Laser welding apparatus employing a tilting mechanism

• US 5,961,858 A
• Filed: 06/06/1996
• Issued: 10/05/1999
• Est. Priority Date: 06/06/1996
• Status: Expired due to Fees

• Current Assignee: En-Gauge, Inc.
• Original Assignee: En-Gauge, Inc.
• Inventors: Britnell, James W.
• Primary Examiner(s): MILLS, GREGORY L
• Application Number:
  US08/659,634
• Time in Patent Office: 1,216 Days
• Field of Search: 219/121.13, 219/121.45, 219/121.6, 219/121.63, 219/121.64, 219/121.75, 219/121.74, 219/121.78, 219/121.79, 219/121.82, 219/121.83 , 219/124.33, 219/125.1, 219/136
• US Class Current: 219/121.63
• CPC Class Codes: B23K 2101/185 Tailored blanks
• CPC Class Codes: B23K 2103/04 Steel or steel alloys
• 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 26/044 Seam tracking
• CPC Class Codes: B23K 26/067 Dividing the beam into multiple beams, e.g. multifocusing
• CPC Class Codes: B23K 26/08 Devices involving relative movement between laser beam and workpiece
• CPC Class Codes: B23K 26/0884 in at least in three axial directions, e.g. manipulators, robots

Abstract

An apparatus for working material employs a tilting mechanism which tilts a head about a theoretical point disposed upon the sheet material. The welding or cutting head is defined as a laser head and the pivot point corresponds with the laser beam focal point. The laser head projects a laser beam directly upon the sheet material without the use of redirecting steerable mirrors. At least a pair of tilting mechanisms are employed to tilt the welding or cutting head along differing rotational planes. Various axial slides are employed in combination with a gantry. A laser vision system tracks a welding seam and a pre-weld gap. The tilting mechanism creates a tailored blank butt weld between dissimilar materials. A method of operating the present invention is also provided.

Claims

1. A machine for producing a weld between material pieces at a seam, said machine comprising:

a welding head;

a gantry suspending said welding head

a first tilting mechanism operably pivoting said welding head along a first plane; and

a second tilting mechanism operably pivoting said welding head along a second plane offset from said first plane;

said welding head being tilted about a pivot point located at said seam.

2. The machine of claim 1 wherein said welding head includes a laser optic, tilting of said laser optic allows a laser beam emanating from said laser optic to reflect off of said material pieces whereby an angle of reflectance of said laser beam is angularly offset from an angle of incidence of said laser beam.

3. The machine of claim 2 further comprising:

a first plate coupled to said gantry and being selectively movable in a vertical direction and a horizontal direction;

a first driving bearing device affixed to said first plate;

a first driven bearing device movably engaged to said first driving bearing device;

an actuator causing relative movement between said first bearing devices;

a second plate affixed to said first driven bearing device; and

a second driving bearing device affixed to said second plate.

4. The machine of claim 2 further comprising an optical sensor tracking said seam, said laser optic moving in response to said optical sensor.

5. The machine of claim 2 wherein said first tilting mechanism includes:

a first bearing device coupled to said laser optic; and

a second bearing device engaged with said first bearing device, said first bearing device selectively movable in relation to said second bearing device;

at least one of said bearing devices having a partially circular engagement surface with a theoretical radius substantially the same as a focal length of said laser beam.

6. The apparatus of claim 5 wherein said first and second bearing devices are disposed adjacent to an end of said laser located closest to a workpiece.

7. The machine of claim 5 further comprising:

a set of teeth located upon said first bearing device, crests of said teeth defining said theoretical radius;

a screw gear of said second bearing device engaging with said set of teeth; and

an actuator operably driving said screw gear which rotates said first bearing device.

8. The machine of claim 2 wherein said laser beam welds said sheets of material together in a butt welding manner, said weld is created substantially at said focal point.

9. The apparatus of claim 8 wherein said laser optic is tilted such that two sheets of said sheet material are welded together even if a pre-weld gap dimension greater than 10 percent of a thickness of one of said sheets of material is present between adjacent edges of said two sheets.

10. The machine of claim 2 further comprising a laser light source and a fiber optic cable, wherein said laser optic is part of a Yag laser having said fiberoptic cable coupling said laser light source to said laser optic, said laser beam moves relative to said sheet material free of rotatable mirrors.

11. The machine of claim 1 further comprising a pre-weld gap disposed at said seam having a width at least 10 percent of a thickness of one of said material sheets.

12. The machine of claim 1 wherein said welding head is selectively tilted in two dimensions in relation to said gantry.

13. The machine of claim 1 further comprising:

a laser optic mounted to said welding head;

said gantry having a movable bridge;

a motor-driven rotatable carousel coupled to said bridge by a rotary bearing; and

a motor-driven substantially vertical slide coupled to said carousel;

said vertical slide serving to maintain a focal length of said laser optic as said bridge moves in relation to said material pieces.

14. The machine of claim 1 wherein said first tilting mechanism is elongated substantially perpendicular to an elongated direction of said second tilting mechanism.

15. A machine for producing a weld between material pieces, said machine comprising:

a welding head;

a gantry suspending said welding head substantially above said material pieces;

adjacent edges of said material pieces defining a seam;

a first driving bearing device having a first set of teeth arranged in a partially circular manner;

a first driven bearing device having a first drive transmission engagable with said first set of teeth for selectively controlling pivoting of said first driving bearing device in relation to said first driven bearing device;

a second driving bearing device having a second set of teeth arranged in a partially circular manner;

a second driven bearing device having a second drive transmission engagable with said second set of teeth for selectively controlling pivoting of said second driving bearing device in relation to said second driven bearing device;

said first driven bearing device being coupled to said second driving bearing device, at least one of said bearing devices being coupled to said gantry; and

a linear slide coupled to said first driving bearing device;

all of said bearing devices being slidable in response to said linear slide and said second bearing devices pivot in response to movement of said first driven bearing device relative to said first driving bearing device so as to move and tilt said welding head;

said welding head being tilted about a pivot point located at said seam whereby said welding head welds together said adjacent edges of said material pieces at said seam.

16. The machine of claim 15 further comprising a slave tilting mechanism having a driving bearing device affixed to said first plate and having a driven bearing device affixed to said second plate, said slave tilting mechanism being disposed on a substantially opposite side of said welding head from said first driving bearing device, said slave tilting mechanism and said first driving bearing device being oriented substantially parallel to each other and substantially perpendicular to said second driving bearing device.

17. The machine of claim 15 further comprising a substantially vertical slide adjustably moving said welding head in a vertical direction, said vertical slide being coupled to one of said bearing devices.

18. The machine of claim 15 wherein said welding head includes a laser optic.

19. In combination, a welding machine and a tailored blank weld between dissimilar thickness material sheets, said combination comprising:

a welding laser optic;

a gantry bridge having a set of linear slides coupling said laser optic to said bridge;

adjacent edges of said material sheets defining a seam, said laser optic being tilted about a laser beam focal point which is disposed at said seam whereby said laser optic tailor blank welds together said adjacent edges of said material sheets at said seam;

a first tilting mechanism operably pivoting said laser optic along a first plane; and

a second tilting mechanism operably causing said laser optic to pivot about said focal point along a second plane substantially perpendicular to said first plane.

20. The machine of claim 19 further comprising an optical sensor tracking said seam, said welding laser optic moving in response to said optical sensor.

21. The machine of claim 19 further comprising:

a first bearing device coupled to said laser optic; and

a second bearing device engaging with said first bearing device, said first bearing device selectively moving in relation to said second bearing device;

at least one of said bearing devices having a partially circular engagement surface with a theoretical radius substantially the same as a focal length of said laser beam.

22. The machine of claim 19 further comprising:

a first driving bearing device having a first set of teeth arranged in a partially circular manner;

a first driven bearing device having a first drive transmission engagable with said first set of teeth for selectively controlling pivoting of said first driving bearing device in relation to said first driven bearing device;

a second driving bearing device having a second set of teeth arranged in a partially circular manner;

a second driven bearing device having a second drive transmission engagable with said second set of teeth for selectively controlling pivoting of said second driving bearing device in relation to said second driven bearing device;

said first driven bearing device being coupled to said second driving bearing device, at least one of said bearing devices moving with said gantry bridge; and

a linear slide coupled to said first driving bearing device;

whereby all of said bearing devices are slidable in response to said linear slide and said second bearing devices pivot in response to movement of said first driven bearing device relative to said first driving bearing device so as to move and tilt said laser.

23. The combination of claim 19 further comprising:

a first plate selectively movable in a vertical direction and a horizontal direction;

a driving bearing device of said second tilting mechanism affixed to said first plate;

a driven bearing device of said second tilting mechanism movably engaged to said driving bearing device;

a knob and drive screw causing relative movement of said bearing devices;

a second plate affixed to said driven bearing device; and

a driving bearing device of said first tilting mechanism affixed to said second plate.

24. A machine for producing a welded seam between material pieces, said machine comprising:

a welding head;

a gantry suspending said welding head;

a first primary bearing device having a first interfacing surface arranged in a partially circular manner;

a first secondary bearing device engagable with said first interfacing surface for selectively pivoting in relation to said gantry;

a second primary bearing device having a second interfacing surface arranged in a partially circular manner;

a second secondary bearing device engagable with said second interfacing surface for selectively pivoting in relation to said gantry;

at least one of said bearing devices being coupled to said gantry; and

a first linear slide coupled to said first bearing devices;

all of said bearing devices moving in response to movement of said linear slide;

said second bearing devices pivoting in response to movement of one of said first bearing devices relative to the other of said first bearing devices thereby tilting said welding head;

said welding head being tilted about a pivot point coinciding with said seam.

25. The machine of claim 24 wherein said welding head includes a laser optic.

26. The machine of claim 25 further comprising:

at least a second, substantially horizontal linear slide mounted to said first linear slide, said first linear slide moving in a substantially vertical direction;

a first plate coupled to said second linear slide being selectively movable in a substantially vertical direction and a substantially horizontal direction;

one of said first bearing devices being affixed to said first plate;

an actuator causing relative movement between said first bearing devices;

a second plate affixed to the other of said first bearing devices, at least one of said plates having an orifice for receiving a portion of said welding head; and

said second bearing devices coupling said welding head to said second plate.