Development and Application of a Precision Micro EDM System

This paper presents the development of a micro-EDM system which is aimed to improve micro machining capability. The system consists of high precision X-Y-Z stages with quick response, a high precision granite machine body, a pulse power generator, a CCD microscopic computer vision system, etc. The X-Y-Z stages are driven by ultrasonic linear motors with a resolution as high as 0.05 μm. The granite machine body can reduce stray capacitance and absorb vibrations. RC pulse power generator can supply discharging energy as small as 10⁻⁹ J. Micro electrode can be measured with a resolution of 1.6 μm by the microscopic computer vision system online. In order to machine precision 3D microstructures, a special CAM software package based on the commercial CAD/CAM software Unigraphics (UG) is developed to generate tool path and NC codes and compensate the electrode wear. Experiments carried out on this machining system show that micro shafts with a minimum diameter of 6 μm and micro holes of 10 μm in diameter can be obtained stably. With the aid of the self-developed CAM software packages, complicated 3D microstructures are machined on this micro-EDM machining system.