| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a wire electric discharge machine having a rust preventive function capable of controlling current density for an object to be worked invariably.SOLUTION: There are such problems that corrosion resistance cannot been satisfactorily attained when current density of an object to be worked is lower than a predetermined value, and the life of a corrosion resistance electrode is shortened and the object to be worked is deteriorated when the current density is too high, in the case of performing corrosion prevention of the object to be worked by applying a voltage between the object to be worked and the corrosion resistance electrode. Accordingly, in order to perform such a control that the current density becomes invariable, it is necessary to supply electric current proportional to the surface area of the object to be worked from a corrosion resistance power source. The current value of current supplied from the corrosion resistance power source is called as a standard electric current value. Is, Is1 and Is2 present relations between the surface area of the object to be worked and the standard current value respectively when the current density is a predetermined value and is invariable, when the current density is a little lower than the predetermined value and when the current density is a little higher than the predetermined value. The control of a corrosion resistant current is performed by controlling the voltage of the corrosion resistance power source so as to fall between Is1 and Is2.</p> |
