# US 2023/0057548 A1 · Laser cutting head for a machine tool > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0057548 A1 - Document ID: US20230057548A1 - Status: Published application - Kind: A1 - Application number: 17/796,131 - Filed: 2021-02-04 - Published: 2023-02-23 - Earliest claimed: 2020-02-07 - Assignees: Salvagnini Italia S.p.A. - Applicants: Salvagnini Italia S.P.A. - Inventors: Bruno SAMBI; Gabriele ANZOLIN - Web page: https://patentgrep.com/patent/US20230057548A1 ## CPC - B23K 26/38: by boring or cutting - B23K 26/032: {using optical means} - B23K 26/705: {Beam measuring devices} - 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 A laser cutting head associable to a machine tool comprises a collimating group to collimate a laser beam coming from a laser emitting apparatus, a focusing group to focus in a focal point the laser beam collimated, an optical element to receive said laser beam focused and reflect a focused first portion thereof, and a wavefront sensor to receive said focused first portion of the laser beam, perform a phase measurement of a wavefront of said focused first portion, obtain a reconstructed wavefront on the basis of the phase measurement and send the reconstructed wavefront to an electronic processor; the electronic processor compares the reconstructed wavefront and a reference wavefront, determines one or more optical aberrations to which the laser beam is subjected, reduces such optical aberrations and changes said focal point. ## Claims ### Claim at position 1 1-15. (canceled) ### Claim 16 A laser cutting head associable to a machine tool, comprising: a collimating group to collimate a laser beam coming from a laser emitting apparatus; a focusing group to focus in a focal point said laser beam exiting collimated from said collimating group; supporting and moving assembly to support and move along an adjustment direction at least one between said collimating group and focusing group; at least one optical element to receive said laser beam exiting focused from said focusing group and reflect a focused first portion of the received laser beam; an electronic processor adapted to operate said supporting and moving assembly to move at least one between said collimating group and focusing group along said adjustment direction; at least one wavefront sensor adapted to receive said focused first portion of the laser beam, perform a phase measurement of a wavefront of said focused first portion, obtain a reconstructed wavefront on the basis of said phase measurement and send said reconstructed wavefront to said electronic processor, the electronic processor being configured to perform a comparison between said reconstructed wavefront and a reference wavefront, determine on the basis of said comparison one or more optical aberrations to which the laser beam is subjected and operate said supporting and moving assembly to reduce said one or more optical aberrations and change said focal point. ### Claim 17 (depends on 16) The laser cutting head according to claim 16, wherein said reference wavefront is an ideal wavefront free of optical aberrations or a predetermined wavefront affected by predefined optical aberrations, said electronic processor being configured to operate said supporting and moving assembly so that said one or more optical aberrations are, respectively, minimized or zeroed or else are less than or equal to said predefined optical aberrations. ### Claim 18 (depends on 16) The laser cutting head according to claim 16, wherein said at least one wavefront sensor is of Shack-Hartmann type. ### Claim 19 (depends on 16) The laser cutting head according to claim 16, wherein said at least one optical element is a beam splitter. ### Claim 20 (depends on 16) The laser cutting head according to claim 16, comprising a casing element forming an internal space adapted to contain at least said collimating group, focusing group, supporting and moving assembly and at least one optical element. ### Claim 21 (depends on 20) The laser cutting head according to claim 20, wherein said optical element is adapted to separate said internal space of the laser cutting head from an external environment. ### Claim 22 (depends on 20) The laser cutting head according to claim 20 wherein said casing element is provided with a lateral opening that is air-tight closed by a transparent optical element for the transmission of said focused first portion of the laser beam towards the external environment, said wavefront sensor being external to said casing element. ### Claim 23 (depends on 16) The laser head according to claim 16, wherein said laser emitting apparatus is a fiber laser. ### Claim 24 A laser cutting head associable to a machine tool, comprising: a collimating group to collimate a laser beam coming from a laser emitting apparatus; a focusing group to focus in a focal point said laser beam exiting collimated from said collimating group; at least one adaptive optical device having adjustable shape; at least one optical element to receive said laser beam exiting focused from said focusing group and reflect a focused first portion of the received laser beam; an electronic processor adapted to adjust the shape of said adaptive optical device; characterized in that it comprises at least one wavefront sensor adapted to receive said focused first portion of the laser beam, perform a phase measurement of a wavefront of said focused first portion, obtain a reconstructed wavefront on the basis of said phase measurement and send said reconstructed wavefront to said electronic processor, said electronic processor being configured to perform a comparison between said reconstructed wavefront and a reference wavefront, determine on the basis of said comparison one or more optical aberrations to which the laser beam is subjected and adjust the shape of said adaptive optical device to reduce said one or more optical aberrations and change said focal point. ### Claim 25 (depends on 24) The laser cutting head according to claim 24, wherein said reference wavefront is an ideal wavefront free of optical aberrations or a predetermined wavefront affected by predefined optical aberrations, said electronic processor being configured to adjust the shape of said adaptive optical device so that said one or more optical aberrations are, respectively, minimized or zeroed or else are less than or equal to said predefined optical aberrations. ### Claim 26 (depends on 24) The laser cutting head according to claim 24, wherein said adaptive optical device is positioned upstream of said focusing group with reference to a propagation direction of said laser beam. ### Claim 27 (depends on 24) The laser cutting head according to claim 24, wherein said at least one wavefront sensor is of Shack-Hartmann type. ### Claim 28 (depends on 24) The laser cutting head according to claim 24, wherein said at least one optical element is a beam splitter. ### Claim 29 (depends on 24) The laser cutting head according to claim 24, comprising a casing element forming an internal space adapted to contain at least said collimating group, focusing group, supporting and moving assembly and at least one optical element. ### Claim 30 (depends on 29) The laser cutting head according to claim 29, wherein said optical element is adapted to separate said internal space of the laser cutting head from an external environment. ### Claim 31 (depends on 29) The laser cutting head according to claim 29, wherein said casing element is provided with a lateral opening that is air-tight closed by a transparent optical element for the transmission of said focused first portion of the laser beam towards the external environment, said wavefront sensor being external to said casing element. ### Claim 32 (depends on 24) The laser cutting head according to claim 24, wherein said laser emitting apparatus is a fiber laser. ### Claim 33 A method for controlling the laser cutting of a workpiece, comprising the steps of: performing the laser cutting of said workpiece by means of a laser cutting head associated to a machine tool; powering said laser cutting head with a laser beam; collimating and focusing in a focal point said laser beam; reflecting at least one focused first portion of said focused laser beam; performing a phase measurement of a wavefront of said at least one focused first portion; obtaining a reconstructed wavefront on the basis of said phase measurement; performing a comparison between said reconstructed wavefront and a reference wavefront; determining on the basis of said comparison one or more optical aberrations to which said laser beam is subjected; reducing said one or more optical aberrations to which said laser beam is subjected in order to change said focal point of the laser beam. ### Claim 34 (depends on 33) The method according to claim 33, wherein said reference wavefront is an ideal wavefront free of optical aberrations and said reducing comprises minimizing or zeroing, said one or more optical aberrations, or said reference wavefront is a target wavefront affected by predefined optical aberrations and said method comprises the step of reducing said optical aberrations so that they are smaller than or equal to said predefined optical aberrations. ### Claim 35 (depends on 33) The method according to claim 33, wherein the steps of performing a phase measurement and obtaining a reconstructed wavefront are implemented by a wavefront sensor. ### Claim 36 (depends on 33) The method according to any claim 33, further comprising the step of emitting an error signal when said optical aberrations exceed a preset threshold value.