A DESIGN METHOD TO EXTEND THE LIFE OF A MOLD BY COLD UPSET PUNCHING BOLT
一种提高冷镦件模具寿命的设计方法

In view of the fact that for the cold upset mold of the whole-mold structure, the fatigue life is rather short, a new design method is proposed to replace the whole mold with the mold structure of a three-layer cylinder and thus to change the loading on the mold and to achieve a longer life. According to the testing results of cold upset bolt and the results of stress analysis, empirical formulas are obtained.