PROCEDE ET DISPOSITIF POUR METTRE EN PLACE ET REGLER UNE ELECTRODE D'USINAGE PAR ELECTRO-EROSION

摘要

An improved method of and apparatus for automatically threading a continuous electrode wire through a workpiece in a traveling-wire electroerosion machine wherein a rotary guide block having a tapered opening is disposed to locate the latter coaxially with a straight throughgoing hole preformed in the workpiece and arranged in alignment with a straight line path defined between a pair of wire guide members. A free end of the electrode wire extending from a wire supply or takeup is located behind the opening in the rotary guide block which is tapered convergently towards the workpiece. The electrode wire is advanced along the straight line path to introduce its free end into the tapered opening of the guide block which is rotated about its rotary axis to allow the free end to smoothly pass through the opening and then into and through the straight through-hole in the workpiece. A sensing/control circuit may be provided and arranged to detect a contact of the free end with the tapered wall of the opening to initiate the rotation of the rotary guide block or to control its rate of rotation and/or the rate of advance of the electrode wire in accordance with the particular position of a point of contact of the free end with the tapered wall.