Abstract: Second electrophoresis flow defect in body in white (BIW) is a long-standing problem in automobile painting plants. Engineers from major automobile manufacturers have tried various solutions and achieved some success. This article explores the reduction of electrophoretic flow marks based on welding technology. It analyzes the causes of electrophoretic flow marks from a numerical model structure perspective and proposes a solution of using body adhesive to seal the electrophoretic flow marks. Finally, the electrophoretic flow marks status of mass-produced cars is tracked for one year, and the conclusion is drawn that by optimizing the paint process and increasing the use of body adhesive, the problem of secondary flow marks in electrophoretic coating can be significantly reduced.

Key words: Welding process; Split rear tail door outer panel; Electrophoresis secondary flow marks; Paint process

摘要： 汽车白车身（BIW）电泳二次流痕问题是汽车涂装车间由来已久的问题，各大主机厂 的涂装工艺工程师尝试了多种方案，也取得了一定成效。文章基于焊装工艺探索降低电泳流 痕的方案，从数模结构上分析了电泳留痕的原因，提出了用车身胶堵住电泳流痕的方案，最 后跟踪一年量产车的电泳流痕状态，得出结论，在优化油漆工艺的基础上，通过增加车身胶 能显著降低电泳二次流痕问题。

关键词: 焊装工艺；分片式后尾门外板；电泳二次流痕；油漆工艺