| 摘要 |
PROBLEM TO BE SOLVED: To provide a wire electric discharge machine capable of starting electric discharge machining from a small-diameter machining start hole in which the hole diameter is minute or burrs remain or which is oblique.SOLUTION: A wire electric discharge machine, if a wire electrode and the electrode of a work are in a short circuit state when starting machining, supplies working liquid while running the wire electrode in a state of applying a low tension in the wire running direction, and performs application of a pulse-like high frequency voltage and supply of a small electric current to such an extent that a wire electrode line is not fused. The small electric current is supplied even in the short circuit state so that, by an insulation film caused by wire vibration or oil adhered to the wire surface or by other factors, the short circuit state between the wire and the work is released but for a short moment and electric discharge is generated at that moment. The wire electrode is pushed back from the work surface by the discharge repulsion force. Further, short-circuited surfaces can be fused and removed even slightly by the electric discharge, and it becomes possible to come out of the short circuit state and start electric discharge machining.SELECTED DRAWING: Figure 14 |
