# US 7,612,314 B2 · Manufacturing method that uses laser surface transformation to produce new and unique surface profiles for rotating bearings

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- Number: US 7,612,314 B2
- Document ID: US7612314B2
- Status: Granted
- Kind: B2
- Application number: 11/231,478
- Filed: 2005-09-21
- Published: 2006-06-29
- Granted: 2009-11-03
- Earliest claimed: 2004-12-23
- Assignees: Chrysler Group LLC; Adcole Corporation
- Inventors: Anthony T Bustamante; John Wilt
- Web page: https://patentgrep.com/patent/US7612314B2

## CPC

- B23K 26/0622: by shaping pulses
- B23K 26/06: Shaping the laser beam, e.g. by masks or multi-focusing
- B23K 26/3576: {Diminishing rugosity, e.g. by grinding, polishing or smoothing}
- B23K 26/3584: {Increasing rugosity, i.e. roughening}
- B23K 26/364: for making a groove or trench, e.g. for scribing a break initiation groove
- 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 ablation method is used to polish a bearing surface of an automotive crankshaft. A laser ablation device generates a laser according to parameters such as wavelength, pulse duration, pulse repetition rate, and beam quality. The laser is applied to the surface of a rotating engine component, such as a crankshaft, as the component is rotated in order to polish the surface according to the parameters. The laser substantially improves tribological performance of the bearing surface by changing the waviness and form of the surface profile. Further, oil-retention reservoirs are formed in the surface. As a result, the friction coefficient of the crankshaft surface is reduced while the roughness of the crankshaft surface is maintained, reduced, or increased.

## Claims

### Claim 1

A laser ablation method for altering a surface of an automotive component comprising:
determining desired characteristics of the surface, the surface being formed of a first material and including a plurality of exposed nodules of a second material, the second material having a higher heat absorption than the first material;
selecting a plurality of parameters for a laser ablation device according to the desired characteristics;
generating a laser at the laser ablation device according to the plurality of parameters;
applying the laser to the surface;
melting the first material of the surface with the laser;
detonating the exposed nodules with the laser to form shallow pockets in the surface; and
modifying a surface profile of the automotive component.

### Claim 2 (depends on 1)

The laser ablation method of claim 1 wherein the desired characteristics include at least one of roughness, friction coefficient, oil-retention, and/or hardness.

### Claim 3 (depends on 1)

The laser ablation method of claim 1 wherein the parameters include at least one of wavelength, power density, pulse duration, pulse repetition rate, and/or beam quality.

### Claim 4 (depends on 1)

The laser ablation method of claim 1 wherein the automotive component is a rotating engine component.

### Claim 5 (depends on 4)

The laser ablation method of claim 4 wherein the surface is a bearing surface of the rotating engine component.

### Claim 6 (depends on 5)

The laser ablation method of claim 5, wherein the rotating engine component is a crankshaft.

### Claim 7 (depends on 1)

The laser ablation method of claim 1 wherein the step of applying includes decreasing a friction coefficient of the surface and at least one of increasing and/or decreasing a roughness of the surface.

### Claim 8 (depends on 7)

The laser ablation method of claim 7, wherein the step of modifying includes decreasing a friction coefficient of the surface and increasing a roughness of the surface.

### Claim 9 (depends on 1)

The laser ablation method of claim 1 wherein the shallow pockets comprise oil-retention reservoirs in the surface.

### Claim 10 (depends on 1)

The laser ablation method of claim 1, wherein the second material comprises ferrite-carbon.