The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 04, 2013
Filed:
May. 07, 2008
Pei-chung Wang, Troy, MI (US);
John D. Fickes, Brighton, MI (US);
Xiaohong Q. Gayden, West Bloomfield, MI (US);
Wuhua Yang, Ann Arbor, MI (US);
Pei-Chung Wang, Troy, MI (US);
John D. Fickes, Brighton, MI (US);
Xiaohong Q. Gayden, West Bloomfield, MI (US);
Wuhua Yang, Ann Arbor, MI (US);
GM Global Technology Operations LLC, Detroit, MI (US);
Abstract
A method of welding two or more workpieces employing a motion-controlled electrode that reduces temperature and residual stresses at a workpiece-to-electrode interface is disclosed. During a first period of time, a first electrode force is applied to the workpieces to be welded, and a weld current is applied that causes heating of an associated workpiece-to-workpiece faying surface, the first electrode force being applied at a first electrode stroke. A temperature of the faying surface indicative of a weld nugget formation thereat is determined, and in response thereto the electrode force is reduced to a second level during a second period of time while maintaining a constant electrode stroke. During a third period of time, the electrode force is further reduced to a third level while simultaneously reducing the electrode stroke to a second level. Welding is stopped after the third period of time, resulting in a weld joint having reduced residual stresses and reduced likelihood of stress crack formation.