Simultaneous laser cutting and welding of metal foil to edge of a plate

• US 5,500,503 A
• Filed: 08/04/1994
• Issued: 03/19/1996
• Est. Priority Date: 08/04/1994
• Status: Expired due to Fees

• Current Assignee: Midwest Research Institute
• Original Assignee: Midwest Research Institute
• Inventors: Pernicka, John C., Tracy, C. Edwin, Benson, David K.
• Primary Examiner(s): Evans, Geoffrey S.
• Assistant Examiner(s): PELHAM, JOSEPH MOORE
• Application Number:
  US08/285,700
• Time in Patent Office: 593 Days
• Field of Search: 219/121.63, 219/121.64, 52/785, 52/791, 52/783.1, 52/788.1
• US Class Current: 219/121.64
• CPC Class Codes: B23K 26/24 Seam welding
• CPC Class Codes: B23K 26/244 Overlap seam welding
• CPC Class Codes: B23K 26/364 for making a groove or trench, e.g. for scribing a break initiation groove

Abstract

A method of welding an ultra-thin foil to the edge of a thicker sheet to form a vacuum insulation panel comprising the steps of providing an ultra-thin foil having a thickness less than 0.002, providing a top plate having an edge and a bottom plate having an edge, clamping the foil to the edge of the plate wherein the clamps act as heat sinks to distribute heat through the foil, providing a laser, moving the laser relative to the foil and the plate edges to form overlapping weld beads to weld the foil to the plate edges while simultaneously cutting the foil along the weld line formed by the overlapping beads.

Claims

1. A method of welding an ultra-thin metal foil to the edge of a metal plate to form a vacuum tight weld comprising

a) providing an ultra-thin foil having a thickness of less than 0.002 inches,

b) providing at least one metal plate having a thickness greater than that of the ultra-thin foil, wherein the plate has a top surface, a bottom surface and an edge between the top and bottom surface defining the thickness of the plate,

c) placing the ultra-thin foil against the edge of the plate,

d) clamping the ultra-thin foil against the edge of the plate,

e) providing a laser having a focused beam,

f) directing the beam of the laser onto the ultra-thin foil to weld the ultra-thin foil to the edge of the plate at a weld line while simultaneously cutting the edge of the foil along one of the surfaces of the plate.

2. The method of claim 1 further comprising the step of moving the laser relative to the ultra-thin foil and the edge of the plate to weld the foil to the plate at successive overlapping locations to form a plurality of connected weld beads forming a continuous weld.

3. The method of claim 1 wherein said step of clamping further comprises providing a clamp as a heat sink to absorb heat transmitted through the foil.

4. The method of claim 3 comprising the step of locating the clamp at a distance from 0.003 inches to 0.015 inches away from the weld line of the foil.

5. The method of claim 3 comprising the step of locating the clamp along the edge to be welded.

6. The method of claim 3 comprising the step of moving the laser and the clamp relative to the foil and the edge of the plate to weld the foil to the plate edge at successive overlapping locations to form a plurality of connected weld beads forming a continuous weld.

7. The method of claim 1 further comprising the step of providing a Neodymium:

YAG laser to weld the foil to the edge of the plate.

8. The method of claim 7 further comprising the step of pulsing the Neodymium:

YAG laser to cut and melt the thin foil.

9. The method of claim 8 wherein the laser is pulsed from 20 to 100 pulses per second.

10. The method of claim 8 wherein the laser has a pulse width from 0.5 msec to 10 msec.

11. The method of claim 7 wherein the step of providing a Neodymium:

YAG laser further comprises providing a Neodymium;

YAG laser having an average power level in a range from 20 to 100 watts.

12. The method of claim 1 comprising the step of locating the focal point of the laser above the surface of the ultra-thin foil.

13. The method of claim 1 comprising

a) providing a second metal plate having a top surface, a bottom surface, and an edge between the top and bottom surface,

b) spacing the second plate from the first plate,

c) placing the ultra-thin foil against the edge of the second plate,

d) clamping the ultra-thin foil against the edge of the second plate, and

e) directing the beam of the laser onto the ultra-thin foil to weld the ultra-thin foil to the edge of the second plate while simultaneously cutting the edge of the foil along one of the surfaces of the plate.

14. The method of making a vacuum insulation panel comprising

a) providing a first metal plate having four corners, a top surface, a bottom surface, and an edge between the top and bottom surfaces,

b) providing a second metal plate having four corners, a top surface, a bottom surface, and an edge between the top and bottom surfaces,

c) placing the first plate parallel to and spaced a distance apart from the second plate,

d) providing an ultra-thin metal foil having a thickness less than 0.002 inches,

e) clamping the ultra-thin foil around the edges of the plates,

f) providing a laser having a focused beam,

g) directing the focused beam onto the ultra-thin foil to weld the ultra-thin foil to the edges of the first and second plate to form a panel which when evacuated of gases will hold a vacuum.

15. The method of claim 14 wherein the foil has a length greater than the perimeter of each plate measured along the edges and further

a) providing the foil at one end with a first excess leading portion and at the other end with a second trailing excess portion,

b) clamping the excess portions together with second clamps,

c) using the laser to simultaneous weld the excess portions together while cutting any excess therefrom along a first weld.

16. The method of claim 15 further comprising welding the excess portions together and to the edges of the plates to form a second weld spaced from the first weld.

17. The method of claim 15 wherein said second clamp acts as heat sink to distribute heat from the foil.

18. The method of claim 15 wherein said step of clamping comprises providing at least one clamp and wherein said clamp acts as a heat sink to absorb heat from the foil.

19. The method of claim 14 comprising the step of moving the laser relative to the foil and edges to provide weld beads at successive overlapping locations while forming a continuous weld line.

20. The method of claim 19 further providing at least one clamp to clamp the foil to the edges of the plates during welding and wherein the said clamp is located at a distance in a range from 0.003 to 0.015 inches away from the center of the weld line.

21. The method of claim 14 wherein the laser is a Neodymium:

YAG laser.

22. The method of claim 14 wherein each plate has at least three rounded corners.

23. The method of claim 15 wherein each plate has one squared corner aligned over the square corner of the other plate, and wherein said excess portions are welded at the square corner.

24. The method of claim 15 wherein the second clamps are located 0.003 to 0.015 inches from the weld.

25. The method of welding an ultra-thin foil to the edge of a metal plate comprising

a) providing an ultra-thin foil having a thickness of less than 0.002 inches,

b) providing at least one metal plate having a thickness greater than that of the ultra-thin foil, wherein the plate has a top surface, and a bottom surface, and an edge between the top and bottom surface defining the thickness of the plate,

c) placing the ultra-thin foil against the edge of the plate,

d) clamping the ultra-thin foil against the edge of the plate,

e) providing a laser having a focused beam,

f) directing the beam of the laser onto the ultra-thin foil to melt the ultra-thin foil to form weld beads and to weld the foil to the edge of the plate, wherein the weld beads have a thickness greater than the thickness of the foil while simultaneously cutting the edge of the foil along one of the surfaces of the plate.

26. The method of claim 25 further comprising the step of moving the laser relative to the edge and the foil to form a series of overlapping weld beads to weld the foil to the plate edge.