| 摘要 |
PROBLEM TO BE SOLVED: To prevent the occurrence of failure by controlling the flow of a molten resin in the vicinity of a recess for forming the projection of a molded article in a cavity to eliminate the turblence of the flow of the resin. SOLUTION: After the cavity 3 is formed between a movable mold 2 and a fixed mold 1 by closing both molds, the mold is heated and the thermoplastic resin 8 is injected in the cavity 3 from a gate 4. The front of a piece 6 is biased by a biasing means 7 and positioned in the same plane as the inner wall surface 2a of the cavity. Since the recess 5 is closed by the piece 6 and the inner wall surface 2a of the cavity is flat, the thermoplastic resin 8 flows smoothly in the cavity as a non-turbulent laminar flow. When the pressure of the resin 8 overcomes the biasing force of the biasing means 7, the piece 6 begins to withdraw gradually by the pressure of the thermoplastic resin 8 so that the resin 8 penetrates into the recess 5. Thereafter, the piece 6 comes into contact with a stopper 9 to become impossible to retreat, and the resin 8 is introduced into the recess 5. COPYRIGHT: (C)2004,JPO&NCIPI
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