Devices and methods for monitoring, in particular for regulating, a cutting process

Patent metadata

Field	Value
Publication number	US-11440141-B2
Application number	US-201916545273-A
Country	US
Kind code	B2
Filing date	Aug 20, 2019
Priority date	Sep 13, 2013
Publication date	Sep 13, 2022
Grant date	Sep 13, 2022

Abstract

The invention relates to devices and methods for monitoring or regulating a cutting process on a workpiece. A focusing element focuses a high-energy beam onto the workpiece. An image capture apparatus captures a region at the workpiece to be monitored. The region includes an interaction region of the high-energy beam with the workpiece. An control apparatus determines at least one characteristic variable of the cutting process, in particular of a kerf formed during the cutting process, on the basis of the captured interaction region.

First claim

What is claimed is:

1. A device for monitoring a cutting process on a workpiece comprising:
a focusing element for focusing a high-energy beam onto the workpiece;
an image capture apparatus for capturing a region at the workpiece to be monitored, the region comprising an interaction region of the high-energy beam with the workpiece,
wherein the image capture apparatus forms an observation beam for observing the interaction region from an observation direction extending at an angle to a beam axis of the high-energy beam in a convergent beam path between the focusing element and the workpiece, and
wherein the image capture apparatus comprises an imaging optic system configured to generate an image of the interaction region from along the observation beam, wherein the image capture apparatus has a stop for modifying an alignment of the observation direction of the observation beam; and
a control apparatus configured to modify the alignment of the observation direction in a projection into a plane perpendicular to the beam axis in a manner dependent on an advance direction of the cutting process.

2. The device of claim 1 , wherein the high-energy beam is a laser beam.

3. The device of claim 1 , wherein the image capture apparatus is configured to modify the alignment of the observation direction of the observation beam in a plane perpendicular to the beam axis of the high-energy beam.

4. The device of claim 3 , wherein the image capture apparatus has a stop for modifying the alignment of the observation direction of the observation beam.

5. The device of claim 1 , wherein the imaging optic system is configured to generate a plurality of images of the interaction region from differently aligned observation directions.

6. The device of claim 5 , wherein the imaging optic system has a plurality of imaging optical elements for generating the plurality of images.

7. The device of claim 6 , wherein the plurality of imaging optical elements form a grid arrangement.

8. The device of claim 5 , wherein, for the purposes of generating the plurality of images, the imaging optic system has an apparatus configured to form a respective observation beam by influencing a beam direction of an observation beam path.

9. The device of claim 1 , further comprising a control apparatus configured to modify the alignment of the observation direction in a plane perpendicular to the beam axis in a manner dependent on an advance direction of the cutting process.

10. The device of claim 8 , wherein the control apparatus is configured to keep the alignment of the observation direction constant relative to the advance direction.

11. The device of claim 1 , wherein the observation direction extends counter to an advance direction of the cutting process in a plane perpendicular to the beam axis of the high-energy beam.

12. The device of claim 11 , wherein the control apparatus is configured to determine one or more of a cutting front angle of the kerf, an overshoot of a predetermined cutting front angle of the kerf, and an undershoot of the predetermined cutting front angle of the kerf as the at least one characteristic variable of the kerf on the basis of the captured interaction region.

13. The device of claim 11 , wherein the angle at which the observation direction extends in relation to the beam axis of the high-energy beam deviates by less than 5° from the predetermined cutting front angle.

14. The device of claim 12 , wherein the angle at which the observation direction extends in relation to the beam axis of the high-energy beam deviates by less than 2° from the predetermined cutting front angle.

15. The device of claim 1 , wherein the angle from the observation direction to the beam axis of the high-energy beam is in the range of 5°-15°.

16. The device of claim 1 , wherein the angle from the observation direction to the beam axis of the high-energy beam is in the range of 5°-10°.

17. The device of claim 1 , wherein the image capture apparatus is configured to form a further observation beam for observing the interaction region from a further observation direction and wherein the imaging optic system is configured to generate a further image of the interaction region from the further observation direction.

18. The device of claim 17 , wherein the control apparatus is configured to compare a first intensity value determined on the basis of the further image of the interaction region with a second intensity value determined on the basis of another image of the interaction region captured counter to the advance direction in a plane perpendicular to the beam axis of the high-energy beam.

19. The device of claim 5 , wherein at least one of the observation directions in a plane perpendicular to the beam axis of the high-energy beam does not extend in, or counter to, the advance direction of the cutting process and wherein the control apparatus is configured to determine at least one of a burr formation, a roughness, and a furrow formation as the at least one characteristic variable of the kerf on the basis of the generated image.

20. The device of claim 1 , further comprising an illumination source for illuminating the workpiece in the region to be monitored.

21. The device of claim 1 , wherein the image capture apparatus is configured to record the image through a nozzle opening of a laser processing nozzle for the passage of a laser beam to the workpiece.

22. The device of claim 1 , wherein the image capture apparatus has a detector with a detector surface, at which the image is generated.

23. The device of claim 1 , wherein the image capture apparatus includes a camera, with a detector surface, at which the image is generated.

24. The device of claim 23 , further comprising: at least one of an open-loop and a closed-loop control apparatus for controlling parameters of the cutting process in a manner dependent on the at least one determined characteristic variable.

25. The device of claim 1 , wherein the control apparatus is configured to determine at least one of a cutting front angle of the kerf, an overshoot of a predetermined cutting front angle, and an undershoot of the predetermined cutting front angle of the kerf as the at least one characteristic variable of the kerf on the basis of the captured interaction region, and wherein the device further comprises a closed-loop control apparatus for regulating the cutting front angle to a predetermined constant value by influencing at least one manipulated parameter of the cutting process.

26. The device of claim 25 , in which the closed-loop control apparatus is configured to select the manipulated parameter for regulating the cutting front angle in a manner dependent on a contour to be cut into the workpiece.

27. The device of claim 25 , wherein the closed-loop control apparatus is configured to influence the advance speed between the high-energy beam and the workpiece as a manipulated parameter for regulating the cutting front angle if the advance speed is restricted to a maximum value by the material and the thickness of the workpiece.

28. The device of claim 27 , wherein the closed-loop control apparatus is configured to keep the power of the high-energy beam at a constant value while influencing the advance speed.

29. The device of claim 25 , wherein the closed-loop control apparatus is configured to influence the power of t

Assignees

• Trumpf Werkzeugmaschinen Gmbh Co Kg

Inventors

• Regaard Boris
• Schindhelm David

Classifications

• B23K26/38 Primary

  by boring or cutting · CPC title

• B23K26/032 Primary

  using optical means · CPC title