| The appearance defects, PVC repainted and rework which are caused by the slippage or movement between inner and outer panels of closures are big problems that urgently needed to solve during the manufacturing process of automobile body. To solve these problems, this paper mainly studies the fixing process called robot single-side welding which is used to connect inner and outer panels that are made of galvanized steel. Firstly, study on theory from welding method, formation mechanism of welding spot, and the influence factors of welding heat source, and introduces the design and selection method of each unit of welding system, such as welding robot, controller, single-side welding gun and fixture. Secondly, the impact of technological process and welding parameters on welding quality were researched, and proposed the process requirements of welded structure and layout based on roller hemming, welding and gluing process; moreover, the causes and influencing factors of common defects in single-side welding were analyzed and established welding quality evaluation standards. Thirdly, the preloading procedure of galvanized steel single-side welding was analyzed by ANSYS Workbench, obtained the electrode size and the applicable range of welding pressure, and the rationality of the conclusions were proved by tests. Finally, the effect rules of welding parameters on the size of solder joint, appearance quality, spatter and solder joint strength were studied by single factor test and the optimal range of parameters were obtained. In addition, the influence of welding parameters on welding spot’s shearing resistance was researched by using the methods of orthogonal experiment, and optimized the process parameters. The mathematic model has been built between process parameters and welding spot’s shearing resistance by the methods of mathematical statistics, then the regression equation’s forecast accuracy of shearing resistance has been proved by tests. |
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