Abstract: At least one machining parameter of an electrode-wire EDM machine, cutting according to a predetermined trajectory, is varied when the electrode-wire reaches the apex of an angle or approaches an arc. The process consists of the following stages:1) calculation of the locations along the trajectory or path at which these variations must be started;2) stopping of relative electrode-wire movement and the work-piece, when the wire reaches one of these points;3) gradual and stepped variations of the parameter up to a final designated value or until a predetermined number of steps have been performed, or during a given period of time;4) resumption of wire-part relative movement, with the new parameter value over a computed predetermined distance, and5) variation of the parameter in the opposite direction so as to return it to its initial value.The durations of the steps are predetermined or correspond to cutting of predetermined lengths along the path.

Abstract: 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.

Abstract: A process and apparatus for monitoring machining conditions in a travelling wire EDM apparatus. The resistivity of the machining fluid in the machining zone is measured and is compared to a reference value. A signal is provided as soon as the measured resistivity increases beyond the reference value and the signal is used for decreasing or interrupting the machining current.

Abstract: A process and apparatus for monitoring the efficiency of an EDM machine by providing an electrical magnitude or signal representing the current flow actually used for machining or, in the alternative, the actual material removal rate. Several circuits are disclosed permitting to provide the operator of an EDM machine with a visual display of the practical efficiency of the machine during a machining operation.

Abstract: In an EDM process and apparatus, an arrangement for automatically correcting machining errors while effecting a cut in a workpiece by means of a wire electrode when the cutting path of the wire electrode relative to the workpiece is along a curve or an angle, for example, rather than along a straight line. The speed of relative displacement between the wire electrode and the workpiece electrode is automatically varied as a function of the shape of the cutting path, such that the distance between the longitudinal axis of the wire electrode and of one of the cut surfaces of the workpiece is maintained constant, irrespective of the curvature or angularity of the cutting path.

Abstract: A pulse generator for an electro-erosion machining apparatus wherein electrical discharges occur at a machining zone formed between an electrode workpiece and an electrode tool, the pulse generator comprising a capacitor charged from a source of direct current through an inductance and a switch for discharging the capacitor through the primary of a transformer, the electrode tool and the workpiece being connected across the secondary of the transformer, the capacitor being charged at a predetermined current rate and being discharged when the voltage across the capacitor reaches a preset level.