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:
Jan. 15, 1985
Filed:
May. 25, 1983
Albert F Houchens, Rochester, MI (US);
Dixon Cleveland, Vienna, VA (US);
Basil A Decina, Jr, McLean, VA (US);
Dale K Watney, Troy, MI (US);
James R Havens, Sterling Heights, MI (US);
Gregory L Nagel, Royal Oak, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
During a weld period the weld parameters are monitored and data representing the weld resistance curve and the power curve are acquired and stored for analysis by a suitably programmed computer. The derivative of R, R is calculated and stored and the function is divided by power P to obtain R/P. The resistance curve is searched to obtain the maximum value R.sub.m which occurs during the heating phase and the function R/P is searched prior to the time of R.sub.m to find the maximum of that curve representing the highest rate of resistance increase. Then the R/P curve is searched subsequent to its maximum to determine when the function reaches a specified percentage of the maximum. That value occurs at the knee of the resistance curve and approximates the onset of melting in the weld. A prediction of whether a weld is a nugget or a sticker is made by calculating the ratio of weld energy after the onset of melting to the total weld energy, the ratio of the resistance drop after the resistance peak to the peak resistance, and then a weighted sum of the energy ratio and resistance drop ratio. An edge weld geometry is detected by calculating from the resistance and power curves the weld energy during the period of expulsion, if any, divided by the cumulative energy between the onset of melting and the end of expulsion, a measure of expulsion intensity based on the maximum degree of resistance inflection, and then a weighted sum of the energy value and the inflection value.