Wire Electrochemical Threading: A Technique for Fabricating Macro/Micro Thread Profiles

Abstract

In the past decades, wire electrochemical machining (Wire-ECM) has been extensively investigated for machining flat surfaces on varying engineering materials. In the present work, an attempt has been made to develop a novel technique (mask-less as well as through-mask) for generating macro as well as micro thread profiles on cylindrical rotating shafts using wire electrochemical turning process (Wire-ECTrg). Profiles with rounded edges like British Standard Whitworth (BSW) thread profile (Thread angle 55°) are fabricated using the mask-less method. Typical thread profiles are characterized and the impact of various input parameters on two key profile features, thread depth and thread angle are investigated. Generation of ball-full radius thread profile is very cumbersome to make through conventional turning process as it also requires a complex profiled tool. This type of thread profile is machined using the through-mask method. Three different engineering materials namely, copper, stainless steel 304 and a bio-compatible alloy of titanium Ti-6Al-4V are adapted for generating different thread profiles to show the versatility and applicability of the proposed technique. A ball-full radius thread of pitch 450 μm on stainless steel 304 is successfully fabricated using a single pass through-mask wire electrochemical turning process with an average percent error in groove radius of 2.42%.