Method and device for processing arbitrary 3D shaped surfaces by means of a laser, in particular for polishing and texturing workpieces, and for producing sealing surfaces on dies

• US 6,043,452 A
• Filed: 10/06/1997
• Issued: 03/28/2000
• Est. Priority Date: 04/06/1995
• Status: Expired due to Fees

• Current Assignee: LFC Laser Finishing Center AG
• Original Assignee: Polierwerkstatt Fuer Stahlformen Bestenlehrer GmbH
• Inventors: Bestenlehrer, Alexander
• Primary Examiner(s): Evans, Geoffrey S.
• Application Number:
  US08/930,429
• Time in Patent Office: 904 Days
• Field of Search: 219/121.68, 219/121.69, 219/121.61, 219/121.62, 219/121.72, 219/121.83, 364/474.08, 700/166
• US Class Current: 219/121.62
• CPC Class Codes: B23K 26/032 using optical means
• CPC Class Codes: B23K 26/04 Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
• CPC Class Codes: B23K 26/0665 by beam condensation on the workpiece, e.g. for focusing
• CPC Class Codes: B23K 26/10 using a fixed support , i.e. involving moving the laser beam
• CPC Class Codes: B23K 26/355 Texturing
• CPC Class Codes: B23K 26/3576 Diminishing rugosity, e.g. grinding; Polishing; Smoothing
• CPC Class Codes: G05B 19/4099 Surface or curve machining, making 3D objects, e.g. desktop manufacturing
• CPC Class Codes: G05B 19/4207 in which a model is traced or scanned and corresponding data recorded
• CPC Class Codes: G05B 2219/35062 Derive mating, complementary, mirror part from computer model data
• CPC Class Codes: G05B 2219/45165 Laser machining
• CPC Class Codes: G05B 2219/49008 Making 3-D object with model in computer memory
• CPC Class Codes: G05B 2219/50063 Probe, measure, verify workpiece, feedback measured values
• CPC Class Codes: G05B 2219/50071 Store actual surface in memory before machining, compare with reference surface

Abstract

A method and device for polishing and texturing workpieces by which arbitrary two-dimensional and three-dimensional shaped surfaces can be processed. The processing is performed by a laser beam. The actual surface shape and surface texture are determined before processing by a contour-measuring device. Processing parameters are calculated from the desired surface shape and the surface shape actually measured, and the processing is carried out subsequently as appropriate.

Claims

1. Method for producing sealing surfaces on complementary dies having at least two complementary partial sealing surfaces, having the following method steps:

a) fixing the three-dimensional co-ordinates of one of the complementary partial sealing surfaces as desired data;

b) scanning at least one complementary partial sealing surface by means of a three-dimensional contour-measuring device in order to determine the precise, actual surface shape of these partial sealing surfaces in a reference coordinate system as actual data;

c) calculating processing parameters for a beam-processing device for removing material layers on the basis of the desired data determined and on the basis of the actual data determined by the three-dimensional contour-measuring device;

d) processing one of the complementary partial sealing surfaces by means of the beam-processing device on the basis of the processing parameters determined in step c);

e) re-scanning of the partial sealing surface processed in step d), by means of the three-dimensional contour-measuring device in order to determine the surface shape of the partial sealing surfaces now present after processing as updated actual data;

f) if appropriate, repeating steps b) to e) until the deviation of the desired data from the actual data is within a determined tolerance range; and

g) fixing of the surface shape, last determined in step e), or of a complementary partial sealing surface which has already been processed as the desired shape for the other complementary partial sealing surfaces; and

h) processing of the other complementary partial sealing surface in accordance with steps c) to f).

2. Method according to claim 1, characterized in that the beam-processing device generates a laser beam as the working beam.

3. Method according to claim 2, characterized in that the beam-processing device generates a pulsed laser beam.

4. Method according to claim 2, characterized in that the working beam of the beam-processing device is used as the measuring beam of the three-dimensional contour-measuring device.

5. Method according to claim 1, characterized in that the cross-sectional surface of the working beam hitting the partial sealing surface to be processed covers the entire width of the partial sealing surface.

6. Method according to claim 1, further comprising the step of using the actual data in place of the desired data for the first time.

7. Method according to claim 1, characterized in that the beam-processing device is operated in a range in which the changes in the removal of material due to fluctuations in beam intensity are as small as possible.

8. Method according to claim 7, characterized in that in the case of laser polishing the beam-processing device is operated in a range of low laser intensity.

9. Method according to claim 1, characterized in that the three-dimensional contour-measuring device operates by means of triangulation.

10. Method according to claim 1, characterized in that the working beam is aligned perpendicular to the surface to be processed.

11. Method for producing sealing surfaces on complementary dies having at least two complementary partial sealing surfaces, having the following method steps:

a) arranging the complementary dies in such a way that the spacing between mutually corresponding surface sections of the partial sealing surfaces is within a first tolerance range;

b) determining the precise spacing of mutually corresponding surface sections of partial sealing surfaces by means of a three-dimensional contour-measuring device as actual data;

c) fixing a desired spacing which is at least as large as the largest actual spacing;

d) calculating processing parameters for a beam-processing device for removing material layers on the basis of the desired data determined and on the basis of the actual data determined by the three-dimensional contour-measuring device;

e) processing at least one of the complementary partial sealing surfaces by means of the beam-processing device on the basis of the processing parameters determined in step d);

f) re-determining of the precise spacing of mutually corresponding surface sections of partial sealing surfaces by means of the three-dimensional contour-measuring device as updated actual data;

g) if appropriate, repeating steps d) to f) until the deviation of the desired data from the actual data is within a second tolerance range which is smaller than the first tolerance range.

12. Method according to claim 11, further comprising the step of using the actual data in place of the desired data for the first time.

13. Method according to claim 11, characterized in that the beam-processing device is operated in a range in which the changes in the removal of material due to fluctuations in beam intensity are as small as possible.

14. Method according to claim 13, characterized in that in the case of laser polishing the beam-processing device is operated in a range of low laser intensity.

15. Method according to claim 11, characterized in that the three-dimensional contour-measuring device operates by means of triangulation.

16. Method according to claim 11, characterized in that the beam-processing device generates a laser beam as the working beam.

17. Method according to claim 16, characterized in that the beam-processing device generates a pulsed laser beam.

18. Method according to claim 16, characterized in that the working beam of the beam-processing device is used as the measuring beam of the three-dimensional contour-measuring device.

19. Method according to claim 11, characterized in that the working beam is aligned perpendicular to the surface to be processed.

20. Device for polishing and texturing, arbitrary three-dimensional shaped surfaces by means of a laser beam, having:

a laser device for generating a laser beam having specific characteristics;

a device for guiding and directing the laser beam in such a way that sub-surfaces of the surface to be processed are swept over sequentially in time by the laser beam;

a first three-dimensional contour-measuring device for scanning and recording the three-dimensional profile of the three-dimensional shaped surface to be processed by scanning the sub-surface regions, swept over by the laser beam, directly ahead of the laser beam sweeping over the sub-surface to be processed; and

a control device for controlling the three-dimensional contour-measuring device and for controlling and regulating the laser device and the device for guiding and directing the laser beam as a function of the three-dimensional profile detected by the three-dimensional contour-measuring device, characterized in that the laser device is a Cu-vapour laser ablation device and comprises a focusing device which generates a focused processing beam having a Raleigh length of greater than or equal to 300 μ

m.

21. Device according to claim 20, characterized in that the control device comprises a storage device in which the desired three-dimensional profile of the shaped surface to be processed is stored in the form of CNC data.

22. Device according to claim 20, characterized in that a second three-dimensional contour-measuring device for scanning and recording the three-dimensional profile of the three-dimensional freeform surface to be processed by scanning the sub-surface regions swept over by the laser beam directly behind the laser beam sweeping over the sub-surface to be processed.

23. Device according to claim 22, characterized in that the measurement results of the second three-dimensional contour-measuring device are fed to the control device for controlling and regulating the laser device and to the device for guiding and directing the laser beam.

24. Device according to claim 20, characterized in that the laser device generates a pulsed laser beam.