凸焊螺栓多工位冷镦成形工艺及模具设计

Multi-station cold headir cess and mold design for projection welding

针对凸焊螺栓多工位镦挤与冲床切边相结合的工艺成形效率低下、成本高的问题,将其原有工序重新组合,设计出6工位凸焊螺栓冷镦成形工艺。利用Deform-3D软件对凸焊螺栓冷镦成形工艺各工序进行有限元仿真,从金属流动规律、填充饱满度和载荷分布状态等角度对模拟结果进行分析,验证工艺的可靠性;在此基础上,对各工位的模具结构进行设计,通过将切边挤孔复合模具的主模模芯设计为浮动结构,解决了该工序坯料杆部过短导致的夹钳传递困难的问题,并在切边挤孔时为坯料下表面提供支撑力,确保其下表面的平面度。凸焊螺栓批量试制结果表明:各工位制件表面光洁,填充完整,尺寸公差均在设计要求范围之内,新工艺生产效率提高了80%,可用于指导异形短杆螺栓的冷镦成形工艺开发和模具设计。

In order to solve the problems of low forming efficiency and high cost caused by the combination process of multi-position upset-ting-extrusion and punching-trimming of projection welding bolt,a six-station cold upsetting process for projection welding bolt was designed by recombining the original process,and each station of cold heading process for projection welding bolt was finite element simulated by De-form-3D.Then,the simulation results were analyzed from the perspectives of metal flow laws,flling fullness and load distribution status,which verified the reliability of the process.Furthermore,on this basis,the mold structure of each station was designed,and the problem of difficult clamp transmission caused by the short rod of the blank in this station was solved by designing the main mold core of trimming-extru-sion composite mold as a floating structure.In addition,the support force was provided for the lower surface of the blank during trimming-ex-trusion process to ensure its flatness.The batch trial production results of projection welding bolts show that the surface of workpieces at each station is smooth,the filling is complete,and the dimensional tolerance is all within the required range.The new process increases the produc-tion efficiency by 80%,which can be used to guide the development of cold heading process and mold design for special-shaped short-rod bolt.