Micro-electro discharge machining characteristics of tungsten-copper for electronic devices

Abstract

ABSTRACT Micro-machining involves the removal of small amounts of material by action other than that of a sharp-edged tool. The most common technique being electrical discharge machining (EDM). The material removal rate and edge definition of the finished product are based on different process parameters. This study is aimed to characterise micro-EDM process parameters for tungsten–copper and to achieve maximum material removal rate without affecting the edge definition and surface roughness while using smaller electrodes. Eight process parameters were studied for their influence on the material removal rate (MRR), surface roughness (Ra) and tool wear rate (TWR). Taguchi design of experiments was carried for 36 experimental runs. The ANOVA analysis showed that the MRR depends largely on voltage, energy and current, while the TWR depends on the energy and voltage. The surface roughness value (Ra) was influenced more by energy, incremental depth and the pulse width, thus differing from MRR and TWR. The optimum parameter set for higher MRR (10e-3 mm3/min) and lower Ra (0.13 µm) was deduced from regression analysis, and the confirmation tests showed less than 8 % deviation from the predicted values. The SEM studies showed greater depths of craters in the surface machined for higher MRR.