Aluminum Resistance Spot Welding and its Welding Quality System

Aluminum Resistance Spot Welding and its Welding Quality System Resistance spot welding (RSW) is a method of assembling a welding piece into a lap joint and pressing it between two electrodes, and using resistance heat to melt the base metal to form a solder joint. Compared with riveting or other welding methods, spot welding has the advantages of high joint quality, fewer auxiliary processes, high production efficiency, no need to add welding materials, and easy to realize mechanization and automated production. It is widely used in automotive, aerospace, and electronic technology industries. In early phase of testing the quality of solder joints is to evaluate through destructive testing, to test the tensile strength of the sample solder joints and to measure the nugget diameters. Although this method can directly correlate the inspection parameters with the quality of the solder joints, it costs enormous time, labor and cost to the welding production, and cannot fully guarantee the quality of the welding. It is not possible to implement online inspection and thus has poor real-time performance. Therefore, by detecting factors that affect the quality of the welding spot, such as welding current, welding voltage, force between electrodes, dynamic resistance, etc., the welding quality can be indirectly judged and the online inspection of the welding quality is realized, which has become a common method for testing the quality of spot welding. This is also the basic idea adopted by the classifier of welding quality system (WQS), which produce on-line classification of the solder joints according to their physical conditions. In this article, a research has been done on the aluminum resistance spot welding. The difficulties of aluminum RSW is introduced, also a comparison has been made between steel RSW. Further, the dynamic behavior of aluminum RSW is explored in detail. On the other hand, a WQS (weld quality system) is introduced, where a classifier embedded is based on fuzzy logic which provides online quality classification of aluminum RSW spots. The implementation of the system is explained.