modeled by Regression analysis method. The objective functions are Dimensional Accuracy (DA) and Volumetric Material Removal Rate (VMRR). Experiments were designed as per Taguchi’s L16 Orthogonal Array (OA) where in Pulse-on duration, Current, Pulse-off duration, Bed-speed and Flushing rate have been considered as the important input parameters. The matrix experiments were conducted for the material Oil Hardened Non Shrinking Steel (OHNS) having the thickness of 40 mm. The results of the study reveals that among the machining parameters it is preferable to go in for smaller pulse-off duration for achieving over all good performance. Regarding MRR, OHNS is to be eroded with medium pulse-off duration and higher flush rate. Finally, the validation exercise performed with the optimum levels of the process parameters. The results confirm the efficiency of the approach employed for optimization of process parameters in this study.
Micro-WEDM is a versatile technique used to machine electrically conductive materials to make components for micro system technologies. This paper presents an attempt to develop an appropriate machining strategy for micro-WEDM of aluminium alloy using zinc coated copper wire of 70 μm diameter. Voltage, capacitance, feed, wire tension and wire speed were taken as input parameters. Surface finish is considered as the measure of process performance. Design of experiments was done using Taguchi L16 orthogonal array and optimisation was carried out using Taguchi S/N ratio technique. The results obtained from the experiments were analysed with ANOVA method to find the significance of each input factor on the surface quality. In addition ANN model was developed and trained.
An extensive study of the wire lag phenomenon in Wire-cut Electrical Discharge Machining (WEDM) has been carried out and the trend of variation of the geometrical inaccuracy caused due to wire lag with various machine control parameters has been established in this paper. In an extremely complicated machining process like Wire-cut EDM, which is governed by as many as ten control factors, it is very difficult to select the best parametric combination for a particular situation arising out of customer requirements. In the present research study, all the machine control parameters are considered simultaneously for the machining operation which comprised a rough cut followed by a trim cut. The objective of the study has been to carry out an experimental investigation based on the Taguchi method involving thirteen control factors with three levels for an orthogonal array L27 (313). The main influencing factors are determined for given machining criteria, such as: average cutting speed, surface finish characteristic and geometrical inaccuracy caused due to wire lag. Also, the optimum parametric settings for different machining situations have been found out and reported in the paper.
The prediction of optimal machining conditions for required surface finish and dimensional accuracy plays a very important role in process planning of wire electrical discharge machining. The present work deals with the features of trim cutting operation of wire electrical discharge machining of γ-titanium aluminide. A second-order mathematical model, in terms of machining parameters, was developed for surface roughness, dimensional shift and cutting speed using response surface methodology (RSM). The experimental plan was based on the face centered, central composite design (CCD). The residual analysis and experimental results indicate that the proposed models could adequately describe the performance indicators within the limits of the factors that are being investigated. Finally the trim cutting operation has been optimized for a given machining condition by desirability function approach and Pareto optimization algorithm. It was observed that performance of the developed Pareto optimization algorithm is superior compared to desirability function approach.