Optimized-coverage selective laser ablation systems and methods

Patent metadata

Field	Value
Publication number	US-10744539-B2
Application number	US-201715796128-A
Country	US
Kind code	B2
Filing date	Oct 27, 2017
Priority date	Oct 27, 2017
Publication date	Aug 18, 2020
Grant date	Aug 18, 2020

Abstract

Optimized-coverage selective laser ablation systems and methods may be utilized to prepare (ablate) a three-dimensional surface. Methods comprise receiving a 3D virtual model of the surface to be ablated, generating a preliminary ablation path, and optimizing the preliminary ablation path to produce an adapted ablation path. Methods may comprise ablating the surface according to the adapted ablation path. The preliminary ablation path may be based on scanning a laser sheet across a two-dimensional projection of the surface. The optimization may adjust one or more waypoints of the preliminary ablation path to achieve complete coverage of the surface at acceptable levels of ablation, with little to no ablation outside the surface, and with acceptable (e.g., at least locally minimal) time to ablate the surface.

First claim

The invention claimed is:

1. A method of laser ablation surface preparation of a three-dimensional surface, the method comprising:
receiving a 3D virtual model of a surface to be ablated;
generating a series of waypoints to form a preliminary ablation path across the surface, wherein each of the waypoints is associated with a waypoint location on the surface and includes a laser head position, a laser sheet orientation, and a scan width;
optimizing the preliminary ablation path to produce an adapted ablation path based upon the laser head position, the laser sheet orientation, and the scan width of each waypoint; and
ablating the surface according to the adapted ablation path with a laser head; and
adjusting the scan width of the laser head during the ablating to match the scan width of each of the waypoints of the adapted ablation path, and independently varying one or more of a scan speed and a traverse speed of the laser head to maintain one or more of a laser fluence and a laser irradiance to within a desired range.

2. The method of claim 1 , wherein the preliminary ablation path is a raster path across the surface.

3. The method of claim 1 , wherein the generating includes generating the series of waypoints to form the preliminary ablation path across a two-dimensional projection of the surface.

4. The method of claim 1 , wherein each waypoint location corresponds to a projected location on a two-dimensional projection of the surface and wherein neighboring ones of the projected locations of the series of waypoints are separated at the two-dimensional projection of the surface by less than 200 mm.

5. The method of claim 1 , wherein the laser head position, the laser sheet orientation, and the scan width for each waypoint are configured to produce an amount of cleaning effectiveness at each location across a two-dimensional projection of the surface that is within a predetermined tolerance limit.

6. The method of claim 5 , wherein the amount of cleaning effectiveness includes one or both of the laser fluence and the laser irradiance.

7. The method of claim 1 , wherein the laser sheet orientation of each of the waypoints of the preliminary ablation path is perpendicular to a two-dimensional projection of the surface.

8. The method of claim 1 , wherein the optimizing includes optimizing the preliminary ablation path by controlling at least one of the laser head position, the laser sheet orientation, or the scan width for one or more waypoints.

9. The method of claim 1 , wherein the optimizing includes optimizing the preliminary ablation path by controlling the waypoint location for one or more waypoints.

10. The method of claim 1 , wherein the optimizing includes optimizing one or both of ablation coverage and total time to ablate.

11. The method of claim 1 , wherein the optimizing is performed until an amount of cleaning effectiveness at all waypoints is within a predetermined tolerance limit.

12. The method of claim 11 , wherein the cleaning effectiveness at the waypoints is a rate of ablation at the waypoints, and wherein the rate of ablation includes one or more of the laser fluence and the laser irradiance, and wherein one or more of the laser fluence and the laser irradiance is estimated based on the scan width.

13. The method of claim 1 , wherein the laser sheet orientation of each of the waypoints of the adapted ablation path is normal to the surface at the waypoint location of the corresponding waypoint.

14. The method of claim 1 , wherein a scan spacing of between each of the waypoints of the adapted ablation path is uniform.

15. A laser ablation system comprising:
a controller that is programmed to perform the method of claim 1 ;
a laser, configured to emit a laser beam;
the laser head, configured to deliver the laser beam as a laser sheet onto the surface; and
a laser positioning apparatus, configured to adjust relative positions of the surface and the laser sheet.

16. The laser ablation system of claim 15 , wherein the laser positioning apparatus comprises at least one of a gantry or a robotic positioner.

17. The laser ablation system of claim 15 , wherein the surface is a surface of a workpiece that is a mold, a form, a mandrel, a vehicle, or a structural component.

18. The laser ablation system of claim 15 , wherein the surface is composed of one or more of a metal, a ceramic, a polymeric material, a glass, a composite material, or a carbon fiber-reinforced polymer.

19. The laser ablation system of claim 15 , wherein the 3D virtual model of the surface is based upon an image of the surface.

20. The laser ablation system of claim 15 , further comprising a machine vision system and wherein the controller is further programmed to cause the machine vision system to acquire an image of the surface and to identify a location and an orientation of the surface in a coordinate system of the laser ablation system based at least in part upon the image of the surface, acquired by the machine vision system.

Assignees

• Boeing Co

Inventors

• Barclay Richard Charles
• Weiss Trent T
• Freeman Philip Lawrence

Classifications

• B23K26/082

  Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head · CPC title

• B23K26/08

  Devices involving relative movement between laser beam and workpiece · CPC title

• B23K26/0732

  into a rectangular shape · CPC title

• B23K26/032

  using optical means · CPC title

• B01J19/121

  Coherent waves, e.g. laser beams (lasers per se H01S3/00) · CPC title