Study On The Variation Analysis And Process Optimization Of Auto Body Welding Assembly

With the consistent development of auto mobile industry in China, themanufacturing and consuming mode had been changed dramatically. As a manufacture,the cost of production plays a critical role and more attentions should be paid on theenhancement of energy efficiency. As a common consumer, the design style and brandrecognition was regarded as the most important criteria. That means, themanufacturing of auto body not only influenced the total cost but also decided thequality and taste of a car. Thus the study and optimization of manufacturing process,tolerance analysis and parameter design, could have great influence on theimprovement of product quality.Based on the above reasoning, this article first studied Computer AidedAssembly Sequence Planning (CAASP). The graph based assembly sequence planningmethod was studied, and the contact matrix was established based on the weldingengineering experience. With the customized strategy constrain method, severalconstrains was proposed to reduce the search space, enhance assembly quality andgenerate feasible plans in engineering. The assembly sequence planning of rear floorskeleton was taken as an example, and variation simulation in different sequence wasconducted with VisVSA to verify the efficiency of the proposed method.Besides the assembly sequence, the detailed locating and clamping in everywelding station also influenced the assembly accuracy significantly. This lead to thestudies on the robust design of assembly locating. The Taguchi method was studied indetail after a brief introduce of robust design, and the design process of Taguchimethod was also clarified. As an example, the robust design of the rear floor locatingwas studied. The result shows that the assembly accuracy and robust was enhancedwithout increasing other expenses.The studies about Computer Aided Tolerancing (CAT) was conducted at last. Theassembly variation model based on deterministic locating, which was used by VisVSA,was first studied. Due to the lack consideration of form errors in current simulationmethod, the Skin Model with form error was used to express the actual part surface,and the assembly variation caused by form error was expressed by torsor. Byintroducing the compensation torsor into Jacobin-Torsor method, the simulationaccuracy was enhanced and could be referenced by related researches.