# US 2014/0151348 A1 · Method for generating at least one through-hole and device for carrying out such a method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0151348 A1 - Document ID: US20140151348A1 - Status: Published application - Kind: A1 - Application number: 14/131,137 - Filed: 2012-06-18 - Published: 2014-06-05 - Earliest claimed: 2011-07-05 - Assignees: Robert Bosch GmbH - Inventors: Thorsten Bauer; Jens Koenig - Web page: https://patentgrep.com/patent/US20140151348A1 ## CPC - B23K 26/389: {of fluid openings, e.g. nozzles, jets} - B23K 26/18: using absorbing layers on the workpiece, e.g. for marking or protecting purposes - B23K 26/382: by boring - F02M 61/18: Injection nozzles, e.g. having valve seats; {Details of valve member seated ends, not otherwise provided for} - F02M 2200/8069: involving removal of material from the fuel apparatus, e.g. by punching, hydro-erosion or mechanical operation - 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 - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF ## Abstract The invention relates to a method for generating at least one through-hole (3, 4) in a wall of a workpiece (2) bounding a hollow space (12) of the workpiece (2), said method using a laser beam (7) directed onto the wall (9) from the exterior. A paste-like protective agent (13) is thereby introduced into the hollow space of the workpiece (2). The paste-like protective agent (13) is applied in an extension (10) of the laser beam (7) guided through the through-hole (3) in front of a rear wall bounding the hollow space (12). Reliable protection of the rear wall (11) during laser drilling of the through-hole (3) is thereby ensured. ## Claims ### Claim 1 (canceled) ### Claim 2 (depends on 8) The method according to claim 8, characterized in that the hollow space (12) of the workpiece (2) is filled with the paste-like protective agent (13) at least along the extension (10) of the laser beam (7) guided through the through-hole (3). ### Claim 3 (depends on 8) The method according to claim 8, characterized in that the paste-like protective agent (13) is replenished in the hollow space (12) at least during laser drilling of the through-hole (3) resulting by means of the laser beam (7). ### Claim 4 (depends on 3) The method according to claim 3, characterized in that a plurality of through-holes (3, 4) is generated by means of the laser beam (7) in at least one of the first wall (9) and a further wall (9) of the workpiece (2) in a laser drilling operation. ### Claim 5 (depends on 3) The method according to claim 3, characterized in that the paste-like protective agent (13) is conveyed with a feed pressure into the hollow space (12) of the workpiece (2), which pressure in turn presses shut gas or vapor bubbles which were generated by the laser beam (7) in the paste-like protective agent (13). ### Claim 6 (depends on 8) A device (1) for carrying out a method having the features according to claim 8, wherein a conveying device (6) is provided which serves to convey the paste-like protective agent (13) into the hollow space (12) of the workpiece (2) and wherein the conveying device is embodied as a screw-conveyor or calender. ### Claim 7 (depends on 6) The device according to claim 6, characterized in that the conveying device (6) which conveys the paste-like protective agent (13) is partially inserted into the hollow space (12), in that a working portion of the hollow space (12) is bounded by the conveying device (6) and in that the working portion of the hollow space (12) is filled with the paste-like protective agent (13) by the conveying device (6). ### Claim 8 A method for generating at least one through-hole (3) in a first wall (9) of a workpiece (2) bounding a hollow space (12) of the workpiece (2), the workpiece having a rear wall (11) bounding the hollow space (12), and the workpiece having an exterior, said method comprising: using a laser beam (7) directed onto the first wall (9) from the exterior; and introducing a paste-like protective agent (13) into the hollow space (12) of the workpiece (2), the paste-like protective agent (13) being applied in the hollow space (12) at least partially in an extension (10) of the laser beam (7) guided through the through-hole (3) in front of the rear wall (11) of the workpiece (2), wherein the paste-like protective agent (13) is formed on the basis of a ceramic powder in an aqueous solution or in a non-aqueous dispersion, in which powder metallic particles or, respectively, pieces of fiberglass are embedded. ### Claim 9 (depends on 8) The method according to claim 8 wherein the paste-like protective agent (13) is formed on the basis of a ceramic powder in an aqueous solution. ### Claim 10 (depends on 8) The method according to claim 8 wherein the paste-like protective agent (13) is formed on the basis of a ceramic powder in a non-aqueous dispersion. ### Claim 11 (depends on 8) The method according to claim 8 wherein the paste-like protective agent (13) is a ceramic powder in which powder metallic particles are embedded. ### Claim 12 (depends on 8) The method according to claim 8 wherein the paste-like protective agent (13) is a ceramic powder in which pieces of fiberglass are embedded. ### Claim 13 (depends on 2) The method according to claim 2, characterized in that the paste-like protective agent (13) is replenished in the hollow space (12) at least during laser drilling of the through-hole (3) resulting by means of the laser beam (7). ### Claim 14 (depends on 13) The method according to claim 13, characterized in that a plurality of through-holes (3, 4) is generated by means of the laser beam (7) in at least one of the first wall (9) and a further wall (9) of the workpiece (2) in a laser drilling operation. ### Claim 15 (depends on 14) The method according to claim 14, characterized in that the paste-like protective agent (13) is conveyed with a feed pressure into the hollow space (12) of the workpiece (2), which pressure in turn presses shut gas or vapor bubbles which were generated by the laser beam (7) in the paste-like protective agent (13).