Micro-Hole Drilling on Ti6Al4V by Sequential Electro-Micro-Machining (SEMM) Approach

Abstract

This research work explores the feasibility of drilling micro-holes on Ti6Al4V by applying a sequential electro-micro-machining process. A novel sequential combination of micro-electrochemical discharge machining ([Formula: see text]ECDM) and micro-electro-chemical machining ([Formula: see text]ECM) is applied for drilling micro-hole in titanium alloy (Ti6Al4V). The machining of titanium alloy by a [Formula: see text]ECDM process is a challenging task and not reported yet. Therefore, the feasibility of machining of Ti6Al4V by [Formula: see text]ECDM using various combinations of electrolytes has been studied. The best-suited electrolyte for drilling by [Formula: see text]ECDM was selected by analyzing the hole depth, radial overcut, hole taper angle and the minimum time required to drill through holes in a 400[Formula: see text][Formula: see text]m thick sheet of titanium alloy. The [Formula: see text]ECDM process produces micro-holes rapidly but it consists of recast layer, micro-cracks, and heat affected zone, etc. The surface characteristics of a [Formula: see text]ECDMed hole were improved by applying [Formula: see text]ECM process subsequent to the [Formula: see text]ECDM process. The sequential combination of [Formula: see text]ECDM shaping and [Formula: see text]ECM finishing results in improved dimensional accuracy, machining depth, taper angle, and surface quality of the hole produced by sequential micro-machining process.