我厂在自行车辐条条母的冷镦过程中,凹模使用一段时间后就开裂损坏,一般是用两层或三层的组合凹模来防止开裂。但组合凹模制造工艺复杂,不经济。后来在弹簧夹头的启发下,将凹模装模套沿 I plant the spokes of the bar spokes cold heading process, the use of concave die after a period of cracking damage, usually with two or three layers of composite die to prevent cracking. But the combination of die manufacturing process is complex, not economical. Inspired by the collet chuck later, the die assembly die along the sleeve