Laser welding of workpieces by machine

• US 10,399,173 B2
• Filed: 12/28/2015
• Issued: 09/03/2019
• Est. Priority Date: 06/28/2013
• Status: Active Grant

• Current Assignee: Trumpf Laser- und Systemtechnik GmbH (TRUMPF SE + Co. KG)
• Original Assignee: Trumpf Laser- und Systemtechnik GmbH (TRUMPF SE + Co. KG)
• Inventors: Petolillo, Stefano, Vehlow, Andreas
• Primary Examiner(s): Jennison, Brian W
• Application Number:
  US14/980,227
• Publication Number:
  US 20160107259A1
• Time in Patent Office: 1,345 Days
• Field of Search: 21912163
• CPC Class Codes: B23K 26/1437 for flow rate control
• CPC Class Codes: B23K 26/206 Laser sealing
• CPC Class Codes: B23K 9/16 making use of shielding gas selection of media B23K35/38

Abstract

A method for machine processing, in particular for machine welding processing of workpieces, in particular of plate-like workpieces, tubes and/or profiles, by means of a thermal processing beam, in particular by means of a processing beam is described, wherein the processing of the workpiece is carried out with a relative movement between the processing beam and the workpiece, wherein a process gas is fed to a processing zone in a settable quantity of process gas per unit of time. After a stored stabilization time, in which the processing of a workpiece is continued with a relative movement between the processing beam and the workpiece, a quantity of process gas per unit of time is automatically reduced. Further a control apparatus of a setting device for process gas feed according to such a method is described.

Claims

1. A method of machine welding of workpieces using a laser beam, the method comprising:

welding two workpieces by moving the laser beam and the two workpieces relative to each other;

feeding an inert gas comprising at least one of helium, argon, carbon dioxide and nitrogen, as a protection gas into a processing zone during the welding process, in which processing zone the laser beam is applied to the workpiece, wherein the protection gas is fed into the processing zone at a first settable quantity of protection gas per unit of time based on a stored first specified value, at the start of welding, wherein the protection gas is configured to shield the processing zone from ambient air; and

then,

after a predetermined stabilization time, in which the welding is continued with the relative movement between the laser beam and the workpiece, feeding the protection gas to the processing zone at a second quantity of protection gas per unit of time,

wherein the second quantity of protection gas per unit of time is set based on a stored second specified value that is smaller than the first specified value.

2. The method according to claim 1, wherein the first settable quantity of protection gas per unit of time is fed to the processing zone during the entire predetermined stabilization time set based on the first specified value.

3. The method according to claim 1, further comprising after the stabilization time, reducing the quantity of protection gas per unit of time fed to the processing zone gradually during a transitional period from the first settable quantity of protection gas per unit of time based on the first specified value to the second quantity of protection gas per unit of time based on the second specified value.

4. The method according to claim 3, wherein the transitional period is between 20% and 60% of the predetermined stabilization time.

5. The method according to claim 3, wherein the transitional period is between 30% and 50% of the predetermined stabilization time.

6. The method according to claim 1, further comprising reducing the quantity of protection gas per unit of time fed to the processing zone after the predetermined stabilization time based on a stored ramp function.

7. The method according to claim 1, further comprising feeding the protection gas together with one or more other protection gases in the form of a protection gas mixture to the processing zone to protect the processing point from the ambient air, and, after the stabilization time, reducing the total quantity of protection gas per unit of time of the protection gas mixture based on the first and second specified value.

8. The method according to claim 1, wherein the laser beam acts continuously on the workpiece as the workpiece is being processed to produce a continuous weld seam.

9. A laser welding machine comprising:

a workpiece support;

a laser processing head comprising a laser processing nozzle emitting a laser beam and an inert gas comprising at least one of helium, argon, carbon dioxide and nitrogen, as a protection gas; and

a numerical machine control configured to cause relative movement between a laser beam and a workpiece being welded by the beam, to set the quantity of the protection gas per unit of time fed to a processing zone during the welding process based on a first specified value and, after the stabilization time, during which welding of the workpiece continues with a relative movement between the laser beam and the workpiece, to set the quantity of protection gas per unit of time based fed to a processing zone on the second specified value,

the numerical machine control further configured to, at the start of the welding, set the quantity of protection gas per unit of time based on the first specified value and, after the stabilization time, during which welding processing of the workpiece continues with a relative movement between the laser beam and the workpiece, set the quantity of protection gas per unit of time based on the second specified value, wherein the protection gas is configured to shield the processing zone from ambient air.

10. One or more non-transitory computer readable media storing instructions that are executable by a processing device, and upon such execution cause the processing device to perform operations during relative movement between a laser beam of a laser welding machine and a workpiece positioned on a workpiece support of the laser welding machine comprising:

causing an inert gas comprising at least one of helium, argon, carbon dioxide and nitrogen, as a protection gas to be fed as a protection gas to a processing zone at a first settable quantity of protection gas per unit of time based on a stored first specified value, at the start of welding processing wherein the protection gas is configured to shield the processing zone from ambient air; and

causing the protection gas to be fed to the processing zone at a second quantity of protection gas per unit of time after a predetermined stabilization time, in which the processing of the workpiece is continued with the relative movement between the laser beam and the workpiece, the second quantity of protection gas per unit of time set based on a stored second specified value that is smaller than the first specified value.