Fine Deep Boring of Cemented Carbide by EDM with YAG Laser (2nd Report)

Method of Precision Adjustment of EDM Axis and Prehole Axis Made by Laser Beam Machining

Abstract

This paper deals with a method of precision adjustment of the EDM axis and prehole axis made by laser beam machining. In the previous paper, we proposed a new method for boring a microhole with a high aspect ratio over 10 for superfine-grain carbide, in which EDM and YAG laser beam machining were combined. We clarified that it was possible to bore a 100-μm-diameter hole for superfine-grain carbide of 1mm thickness. However, it is difficult to precisely adjust both axes of the prehole and the electrode in this method, because when the electrode does not fit with the axis of the prehole, it is impossible to bore a high-precision hole. Alignment error inevitably occurs during mounting and dismounting of the workpiece, which leads to the deterioration of the finished hole. In this study, the angle measuring system composed of a He-Ne laser and goniometer is used and the tilt angle of the prehole is corrected using this measuring system. The main conclusions obtained are as follows. (1) It is possible to adjust the tilt angle of the prehole bored in a workpiece by controlling the laser intensity through the micro deep hole. (2) In fine deep boring, a highly perpendicular hole with a high aspect ratio value over 10 can be obtained using the proposed method.