LASER WELDING TECHNIQUE

• US 3,610,874 A
• Filed: 11/21/1969
• Issued: 10/05/1971
• Est. Priority Date: 11/21/1969
• Status: Expired due to Term

• Current Assignee: AT&T Technologies Inc (Nokia Corporation)
• Original Assignee: Francis Patrick Gagliano
• Inventors: Gagliano, Francis Patrick
• Primary Examiner(s): Truhe, J. V.
• Assistant Examiner(s): Rouse, Lawrence A.
• Application Number:
  US04/878,634
• Time in Patent Office: 683 Days
• Field of Search: 219/121L,121EB
• US Class Current: 219/121.64
• CPC Class Codes: B23K 26/22 Spot welding

Abstract

In bonding a conductive metal tab to a fusible fine gauge metal wire of a strip potentiometer, a beam of radiant energy such as a laser beam is applied onto a surface of the tab adjacent a region of contact between the wire and the tab. The tab is tilted so that the tab surface forms an acute angle of between 30* to 50* with respect to the laser beam, and the wire and the tab are so positioned with respect to each other that a portion of the tab immediately adjacent to the wire is rendered molten by the laser beam and flows to the region of contact between the tab and the wire and over the wire by force of gravity, and effect a strong fusion bond between the wire and the tab without melting an entire cross section of the wire.

Claims

1. A method of bonding a first elongated element to a second element comprising the steps of:

bringing said first element and said second element into contact with each other, directing a beam of radiant energy only onto a surface of said second element at a horizontally displaced region of contact between said first element and said second element to form a molten portion of said second element, and causing a flow of the molten portion into engagement with said first element in the region of contact to effect wetting and a bond therebetween without severing said first elEment.

2. A method as recited in claim 1, wherein said beam of radiant energy is a laser beam;

said laser beam being focused to a spot of predetermined size by interposing a convergence lens between the laser source and said tab.

3. A method as recited in claim 1 wherein said wire is coated with enamel insulation;

the heat from said laser beam causing the evaporation of said insulation at said region of contact to thereby facilitate formation of said bond.

4. A method according to claim 1, wherein said second element is oriented with respect to said first element to cause said flow of the molten portion of said second element into engagement with said first element in the region of the contact by force of gravity.

5. A method for bonding a conductive metal tab to a fusible fine gauge metal conductor wire comprising the steps of:

bringing said wire and said tab into contact with each other, directing a beam of radiant energy only onto a surface of said tab at a horizontally displaced region of contact between said tab and said wire to form a molten portion of said tab, and causing a flow of the molten portion of said tab to said wire to effect a fusion bond between said tab and said wire, without breaking said wire.