Investigation on corner accuracy in wire cut EDM of AISI D3 tool steel

Abstract

Wire cut electrical discharge machining (WEDM) of AISI D3 tool steel has been reported in this study. The AISI D3 steel is extensively used in tool and die making industries. The machining of ulta-precision dies with the required corner accuracy and surface finish is only possible through WEDM process. It is known fact that the wire deflection and the wire rupture are the problems associated with the WEDM process (Lin et al., 2001; Sarkar et al., 2011). The wire deflection at the corner is causing corner error. The objective of the present work is to minimise the corner error by modifying the programmed path of the wire. The experiments were conducted based on Taguchi's L-27 orthogonal array. The influence of the control factors namely workpiece thickness, flushing nozzle height, corner angle, pulse on time, pulse off time, peak current and wire tension on the process responses such as area removal rate (ARR), surface roughness (Ra) and corner error (CE) were studied. A set of pilot experiments were carried out by modifying the programmed path (wire path) in view of improving the corner accuracy of the profile. A good improvement in corner accuracy (about 25%) has been achieved.