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Evaluations of surface morphology in EDMed MoSi2-SiC intermetallic ceramic composite surfaces

Machining a 5 mm hole in molybdenum disilicide-silicon carbide, an extremely rigid and robust intermetallic compound, is challenging. The effectiveness of Electrical Discharge Machining (EDM) was evaluated using standard metrics such wear ratio, material removal rate, electrode wear rate, average surface roughness, and geometrical tolerances. This research article notably features an in-depth analysis of the melting and evaporation mechanism of metal removal, along with the topography of the machined surface, using an EDS and XRD report, machined electrodes, and WEDM machined brass wire. Surface morphologies have been characterized using scanning electron microscopy (SEM) at the several experimental levels for the machined composite, electrode, and wire. Current of 5 A, pulse on time of 8 µs, pulse off time of 6 µs, spark gap of 0.16 mm, dielectric pressure of 20.5 kg/cm2, metal removal rate of 0.00117 g/min, electrode wear rate of 0.00011 g/min, wear ratio of 10.60%, and surface roughness of 0.441 µm achieved the best results. According to the evaluation and analysis of porosity values, the level 1 trial’s hole has a porosity value of 0.966%, the level 3 trial’s t hole has a porosity value of 5.655%, and the level 2 trial’s hole has a porosity value of 1.424%. The experimental results on the machined surface of the copper electrode show that by selecting the best level of process parameter combination, the machining accuracy with good geometrical tolerances, surface quality are enhanced and number of micro voids, and size of cracks were all minimized.

Electric Discharge Machining of Ti6Al4V ELI in Biomedical Industry: Parametric Analysis of Surface Functionalization and Tribological Characterization.

The superior engineering properties and excellent biocompatibility of titanium alloy (Ti6Al4V) stimulate applications in biomedical industries. Electric discharge machining, a widely used process in advanced applications, is an attractive option that simultaneously offers machining and surface modification. In this study, a comprehensive list of roughening levels of process variables such as pulse current, pulse ON time, pulse OFF time, and polarity, along with four tool electrodes of graphite, copper, brass, and aluminum are evaluated (against two experimentation phases) using a SiC powder-mixed dielectric. The process is modeled using the adaptive neural fuzzy inference system (ANFIS) to produce surfaces with relatively low roughness. A thorough parametric, microscopical, and tribological analysis campaign is established to explore the physical science of the process. For the case of the surface generated through aluminum, a minimum friction force of ~25 N is observed compared with the other surfaces. The analysis of variance shows that the electrode material (32.65%) is found to be significant for the material removal rate, and the pulse ON time (32.15%) is found to be significant for arithmetic roughness. The increase in pulse current to 14 A shows that the roughness increased to ~4.6 µm with a 33% rise using the aluminum electrode. The increase in pulse ON time from 50 µs to 125 µs using the graphite tool resulted in a rise in roughness from ~4.5 µm to ~5.3 µm, showing a 17% rise.

A Response Surface Modeling Study on Effects of Powder Rate and Machining Parameters on Surface Quality of CoCrMo Processed by Powder Mixed Electrical Discharge Machining

Due to the high mechanical strength of the metals used in implant manufacture, which makes them difficult to work with using other machining techniques, electrical discharge machining (EDM) is frequently employed in the production of implants. In this study, the effect of powder ratio and other EDM parameters used in the machining of CoCrMo alloy, which used in implant production widely, with powder-mixed EDM on the surface roughness of the machined part was investigated through the response surface methodology. AISI 316L stainless steel was chosen as the electrode material, and Ti6V4Al was chosen as the additive powder, taking into account their biocompatibility properties. Using a Taguchi L16 array, an experimental design was created by selecting 4 levels for each parameter of additive ratio, discharge current, pulse on time (Ton), and pulse off time (Toff). The response surface method was used, along with the experimental data, to estimate how the parameters affected the arithmetic average roughness (Ra) and mean roughness depth (Rz).

Processing of Al/SiC/Gr Hybrid Composite on EDM by Different Electrode Materials Using RSM-COPRAS Approach

The present research used the stir-casting method to develop an Al-based composite. The developed composite exhibited challenges while being processed on conventional machining. Thus, a non-traditional machining process was opted to process the composite. The machining variables selected for the current research were the pulse off time (Toff), pulse on time (Ton), servo voltage (SV), current (I), and tool electrode. Three tool electrodes (SS-304, copper, and brass) were used to process the developed composite (Al/SiC/Gr). The experimental plan was designed using response surface methodology (RSM). The output responses recorded for the analysis were the material removal rate (MRR) and tool wear rate (TWR). The obtained data was optimized using complex proportional assessment (COPRAS) and machine learning methods. The optimized settings predicted by the RSM–COPRAS method were Ton: 60 µs; Toff: 60 µs; SV: 7 V; I: 12 A; and tool: brass. The maximum MRR and TWR at the suggested settings were 1.11 g/s and 0.0114 g/s, respectively. A morphological investigation of the machined surface and tool surface was conducted with scanning electron microscopy. The morphological examination of the surface (machined) presented the presence of cracks, lumps, etc.

Experimental analysis of SS316 using brass electrode in electric discharge machining

The current work is directing an exploratory study of EDM on SS316 using brass metal as the electrode. Copper and zinc are combined to form the alloy known as brass. Small tubular electrodes are made of brass materials. Brass is significantly simpler to process, but it does not have the same wear rate as copper or tungsten. Because new material may be introduced continually all across the EDM machining process, the EDM electrodes need not be resistant to wear or arc erosion.These uses current, pulse on time and pulse off time as input parameters. Gap voltage, dielectric, and cutting depth were fixed parameters in the experiments performed. The resulting observations are material removal rate, tool wear rate, and surface roughness determined to quantify the occurrence of EDM. To collect and evaluate the impact of various process parameters to improve response variables such as material removal rate (MRR), tool wear rate (TWR), and surface roughness (SR) according to the three level and three variable (L9) Taguchi orthogonal matrix.

Optimization of process parameters for wire electrical discharge machining of aluminium based metal matrix composite by Taguchi’s approach

Aluminum alloy is a common material used in various engineering projects due to its exceptional properties. Due to its exceptional mechanical properties, composites are becoming more popular.Metal Matrix Composites (MMC) showing better properties than aluminium alloy by the addition of reinforcements such as Al2O3, SiC, BC and BN. Due to this, the machining of these materials becomes difficult by conventional methods of machining and there is a need of developing alternate machining practices. WEDM (Wire Electrical Discharge Machining) is one type of non-traditional forms of cutting that was intended for machining harder materials. The various independent variables considered in this investigation are pulse on duration (Ton), pulse off duration (Toff) to study the effects of these variables on various performance indicators, such as surface roughness, material removal rate. Multiple Regression Analysis was adopted to analyze the relationship between the various process variables and the consequent desired output attributes.

Optimization of EDM process parameters using MCDM based on customer preference rating method

Nowadays, multi-objective optimization tools have been used in manufacturing processes to decide the optimal process parameters. Optimization method with a more advanced tool is required to obtain the finest EDM process parameters such as peak current, voltage, pulse on duration, pulse off duration, pressure. This research work utilizes the Multi-Criteria Decision Making Method (MCDM) for identifying the optimal process parameters according to customer preference rating method (CPR). CPR draws a weightage to the output responses of the machine and characteristics of the machined surface as per customer requirement. Genetic Algorithm (GA) and TOPSIS are extensively involved in solving multi-objective optimization problems. Optimization of process parameters were determined using Genetic Algorithm (GA) integrated with TOPSIS to achieve higher Metal Removal Rate, Micro Hardness, low surface roughness, tool wear rate and actual depth. There are fifty Pareto-optimal solutions performed and the best solution has been selected based on rank. The optimal solution of the GA was given to the TOPSIS as input for further improvement. The optimal value obtained through GA has been enhanced with TOPSIS.

Effect of graphene dispersed coconut biodiesel on the Micro ED milling characteristics of Inconel 718 alloy

Micro Electrical discharge milling is a familiar micromachining process for machining of complex microstructures using a cylindrical tool. In this research work, the influence of process parameters namely capacitance, voltage, threshold on response indicators during machining of Inconel 718 with coconut biodiesel and graphene nano powder dispersed coconut biodiesel is investigated in detail. Further, surface-topography of the machined surface was critically examined using scanning electron microscopy and three-dimensional non-contact roughness tester. Graphene nano powder concentration (0.3 g l−1) increased the MRR around 68% compared to coconut biodiesel (BD). A medium order of capacitance (10 nF) offered a maximum MRR irrespective of dielectric used. With higher order capacitance, the minimum TWR is obtained due to longer pulse off duration. High surface finish is achieved with graphene nano powder dispersed coconut BD due to uniformly distributed of craters on the machined surface. Recast layer thickness is 3.08 μm, 1.62 μm and 2.34 μm with coconut biodiesel, 0.3 g l−1 and 0.6 g l−1 graphene particles mixed coconut biodiesel, respectively. Minimum recast layer is observed with graphene particles mixed coconut biodiesel under considered parametric conditions due to lesser eroded particle deposition. EDS results confirm that the sedimentation of graphene nano powder (increase in carbon %) on work surface results in increase in hardness. Crater size, voids and cracks were reduced with graphene nano powder dispersed coconut BD due to uniform distribution of heat energy over machining region. Results showed that the graphene nano powder mixed coconut biodiesel can be the substitute for mineral oil.

Effect of time-modulation bias on polysilicon gate etching

The etching characteristics were studied via time-modulation bias (bias pulsing) by varying the pulsing parameters. The etch profiles were verified using polysilicon gate structures with dense and isolated patterns. Ion energy was defined as the peak-to-peak voltage (V pp) controlled by the RF bias power. The durations of the on period and off period (off time) of bias pulsing were adjusted by the pulse frequency and duty cycle. Profile evolution was observed in the variations in V pp and off time. Increasing the ion energy induced vertical profiles of dense patterns and the tapered profiles of isolated patterns. Extending the off time of bias pulsing induced tapered profiles of dense patterns and vertical profiles of isolated patterns. These results indicated that increasing the ion energy and pulse off time simultaneously was the direction to achieve anisotropic etch profiles for both the isolated and dense patterns.

High energy electrons induced by nonlinear effect in synchronized dual-level radio frequency pulsing capacitively coupled plasmas

The surface charging effect of positive ions at the trench bottom during the etching of dielectric materials has become a severe problem with the shrinkage of electronic feature dimensions. Pulsed plasmas have been widely used to overcome surface charging issues during plasma etching in industry. In this work, synchronized dual-level radio frequency pulsed modulation on capacitively coupled plasmas is investigated based on 1D3V particle-in-cell/Monte Carlo collision simulations. It is found that the plasma always remains a certain initial density during the dual-level pulse modulation, as the high frequency (HF) source still presents during pulse off time (with a reduced voltage amplitude), which may facilitate high processing efficiency. Meanwhile, many HF sheath oscillations are simulated at the initial stage of a pulse period, which induces vast high energy electrons to strike the electrode. When the HF voltage is maintained at a very low value during the pulse off (i.e. 0.1), more electrons with higher energy bombard the bottom of the trench, effectively alleviating the charging effect. Furthermore, the nonlinear behavior of sheath oscillations is proved to be very sensitive to dual-frequency voltage amplitudes and pulse ramp-up times.

A modified approach on modeling-design-optimization procedure for cutting of pure titanium using wire electric discharge machining (WEDM)

The main goal of this study is to introduce a modified approach to the modeling-design-optimization triple procedure for cutting pure titanium. The manufacturing process is selected as wire electric discharge machining. To achieve a smooth cutting operation of the pure titanium plate (grade 2), the independent cutting parameters, peak current, pulse off time, pulse on time, spark gap voltage, wire feed, and wire tension are taken into consideration. Their effects on machining rate, surface roughness, dimensional deviation, and wire wear ratio are also examined. The mathematical model of the process is determined with the multiple nonlinear neuroregression approach. Stability study that measures the ability to realize the cutting parameters was conducted during the modeling phase. This type of step has not been used as a criterion for model determination before in modeling studies. Comparisons were accomplished with the traditional and nontraditional models, and it is shown that the nontraditional models’ accuracy was more reasonable. Besides, this study contains the design optimization of the manufacturing process parameters using modified version of different stochastic and derivative-free optimization methods: differential evaluation, random search, simulated annealing, and Nelder-Mead algorithm, (MDE, MRS, MSA and MNM) simultaneously.

MRR and TWR Study of Powder Mix EDM and Pure EDM Based on Response Surface Methodology

Powder-mixed electrical discharge machining (PMEDM) is the process of enhancing the output of the machined surface by combining dielectric fluid with various types of powders. This process is quickly gaining acceptance in the electrical discharge machining (EDM) sector. The purpose of this study is to determine whether a dielectric fluid containing tantalum carbide (TaC) powder can improve material removal rate (MRR) also lessen tool wear rate (TWR) during the subsequent EDM machining of stainless steel material. During the machining, the material removal rates, tool wear rate, and mathematical models of two different EDM mediums were examined. For the machining procedure, kerosene dielectric fluid containing TaC powder at a concentration of 25.0 g/L was used. The machining input variables were used peak current, pulse on time, and pulse off time. We determined how these variables affected the MRR and TWR of the copper-based EDMed electrode tools. During electrical discharge machining, the MRR for stainless steel (SUS 304) was increased by MRRPMEDM by 4.3 to 5.3% and TWRpEDM was reduced by 37.9% when TaC powder additive was used. Optimized results also show that TWR and maximum MRR can be achieved at 81.98% and 13.779mm3/min respectively with 83.50% desirability whenever the pulse on-time and pulse off-time are 6.20 µs and 6.50 µs respectively. The models are reliable and can be used to forecast the machining responses within the experimental region, it can be said. The MRR and TWR model for EDM with TaC powder additive (MRRPMEDM) identifies current as the most significant factor, followed by pulse on time and pulse off-time.

Analyzing the geometrical errors of silicon nitride-titanium nitride on performing electric discharge machining using response surface methodology

Ceramic materials that find their applications in die extrusion and the balls used in bearings have a longer service life compared to that of traditional materials. Since ceramic materials are having high hardness properties, they cannot be machined traditionally, because traditional machining processes rely on the relative hardness of the tool material to the workpiece material. However, electric discharge machining aids in the machining of ceramic composites with good surface integrity performed by the copper electrodes. As a result, Spark Erosion Machining was used to investigate the geometrical tolerance of Si3N4-TiN composites. Electric discharge machining parameters range over five levels, like current from 2 to 6 A, voltage from 30 to 50 V, dielectric pressure (kg/cm2) from 16 to 24 kg/cm2, pulse on time (µs) from 15 to 19 μs, and pulse off time (µs) from 7 to 11 μs have been analyzed through an L25 orthogonal array. Main effect plots and two-dimensional and three-dimensional interaction plots have been drawn to investigate the effect of the input parameter on the output parameters like circularity, cylindricity, perpendicularity, runout, top radial overcut, and bottom radial overcut. The grey relational analysis is employed in finding the significant parameters through analysis of variance, and for each model, the regression coefficient is found. The optimal input parameters for the desired output parameters are found to be a current of 5.855 A; pulse-on time of 16.55 µs; pulse-off time of 7.22 µs; dielectric pressure of 16.32 kg/cm2; and a voltage of 40.3729 V. This research will help to enhance the geometric accuracy and precision of machined holes in Si3N4-TiN composites. The results are finally estimated using a residual data analysis, which shows that spark erosion can be improved.

Simultaneous optimization of wire electric discharge drilling responses

Trepan drilling with wire electrical discharge machine is performed to make macro size hole in tool steel. Electrical discharge drilling is thermal energy based non-traditional machining process. In this process metal removes from the work is due to melting phenomena. In present study L9 orthogonal array approach is used for the drilling experimentation. Pulse on time, pulse off time, wire feed and current are elected as machining parameters. After experimentation surface quality and material removal rate are considered as responses of drilled hole. Grey relational technique is used to determine the optimum level of machining parameters for drilled hole quality responses. Wire feed is found significant factor followed by pulse off time, pulse on time and current for the combined responses.

Optimization of Wire Cut Electro Discharge Machining Process Parameters for HCHCr-D2 Steel

Abstract: The process parameters for wire cut electro discharge are optimised in this paper. The analysis takes into account the process parameters pulse on time, pulse off time, and current. High Carbon High Chromium (HCHCr-D2) steel is a high tensile strength alloy that is typically utilised in cold dies and tooling applications that demand a high level of and dimensional accuracy. For the machining procedure, a rectangular-shaped plate of the alloy steel HCHCr-D2 was used. By examining the material removal rate (MMR) and surface roughness, wire cut electro discharge machine (WEDM) performance using a molybdenum wire has been evaluated (SR).

Prediction of Wire-EDM Machining Parameters for Optimum of Surface Finish and MRR in an Aluminum Alloy 7075-T6

Wire-cut EDM is a process that works by continuously feeding a wire electrode under tension on a vertical axis. A discharge voltage is applied through the wire, crosses via a dielectric liquid, and strikes the grounded work-piece. The work-piece is moved in an X-Y plane to trace a cut pattern through the material. The process is applicable to cut complex and elaborate shapes of workings in all conductive, hard and thicker materials. An appropriate modeling can advance the machining presentation and the product exactness. Surface Response Methodology (RSM) coupled with grey relation analysis method has been proposed to predict the performance characteristics namely the surface roughness and material removal rate of WEDM on the alloy AL7075-T6 work-piece material. Selected input parameters such as pulse on time, pulse off time, wire feed, wire tension and dielectric pressure. ANOVA is applied to determine significance of the input parameters for optimizing the process. Keywords Wire-cut EDM, RSM, grey relation analysis, ANOVA, WEDM

Investigation of aluminum alloy 6061 in Wire-EDM regarding surface roughness and material removal rate by adopting optimization techniques

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.

Effect of Process Parameters on Material Removal Rate and Surface Characteristics in WEDM Machining of Titanium Grade 7 Alloy

Wire Electrical Discharge Machining (WEDM) is a modern machining technique. WEDM is electro-thermal non-conventional machining processes follow to cut very hard materials. WEDM is non-traditional material cutting operation employed to machine complex geometries and shapes. The present paper attempts to study surface and sub-surface variations during WEDM of titanium grade 7 alloy with Brass wire coated with Zn. This paper presents experimental studies with varying three key process parameters viz. pulse ON time (TON), pulse OFF time (TOFF), peak current (IP). The investigation is focused on assessment of material removal rate, surface roughness as well as recast layer. Scanning electron Microscope (SEM) examinations are carried out on surface textures and are discussed in the article. The obtained results indicated that the stretched pulse time discharges more energy causes rough surface finish. The MRR is also strongly influenced by TON.

Precise Internal Turning of Axi-symmetric SS316 Thin-walled Component: Experimentations on ED-Machining Setup

ABSTRACT Axis-symmetric thin-walled cylindrical components like couplers and concentric reducers are needed in mechanical assemblies. These components do not have enough rigidity to hold in the chuck for conventional machining. It is difficult to control their radial dimensions accurately and cost-effectively. In this work, an attempt is made to enlarge the diameter of axis-symmetric thin-walled cylindrical components. Electric discharge machining (EDM) with a centreless turning attachment is utilised. Three variables were selected as input variables: impulse current (IP), pulse on time (Ton), and pulse off count (Toff count). Workpiece RPM, electrode gap, spark, lift, and machining time were constant parameters. Response surface methodology (RSM) was used in planning the experiments. The response variables were material removal rate (MRR), enlargement in diameter (EN), and circularity (Cir). It was found that MRR and EN increase with the increase in IP and Ton and decrease with the rise in Toff time. The values of optimum process parameters found at impulse current (15 A), pulse on time (490 µs) and pulse off count (6) were MRR (366 mg/min), enlargement in diameter (229 µm) and circularity (0.014 µm). Moreover, the sample’s topography changed as hardness and corrosion resistance increased.

Bakır ve pirinç elektrot ile EDM yönteminde soğuk iş takım çeliği işlemede MRR, EWR ve KERF Analizi

In this study, holes were drilled on the Sleipner cold work tool steel with a hardness of 60-62 HRC by copper and brass electrodes using three different current values (50, 25, 12.5 A), pulse on times (3, 6, 9 μs) and pulse off times (4, 6, 8 μs) parameters in the EDM method; the effects of these working parameters on machining times, material removal rate (MRR), electrode wear rate (EWR), the hole inlet-outlet diameters of the machined parts, the kerf on workpiece and electrode were analyzed. As a result of the analyzes made, in the use of copper electrodes, the MRR increased by 311.25% on average compared to the use of brass electrodes, while the EWR and machining time decreased by 42.01% and 38.46%, respectively. The increase in sparking and thermal effects between the workpiece and the electrode resulted in an increase in the MRR and a decrease in the machining time. In the use of copper and brass electrodes with different processing parameters, the inlet diameters of the drilled holes were found to be larger than the outlet diameters as well as an irregular kerf formation was observed due to debris evacuation due to worn electrodes.