Title: Force-based weld quality monitoring algorithm

Authors: Mahmoud El-Banna, Dimitar Filev, Finn Tseng

Addresses: Department of Industrial Engineering, American University of the Middle East (AUM), P.O. Box 220, Dasman 15453, Kuwait. ' Ford Motor Company, Dearborn, MI 48121, USA. ' Ford Motor Company, Dearborn, MI 48121, USA

Abstract: Traditionally, to check weld quality, destructive (the dominant method at industry until now) and non-destructive tests are used on randomly sampled work pieces at the production site. These processes tend to be predominantly off-line or end-of-line processes. The objective of the force-based weld monitoring algorithm is to classify the weld status, i.e. cold, normal and expulsion, by using non-intrusive force sensor. It is composed mainly from two sub-algorithms: expulsion and normal welds detection. This algorithm has been tested on medium frequency direct current (MFDC) constant current (CC) control. The results were as follows: the percentage of the false alarm (I) type-1 error is the lowest for cold welds case at 3.6%, 11.0% for normal welds and 21.7% for expulsion welds. As for the failed alarm (β) type-2 error, the lowest percentage is for expulsion welds 1.9%, 3.4% for cold welds and 16.5% for normal welds.

Keywords: nondestructive testing; NDT; online monitoring; indirect estimation; resistance spot welding; force sensors; soft sensors; medium frequency; direct current; constant current; weld quality; weld defects; expulsion welds; cold welds; quality monitoring; weld monitoring.

DOI: 10.1504/IJISTA.2011.038261

International Journal of Intelligent Systems Technologies and Applications, 2011 Vol.10 No.1, pp.1 - 14

Published online: 25 Jan 2011 *

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