Abstract: Self-tapping screw is a fastener that does not require pre-tapping internal threads, in the self-tapping screw is screwed in by self-extrusion to form threads. In this paper, for the production process, self-tapping screws in the automatic tightening of frequent tightening not in place, jamming, overflow buckle and other failure problems, combined with the actual production of tightening equipment and process, the size of the screw and screw defect analysis. Through the optimization of the structure of the tightening gun, tightening programs, reduce the tightening defect rate. Through the screw processing mode and the composition of the screw thread analysis, to determine the root cause of the tightening failure, and screw thread processing process improvement. Through the full verification of the actual production process, after the change of the program and the improvement of screws to meet the actual production requirements. Process defects are almost completely eliminated in the tightening process, which improves the quality of the car body and production efficiency.

Key words: self-tapping screws; torque; folding defects; process optimization

摘要： 自攻螺钉是一种不需要预先攻内螺纹的紧固件，在自攻螺钉拧入时通过自挤压形成螺 纹。文章针对生产过程中，自攻螺钉自动拧紧中频繁拧紧不到位、卡死、溢扣等失效问题， 结合实际生产拧紧设备及过程、螺钉的尺寸及螺牙缺陷分析。通过优化了拧紧枪的结构、拧 紧程序，一定程度上降低拧紧缺陷率；通过对螺钉加工方式以及螺牙的涂层成分进行分析， 确定了拧紧失效的根本原因，并对螺钉螺纹加工工艺改进。经过实际生产过程中的充分验证， 变更后的程序及改进后螺钉能够很好地满足实际生产需求，并且几乎完全消除了拧紧过程的 工艺缺陷，提高了车身质量和生产效率。

关键词: 自攻螺钉；扭矩；折叠缺陷；工艺优化