Working fluid filtration device of electric discharge machine

摘要

An electric discharge unit of an electric discharge machine is disposed in a working tank, and a working fluid in the working tank is delivered to a filter tank by a pump. A filter for working fluid filtration wound off from a roll faces apertures in the bottom of the filter tank. When the internal pressure of the filter tank exceeds a predetermined value, the filter is moved a predetermined distance downward of the filter tank. In a position off the filter tank, that part of the filter which has been used for filtration is cleaned.