Statistical multi-objective optimization of electrical discharge machining parameters in machining titanium grade 5 alloy using graphite electrode

Abstract

In industrial applications, particularly in aero, marine and medical industries, titanium has received great attention as a useful material and electrical discharge machining as its machining process. Selection of optimal machining parameters in a multi-objective environment is essential for specific workpiece and tool material combination, which is the concern of industries to improve the overall productivity at less cost. In this article, optimization of critical electrical discharge machining parameters such as pulse current, on time of pulse, off time of pulse and tool geometry depending on the responses such as titanium machining rate, graphite wear rate, surface roughness and deviation between entry and exit while machining titanium grade 5 alloy with graphite tool electrode at negative polarity is presented. Taguchi’s L27 orthogonal array was used to design the experiment with interaction between factors. The weighing method was used to integrate different objectives into one performance. The optimal combination of process parameters was found statistically using signal-to-noise ratios. Significance was checked by analysis of variance. Optimum parameters were found to be pulse current 15 A, on time of pulse 50 µs, off time of pulse 200 µs and cylindrical tool geometry. Resultant percentage improvements in different responses were presented.

Micro-electrical discharge machining of difficult-to-machine materials: A review

“…Sivam et al 42 performed multi-objective optimization of EDM parameters for machining of holes in titanium grade 5 alloy using graphite electrodes. They reported that as per the analysis of variance (ANOVA) table, the most effective parameters are the pulse on-time, pulse current and pulse off-time.…”

Effect of slotted electrodes on improvement in machining performance of large-scale electrical discharge machining

“…Generally, the following methods are used in EDM to remove debris deposits: Z-axis retraction, flushing, EDM parameter optimization, and electrode planetary motion. 7–14 However, large-scale machining and hemisphere machining involve area effect as well as materials with special geometric shapes that hinder machining debris removal. Therefore, this study combined slotted electrodes with rotary machining to improve the debris removal effect, increase MRRs, obtain the optimal slotted electrode model, and analyze the electrical discharge waveforms.…”

Effects of grain size of AISI 304 on the machining performances in micro electrical discharge machining

“…Electrical discharge machining (EDM) is carried out by a series of repetitive discharge pulses produced between the tool electrode and the workpiece. 1 Owing to its unique noncontact machining characteristics, EDM has become one of the most popular micro machining techniques. More and more attention has been paid to micro EDM, especially in the industries of aerospace, die and mold making, automotive, medical and so on.…”