Development of Ultra Precision Fine EDM Device for Micro Machining

本研究从1995年4月至1998年3月进行了三年的工作，目的是研制一种用于微细加工的超精密微细电火花加工装置。在第一年，我们尝试制造一台超精密电火花加工机，并完成了适合精细微加工的电容电路机器。第二年，提出了用简单电极高效加工复杂形状的新方法，开发了直角等边三角形细长电极挤压法。电极材料采用银，因为它易于挤压成形，而且具有电火花加工的性能。第三年，我们尝试了用挤压成形的电极加工复杂形状的一些零件。首先通过简单的穿孔实验，研究了加工结果与加工条件之间的关系。然后，用直角三角形组合的方法，对多边形、星星形和字母形进行了加工试验。该方法在显微镜下进行坐标排列，实现了精密微加工。由于不可能使拐角半径过小，提出了减小拐角半径的方法。阐明了用反向电火花加工方法可以将圆角半径减小到10- 25 μ m，并研究了使圆角角度小于45 °的方法，表明用同样的反向电火花加工方法是可能的。此外，还对型腔的加工进行了尝试，证明了其可行性。最后，对单晶硅的微细加工进行了研究。实验证明，硅材料可以像不锈钢一样进行加工，表明该方法对单晶硅微传感器和微执行器的微加工是有效的。

This study has done for 3 years from Apr.1995 to Mar.1998 in order to develop a ultra precision fine electric discharge machining device for micro machining. In the first year, we tried to make a ultra precision fine EDM machine, and completed the machine with condenser circuit which was suitable for fine micro machining. In the second year, a new method for high efficiency machining of complicated shape using simple electrode was proposed, and the the extrusion method for long fine electrode with a right angled equilateral triangle was developed. Silver is used as the material of electrode because of the easiness of extrusion and the performance of EDM.In the third year, some kinds of machining of complicated shapes are tried with the shaped electrode made by extrusion. First the relationship between the machining result and the machining condition was investigated by simple piercing experiment. Next, machinings of some polygon shapes, star shape and letter were tried by combining the right angled triangles. In the method, the coordinates were arranged under the microscope, which led to the precision micro machining. Then, the reduction method of corner radius was proposed, because it was impossible to make the corner radius so small. It was clarified that the corner radius could be reduced to 10-25micron by the reverse EDM.The method to make the corner angle less than 45 degrees was also investigated and it was shown that it was possible by the same reverse EDM method. Furthermore, the machining of cavity was tried, and it was shown to be possible. Lastly, the micro machining of single crystalline silicon was investigated. it was proved that silicon could be machined like the stainless steel, and it was shown that this method was effective for micro machining of micro sensors and actuators made of single crystalline silicon.