Method and device for treating work pieces with laser radiation

• US 6,365,870 B1
• Filed: 04/07/2000
• Issued: 04/02/2002
• Est. Priority Date: 10/22/1997
• Status: Expired due to Fees

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Treusch, Hans-Georg, Loosen, Peter, Petring, Dirk, Poprawe, Reinhart
• Primary Examiner(s): Heinrich, Samuel M.
• Application Number:
  US09/529,468
• Time in Patent Office: 725 Days
• Field of Search: 219/121.63, 219/121.64, 219/121.67, 219/121.72, 219/121.73
• US Class Current: 219/121.67
• CPC Class Codes: B23K 26/035 Aligning the laser beam automatically B23K26/042
• CPC Class Codes: B23K 26/073 Shaping the laser spot
• CPC Class Codes: B23K 26/08 Devices involving relative movement between laser beam and workpiece
• CPC Class Codes: B23K 26/0876 in at least two axial directions

Abstract

A method for processing moving workpieces with laser radiation that is focused on a to-be-processed workpiece surface by means of a laser beam that is moved but not relative to the workpiece. The laser beam is focused in a line-like manner and its beam spot corresponds practically exclusively and with full a real coverage to the work piece surface to be processed.

Claims

1. A method for processing workpieces with laser radiation, the method comprising the steps of:

focusing a laser beam in a line-like manner on a portion of a surface of a workpiece such that a beam spot projected by the laser beam covers fully the surface portion of the workpiece and is confined thereto;

moving the workpiece; and

moving the laser spot simultaneously with the workpiece, such that there is no relative movement between the beam spot and the workpiece surface portion.

2. The method according to claim 1, wherein the focused line is uniformly narrow over its entire length.

3. The method according to claim 1, wherein the beam spot extends over the entire width of the surface portion and the beam forms a selected one of (i) a contour with an unirradiated center, (ii) an arbitrarily predetermined course, and (iii) a line width that is nonuniform over the course of the line.

4. The method according to claim 1, wherein the focused line is made up of component lengths that cover the entire line length a selected one of (i) simultaneously and (ii) in cycles consecutively.

5. The method according to claim 1, wherein the laser radiation comprises a selected one of (i) an uninterrupted sequence of individual beams, and (ii) groups thereof that simultaneously cover a selected one of (i) the entire line length, and (ii) a component length.

6. The method according to claim 1, wherein the laser radiation is generated by means of a selected one of (i) diode laser bars and (ii) diode laser stacks.

7. The method according to claim 1, wherein the laser radiation is used for severing.

8. The method according to claim 7, wherein the full width of a workpiece is severed in a pulse-like manner by means of the linear laser radiation.

9. The method according to claim 7, wherein a source of laser radiation delivering the laser radiation is comoved with and at the same speed as a moved workpiece as it is being irradiated.

10. The method according to claim 7, wherein a selected one of a (i) mechanical, or (ii) magnetic means is used to sever the to-be-severed pieces during the irradiation of the workpiece.

11. The method according to claim 10, wherein gas nozzles are used to expel melt from a melted region of the workpiece.

12. The method according to claim 10, wherein the mechanical means comprises a source of parting force that removes the severed pieces of the workpiece from one another.

13. The method according to claim 12, wherein the workpiece is conveyed by spaced-apart conveying means between which the laser-radiation processing takes place and which serve as sources of the parting force.

14. The method according to claim 13, wherein the conveying means comprise driving-roller pairs having differently controlled conveying speeds for severing the pieces to be severed.

15. The method according to claim 1, wherein the line-like laser radiation is used for line joining.

16. The method according to claim 1, wherein the workpiece comprises a selected one of (i) a thin plate, (ii) a foil and (iii) a molded plastic part.

17. A device for processing surface portions of moving workpieces with laser radiation that is focused on a to-be-processed workpiece surface portion by means of a moving laser beam that is not moved relative to the workpiece, wherein the laser beam is focused in a line-like manner and its beam spot corresponds exclusively and with full area coverage to the workpiece surface portion to be processed.

18. The device according to claim 17, wherein the device comprises a controlled drive that is adapted to adjust, in accordance with any movements of the workpiece, a laser source serving to generate the laser beam, and a device for delivering the laser beam.

19. The device according to claim 17, wherein the laser beam covers with a line-like beam spot the entire length of a predetermined parting line on the workpiece, and the device comprises severing means for severing a to-be-severed piece of the workpiece during the irradiation thereof.

20. The device according to claim 17, wherein the workpiece is conveyed by driving rollers and a controller is present for tensioning and severing the workpiece.

21. The device according to claim 17, wherein the device comprises a diode laser beam generator for generating the laser radiation.

22. The device according to claim 17, wherein the device further comprises an eccentric drive to effect comovement of the laser beam with, and at the same speed as, the workpeice during irradiation.

23. The device according to claim 17, wherein two line-like laser beams are present and are directed at workpeice surfaces disposed one on top of the other in a selected one of (i) a same processing zone, and (ii) consecutive processing zones.

24. The device according to claim 23, wherein the two laser beams are disposed at angles to each other.

25. The device according to claim 17, and further comprising adjusting means for a selected one of (i) the course, and (iii) focus on the line, and (iv) the intensity variations of the laser radiation over the length of the line.