Cold cave and pulling rod design: a new injection cycle begins, the nozzle end of the plastic melt temperature is lower than the process requirements, this part of the flow properties and formability and forming performance of plastic, if enter the runner and cavity, will produce substandard products. In order to overcome the influence of this phenomenon, with a well points to the mainstream extended to accept the cold material, the injection interval to accommodate the cold material well points called cold cave. Cold cave in addition to having a cold material beyond the effect, but also has the condensation in the mold material flow out and attached to the dynamic side of the function. Therefore, the push rod to form cold cave bottom, in addition to the introduction of condensed material effect, both from the sprue bush sprue runner pulled effect called pulling rod.
  Cold cave generally open dynamic template in the mainstream Road on the opposite side of the main channel, nominal diameter and big end diameter equal to or slightly larger, the depth is about 1-1.5 times the diameter, the volume is larger than the cold material volume.
  Because the runner is longer, the plastic melt filling temperature drop is large, cold cave also requires a longer extension opened small, to prevent cold material into the cavity of the shunt end. Plastic parts of some process control or better performance, rarely produces cold material of plastic and some less demanding, but do not have to set the cold cave.