AUTOMATIC WIRE-THREADING WITH A TUBULAR ELECTRODE IN A TW-E MACHINE

摘要

AT (automatic threading) of wire through a workpiece without the need for a preformed through-hole therein is achieved on a TW (traveling-wire) electroerosion machine (TW-E machine) by utilizing a tubular electroerosion electrode positioned in axial alignment with a wire-threading path. Wire from a wire supply is introduced into the tubular electrode so as to extend through a tool holder therefor. The tubular electrode is advanced along the wire-threading path into and through the workpiece while electroerosively forming a bore therein. Wire is dispensed from the supply to allow wire to move out of the tubular electrode while the latter at least partially remains in the bore so that the wire passes into the wire outlet side of the cutting zone towards a takeup assembly. The tubular electrode may then be retracted along the wire-threading path from the workpiece while leaving wire in the bore finished in the workpiece.