Laser work station with optical sensor for calibration of guidance system

• US 5,304,773 A
• Filed: 02/19/1992
• Issued: 04/19/1994
• Est. Priority Date: 02/19/1992
• Status: Expired due to Term

• Current Assignee: TRUMPF, Inc. (TRUMPF SE + Co. KG)
• Original Assignee: TRUMPF, Inc. (TRUMPF SE + Co. KG)
• Inventors: Kilian, Friedrich, Bolton, Stephen R., Troiani, Joseph J.
• Primary Examiner(s): ALBRITTON, CLARENCE
• Application Number:
  US07/841,661
• Time in Patent Office: 790 Days
• Field of Search: 219/121.64, 219/171.78, 219/121.79, 219/121.83, 219/121.67, 219/121.72, 219/121.82, 219/121.63, 219/121.61, 219/121.62
• US Class Current: 219/121.78
• 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 26/0853 Devices involving movement of the workpiece in at least in two axial directions, e.g. in a plane
• CPC Class Codes: G05B 19/4083 Adapting programme, configuration
• CPC Class Codes: G05B 2219/36503 Adapt program to real coordinates, software orientation
• CPC Class Codes: G05B 2219/49114 Go to coarse programmed reference, detector for fine alignment
• CPC Class Codes: G05B 2219/50151 Orient, translate, align workpiece to fit position assumed in program

Abstract

A laser work station has a base member, a laser head mounted on a laser head support carried on the base member for movement of the laser head relative to the base member, so that it is movable thereon in X, Y and Z axes. A guidance system effects precision movement of the laser head in the X, Y and Z axes to move the beam about a workpiece, and an optical sensor assembly comprising a light source and light sensors about the light source to detect light reflected from the surface of the workpiece. The sensor assembly is operable to detect reference formulations on the workpiece as it is moved thereabout. The computer control indexes the sensor assembly to a preselected position relative to the approximate position of a reference formation on the workpiece, and moves it in a predetermined path from the preselected position to sense passage of the beam over the edge of the reference formation, and the work station uses data obtained from such sensing of the passage of the beam over the edge of the reference formation to adjust the coordinates of the guidance system to reflect the actual position of the workpiece.

Claims

1. A laser work station enabling precise positioning of a workpiece relative to its X-Y guidance system, the workpiece having a reference formation with at least one edge, said work station comprising:

(a) a base member;

(b) a workpiece support;

(c) a laser head spaced above said workpiece support;

(d) a laser head support member mounted on said base member for movement of said laser head relative to said base member, said laser head being movable thereon in X, Y and Z axes relative to the workpiece support;

(e) movement means for moving said laser head in said X, Y and Z axes;

(f) a guidance system connected to said movement means for effecting precision movement of said laser head in said X, Y and Z axes to permit said laser head to direct a laser beam onto an associated workpiece supported on said workpiece support;

(g) an optical sensor assembly comprising (i) a light source for directing onto an associated workpiece on said workpiece support a light beam parallel to the Z-axis of movement of said laser head and (ii) light sensors about said light source for detecting light reflected from the surface of the associated workpiece upon which said light beam impinges, said sensor assembly being operable to detect reference formations on an associated workpiece carried by said workpiece support;

(h) sensor assembly mounting means mounting said sensor assembly on said laser head for movement therewith in X-Y axes relative to an associated workpiece on said workpiece support; and

(i) position determining means cooperating with said sensor assembly and said guidance system to;

(i) index said laser head and sensor assembly to a preselected X-Y position relative to the approximate position of a reference formation on the associated workpiece;

(ii) move said laser head and sensor assembly in a predetermined path from said preselected position to sense passage of the beam over an edge of a reference formation; and

(iii) use data obtained form such sensing of the passage of the beam over an edge of the reference formation to adjust the coordinates of said guidance system to reflect the actual position of the associated workpiece on said workpiece support.

2. The laser work station in accordance with claim 1 wherein there is an elongated base member defining a work station therealong, wherein said laser head support member is a laser head support carriage mounted on said base member for movement along the length thereof, wherein there is included a laser head mounting assembly movable along said laser head support carriage relative to said base member;

and wherein said movement means is adapted to move (i) said laser head support carriage along the length of said base member (ii) said mounting assembly along said laser head support carriage, and (iii) said laser head vertically on said mounting assembly, whereby said laser head is movable along said laser support carriage (Y axis), and movable with said laser support carriage along said base member (X axis), and movable in the vertical axis (Z axis) on said laser mounting assembly.

3. The laser work station in accordance with claim 1 wherein said workpiece support is a carrier movable in a path parallel to said base member, said carrier having a workpiece supporting surface on the top thereof, and wherein there are included guide means for guiding said carrier along said base member in said parallel path and carrier positioning means along said path for locating said carrier in a predetermined position along said base member.

4. The laser work station in accordance with claim 3 wherein said carrier positioning means includes a first positioning element on said carrier and a second positioning element at a fixed location along the length of said base member, said first and second positioning elements cooperating to position said carrier at a predetermined point along the length of said path.

5. The laser work station in accordance with claim 1 wherein said workpiece support includes aligning means for positioning a workpiece placed thereon.

6. The laser work station in accordance with claim 1 wherein said work station includes a computer for controlling said movement means and said guidance system.

7. The laser work station in accordance with claim 6 wherein said computer is operative in cooperation with said position determining means to move said sensor assembly to each preselected position, to effect said movement in a preselected path, to receive the sensed data, and to adjust the coordinates of said guidance system.

8. The laser work station in accordance with claim 1 wherein said light sensors are disposed concentrically about said light source.

9. The laser work station in accordance with claim 8 wherein said light source and light sensors are fiberoptics.

10. The laser work station in accordance with claim 1 wherein said work station includes means for establishing a preselected distance between said laser head and the associated workpiece and said sensor assembly includes movement means operable to move said sensor assembly relative to said laser head to a predetermined distance above the associated workpiece based upon the preselected distance of said laser head.

11. The laser work station in accordance with claim 1 wherein said position determining means indexes said laser head and sensor assembly to at least two different locations about each reference formation.

12. The laser work station in accordance with claim 11 wherein said position determining means is effective to determine the actual center of a circular reference formation and to calculate the offset of said actual center from the center of said circular reference formation as approximated to effect the adjustment of said guidance system.

13. The laser work station in accordance with claim 11 wherein said position determining means is effective to determine the actual intersection of a formation having a pair of intersecting rectilinear edges and to calculate the offset of the actual intersection from the intersection as approximated to effect the adjustment of said guidance system.

14. The laser work station in accordance with claim 11 wherein said position determining means is effective to determine the actual angular orientation of a substantially rectilinear edge and to calculate the offset of the actual angular orientation relative to the angular orientation as approximated to effect the adjustment of the guidance system.

15. The laser work station in accordance with claim 1 wherein said position determining means is operative to effect movement of said sensor assembly to at least two different reference formations on the associated workpiece and to process the data obtained from sensing said at least two formations to adjust said guidance system.

16. A laser work station enabling precise positioning of a workpiece relative to its X-Y guidance system, with workpiece having a reference formation with at least one edge, said work station comprising:

(a) a base member;

(b) a workpiece support including aligning means for positioning a workpiece placed thereon;

(c) a laser head spaced above said workpiece support;

(d) a laser head support member mounted on said base member for movement of said laser head relative to said base member, said laser head being movable thereon in X, Y and Z axes relative to the workpiece support;

(e) movement means for moving said laser head in said X, Y and Z axes;

(f) a guidance system connected to said movement means for effecting precision movement of said laser head in said X, Y and Z axes to permit said laser head to direct a laser beam onto an associated workpiece supported on said workpiece support;

(g) an optical sensor assembly comprising (i) a light source for directing onto an associated workpiece on said workpiece support a light beam parallel to the Z-axis of movement of said laser head and (ii) light sensors about said light source for detecting light reflected from the surface of the associated workpiece upon which said light beam impinges, said sensor assembly being operable to detect reference formations on an associated workpiece carried by said workpiece support;

(h) sensor assembly mounting means mounting said sensor assembly on said laser head for movement therewith in X-Y axes relative to an associated workpiece on said workpiece support; and

(i) position determining means cooperating with said sensor assembly and said guidance system to;

(i) index said laser head and sensor assembly to a preselected position relative to the approximate position of a reference formation on the associated workpiece;

(ii) move said laser head and sensor assembly in a predetermined path from said preselected position to sense passage of the beam over an edge of a reference formation; and

(iii) use data obtained form such sensing of the passage of the beam over an edge of the reference formation to adjust the coordinates of said guidance system to reflect the actual position of the associated workpiece on said workpiece support; and

(j) a computer for controlling said movement means and said guidance system, said computer being operative in cooperation with said position determining means to move said sensor assembly to each preselected position, to effect said movement in a preselected path, to receive the sensed data, and to adjust the coordinates of said guidance system.

17. The laser work station in accordance with claim 16 wherein said light sensors are disposed concentrically about said light source and said light source and light sensors are fiberoptics.

18. The laser work station in accordance with claim 16 wherein said work station includes means for establishing a preselected distance between said laser head and the associated workpiece and said sensor assembly includes movement means operable to move said sensor assembly relative to said laser head to a predetermined distance above the associated workpiece based upon the preselected distance of said laser head.

19. The laser work station in accordance with claim 16 wherein said position determining means indexes said laser head and sensor assembly to at least two different locations about each reference formation.

20. The laser work station in accordance with claim 16 wherein said position determining means is operative to effect movement of said sensor assembly to at least two different reference formations on the associated workpiece and to process the data obtained from sensing said at least two formations to adjust said guidance system.