Wire threading method for a wire discharge machine

• US 5,130,508 A
• Filed: 08/16/1989
• Issued: 07/14/1992
• Est. Priority Date: 08/16/1988
• Status: Expired due to Fees

• Current Assignee: Amada Wasino Co. Ltd. (Amada Company Limited)
• Original Assignee: Amada Wasino Co. Ltd. (Amada Company Limited)
• Inventors: Yokomichi, Shigeharu, Umetsu, Masahito
• Primary Examiner(s): Evans, Geoffrey S.
• Application Number:
  US07/394,643
• Time in Patent Office: 1,063 Days
• Field of Search: 219/69.12, 140/139, 140/140, 140/147
• US Class Current: 219/69.12
• CPC Class Codes: B23H 7/10 Supporting, winding or electrical connection of wire-electrode

Abstract

In a wire discharge machine, threading of the wire is accomplished by tensioning the wire to straighten same and applying an electric current thereto to facilitate separation thereof. Clamps hold and help tension the wire by securing one or more ends at a particular location. The tensioning is accomplished with drive motors, which may be or include pulse motors.

Claims

1. A method of threading a wire electrode in a wire discharge machine having a normal advancement path, comprising the steps of:

straightening the wire electrode along said normal advancement path by applying tension force to said wire electrode;

melting a portion of the straightened wire electrode by passing an electrical current through said wire electrode;

separating the wire electrode at the melted portion thereof by applying tension force to the wire electrode; and

inserting an end of the separated wire electrode into a through-hole in a workpiece;

wherein said wire discharge machine further includes a pulse motor mounted on a tension device, further including the step of applying said tension force by reversing said pulse motor.

2. A method of threading a wire electrode in a wire discharge machine having a normal advancement path, comprising the steps of:

straightening and separating the wire electrode along said normal advancement path by applying tension force exceeding the limit of elasticity of said wire electrode and passing an electric current through said electrode wire sufficient to melt said electrode wire; and

inserting an end of the separated wire electrode into a through-hole in a workpiece;

wherein said wire discharge machine further includes a pulse motor mounted on the tension device, further including the step of applying said tension force by reversing said pulse motor.

3. A device for threading a wire electrode in a wire discharge machine having a normal advancement path, comprising:

pulse motor means for applying tension force to the wire electrode to straighten and separate the wire electrode along said normal advancement path;

means for inserting an end of a separated wire electrode into a through-hole in a workpiece; and

means for melting a portion of the straightened wire electrode by passing an electrical current through said wire electrode while applying tension force to the wire electrode by said pulse motor means, wherein said means for melting the portion of said straightened wire comprises;

wire guide means having conductive elements;

means for elevating said wire guide means along said normal advancement path;

clamp means for clamping said wire electrode;

means for causing said clamp means to move into and retreat from said normal advancement path so that said clamp means clamps said wire electrode before being elevated; and

a power supply device for applying electrical current to said conductive elements of said wire guide means and said clamp means.