Micro Drilling EDM with Non-contact Controlled Pulse Train Method

Abstract

This paper describes the machining characteristics of non-contact micro electrical discharge machining (EDM) using the controlled pulse train method (CPTM). The CPTM was introduced to increase discharge energy and enlarge unit removal per crater in micro EDM. With this, group of discharges generated within a controlled predetermined time is allowed to occur at a single location on the machined surface. By fixing a cylindrical feeding electrode coaxially to the mandrel, capacitance C1 can be formed between the feeding electrode and the tool to realize the non-contact electrical feeding. Using a newly made feeding electrode, micro holes will be drilled at different speed of tool electrode rotation. The influence of the tool rotation speed on material removal rate (MRR) and tool wear rate (TWR) will be investigated. By drilling deep holes, hole straightness and machining accuracy will be observed.