| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an injection molding method which can contribute to inhibiting the clogging of a gas vent, simplifying the maintenance service and control operation of a mold assembly and improving the productivity of a preform. <P>SOLUTION: The injection molding method is applicable to an injection molding machine equipped with a split mold which has a gas discharge portion formed in a parting line. The flow path section of the gas discharge portion is reduced at a predetermined timing after starting the packing of a molding material. Since the cross-section of the flow passage of the gas discharge portion is reduced after a cavity space starts being filled with a molding material, it may be possible to make the amount of gas, which flows through the gas discharge portion, large until the cross-section of the flow passage of the gas discharge portion is reduced. Further, it is possible to prevent a foreign material from adhering to the inner circumferential surface of the gas discharge portion. <P>COPYRIGHT: (C)2012,JPO&INPIT |
