MICRO-EDM OF HARD TO CUT MATERIALS

Abstract

The machining processes of hard-to-cut materials concern hardness of 5-68 HRC. Due to increase in demand of light weight and high strength materials such as, titanium alloy (Ti- 6A1-4V), polymer matrix composites are playing a very important role. Carbon liher reinforced composite (CFRCs) laminates are a type of polymer matrix composite which is the most promising material because of its properties such as light weight, low density, high strength, good corrosion resistance etc. However machining of' this class of materials is very difficult. In order to achieve better removal rate, tool wear and surticc finish, nonconventional machining is the best process. The present experimental investigation deals with the drilling behaviour of titanium alloy (Ti-6Al-4V) and CFRCs laminates using Micro- Electric discharge machining (EDM) process. Through hole drilling has been carried out on titanium alloy (Ti-6Al-4V) and CFRC laminates using Micro-Electric discharge machining process with input parameters as voltage, capacitance and i'otational speed of the tool, keeping other parameters constant. The objective of this work is to study the effect of these input parameters on material removal rate (MRR) and tool wear rate (TWR) during machining of titanium alloy (Ti-6Al-4V) and CFRC laminates with tungsten as electrode material using Micro-FDM. Comparison of the material removal rate (MRR) and tool wear rate (TWR) values for both materials during machining has been performed. Design of experiments has been employed using Taguchi methodology. The experimental results show that voltage and capacitance have significant effect on MRR and TWR while rotational speed has non-significant effect in both cases. Comparing the MRR and TWR, it was found that MRR is comparatively high during machining of' CFRCs laminates while TWR is low in comparison to titanium alloy ('I'i-6Al-4V) because of titanium alloy being conductive and isotropic material whereas CFRC laminates are partially conductive and anisotropic.