# US 12,759,090 B2 · Laser cutting method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,759,090 B2 - Document ID: US12759090B2 - Status: Granted - Kind: B2 - Application number: 18/187,821 - Filed: 2023-03-22 - Published: 2023-07-13 - Granted: 2026-10-13 - Earliest claimed: 2020-09-25 - Assignees: TRUMPF Werkzeugmaschinen GmbH + Co. KG - Applicants: TRUMPF Werkzeugmaschinen SE + Co. KG - Inventors: Michael Krutzke; Patrick Mach; Christoph Kraus - Web page: https://patentgrep.com/patent/US12759090B2 ## CPC - B23K 31/10: relating to cutting or desurfacing - B23K 26/0869: {Devices involving movement of the laser head in at least one axial direction} - B23K 26/1462: {Nozzles; Features related to nozzles} - B23K 26/38: by boring or cutting - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM ## Abstract In a method for laser fusion cutting in particular a plate-shaped workpiece, preferably with a thickness D of at least 1 mm, a laser beam and a cutting gas, in particular nitrogen, at a cutting gas pressure are directed at the workpiece surface by a convergent cutting nozzle. The laser power is at least 6 kW and the cutting nozzle has a nozzle end face on the workpiece side. A distance A between the nozzle end face and the workpiece surface during the cutting operation is 2 to 8 mm. The cutting nozzle has a nozzle channel with a diameter dD at the nozzle end face on the workpiece side of 1.5 to 4 mm. The cutting gas pressure before emergence from the cutting nozzle is 15 to 30 bar. This makes it possible to achieve high productivity along with a reduced risk of collision, i.e. higher process reliability. ## Claims ### Claim 1 A method for laser fusion cutting a workpiece, which comprises the steps of: directing a laser beam and a cutting gas at a cutting gas pressure at a workpiece surface by means of a convergent cutting nozzle, the convergent cutting nozzle having a nozzle end face on a workpiece side; setting a laser power to be at least 6 KW; setting a distance between the nozzle end face and the workpiece surface during the laser fusion cutting to be 2 to 8 mm; setting a diameter of a nozzle channel of the convergent cutting nozzle at the nozzle end face on the workpiece side to be 1.5 to 4 mm; setting the cutting gas pressure before emergence from the convergent cutting nozzle to be 15 to 30 bar; advancing the convergent cutting nozzle towards at least one puncture point on the workpiece surface at an advancement speed; at a predetermined displacement distance upstream of the puncture point, reducing the advancement speed to a puncture speed lower than the advancement speed, such that the convergent cutting nozzle reaches the at least one puncture point at the puncture speed; puncturing the workpiece surface with the laser beam at the at least one puncture point. ### Claim 2 (depends on 1) The method according to claim 1, which further comprises maintaining the distance between the nozzle end face and the workpiece surface throughout a cutting process. ### Claim 3 (depends on 1) The method according to claim 1, which further comprises providing a single-channel nozzle or an annular die as the convergent cutting nozzle. ### Claim 4 (depends on 1) The method according to claim 1, wherein the cutting gas pressure before emergence from the convergent cutting nozzle is more than 18 bar. ### Claim 5 (depends on 1) The method according to claim 1, which further comprises moving the convergent cutting nozzle relative to the workpiece at least at times at a cutting speed of at least 60 m/min. ### Claim 6 (depends on 1) The method according to claim 1, wherein a focal position of the laser beam lies on the workpiece surface or in a workpiece half facing towards the convergent cutting nozzle. ### Claim 7 (depends on 1) The method according to claim 1, which further comprises setting the laser power during a cutting operation to be at least 10 kW. ### Claim 8 (depends on 1) The method according to claim 1, which further comprises carrying out the method on workpieces with a workpiece thickness of at least 4 mm. ### Claim 9 (depends on 1) The method according to claim 1, wherein the laser beam punctures the workpiece surface at the least at one puncture point while the convergent cutting nozzle and the workpiece are being moved relative to one another. ### Claim 10 (depends on 1) The method according to claim 1, which further comprises reducing the advancement speed to the puncture speed over a displacement distance of less than 2 mm with a result that the puncture speed is reached at the at least one puncture point. ### Claim 11 (depends on 1) The method according to claim 1, wherein after the laser beam punctures the workpiece surface, the puncture speed is maintained for a few milliseconds and then the advancement speed is increased back up to a cutting speed. ### Claim 12 (depends on 1) The method according to claim 1, wherein: the workpiece is a plate-shaped workpiece; the cutting gas is nitrogen; and the distance between the nozzle end face and the workpiece surface during the laser fusion cutting is 4 to 8 mm. ### Claim 13 (depends on 1) The method according to claim 1, wherein a focal position of the laser beam lies on the workpiece surface or in a workpiece half facing towards the convergent cutting nozzle and lies between 0.2 mm and 1.5 mm below a top side of the workpiece. ### Claim 14 (depends on 1) The method according to claim 1, which further comprises reducing an advancement speed to the puncture speed, by 10%-90% of a cutting speed, at the at least one puncture point. ### Claim 15 (depends on 1) The method according to claim 1, which further comprises reducing the advancement speed to the puncture speed over a displacement distance of less than 0.5 mm, with a result that the puncture speed is reached at the at least one puncture point.