In electrical discharge machining (EDM) process, the production of separate electrodes for rough, semi‐rough and finish machining of dies and moulds having complex surfaces…
Abstract
Purpose
In electrical discharge machining (EDM) process, the production of separate electrodes for rough, semi‐rough and finish machining of dies and moulds having complex surfaces, results in high cost and long lead‐time in manufacturing. The purpose of this paper is to describe the machining performance of electrodes formed by using copper wire bunches (WBs) positioned to conform the surface to be machined was experimentally and theoretically analyzed. In the study, the variations in the machining rate, electrode wear rate, relative wear and workpiece surface roughness were examined for various discharge current and pulse‐time settings.
Design/methodology/approach
Copper WBs positioned to conform the surface to be machined in electric discharge machining. The variations in the machining rate, electrode wear rate, relative wear and workpiece surface roughness were examined experimentally for various discharge current and pulse‐time settings. The WB electrodes (WBEs) are proven to be satisfactory as electrodes for roughing operations in electric discharge machining.
Findings
The increase in number of wires and pulse energy result in decrease of relative wear for each wire in the electrode. The increase in number of wires in electrodes causes increase in machining area and in machining time in WBE method. With the increase of discharge current and pulse time, the electrode wear rate and material removal values increase and machining time decreases. By using the mathematical models obtained from the result of the experiments, the electrode wear rate, material removal rate, relative wear and the set length of wires for the desired cavity profile can be calculated. The labor cost of electrode manufacturing in the WBE method is lower compared to conventional solid electrodes. The use of WBE method for rough machining decreases machining cost and time. The use of WBE method decreases both the number of the electrodes required and the delay in starting machining due to the preparation of electrode in EDM.
Originality/value
This paper introduces the benefits of using WBE in electric discharge machining; wear and material removal characteristics of WBEs are introduced; the surface roughness characteristics of surfaces produced by WBEs are examined experimentally; and the effect of number of wires used in WBEs given (experimental findings).
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Devrim Anil and Can Çoğun
The purpose of this paper is to produce electric discharge machining (EDM) electrodes by using stereolithography (SLA) rapid prototyping technique and investigate the machining…
Abstract
Purpose
The purpose of this paper is to produce electric discharge machining (EDM) electrodes by using stereolithography (SLA) rapid prototyping technique and investigate the machining performance of these electrodes. In the experimental part of the study, the performance of solid copper and copper‐coated SLA (cc/SLA) electrodes are observed and compared.
Design/methodology/approach
The performance outputs such as material removal rate, machining depth, workpiece surface roughness and electrode front surface wear are used as metrics of comparison. The temperature measurements taken from the face of both solid copper and cc/SLA electrodes indicated that the heat build up during machining significantly accelerated the failure of cc/SLA electrodes.
Findings
The paper finds that circulating the cooling liquid inside the internal cooling channels formed with SLA technique, elongated the life of cc/SLA electrodes by dissipating the heat from the coating.
Originality/value
The Fluent Computational Fluid Dynamics (CFD) Software is used to numerically analyze various aspects of cooling of cc/SLA electrodes. The key findings of the study are presented in this paper.
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Ramesh S. and Jenarthanan M.P.
This study aims to focus on experimenting the performance of aluminum (Al) powder mixed electric discharge machining (PMEDM) of two different materials viz plastic mould die steel…
Abstract
Purpose
This study aims to focus on experimenting the performance of aluminum (Al) powder mixed electric discharge machining (PMEDM) of two different materials viz plastic mould die steel (AISI P20) and nickel-based super alloy (Nimonic 75). This experimental study also focuses on using three different tool materials such as copper, brass and tungsten to analyze their influence on the process output. These materials find many uses in industrial as well as aerospace applications. The performance measures considered in this work are material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR).
Design/methodology/approach
The experimental design used in this work is based on Taguchi’s L18 orthogonal array. Besides considering work and tool material as one of the process variables, other process variables are peak current (Ip), pulse on time (Ton) and concentration of powder (Cp). The analysis of variance (ANOVA) is performed on the experimental data to determine the significant variables that influence the output.
Findings
It is found that copper produced maximum MRR and brass tool exhibited higher TWR. However, the surface finish of the machined work piece was very much improved by using the brass tool. Though the performance of tungsten tool lies between the above two tool materials, it showed very little wear during EDM with or without the addition of Al powder.
Originality/value
The experimental investigation of PMEDM of nickel-based super alloy (Nimonic 75) has not been attempted before. Besides that, the study on the influence of tungsten tool on the performance of EDM is also very limited.
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Atul Raj, Joy Prakash Misra, Dinesh Khanduja and Vikas Upadhyay
The purpose of this study is to examine the postprocessed wire tool surface using scanning electron microscopy and find out the streamlined conditions of input process variables…
Abstract
Purpose
The purpose of this study is to examine the postprocessed wire tool surface using scanning electron microscopy and find out the streamlined conditions of input process variables using multi-objective optimization techniques to get minimum wire wear values.
Design/methodology/approach
A federated mode of response surface methodology (RSM) and artificial neural network (ANN) is used to optimize the process variables during the machining of a nickel-based superalloy.
Findings
The study explores that with the rise in spark-off time and spark gap voltage, the rate of wire tool consumption also escalates.
Originality/value
Most of the researchers used the RSM technique for the optimization of process variables. The RSM generates a second-order regression model during the modeling and optimization of a manufacturing process whose major limitation is to fit the collected data to a second-order polynomial. The leading edge of ANN on the RSM is that it has comprehensive approximation capability, i.e. it can approximate virtually all types of nonlinear functions, including quadratic functions also.
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Fred L. Amorim, Armin Lohrengel, Volkmar Neubert, Camila F. Higa and Tiago Czelusniak
This work is focused on the investigation of direct production of electrical discharge machining (EDM) electrodes through the selective laser sintering (SLS) technique using a new…
Abstract
Purpose
This work is focused on the investigation of direct production of electrical discharge machining (EDM) electrodes through the selective laser sintering (SLS) technique using a new metal-matrix composite material made of molybdenum and a copper-nickel alloy (Mo-CuNi). The influence and optimization of the main SLS parameters on the densification behavior and porosity is experimentally studied. Additionally, EDM experiments are performed to evaluate the electrodes performance under different machining conditions. The paper aims to discuss these issues.
Design/methodology/approach
The new EDM electrode material used was a powder system composed of Mo and pre-alloyed CuNi. A systematic experimental methodology was designed to evaluate the effects of layer thickness, laser scan speed and hatch distance. The densification behavior, porosity and surface morphology of the samples were analyzed through microstructural and surface analysis. EDM experiments were conducted under three different regimes in order to observe the electrodes behavior and performance. The results were compared with copper powder electrodes manufactured by SLS and solid copper electrodes EDMachined under the same conditions.
Findings
The experimental results showed that the direct SLS manufacturing of composite electrodes is feasible and an adequate combination of parameters can produce parts with good quality. The laser scan speed has a great effect on the densification behavior of the samples, while the effect of hatch distance on the porosity is more visible when the overlapping degree is considered. The overlapping also had a significant effect on the surface morphology. The EDM results showed that the Mo-CuNi electrodes had superior performance to the copper powder electrodes made by SLS for all the EDM regimes applied, but inferior to those achieved with solid copper electrodes.
Originality/value
Significant results on the direct SLS manufacturing of a new material which has a great technological potential to be used as an EDM electrode material are presented. Valuable guidelines are given in regard to the SLS optimization of Mo-CuNi material and its performance as an EDM electrode. This work also provides a systematic methodology designed to be applied to the SLS process to produce EDM electrodes.
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Vaibhav Sidraya Ganachari, Uday Chate, Laxman Waghmode, Prashant Jadhav and Satish Mullya
Many engineering applications in this era require new age materials; however, some classic alloys like spring steel are still used in critical applications such as aerospace…
Abstract
Purpose
Many engineering applications in this era require new age materials; however, some classic alloys like spring steel are still used in critical applications such as aerospace, defense and automobile. To machine spring steel material, there exist various difficulties such as rapid tool wear rate, the rough surface formation of a workpiece and higher power consumption. The purpose of this paper is to address these issues, various approaches in addition to electrical discharge machines (EDM) are used such as dry EDM (DEDM) and near dry EDM (NDEDM).
Design/methodology/approach
This study focuses on these two approaches and their comparative analysis with respect to tool wear during machining of spring steel material. For this study, current, gap voltage, cycle time and dielectric medium pressure are considered input variables. This study shows that the near dry EDM approach yields better results. Hence, the thermo-electrical model for this approach is developed using ANSYS workbench, which is further validated by comparing with experimental results. This thermo-electrical model covers spark radius variation and formation of temperature profile due to electric discharge. Transient thermal analysis is used to simulate the electric discharge machining.
Findings
It is observed from this study that discharge environment parameters such as debris concentration and fluid viscosity largely influences the dielectric fluid pressure value. Experimental results revealed that NDEDM yields better results in comparison with DEDM as it shows a 25% lesser tool wear rate in NDEDM.
Originality/value
The range of predicted results and the experimental results are in close agreement, authenticating the model.
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Mounir Elleuch, Habib Ben Bacha, Faouzi Masmoudi and Aref Y. Maalej
The aim of this paper is to illustrate a solution that can be used to reduce the severity of breakdowns and improve performances in the cellular manufacturing (CM) system with…
Abstract
Purpose
The aim of this paper is to illustrate a solution that can be used to reduce the severity of breakdowns and improve performances in the cellular manufacturing (CM) system with unreliable machines.
Design/methodology/approach
The performance of CM system is conditioned by disruptive events, such as the failure of machines, which randomly occurs and penalizes the performance of the cells, seriously disturbing the smooth working of the factory. To overcome the problem caused by the breakdowns, the authors develop a solution, based on the principle of virtual cell and the notion of intercellular transfer that can improve the availability of the system. In this context, the use an analytical method based on Markov chains to model the availability of the cell. The results are validated using simulation.
Findings
The proposed solution in this paper confirmed that it is possible to reduce the severity of breakdowns in the CM system and improve the availability of the cells through an intercellular transfer created at the time of a breakdown. Simulation allowed a validation of the analytical model and showed the contribution of the suggested solution.
Originality/value
The developed approach studies the performance of the production cells formed by unreliable machines. It uses the notion of the intercellular transfer to improve the availability of the cells.
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Ramesh S., M.P. Jenarthanan and Bhuvanesh Kanna A.S.
The purpose of this paper is to investigate the performance of powder-mixed electric discharge machining (PMEDM) using three different powders which are aluminium (Al), silicon…
Abstract
Purpose
The purpose of this paper is to investigate the performance of powder-mixed electric discharge machining (PMEDM) using three different powders which are aluminium (Al), silicon carbide (SiC) and aluminium oxide (Al2O3). Besides that, the influence of different tool materials was also studied in this experimental investigation. Hence, the work material selected for this purpose was AISI P20 steel and tool materials were copper, brass and tungsten. The performance measures considered in this work were material removal rate (MRR), tool wear rate and radial over cut (ROC).
Design/methodology/approach
The process variables considered in this study were powder types, powder concentration, tool materials, peak current and pulse on time. The experimental design, based on Taguchi’s L27 orthogonal array, was adopted to conduct experiments. Significant parameters were identified by performing the analysis of variance on the experimental data.
Findings
Based on the analysis of results, it was observed that copper tool combined with Al powder produced maximum MRR (58.35 mm3/min). Similarly, the Al2O3 powder combined with tungsten tool has resulted least ROC (0.04865 mm). It was also observed that wear rate of tungsten tool was very low (0.0145 mm3/min).
Originality/value
The experimental investigation of PMEDM involving three different powders (Al, SiC and Al2O3) was not attempted before. Moreover, the study of influence of different tool materials (Cu, brass and W) together with the different powders on the electric discharge machining performance was very limited.
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The purpose of this paper is to represent the innovative process of powder-mixed electrical discharge machining of high-speed steel T1 grade and to conduct experimental…
Abstract
Purpose
The purpose of this paper is to represent the innovative process of powder-mixed electrical discharge machining of high-speed steel T1 grade and to conduct experimental investigation to optimize the machining parameters associated with multiple performance characteristics using grey relational analysis. The machining of high-speed steel T1 grade via conventional machining is a difficult process. However, it can be easily machined by powder-mixed electric discharge machining.
Design/methodology/approach
Carefully selected machining parameters give the optimum output results. For experimentation, the following input parameters have been used: pulse on-time, discharge current, tool material and powder concentration. The effects of input parameters, namely, material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR), have been investigated in this research.
Findings
Grey relational analysis and analysis of variance have been performed to optimize the input parameters for better output response. Optimized results show increment of TWR, MRR and SR, which is 63.24, 52.18 and 42.49 per cent, respectively.
Originality/value
This research paper will be beneficial for the industrial application. The GRA result gives the better output response.
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Harvinder Singh, Vinod Kumar and Jatinder Kapoor
This study aims to investigate the influence of process parameters of wire electrical discharge machining (WEDM) of Nimonic75. Nimonic75 is a Nickel-based alloy mostly used in the…
Abstract
Purpose
This study aims to investigate the influence of process parameters of wire electrical discharge machining (WEDM) of Nimonic75. Nimonic75 is a Nickel-based alloy mostly used in the aerospace industry for its strength at high temperature.
Design/methodology/approach
One factor at a time (OFAT) approach has been used to perform the experiments. Pulse on time, pulse off time, peak current and servo voltage were chosen as input process parameters. Cutting speed, material removal rate and surface roughness (Ra) were selected as output performance characteristics.
Findings
Through experimental work, the effect of process parameters on the response characteristics has been found. Results identified the most important parameters to maximize the cutting speed and material removal rate and minimize Ra.
Originality/value
Very limited research work has been done on WEDM of Nickel-based alloy Nimonic75. Therefore, the aim of this paper to conduct preliminary experimentation for identifying the parameters, which influence the response characteristics such as material removal rate, cutting speed, Ra, etc. during WEDM of Nickel-based alloy (Nimonic75) using OFAT approach and found the machinability of Nimonic75 for further exhaustive experimentation work.