| 摘要 |
PURPOSE:To prevent the polyester form from whitening by a method wherein a specified spool structure and a gete heater heating the external part of a gate section are provided in an external heating type hot runner mold while the heater is enabled to be supplied with electricity intermittently in synchornizing with the molding cycle of the mold. CONSTITUTION:An external heater 7 heating the hot runner block 6 and the heater 1 for heating principally the external part of the gate 8 are provided while the spool section consisting of the spool 2 of up to 5mm. in length and 1.2mm. or more in diameter thereof, located with in the hot runner block 6, and the spool 3 of 3mm. or more in length and 1.5mm. or more in diameter thereof, located in a cavity plate 11 successive to the hot runner block 6, is provided between the gate 8 and a product section. Further, the gate heater 1 is provided with an electric source capable of feeding the electricity intermittently in synchronism with the molding cycle of the mold. |
