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:
Oct. 31, 2000
Filed:
May. 12, 1998
Koji Fujii, Osaka, JP;
Yasuhiro Goto, Kawanishi, JP;
Makoto Ryudo, Minoo, JP;
Kin-ichi Matsuyama, Suita, JP;
Matsushita Electric Industrial Co., Ltd., Osaka-fu, JP;
Abstract
A method for evaluating quality of a resistance weld is provided, in which a nugget generation state during a welding process is evaluated by observable numerical values based on physical phenomena, and which can afford a wide application range in welding material as well as a capability of accurate knowledge as to the nugget generation state of the weld. Based on that a specific resistance value of a metal material to be welded has a temperature dependency in a conduction state of AC or current-pulsated welding current, a rate of change of inter-chip dynamic resistance instantaneous value during a current changing period is determined, a changing state of the dynamic resistance instantaneous value is further calculated, and a heat-generating state of a weld zone, i.e., a nugget formation state is estimated. Thus, a quality evaluation of a weld is performed accurately.