Patent ID: 6900407
Filing Date: 2005-05-31
Classification: B23H

Abstract:
1. An electric discharge machine, wherein a machining electric power supply means supplies electric power between an electrode and a workpiece provided in a machining solution for machining the workpiece, wherein the electrode and the workpiece are relatively movable by a positioning means, and wherein a jumping motion, which relatively moves the electrode from the workpiece by the positioning means so as to increase temporarily a distance between the electrode and the workpiece, is conducted, the electric discharge machine comprising: a machining reaction force detecting means for detecting a machining reaction force; a machining reaction force specified value setting means for setting a specified value of the machining reaction force; a machining reaction force comparing means for comparing a detected value of the machining reaction force, which is detected by the machining reaction force detecting means, with a specified value of the machining reaction force, which is set by the machining reaction force specified value setting means; and a motion locus changing means for changing a locus of the jumping motion so that the machining reaction force can be reduced if the machining reaction force comparing means finds that the detected value of the machining reaction force is greater than the specified value of the machining reaction force. wherein a command value of the relative moving speed of the electrode to the workpiece in the jumping motion is synthesized as a Fourier series, and the Fourier series is synthesized while the n-th component of the Fourier series is being removed or the Fourier series is synthesized while the components of higher degrees than the n-th component are being removed if the n-th frequency component of the Fourier series coincides with the resonance frequency of the mechanical system or the n-th frequency component of the Fourier series is similar to the resonance frequency of the mechanical system.