Fabrication of Ti-6Al-4V thin sheet using wire-EDM and its characterisation

Abstract

An appreciable demand for thin titanium sheets is observed in recent years due to technological development in various sectors. The existing sawing methods are uneconomical to produce high aspect ratio sheets with good dimensional accuracy. The current work focuses on extracting thin sheet of 380 mm × 50 mm × 0.2 mm from Ti-6Al-4V using wire electric discharge machining and investigated the dimensional and surface variations. The preliminary study using usual wire EDM procedure resulted in poor dimensional accuracy for a thickness in the range of 500 µm due to the lateral movement of sheet free end. Hence, in this work, a support system is attached to workpiece to minimise sheet movement and to improve the flushing during extraction. This helped to reduce the thickness variation up to 6% for a 0.2 mm Ti-6Al-4V sheet. The root mean square roughness is found to be consistent up to a height of 240 mm from the top surface. Also, majority of the measured skewness are positive. Altogether, the results of the study can be applied to fabricate thin sheets for additive manufacturing process.