Granted Patent B2

US 12,508,673 · App. 16/381,059 · Granted Dec 30, 2025

Inventors: Winfried Magg (Ditzingen, DE); David Schindhelm (Stuttgart, DE); Boris Regaard (Gerlingen, DE)

Assignee: TRUMPF Werkzeugmaschinen SE + Co. KG

B23K26/38B23K26/032B23K26/046B23K26/0643B23K26/0648

Abstract

Claims (21)

1 . A method of regulating a focal position of a processing beam relative to a workpiece during cutting of the workpiece with the processing beam, wherein the cutting forms a cutting gap, the method comprising:

illuminating an area of the workpiece with a first illuminating beam from a first illumination source and with a second illuminating beam from a second illumination source, wherein the first illuminating beam is aligned coaxially with the processing beam, and the second illuminating beam is directed across a direction of the cutting gap;

recording at least one spatially resolved image of an area of the workpiece that is to be monitored, wherein the at least one image shows cut edges of said cutting gap formed on a top side of the workpiece during the cutting;

determining, based on the cut edges in the at least one spatially resolved image, a top gap width of said cutting gap on the top side of the workpiece;

measuring a minimal gap width of said cutting gap in the thickness direction of the workpiece, wherein the minimal gap width defines a minimal value of a gap width of said cutting gap in the thickness direction of the workpiece;

determining the focal position of the processing beam relative to the workpiece, based on

(i) the top gap width of said cutting gap on the top side of the workpiece,

(ii) the minimal gap width of said same cutting gap as in (i), and

(iii) a beam caustic of the processing beam; and

changing the focal position of the processing beam relative to the workpiece until the focal position matches a target focal position;

wherein the gap width of said cutting gap varies in the thickness direction of the workpiece; and

wherein determining the top gap width on the top side of the workpiece and measuring the minimal gap width comprises:

determining the respective gap widths from at least two images, wherein determining the respective gap widths comprises directing the first and second illuminating beams at the top side of the workpiece in recording the second image and directing no illuminating beam at the top side of the workpiece in recording the first image; and

subtracting the first image from the second image pixel by pixel.

2 . The method of claim 1 , wherein the first illuminating beam provides areal illumination and the second illuminating beam provides structured illumination.

3 . The method of claim 1 , wherein measuring the minimal gap width comprises determining, based on process emissions from the cutting, the minimal gap width of said cutting gap.

4 . The method of claim 1 , wherein recording the at least one image of the area to be monitored comprises recording at wavelengths in the infrared wavelength range.

5 . The method of claim 1 , wherein recording the at least one image of the area to be monitored comprises recording the at least one image of the area coaxially with a beam axis of the processing beam.

6 . The method of claim 1 , wherein determining the top gap width on the top side of the workpiece and measuring the minimal gap width is performed on the at least one image.

7 . The method of claim 1 , wherein determining the top gap width on the top side of the workpiece and measuring the minimal gap width comprises determining the respective gap widths from at least three images, and wherein determining the respective gap widths comprises directing no illuminating beam at the top side of the workpiece when recording a third image.

8 . The method of claim 1 , wherein the first illumination source provides the first illuminating beam having a wavelength of 660 nm, 808 nm, 915 nm, or 980 nm.

Assignments (3)

Priority Claims (1)

Continuity (2)

References Cited (72)