# US 2022/0032402 A1 · Methods and systems for machining precision micro holes into thick ceramic substrates > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0032402 A1 - Document ID: US20220032402A1 - Status: Published application - Kind: A1 - Application number: 17/390,891 - Filed: 2021-07-31 - Published: 2022-02-03 - Earliest claimed: 2020-08-01 - Assignees: Avonisys AG - Applicants: Avonisys AG - Inventors: Jens Guenter Gaebelein; Ralf Giebmanns; Jeroen Hribar - Web page: https://patentgrep.com/patent/US20220032402A1 ## CPC - B23K 26/382: by boring - B23K 26/032: {using optical means} - B23K 26/146: the fluid stream containing a liquid - B23K 26/402: involving non-metallic material, e.g. isolators - B23K 26/70: Auxiliary operations or equipment - B23K 2103/52: {Ceramics} - 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 combination of a liquid jet and a mechanical rotary tool can be used to machine precision micro holes in thick substrates. A liquid-jet guided laser can be used to rapidly drill core holes into the ceramic substrate. A sensor can be applied to detect the cut through point of the liquid-jet guided laser drilling step to allow a rapid and closed-loop controlled machining process. The substrate can be heated up for speeding up a liquid-jet guided laser drilling process. A mechanical tool such as a drill, a reamer or a mill can be applied to finish the core holes to a desired bore diameter. The mechanical tool cutting main surface can preferably consist of a diamond material. An inspection camera and illumination system can be applied to inspect each mechanically finished bore as part of the drilling process. ## Claims ### Claim 1 A method comprising forming a hole in a substrate using a liquid-jet guided laser beam, wherein the liquid-jet guided laser beam comprises a laser beam internally reflected within a column of liquid, wherein the column of liquid is formed by flowing the liquid through a nozzle, wherein the internally reflected laser beam is formed by focusing a laser beam into the column of liquid; smoothing the hole using a mechanical rotary tool to achieve a final dimension, wherein the mechanical rotary tool is operated by a mechanical rotating system, wherein the mechanical rotary tool comprises a diameter suitable for the final dimension of the hole. ### Claim 2 (depends on 1) A method as claim 1, wherein the hole is configured to provide a fluid connection between a top surface and a bottom surface of the substrate. ### Claim 3 (depends on 1) A method as claim 1, wherein forming the hole using the liquid-jet guided laser beam comprises forming the hole using at least one of a circular motion or a spiral motion, wherein the circular motion or the spiral motion is configured to form the hole having a diameter of between 75 and 99% of the final dimension. ### Claim 4 (depends on 1) A method as claim 1, wherein forming the hole using the liquid-jet guided laser beam comprises forming the hole having a diameter of less than 0.05mm than the final dimension. ### Claim 5 (depends on 1) A method as claim 1, wherein a diameter of the hole formed by the liquid-jet guided laser system is configured to minimizing a total processing time of the liquid-jet guided laser beam and the mechanical rotary tool. ### Claim 6 (depends on 1) A method as claim 1, wherein the mechanical rotary tool is configured to smooth the hole to achieve a surface finish having a roughness average (Ra) less than 0.3 micrometers. ### Claim 7 (depends on 1) A method as claim 1, wherein the liquid-jet guided laser beam and the mechanical rotary tool are configured to form and smooth the hole having a sharp edge without circumferential damages. ### Claim 8 (depends on 1) A method as claim 1, wherein the substrate comprises at least one of silicon, silicon carbide, aluminum nitride, silicon nitride, titanium nitride, boron carbide, ceramic matrix composites (CMC), or metal matrix composites (MMC). ### Claim 9 (depends on 1) A method as claim 1, further comprising forming a coaxial flow of gas surrounding the column of liquid, wherein the coaxial gas flow is configured to minimize disturbance to the column of liquid due to a back spray of the column of liquid when hitting the substrate. ### Claim 10 (depends on 1) A method as claim 1, wherein forming the hole using the liquid-jet guided laser beam and finishing the hole using the mechanical rotary tool are performed in a same machine. ### Claim 11 (depends on 1) A method as claim 1, wherein forming the hole using the liquid-jet guided laser beam and finishing the hole using the mechanical rotary tool are performed in different machines. ### Claim 12 (depends on 1) A method as claim 1, wherein the mechanical rotary tool comprises a mechanical drill bit, a mechanical reamer, a mechanical boring bar, a mechanical milling tool, or a mechanical honing tool. ### Claim 13 (depends on 1) A method as claim 1, wherein the mechanical rotary tool comprises an end portion made of a polycrystalline diamond or a single crystalline diamond material. ### Claim 14 (depends on 1) A method as claim 1, wherein the hole is configured to pass completely through the substrate, wherein the method further comprises detecting a cut through of the hole by at least one of an optical sensor or an acoustic sensor. ### Claim 15 (depends on 1) A method as claim 1, further comprising heating the substrate during the formation of the hole using the liquid-jet guided laser beam, wherein heating the substrate comprises at least one of flowing a higher-than-ambient-temperature liquid over a surface of the substrate, flowing a higher-than-ambient- temperature gas over the surface of the substrate, applying an infrared or an inductive energy over the surface of the substrate, or submerging the substrate in a higher-than-ambient-temperature liquid, wherein a temperature of the higher-than-ambient-temperature liquid or gas is between 50 and 100 degrees Celsius. ### Claim 16 (depends on 1) A method as claim 1, further comprising inspecting the hole after the hole is smoothed by the mechanical rotary tool, wherein the inspection comprises a camera. ### Claim 17 A method comprising disposing a substrate having a first surface facing a liquid-jet guided laser head; forming multiple blind holes in a substrate using a liquid-jet guided laser beam generated from the liquid-jet guided laser head, wherein the liquid-jet guided laser beam comprises a laser beam internally reflected within a column of liquid, wherein the column of liquid is formed by flowing the liquid through a nozzle; flipping the substrate to have a second surface of the substrate facing the liquid-jet guided laser head, wherein the second surface is opposite the first surface; aligning each blind hole of the multiple blind holes with the liquid-jet guided laser beam; forming a through hole passing through the each blind hole by the liquid-jet guided laser beam; smoothing the through holes using a mechanical rotary tool. ### Claim 18 (depends on 17) A method as claim 17, further comprising detecting the liquid-jet guided laser beam forming the through hole by at least one of an optical sensor or an acoustic sensor. ### Claim 19 (depends on 17) A method as claim 17, further comprising inspecting the hole after the hole is smoothed by the mechanical rotary tool, wherein the inspection comprises a camera. ### Claim 20 A method comprising forming a hole in a substrate using a liquid-jet guided laser beam, wherein the liquid-jet guided laser beam comprises a laser beam internally reflected within a column of liquid, wherein the column of liquid is formed by flowing the liquid through a nozzle; smoothing the hole using a mechanical rotary tool, wherein the mechanical rotary tool comprises an end portion comprising a synthetic diamond material.