# US 2013/0153548 A1 · Reopening of cooling-air bores using a nanosecond laser in the microsecond range

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- Number: US 2013/0153548 A1
- Document ID: US20130153548A1
- Status: Published application
- Kind: A1
- Application number: 13/713,100
- Filed: 2012-12-13
- Published: 2013-06-20
- Earliest claimed: 2011-12-15
- Assignees: Siemens Aktiengesellschaft
- Inventors: Andrea Massa; Rolf Wilkenhöner; Adrian Wollnik
- Web page: https://patentgrep.com/patent/US20130153548A1

## CPC

- B23K 26/38: by boring or cutting
- B23K 26/382: by boring
- B23K 26/389: {of fluid openings, e.g. nozzles, jets}
- B21D 53/78: propeller blades; turbine blades
- B23K 2101/001: {Turbines}
- Y10T 29/49341: with cooling passage
- 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
- B21D: WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL (working or processing of wire B21F)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A process for reopening cooling-air holes by a laser in order to remove coat down is provided. A nanosecond laser is provided and used for reopening the holes, wherein pulse times between 1 μs and 20 μs and a pulse frequency between 20 kHz and 40 kHz provided by the nanosecond laser are used.

## Claims

### Claim 1

A process for reopening cooling-air holes by a laser in order to remove coat down, comprising:
providing and using a nanosecond laser, and
opening holes with the nanosecond laser in order to remove coating material,
wherein pulse times between 1 μs and 20 μs and a pulse frequency between 20 kHz and 40 kHz, provided by the nanosecond laser, are used.

### Claim 2 (depends on 1)

The process as claimed in claim 1, wherein pulse times of 10 μs are used.

### Claim 3 (depends on 1)

The process as claimed in claim 1, wherein a pulse frequency of 30 kHz is used.

### Claim 4 (depends on 1)

The process as claimed in claim 1, wherein a laser power between 180 W and 200 W is used.

### Claim 5 (depends on 1)

The process as claimed in claim 1, wherein the nanosecond laser is an ablation laser, and wherein the ablation laser is moved over a surface to be removed at a feed rate of between 200 mm/s and 300 mm/s, in particular at 250 mm/s.

### Claim 6 (depends on 1)

The process as claimed in claim 1, wherein a cylindrical part is cleared away from a first coat down, and wherein a diffuser region is cleared away from a second coat down.

### Claim 7 (depends on 6)

The process as claimed in claim 6, wherein the nanosecond laser is used with pulse times of less than 800 ns, in particular less than 600 ns, for removal of the second coat down from the diffuser region.

### Claim 8 (depends on 6)

The process as claimed in claim 6, wherein the nanosecond laser is used with identical laser parameters for removal of the first coat down from the cylindrical part and for removal of the second coat down from the diffuser region.

### Claim 9 (depends on 6)

The process as claimed in claim 6, wherein the first and/or second coat downs are removed in layers.

### Claim 10 (depends on 6)

The process as claimed in claim 6, wherein metallic and/or ceramic coat downs are removed.