Laser beam machining method with interrupt and restart functions

• US 5,994,668 A
• Filed: 10/09/1997
• Issued: 11/30/1999
• Est. Priority Date: 01/31/1995
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Mori, Toshihiro, Sugahara, Masayuki
• Primary Examiner(s): MILLS, GREGORY L
• Application Number:
  US08/947,749
• Time in Patent Office: 782 Days
• Field of Search: 219/121.6, 219/121.61, 219/121.62, 219/121.67, 219/121.72, 219/121.78, 219/121.85, 364/474.08
• US Class Current: 219/121.72
• CPC Class Codes: B23K 26/08 Devices involving relative movement between laser beam and workpiece
• CPC Class Codes: B23K 26/0861 in at least in three axial directions
• CPC Class Codes: G05B 2219/45041 Laser cutting

Abstract

A method for irradiating a workpiece making a relative move in accordance with a work program with a laser beam for cutting the workpiece includes steps of interrupting the cutting being executed and then restarting the cutting. As the cutting is restarted, machining of the workpiece is performed under specified conditions for a predetermined distance and a predetermined time to provide sufficient machining of the workpiece.

Claims

1. A laser beam machining method for irradiating a workpiece making a relative move in accordance with a work program with a laser beam for cutting the workpiece, to interrupt the cutting being executed and restart the cutting at an interrupt position, said method comprising the steps of:

(a) after restart of the cutting;

working on a moving path specified in the work program under restart work conditions;

(b) determining a total distance through which the workpiece moves under the restart work conditions as a restart work distance,

(c) comparing the restart work distance with a predetermined distance L1;

(d) continuing the working under restart conditions of step (a), the determining of total distance of step (b) and the comparing of step (c) until the restart work distance matches L1;

(e) changing the restart work conditions to original work conditions for continuing the cutting when the restart work distance matches L1.

2. The method of claim 1, wherein the restart work conditions comprise a lower irradiation output than the original work conditions and wherein said step (e) comprises a sub-step of pausing the workpiece for a predetermined time to permit stabilizing of the lower irradiation output back to the original work conditions and then moving the workpiece to continue cutting after lapse of the predetermined time.

3. A laser beam machining method for irradiating a workpiece making a relative move in accordance with a work program with a laser beam for cutting the workpiece, to interrupt the cutting being executed and restart the cutting at an interrupt position, said method comprising the steps of:

cutting the workpiece while making a backward move of a moving path before an interrupt specified in the work program by a predetermined distance under backward move work conditions; and

continuing cutting the workpiece again in an original cutting direction under original work conditions.

4. A laser beam machining method for irradiating a workpiece making a relative move in accordance with a work program with a laser beam for cutting the workpiece, said method comprising the steps of:

stopping a work path move of the workpiece for a predetermined time as a work condition is changed from a low-output laser beam to a high-output laser beam, wherein the predetermined time corresponds to a stabilizing time for the high-output laser beam; and

irradiating the workpiece with the high-output laser beam.