Deep Microholes Machining by EDM

Abstract

Machining microholes with high aspect ratios has become important in various industrial fields. Since the development of WEDG (wire electro discharge grinding), micro-EDM has been an excellent process for machining microholes in metals and alloys. However problems remain in machining the high-aspect-ratio holes. As the depth of microholes becomes deeper, drilling through the microholes becomes more difficult. In addition, the removal of debris and renewal of dielectric from the machining gap are difficult because unstable discharge and arcing usually result. In this study, the jump flushing system is proposed for drilling microholes with high aspect ratios, by inducing an intermittent jump of the workpiece. The system is assisted by the horizontal main spindle and pure water dielectric. As a result, a 1.5mm-deep hole with the diameter of 100μm was successfully machined in to stainless steel which is one of the more difficult materials in which to drill deep microholes.