Systems and methods for laser marking work pieces

• US 8,585,956 B1
• Filed: 10/25/2010
• Issued: 11/19/2013
• Est. Priority Date: 10/23/2009
• Status: Active Grant

• Current Assignee: Therma-Tru Corporation (Fortune Brands Home & Security, Inc.)
• Original Assignee: Therma-Tru Corporation (Fortune Brands Home & Security, Inc.)
• Inventors: Pagryzinski, William V., Ziebold, Caleb A.
• Primary Examiner(s): THROWER, LARRY W
• Application Number:
  US12/911,336
• Time in Patent Office: 1,121 Days
• Field of Search: 264/400
• US Class Current: 264/400
• CPC Class Codes: B23K 26/355 Texturing
• CPC Class Codes: B41M 5/24 Ablative recording, e.g. by burning marks; Spark recording marking by high energetic means, e.g. by laser otherwise than burning or ablative removal B41M5/26; materials or methods for recording or reproduction by optical means G11B7/00
• CPC Class Codes: B41M 5/267 Marking of plastic artifacts, e.g. with laser
• CPC Class Codes: B44C 1/228 by laser radiation
• CPC Class Codes: B44F 9/02 wood grain effects

Abstract

A method of laser marking a work piece involves reproducing a pattern having a surface marked portion and a depth engraved portion from a digital image of the pattern. The grayscale shades of pixels in one portion of the image are adjusted while maintaining grayscale shades of pixels in the other portions of the image constant, wherein the adjusted grayscale shades of pixels corresponding to a surface marked portion are within a first range and the adjusted grayscale shades of pixels corresponding to a depth engraved portion are within a second range separate from the first range. The modified image is converted to a computer readable code, such that the first and second ranges of grayscale shades are associated with surface marking and depth engraving ranges of laser power settings. A laser marking apparatus is then operated in accordance with the computer readable code to laser mark the work piece.

Claims

1. A method of producing a pattern for use with a laser marking apparatus configured to mark visible surface markings on a work piece within a first predetermined range of power settings electronically stored on at least one computer, and further configured to engrave depth engravings on the work piece within a second predetermined range of power settings electronically stored on the at least one computer, the pattern having at least one surface marked portion and at least one depth engraved portion, the method comprising:

associating a first range of grayscale shades with the first predetermined range of power settings, such that a lightest shade in the first range of grayscale shades corresponds to a low end of the first predetermined range of power settings, and a darkest shade in the first range of grayscale shades corresponds to a high end of the first predetermined range of power settings;

associating a second range of grayscale shades with the second predetermined range of power settings, such that a lightest shade in the second range of grayscale shades corresponds to a low end of the second predetermined range of power settings, and a darkest shade in the second range of grayscale shades corresponds to a high end of the second predetermined range of power settings;

electronically storing, on the at least one computer, a digital grayscale image of the pattern to be laser marked, the digital grayscale image including a first layer including a surface marked portion of the pattern, and a second layer separable from the first layer, the second layer including a depth engraved portion of the pattern;

obtaining, on the at least one computer, a modified grayscale image in which grayscale shades of pixels in the first layer have been adjusted while maintaining grayscale shades of the second layer constant, wherein the adjusted grayscale shades of the first layer pixels that correspond to the surface marked portion of the pattern are within the first range of grayscale shades, and in which

the grayscale shades of the second layer have been adjusted while maintaining the grayscale shades of the first layer constant, wherein the adjusted grayscale shades of the second layer pixels that correspond to the depth engraved portion of the pattern are within the second range of grayscale shades; and

operating the laser marking apparatus at power settings associated with the adjusted grayscale shades of the first and second layers to produce the pattern on the work piece.

2. The method of claim 1, wherein the grayscale image of the pattern comprises a digital photograph of a wood grain pattern.

3. The method of claim 1, wherein the adjusted grayscale shades of the first layer comprise lightened or omitted pixels in the first layer that do not correspond to the surface marked portion of the pattern.

4. The method of claim 1, wherein the adjusted grayscale shades of the first layer comprise darkened pixels in the first layer that do not correspond to the surface marked portion of the pattern, such that the darkened pixels are within the second range of grayscale shades.

5. The method of claim 1, further comprising operating the laser marking apparatus at power settings associated with the adjusted grayscale shades of the first and second layers to produce the pattern on the work piece.

6. The method of claim 1, wherein the grayscale shades of pixels in the first layer have been adjusted by isolating the first layer from the second layer, and wherein the grayscale shades of pixels in the second layer have been adjusted by isolating the second layer from the first layer.

7. The method of claim 1, further comprising converting the modified grayscale image to a computer readable code, such that the first range of grayscale shades is associated with the first range of laser power settings, and the second range of grayscale shades is associated with the second range of laser power settings.

8. The method of claim 7, wherein operating the laser marking apparatus comprises operating the laser marking apparatus in accordance with the computer readable code.

9. The method of claim 1, further comprising operating a laser marking apparatus at graduated incremental power settings from a minimum predetermined power setting to a maximum predetermined power setting to produce a corresponding grayscale grid pattern on a test piece, and measuring relative shades of incremental locations on the grayscale grid pattern of the test piece to identify the first range of power settings and the second range of power settings.

10. The method of claim 9, further comprising applying a shade enhancing material to the grayscale grid pattern on the test piece before measuring relative shades of incremental locations on the grayscale grid pattern.

11. The method of claim 10, wherein the shade enhancing material comprises a stain.

12. The method of claim 9, further comprising excluding from the first range of power settings a sub-range of power settings over which a change in power produces no noticeable change in visible marking.

13. The method of claim 9, wherein the adjusted-grayscale shades of the first layer pixels comprise pixels in the first layer that do not correspond to the surface marked portion of the pattern that have been adjusted to correspond with a third range of power settings for which no visible markings are produced when operating the laser marking apparatus on the test piece.

14. The method of claim 1, further comprising storing, on the at least one computer, a plurality of first wood model images, each of the first wood model images including a different wood grain pattern, storing a plurality of second wood model images, each of the second wood model including a different wood grain pattern, and combining a selected one of the plurality of first wood model images for a first portion of the wood grain pattern with a selected one of the plurality of second wood model images for a second portion of a wood grain pattern to generate the digital grayscale image.

15. The method of claim 1, wherein obtaining the digital grayscale image comprises at least one of providing the digital grayscale image, generating the digital grayscale image;

and receiving the digital grayscale image.

16. The method of claim 14, further comprising applying a shade enhancing material to the pattern on the work piece.

17. The method of claim 1, wherein the at least one computer comprises a plurality of computers.

18. The method of claim 1, wherein the first and second predetermined ranges of power settings are electronically stored on a first computer of the at least one computer, and the grayscale image is obtained on a second computer of the at least one computer.

19. A method of producing a pattern for use with a laser marking apparatus configured to mark visible surface markings on a work piece within a first predetermined range of power settings electronically stored on at least one computer, and further configured to engrave depth engravings on the work piece within a second predetermined range of power settings electronically stored on the at least one computer, the pattern having at least one surface marked portion and at least one depth engraved portion, the method comprising:

electronically storing, on the at least one computer, a digital grayscale image of the pattern to be laser marked, the digital grayscale image including a first layer including a surface marked portion of the pattern, and a second layer separable from the first layer, the second layer including a depth engraved portion of the pattern;

modifying, on the at least one computer, the grayscale image by adjusting grayscale shades of pixels in the first layer while maintaining grayscale shades of the second layer constant, wherein the adjusted grayscale shades of the first layer pixels that correspond to the surface marked portion of the pattern are within a first range of grayscale shades, wherein the first range of grayscale shades is associated with the first predetermined range of power settings, such that a lightest shade in the first range of grayscale shades corresponds to a low end of the first predetermined range of power settings, and a darkest shade in the first range of grayscale shades corresponds to a high end of the first predetermined range of power settings; and

modifying, on the at least one computer, the grayscale image by adjusting the grayscale shades of the second layer while maintaining the grayscale shades of the first layer constant, wherein the adjusted grayscale shades of the second layer pixels that correspond to the depth engraved portion of the pattern are within a second range of grayscale shades, wherein the second range of grayscale shades is associated with the second predetermined range of power settings, such that a lightest shade in the second range of grayscale shades corresponds to a low end of the second predetermined range of power settings, and a darkest shade in the second range of grayscale shades corresponds to a high end of the second predetermined range of power settings; and

exporting the modified grayscale image to the laser marking apparatus to enable the laser marking apparatus to produce the pattern on the work piece.

20. The method of claim 19, further comprising operating the laser marking apparatus at the power settings associated with the grayscale shades of the first and second layers to produce the pattern on the work piece.

21. The method of claim 20, wherein the laser marking apparatus uses a maximum power of 150 W.

22. The method of claim 20, wherein the work piece comprises fiberglass reinforced plastic.

23. The method of claim 20, further comprising operating the laser marking apparatus at non-zero power settings below the first range of power settings to laser treat non-patterned portions of the work piece.

24. The method of claim 19, wherein the grayscale image of the pattern comprises a digital photograph of a wood grain pattern.

25. The method of claim 19, wherein electronically storing the digital grayscale image of the pattern to be laser marked comprises selecting one of a plurality of first wood model images, each of the first wood model images including a different wood grain pattern, selecting one of a plurality of second wood model images, each of the second wood model including a different wood grain pattern, the digital grayscale image being generated from a combination of the selected ones of the first and second wood model images.

26. The method of claim 19, wherein electronically storing the digital grayscale image comprises at least one of providing the digital grayscale image, generating the digital grayscale image;

and receiving the digital grayscale image.

27. The method of claim 19, wherein the at least one computer comprises a plurality of computers.

28. The method of claim 19, wherein the grayscale image is electronically stored on a first computer of the at least one computer, and the grayscale image is modified on a second computer of the at least one computer.