The wear - out of the edges of upper & lower punches as well as the liners would be decreased and the life span of the mould be lengthened because of the positioning of upper punch and enlargement of exhaust passage 由于上冲头的定位和下排气通道的增大，减小了上下模芯刃口的侧板的磨损，延长了模具的使用周期。
