Influence of electrode tool length on the micro EDM drilling performance

Micro electrodischarge (micro EDM) machining, due to its wide application range, is one of the most commonly used technologies for machining in micro scale. Common application of precise micro EDM drilling among others concerns machining of holes in fuel injectors or drug delivery orifices. The paper presents results of research of the micro EDM drilling at Institute. There are derived characteristics of micro drilling in the stainless steel samples depending on the electrode tool length (distance between machined surface and tool electrode clamp). The main comparison coefficients are tool wear ratio, material removal rate / machining efficiency and machining accuracy / quality. Presented results concern micro EDM drilling experiments which were performed for tool electrode diameter of 0,1 mm and workpieces of 1 mm thick. There are also derived conclusions on process optimization and process planning for cost and time effective machining, taking into account the machining time, electrode tool re-clamping time depending on the number of micro-holes to be drilled in the single workpiece. Presented results and their discussion cover problems which we came across during investigations and commercial micro EDM drilling services. (C) 2018 The Authors. Published by Elsevier B.V.