| 摘要 |
The present invention relates to a hot runner sealed edge gated injection molding system. The system includes a mold cavity plate (28) with at least one injection gate (16) and a nozzle assembly (12) having a tip end (40) and at least one melt channel (14, 38) for transporting molten plastic material. The system further includes an annular seal ring (42) which fits snugly over the tip end of the nozzle assembly. The seal ring has at least one melt channel (56) and at least one orifice (54) for transporting molten plastic material from the at least one melt channel in the nozzle assembly to the at least one injection gate in the mold cavity plate. In a preferred embodiment, the seal ring is formed from a material having a thermal coefficient of expansion lower than the thermal coefficient of expansion of the material forming the nozzle. As a result, the nozzle when heated will expand at a greater rate than the seal ring resulting in an effective sealing arrangement with the seal ring being pressed against the mold cavity plate and being gripped by the nozzle. <IMAGE> |
