Abstract: To provide constant tension on an electro-erosive electrode machining wire, tape or ribbon stretched in a working path between advancing rollers and pulling rollers, a tension loading arrangement, for example weights, springs, or the like, are applied to the wire to maintain the tension thereof at a constant value. The deflection of the wire, due to elongation thereof as a result of heating, differences in manufacturing technologies and the like, is sensed and fed back to the motors driving the advancing and pulling rotors to maintain the tension, as controlled by the motor torques and speeds at a uniform value.

Abstract: A head assembly for an electro-erosion machine tool comprises, in a housing, a guide for guiding the moving filamentary or strip-form tool electrode and first contact means for supplying erosion energy to the electrode. The scavenging medium is fed into the housing so as to cool the contact means and guide, and leaves it by way of a nozzle through which also the electrode leaves the housing on its way to another head assembly arranged on the opposite side of the location where machining is performed, the scaverging medium being thereby fed to the machining location as an envelope coaxial to the electrode. Second contact means for contacting the workpiece to be machined are fixed to the nozzle and the connections to each contact means are arranged for low inductive energy loss.

Abstract: Electroerosion machining (EDM or ECM) is carried out with a minimum of manual intervention. Under control of recorded data an electronic control system utilizing control logic directs the set-up operations as well as the actual machining process. The operations automatically (i.e., without the necessity of manual intervention) include loading and removal of workpieces and electrode material, trueing up of the workpiece (which may be by providing a transformation of the data rather than by adjusting the position of the workpiece), making starting bores, threading the electrode through a starting bore, applying a low melting alloy or other conducting adhesive to cement a core in the process of being cut out by machining, cutting the electrode after completing a starting bore and joining electrode ends after rethreading in a new starting bore. In threading the electrode it may be pushed simply or with the support of a surrounding jet of pressure medium, or it may be pulled by a grapple member.