METHOD FOR SUPERVISING SPOT WELDING

• US 3,632,956 A
• Filed: 04/10/1970
• Issued: 01/04/1972
• Est. Priority Date: 04/14/1969
• Status: Expired due to Term

• Current Assignee: Klaus Herbst
• Original Assignee: Klaus Herbst
• Inventors: Herbst, Klaus
• Primary Examiner(s): Truhe, J. V.
• Assistant Examiner(s): Smith, J. G.
• Application Number:
  US05/027,415
• Time in Patent Office: 634 Days
• Field of Search: 219/109,110,86,117
• US Class Current: 219/109
• CPC Class Codes: B23K 11/115 by means of two electrodes placed opposite one another on both sides of the welded parts
• CPC Class Codes: B23K 11/251 using analog means

Abstract

Spot welds are monitored for determining the quality of the weld by measuring the amount of shrinkage that occurs at the weld, beginning subsequently to the termination of the welding current. The amount of shrinkage is compared to the shrinkage of reference welds which are known to be satisfactory.

Claims

1. Method for supervising quality of electric spot welding comprising:

measuring change in electrode distance, beginning subsequently to termination of welding current flow, in representation of shrinking of the workpiece due to cooling, during application of pressure by the electrodes for squeezing the workpieces;

providing reference representation of shrinking of other welding spots, after termination of welding current flow therein and satisfying particular parameters and determining a satisfactory weld; and

comparing the measured shrinkage with the reference representation.

2. Method as in claim 1, the providing step including providing of characteristics representing shrinking and constituting representation of a range for satisfactory welds.

3. Method as in claim 1, the providing step including the providing of two limits delineating a range, the shrinking of a weld being measured after current flow termination, a particular time in the pressure application period, the measured shrinking to fall into the range.