| 摘要 |
PROBLEM TO BE SOLVED: To enhance the design properties of a molded ring-shaped product made of a resin by suppressing the development of a weldline when the ring-shaped product is injection-molded. SOLUTION: A mold (fixed mold 9) is constituted by forming two resin sump parts 21 in the vicinity of a confluent part 23, where a thermoplastic resin R flows through a cavity 13 in a mutually opposite direction at the time of injection molding and the respective flows of the thermoplastic resin R meet with each other, so that the resin sump parts 21 become point symmetry with respect to the center 23a of the confluent part 23 and an iris part 21a is provided to the boundary with the cavity 13. The flows of the thermoplastic resin R injected in the cavity 13 of the mold (fixed mold 9) are allowed to meet with each other at the confluent part 23 and subsequently introduced into the resin sump parts 21 on the downstream side of the confluent part 23 to mold the ring-shaped product. The resin solids solidified in both resin sump parts 21 are demolded to be cut off from the ring-shaped product. COPYRIGHT: (C)2006,JPO&NCIPI |
