| 摘要 |
PURPOSE:To prevent the mark of a gate from remaining on an injection molded item and to obviate leakage of a melted resin, by providing an attachment of a hot runner with a nozzle having a pin gate and also with a rod extendable to one end of a port. CONSTITUTION:The injected plastic is passed through the pin gates 12 that are thinner than the hot runners 9 and fills cavities 15 between female and male molds 4, 4', 5, 5'. First the pin gates 12 are cooled to solidify the plastic, than the cavities 15 are cooled, and when the molds are opened to remove the molded items 1, 2, the rod 14 is hydraulically operated to be retracted by a certain space (to the position shown by B) so that the insides of the runners are depressurized. Then when the next injection is performed, the rod 14 is moved hydraulically forward to occupy the space 14' to be returned to the original position A. Due to the cooling effect of the female mold, following the runner 9, the pin gate is cooled and solidified and is cut at its smaller diameter section, and will be melted by the subsequent hot runner that is kept at high temperatures and will be used in the next injection. |
