Rapid EDM systems for micro and small holes with high-aspect-ratio

To overcome the shortcomings in rapidly machining micro and small holes with a high-aspect-ratio by Electric Discharge Machine(EDM), such as slow cooling, poor debris flushing, high tool wear and complex manipulation, a rapid EDM machine for micro and small holes is developed based on analyzing the mechanics and characteristics of EDM. Laid up vertically, the machine applies a rotary-vibrate mechanism with tool rotating and workpiece vibrating to the rapid cooling and debris flushing, and adopts an industrial PC (IPC) with PCI card and PMAC card plugged to acquire data to implement the integratization of machining and testing. In order to solve the problem that discharge states are difficult to detect due to severely distorting sparking signals and unstable sparking states in EDM, a successive mapping detection method of discharge states based on two-stage fuzzy logic is proposed and a double-closed-loop control system is designed to achieve rapid response and precise control of the working process. Experiments show that this machine is suitable for rapidly manufacturing the micro and small holes with high-aspect-ratio (>10) and diameters from 60 μm to 200 μm and has stable performance and high reliability.