Process and apparatus for monitoring thermal stresses in an electrode wire in an EDM apparatus

摘要

In a travelling wire EDM apparatus in which a workpiece is cut by an electrode wire by electrical discharges between the wire and the workpiece, a detector circuit detecting each electrical discharge occuring in each sector along the length of the wire in the machining zone. The information detected by the detector circuit is supplied to a circuit simulating the increase of heat of the wire, and the convection of heat into the ambient and into adjoining wire sectors. A control signal for modifying a machining parameter is supplied when the simulator circuit provides an indication of abnormal heating of the wire in one of the wire sectors. Accidental rupture of the wire is thus avoided while assuring that machining is effected at maximum efficiency.