Maximum Material Removal Rate Research Articles

Material Removal Rate Prediction for Sapphire Double-Sided CMP Based on RSM-SVM

As a crucial substrate material for optoelectronic materials, sapphire has important applications in both military and civilian fields. In order to achieve the final processing quality of sapphire substrate materials, double-sided chemical mechanical polishing (DS-CMP) is a necessary process, which is also a guarantee for the preparation of high-end LED chips. In this article, the sapphire DS-CMP processing plan based on the Box-Behnken design is obtained and experimented. Then, a hybrid approach of response surface method (RSM) and support vector machines (SVM) algorithm is established as the material removal rate (MRR) prediction model for sapphire DS-CMP. Furthermore, the material removal process of sapphire DS-CMP, the influence of response variables on the MRR of sapphire DS-CMP, and the prediction results of RSM-SVM on sapphire DS-CMP are analyzed respectively. From the experimental results, the maximum MRR obtained is 387.59 nm min−1, which is more than 6 times the reported MRR of single-sided CMP under similar process parameters. The mean square error of predicted value through RSM-SVM is basically around ±10% of the experimental value, which possess satisfied validity for the MRR prediction of sapphire DS-CMP. Finally, both top and bottom surface quality of sapphire wafers after DS-CMP processing was investigated.

Machinability of squeeze cast (TiB2+CNT)/Al 7075 metal matrix nano-composite during EDM with untreated and cryogenic treated Cu electrodes: A comparative study

This paper accentuates investigation of machining responses and surface integrity of (TiB2+CNT) reinforced Al 7075 metal matrix nano-composite intended for aerospace and automotive applications, which was processed through modified liquid metallurgy squeeze casting route. Microstructure of the developed composite was investigated through scanning electron microscopy, elemental distribution was identified through Energy-dispersive X-ray spectroscopy and mechanical properties were determined following recommended ASTM standards. However, focus was emphasized on exploration of the influence of peak current ( IP), pulse-on time ( TON), and gap voltage ( VG) on material removal rate (MRR), tool wear rate (TWR), and surface integrity during electrical discharge machining of the hybrid nano-composite with untreated and cryogenic treated Cu tools. MRR, TWR, and average roughness ( Ra) of the machined surfaces showed distinctive pattern in their variations when the machining parameters were changed; however, hardness of the machined surfaces did not show any specific trend with respect to the increase of the considered parameters. Cryogenic treated Cu tools outperformed the untreated tools, as perceived from the experimental results. For instance, while machining at TON = 100 µs, VG = 55 V, and IP = 10 A, maximum MRR for untreated tools was 27.43 mm3/min, and that for cryogenic treated tool was 29.12 mm3/min, leading to an improvement of about 5.8%. But at VG = 55V, IP = 4 A, and TON = 300 µs, maximum MRR for untreated tools was 16.71 mm3/min, and that for cryogenic treated tool was 18.22 mm3/min, leading to an improvement of about 8.3%. Similarly, at IP = 4A and TON = 100 µs and VG = 75V, maximum MRR for untreated tools was 14.88 mm3/min, and that for cryogenic treated tool was 22.7 mm3/min, leading to an improvement of about 34.4%. Similar outperformed results for cryogenic treated tools were also achieved while analyzing the experimental results of TWR, surface hardness and Ra. Finally, surface defects were analyzed through SEM at the disparate parametric combinations.

EXPERIMENTAL RESEARCH OF PARAMETRIC OPTIMIZATION ON WIRE ELECTRICAL DISCHARGE MACHINING OF AA7075/ZRB2 IN SITU COMPOSITES

The AA7075 composites reinforced with 3, 6, and 9 volume fractions (vol.%) of ZrB2 particles have been successfully fabricated using in situ fabrication method. In this technique, the inorganic salts K2ZrF6 and KBF4 were added to the molten aluminum and retained the melting at 900∘C to form the required vol.% of ZrB2 particles. The aluminum-reinforced metal matrix composites (MMCs) are commonly known as aluminum matrix composites (AMCs). This work carries the effects of various wire electrical discharge machining (WEDM) input process parameters like pulse-on-time ([Formula: see text]), pulse-off-time ([Formula: see text]), wire feed rate (WFR), and gap voltage (GV) on the output responses such as material removal rate (MRR), surface roughness (SR), and Kerf-width ([Formula: see text]) of the fabricated AA7075/(3, 6, and 9) vol.% ZrB2 in situ AMCs. Based on Taguchi’s L9 orthogonal array method, the design of experiments (DoE) was used to carry out the operations on the fabricated AMCs. The optimal level of process parameters was found by the main effects plot for signal-to-noise (S/N) ratio, contour plots, and the analysis of variance (ANOVA). The effect of these process parameters on MRR and SR was analyzed and it is found that the maximum MRR was attained in the optimal parametric combination of GV [Formula: see text][Formula: see text]V; [Formula: see text][Formula: see text][Formula: see text]s; [Formula: see text][Formula: see text][Formula: see text]s; WFR [Formula: see text][Formula: see text]mm/s; Reinforcement [Formula: see text] vol.%, and the minimum SR was attained in the optimal parametric combination of GV [Formula: see text][Formula: see text]V; [Formula: see text][Formula: see text][Formula: see text]s; [Formula: see text][Formula: see text][Formula: see text]s; WFR [Formula: see text][Formula: see text]mm/s; Reinforcement [Formula: see text] vol.%.

Optimization of wire-EDM process of titanium alloy-Grade 5 using Taguchi’s method and grey relational analysis

Wire-EDM is an unconventional machining practice that is extremely capable for precision machining of superalloys having high electrical conductivity. Titanium alloy Grade 5-Ti-6Al-4 V is a superalloy with an increasingly high demand in various industries such as the aerospace, biomedical and automobile industry by virtue of its high corrosion resistance, biocompatibility and high strength to weight ratio. The Wire-EDM operation becomes advantageous for machining of Ti-6Al-4 V if the input process parameters are optimised for attaining minimum surface roughness and maximum material removal rate. The methodology adopted for this optimization process is Taguchi’s Method coupled with Grey Relational Analysis. ANOVA has been done to analyse the efficacy of considered input specifications. The outcome reveals that peak current and pulse-off time have the highest contribution on the process performance. Material removal rate and surface roughness both increase with the increase in peak current as well as pulse-off time. Grey Relational Analysis imparts the optimal set of values of input parameters for achieving, in combination, maximum material removal rate and minimum surface roughness as 3A peak current, 30 µs pulse-on time and 9 µs pulse-off time.

Determination of Optimum Machining Parameters for Face Milling Process of Ti6A14V Metal Matrix Composite.

This paper shows the novel approach of Taguchi-Based Grey Relational Analysis of Ti6Al4V Machining parameter. Ti6Al4V metal matrix composite has been fabricated using the powder metallurgy route. Here, all the components of TI6Al4V machining forces, including longitudinal force (Fx), radial force (Fy), tangential force (Fz), surface roughness and material removal rate (MRR) are measured during the facing operation. The effect of three process parameters, cutting speed, tool feed and cutting depth, is being studied on the matching responses. Orthogonal design of experiment (Taguchi L9) has been adopted to execute the process parameters in each level. To validate the process output parameters, the Grey Relational Analysis (GRA) optimization approach was applied. The percentage contribution of machining parameters to the parameter of response performance was interpreted through variance analysis (ANOVA). Through the GRA process, the emphasis was on the fact that for TI6Al4V metal matrix composite among all machining parameters, tool feed serves as the highest contribution to the output responses accompanied by the cutting depth with the cutting speed in addition. From optimal testing, it is found that for minimization of machining forces, maximization of MRR and minimization of Ra, the best combinations of input parameters are the 2nd stage of cutting speed (175 m/min), the 3rd stage of feed (0.25 mm/edge) as well as the 2nd stage of cutting depth (1.2 mm). It is also found that hardness of Ti6Al4V MMC is 59.4 HRA and composition of that material remain the same after milling operation.

Finite Element based Numerical Modelling of Near-Dry EDM with Glycerin-Air Dielectric Mixture

Electrical discharge machining (EDM) is an advanced, non-traditional machining process that is widely employed in sectors such as manufacturing, automotive, aerospace, and medicine. Near-dry EDM is a prospective technology that offers advantages over dry and wet EDM in terms of material removal rate (MRR), tool wear rate (TWR), and surface integrity. A 2D model of the axi-symmetric workpiece based on the Gaussian distribution of the heat flux is used to simulate the single spark in near-dry EDM. The MRR of near-dry EDM is determined at various glycerin flow rates in the glycerin-air combination. The simulation is then performed on the SS304 workpiece with different glycerin flow rates. The results are compared to EDM simulations using N2 and O2 as the dielectric medium. The average MRR of near-dry EDM with an 8 ml/min glycerin flow rate is determined to be 204% higher than that of N2 and 117% higher than that of O2 gas dielectric. When the volumetric ratio of glycerin in the glycerin-air combination increases, the MRR was also found to be increasing. The maximal MRR of near-dry EDM was found to be 129.30703 mm3/min with an 8 ml/min glycerin flow rate and a 0.18 volumetric ratio and a maximal MRR of 144.3407 mm3/min was found with a 15 ml/min glycerin flow rate and a 0.35 volumetric ratio.

Parametric Optimization and Influence of Near-Dry WEDM Variables on Nitinol Shape Memory Alloy.

Nitinol-shape memory alloys (SMAs) are widely preferred for applications of automobile, biomedical, aerospace, robotics, and other industrial area. Therefore, precise machining of Nitinol SMA plays a vital role in achieving better surface roughness, higher productivity and geometrical accuracy for the manufacturing of devices. Wire electric discharge machining (WEDM) has proven to be an appropriate technique for machining nitinol shape memory alloy (SMA). The present study investigated the influence of near-dry WEDM technique to reduce the environmental impact from wet WEDM. A parametric optimization was carried out with the consideration of design variables of current, pulse-on-time (Ton), and pulse-off-time (Toff) and their effect were studied on output characteristics of material removal rate (MRR), and surface roughness (SR) for near-dry WEDM of nitinol SMA. ANOVA was carried out for MRR, and SR using statistical analysis to investigate the impact of design variables on response measures. ANOVA results depicted the significance of the developed quadratic model for both MRR and SR. Current, and Ton were found to be major contributors on the response value of MRR, and SR, respectively. A teaching–learning-based optimization (TLBO) algorithm was employed to find the optimal combination of process parameters. Single-response optimization has yielded a maximum MRR of 1.114 mm3/s at Ton of 95 µs, Toff of 9 µs, current of 6 A. Least SR was obtained at Ton of 35 µs, Toff of 27 µs, current of 2 A with a predicted value of 2.81 µm. Near-dry WEDM process yielded an 8.94% reduction in MRR in comparison with wet-WEDM, while the performance of SR has been substantially improved by 41.56%. As per the obtained results from SEM micrographs, low viscosity, reduced thermal energy at IEG, and improved flushing of eroded material for air-mist mixture during NDWEDM has provided better surface morphology over the wet-WEDM process in terms of reduction in surface defects and better surface quality of nitinol SMA. Thus, for obtaining the better surface quality with reduced surface defects, near-dry WEDM process is largely suitable.

Optimization of process parameters in turning of magnesium AZ91D alloy for better surface finish using genetic algorithm

This research examined at the optimum cutting parameters for producing minimum surface roughness and maximum Material Removal Rate (MRR) when turning magnesium alloy AZ91D. Cutting speed (m/min), feed (mm/rev), and cut depth (mm) have all been considered in the experimental study. To find the best cutting parameters, Taguchi's technique and Response Surface Methodology (RSM), an evolutionary optimization techniques Genetic Algorithm (GA) and Non-dominated Sorting Genetic Algorithm-II (NSGA-II) were employed. GA gives better results of 34.04% lesser surface roughness and 15.2% higher MRR values when compared with Taguchi method. The most optimal values of surface roughness and MRR is received in multi objective optimization NSGA-II were 0.7341 µm and 9460 mm3 /min for the cutting parameters cutting speed at 140.73m/min, feed rate at 0.06mm/min and 0.99mm depth of cut. Multi objective NSGA-II optimization provides several non-dominated points on Pareto Front model that can be utilized as decision making for choice among objectives

Effect of End Milling Process Parameters and Corrosion Behaviour of ZE41A Magnesium Alloy using Taguchi Based GRA

The purpose of the study is to optimize the machining characteristics for milling ZE41A Mg alloy on a CNC milling by Taguchi-based Grey relational analysis (GRA) to achieve the maximum material removal rate (MRR), lowest corrosion rate (CR), and surface roughness (SR). After one week of immersion in simulated body fluid (SBF), weighing samples determined the corrosion rate. The process attributes, which include tool rotation cutting speed, feed rate, and depth of cut, are opted. The experiments were conducted using a Taguchi L16 orthogonal array (OA). Additionally, variance analysis (ANOVA) was used to determine the influence of process parameters on the responses. The study discusses the significance of machining process parameters concerning the degradation behavior of biomedical implant materials in a simulated body fluid (SBF). According to the current study, the most influential parameters in multi-objective optimization are the tool rotation cutting speed and feed rate. Thus, the results obtained with GRA of MRR: 492.25mm3/min, SR: 0.3112µm, and CR: 6.386mm/year with the experimental confirmatory test were close to the expected values. ZE41A Mg alloy machined samples at optimum end-milling parameters enhanced performance in reduced surface roughness and low in-vitro corrosion rate for ZE41A Mg alloy.

Electrochemical Properties and Electrochemical Milling of (TiB + TiC)/TC4 Composites

The (TiB + TiC)/TC4 composite is a new material with superior high-temperature resistance properties and structural strength. However, it cannot be easily machined by conventional methods. Electrochemical machining is an ideal method for the processing of titanium-matrix composites. In this study, the electrochemical properties of (TiB + TiC)/TC4 composites were investigated. The polarization curve of (TiB + TiC)/TC4 in a NaCl solution with a volume fraction of 20% was measured. The decomposition voltage was approximately 7.2 V. Basic electrochemical dissolution experiments were carried out on TC4 and (TiB + TiC)/TC4. The surface morphology was measured to investigate the dissolution mechanism. It was demonstrated that the reinforcing phase will fall off with the dissolution of TC4 and will not participate in the electrochemical dissolution reaction. Finally, electrochemical milling experiments on (TiB + TiC)/TC4 with different voltages and cathode feed rates were carried out to study the removal rate and surface roughness of the material. The material removal rate (MRR) increased, while the surface roughness decreased with the increases in the voltage and feed rate. A maximum MRR of 171.11 mm3/min and minimum surface roughness of 4.281 μm were obtained at a voltage of 50 V with a feed rate of 20 mm min−1.

Simulating turning cycles on CNC lathe machines

It is shown that the turning of the contour shaped surfaces of parts is mainly carried out according to the cycles of rough turning G71, G72, G73 with a finishing pass according to the cycle G70. In any case, the cutting process is quasi-stationary, which determines the need to control the cutting mode to stabilize and optimize the process. It is proposed to use a special program for designing the control program of a CNC machine tool, which, based on a priori information about the technological machining system, performs the simulation of the process. During simulation, in the process of solving the optimization problem according to the criterion of maximum Material Removal Rate, all components of the cutting mode are automatically determined: depth, feed and spindle speed. The results are presented in the form of control files, according to which a control program in G-codes can be compiled to optimize the process. In addition, it is additionally possible to obtain a prediction about the actually machined contour, taking into account the elastic deformation during the cutting process, and data on the correction of the trajectory of the shaping movement in the last pass.

Parametric study and multi-criteria optimization during turning of X210Cr12 steel using the desirability function and hybrid Taguchi-WASPAS method

The present study examines the machining of a cold work tool steel (X210Cr12) using a triple chemical vapor deposition coated carbide tool (Al2O3/TiC/TiCN). The paper is focused on an experimental investigation as well as a modeling and optimization of the working cutting parameters in relationship with the studied material. For that, first, a set of experimental tests were built in order to evaluate the effect of cutting parameters (r, Vc, f, and ap) on the output parameters, namely surface roughness (Ra), cutting force (Fz), insert flank wear (Vb), and 3D roughness distribution. In a second step, a Taguchi L16 (4^3 2^1) design of experiment (DoE) was exploited with the aim to develop a modeling of output working parameters based on the response surface methodology. An optimization of the cutting conditions was performed using the desirability function (DF) approach and the hybrid Taguchi-weighted aggregate sum product assessment method. The desired objective is to obtain optimal cutting regime corresponding to the simultaneous minimization of parameters Ra and Fz, and maximization of material removal rate. The results found show that the factor f influences Ra with 42.55% and that parameter ap affects parameters Fz and Pc with 67.55 and 60.88%, respectively. For the DF and WASPAS methods, the optimal regimes selected is r = 1.6 mm, Vc = 366 m/min, ap = 0.17 mm, f = 0.16 mm/rev and r = 1.6 mm, Vc = 180 m/min, ap = 0.3 mm, and f = 0.08 mm/rev, respectively. The proposed work concerns all mechanical manufacturing companies, as it provides the necessary information on the optimal working conditions of the tool/material pair.

Machining and characterization of holes machined on a biomaterial Ti-6Al-4V ELI using an indigenously developed electrochemical machining cell with IEG control mechanism

This article presents a comprehensive study on the machining and characterization of the holes machined on a biomaterial Ti-6Al-4V ELI of 350 µm thickness with hollow stainless steel tool electrode of outside diameter 250 µm using the tailor-made µ-ECM experimental setup. The distinct feature of the experimental unit is an indigenously made pulse generator circuit and a closed-loop tool feed circuit made from a current-based sensor to retain a constant inter-electrode gap (IEG) between the tool electrode and the workpiece electrode during the machining operation. The machining process parameters are electrolyte concentration (wt % C), voltage (V) and duty factor (% DF). The output responses of interest are Circularity (C), Material Removal Rate (MRR), Taper Angle (TA), Stray Corrosion Zone (SCZ) Width and Radial Over Cut (ROC) of the hole machined. The maximum MRR obtained is 7.2 µg/s at the parametric combination of 12 V, 15 wt % C and 50% DF. The maximum circularity of 0.989 and minimum SCZ width of 309.796 µm is produced by the combination of 8 V, 15 wt % C and 30% DF. The minimum ROC of 181.091 µm is generated by the combination of 10 V, 20 wt % C and 50% DF. The combination of 12 V, 25 wt % C and 40% DF resulted a minimum TA of 0.235 degrees. The machined hole topography study based on the High Resolution Scanning Electron Microscope (HRSEM) images of all the machined holes revealed that the parametric combination of 8 V, 15 wt % C and 30% DF yielded uniform microstructure in the SCZ no pitting corrosion, smooth and precise hole edge. The presence of sodium and bromine is found in Energy Dispersive Spectroscopy (EDS) analysis of the machined hole surface. In addition to these elements, titanium and vanadium are found in the used tool electrode.

Performance evaluation of electro-spark eroded high-volume fraction of Cr-Fe-Ni superalloy

Current research aims to execute a viability study of electro-spark erosion technique to process Inconel 690, a high-volume fraction of Cr-Fe-Ni superalloy (∼32% Cr). The Box-Behnken design of response surface methodology with varying processing conditions is used to execute the experimental trails. Process performance is examined in terms of material removal rate and surface topography. The surface conditions of the processed surface are studied using scanning electron microscopy. The tool wear character and tribological behavior of the processed surface are also scrutinized to check the post-process consequences. The study explores the formation of oxide layers, craters, spherical droplets, and micro-cracks on the surface processed at Ton: 118 mu; Toff: 45 mu; Ip: 130 mu; Sv: 50 V ( parametrical settings for maximum material removal rate), and at Ton: 118 mu; Toff: 30 mu; Ip: 220 mu; Sv: 50 V ( parametrical settings for maximum surface roughness) attributing a deteriorating surface quality. The maximum material removal rate of 9.38 mm3/min and minimum surface roughness of 0.47 μm are achieved. A significant improvement of approximately 20 HV in micro-hardness is detected owing to the formation of a recast layer on the processed surface. Consequently, a noticeable improvement is observed in the wear resistance of the processed surface.

Enhancing EDM performance characteristics of Inconel 625 superalloy using response surface methodology and ANFIS integrated approach

The objective of the present work is to find out the optimal level as well as the influence of the electrical discharge machining (EDM) process on material removal rate (MRR), surface roughness (SR), and tool wear rate (TWR). The machining is carried out on Inconel 625 superalloy by using a copper tool electrode in a kerosene submerged medium. The optimum level of input parameters such as current, pulse on time (Ton), pulse off time (Toff), and gap voltage are calculated to achieve maximum MRR and minimum SR and TWR. L27 orthogonal design is used to perform the experiments and optimum levels of MRR, SR and TWR have been obtained by the response surface methodology (RSM) and adaptive network-based fuzzy inference system (ANFIS) approach. Analysis of variance (ANOVA) is used to identify the significant and non-significant parameters. For implementing, RSM methodology, the Design Expert 13 software was used for the optimization and modelling of the experimental data. MATLAB R20b software was utilized for developing the ANFIS model. It is found that the pulse on time (Ton) and pulse off time (Toff) are the significant parameters for MRR and SR and more wire wear increases as the value of pulse on time (Ton) increases. The obtained quadratic RSM model is found significant for MRR, SR, and TWR. Similarly, ANFIS proved to be accurate for the optimization of output responses with model accuracy percentages noted as 95.55% for MRR, 90.35% for TWR, and 97.82% for SR. The obtained results show that the predicted values and experimental values are very well suited for the proposed objective. The obtained data can be utilized for the EDM industry during the machining of Inconel alloy.

Experimental investigation on material removal rate, kerf width, surface roughness and the dimensional accuracy the accuracy of hole in Inconel 718 using wire electric discharge

The main objective of research work to investigates the effects of various process parameters on the material removal rate, kerf width, surface roughness and the dimensional accuracy of Inconel 718 workpiece subjected to wire electrical discharge machining (WEDM). The input parameters of this study were wire speed, wire tension and flushing rate. The individual as well as interacting effect of process parameters on surface roughness, kerf width and dimensional accuracy. It was found that, in order to minimize the diameter error for circular cuts, the flushing rate, wire speed and wire tension should all be held at maximum values. The wire tension and wire speed both exhibited an insignificant effect on the surface roughness. The dimensional accuracy of the machined holes decreased with increasing wire tension and in order to achieve maximum material removal rate, wire tension and wire speed must be around 1400–1600 gf and at 8 m/min respectively. The flushing rates over 5 L/min had a negligible effect on the material removal rate. The highest kerf width and material removal rate were obtained at medium values of wire tension (1400–1600 gf) and wire speed (8 m/min). The lowest diameter error is achieved in a combination of maximum flushing rate, wire speed and wire tension. Factors such as circularity, cylindricity and hole diameter were closely examined in order to gain a deeper understanding of their influence on dimensional accuracy.

Ball-end milling cutter design method towards the maximum material removal rate under surface roughness constraints

Cutter design and selection, as one of the indispensable tasks in discrete parts' manufacturing process planning, has seldom been investigated in terms of high machining quality and machining efficiency. In order to fill this gap, this paper studies the influences of main geometric parameters of ball-end cutter (helix angle, flute number, cutter radius) on surface roughness and material removal rate (MRR). Firstly, it is revealed that the fundamental reason why the helix angle affects the cutting force coefficients is the oblique angle, not the axial height or axial position angle. And a novel method of cutting force coefficients prediction for newly designed cutter based on local helix angle is proposed. Then, the influences of cutter parameters on surface roughness and MRR are investigated by theoretical and experimental method. Based on this analysis, cutter evaluation models for machining quality and machining efficiency are established, respectively. Particle swarm optimization (PSO) is used as optimization method to search the optimal cutter. Finally, a novel cutter design method combined with cutter evaluation models is proposed to obtain better surface performance and machining efficiency. According to the experimental results, it can be proved that the cutter designed by this method can maximize MRR under the constraint of meeting the parts' surface roughness requirements. This is of great significance for improve parts' performance and reduce machining cost.

Study on Lapping Process of 304 Stainless Steel Using Tribochemical Fixed-Abrasive Lapping Platen

Based on the previous research on the 304 stainless steel lapping and polishing in our research group, the tribochemical fixed-abrasive lapping platen for 304 stainless steel lapping and polishing were developed. The effects of the different pressure, the rotation speed, the lapping time and the abrasive size on the surface roughness and the material removal rate (MRR) were researched. It was concluded that when the abrasive size is 28 µm, the lapping time is 15 min, the lapping speed is 90r/min, the lapping pressure is 27.580 KPa, and the maximum MRR is 412.524 nm/min. When the lapping time is 15 minutes, the rotating speed is 15 r/min, the lapping pressure is 13.790 KPa, the surface roughness Ra drops to 41nm. These findings show that the influence degree on the MRR from better to worse is the abrasive size, the lapping pressure, the rotation speed of the lapping platen and the lapping time. The order of the influence degree on the surface roughness from better to worse is the abrasive size, the rotation speed of the lapping platen, the lapping pressure and the lapping time. The results can give an important reference for next study on the tribochemical mechanical lapping of fixed-abrasive.

Experimental research on WEDM of copper tungsten alloy based on orthogonal test

Abstract WEDM is an important process method for machining copper tungsten alloy electrode. Using orthogonal experiment, range analysis and variance analysis, the influence of pulse width, peak current and servo voltage on the material removal rate in WEDM of copper tungsten alloy was studied. The parameter combination was optimized under the maximum material removal rate. The results show that after the duty cycle is set, the degree of influence on material removal rate is as follows: peak current, servo voltage and pulse width. Ton 50μs, IP 12A and SV 8V, the maximum material removal rate is 25.28 mm2/min, which has an important theoretical guidance for the realization of rapid and efficient WEDM processing of copper tungsten alloy electrode.

Parametric Optimization of Material Removal Rate of EDM (AISI-4147) by using Taguchi Approach

Electric discharge machine is a non-conventional machining. In which there is no contact between tool and work piece. By EDM process machining of hard material components that are difficult to machine such as heat treated tool steels, ceramics, composites, carbides, heat resistance steel which are used in die and mould producing industries, aero space and nuclear industries. EDM is a non-contact type technique of material removal and in this spark is used to remove the material from the work piece. Since the EDM is an attractive means of making tool and dies with high accuracy in dimension and surface finish quality of micro scale parts. The present experimental research studies the process parameters that are influencing the machining concert and its productivity. A collective approach is used for the optimization in parameters and performance characteristics which are based on Taguchi method. The experiments are based on Taguchi‟s L9 orthogonal array. The reaction graph and reaction table of each near of machining constraints are took from Taguchi method to select the optimum levels of machining factors. In the work, the machining parameters for thesis are current, pulse on time and pulse off time, which are optimized for minimum tool wear rate (TWR), maximum material removal rate (MRR) and minimum surface roughness during electro discharge machining of AISI 4147. Analysis of Variance is also used to find out variable affecting the various responses mentioned above.