Abstract: In this paper, the purpose, common method of pressing edge fixing for inner and outer panel of door and cover of body in white in automobile manufacturing process and the surface quality defect and bonding strength problem are studied briefly. In order to solve these problems completely, a new method is explored in this paper. Without contacting part surface, the pressing edge of inner and outer panel can be fixed with a good bonding strength, namely a fixing technology of cold metal transfer (CMT) in the form of spot welding for pressing edge of inner and outer panel of door and cover. It is analyzed and demonstrated from equipment principle and process characteristics. After equipment installation, process commissioning and quality verification etc., this improvement is put into use in models of series production and the product quality stability is verified in practical production. The production efficiency has also improved significantly and the maintenance cost has reduced effectively. This improvement has a high promotion value in the automobile manufacturing industry.

Key words: Fixing for inner and outer panel; Single side welding; Quality defect; Bonding strength problem; CMT; Quality improvement

摘要： 文章简要阐述了汽车制造过程中白车身门盖内外板压合边固定的目的、常用方法以及 产生的表面质量缺陷和连接强度问题。为了彻底解决这些问题，探索了一种新的方法，不接 触零件表面，即可实现内外板压合边的固定，并且有较好的连接强度，也就是把冷金属过渡 技术（CMT）以点焊的形式应用于门盖内外板压合边的固定工艺，并从设备原理、工艺特点 上分析论证。此项改进工作经过设备安装、工艺调试、质量验证等过程，并且在批量生产车 型中投入使用，在实际生产中验证了产品质量的稳定性，同时在生产效率上也有了明显提高， 维护成本也得到有效降低，此项改进工作在汽车制造业内具有较高的推广价值。

关键词: 门盖内外板固定；单边焊；质量缺陷；连接强度问题；CMT；质量改进