The Puller Used In Ejector Pin Mechanism

(1) The Z-pullers

The Z-pullers design shown in Fig. 6. 8a is widely used in ejector pin or sleeve mechanism, and especially used when the height of the runner(h)is at least 5 mm and the diameter(D,)of the central ejector pin is at least 6 mm. The disadvantage is that construction cannot be used in automatically operated molds. because the residual does not fall down safely in most cases during the ejection cycle.

(2) The Reverse Taper Pullers

According to the construction shown in Fig. 6. 8b that the removal of the waste from the sprue bush and ejection from the mold upon opening are ensured. the solid plastic is pulled out of the sprue bush by the cold slug well in reverse taper shape and then ejected from the mold plate by an ejector pin(diameter D,). That can be used in automatic molds. The plastic material should have elasticity without broken during ejecting process. The ejection mechanism of reverse taper pullers is also widely used

(3) The Ring Pullers

The construction of ring puller shown in Fig. 6.8c, the polymer solidifies into the groove machined in the bush insert, whereby the solid plastic is pulled out of the sprue bush by the cold slug well with ring and then ejected from the mold plate by an ejector pin(diameter D). The size of the groove(D3)is necessary to take into account the processed plastic elasticity at the temperature of ejection. Higher values of L2 can be selected such as processing of PE, PP, PVC and ABS plastics.