| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve problems wherein even if a molding having un-undercut is forcibly drawn, degrees of crack and whitening are different according to the elastic modulus of the molding to cause defects, though polycarbonate resin can be separated by forced draw, acrylonitrile and ethylenic resins crack, and an amount of un-undercut of forced draw is different in relation to the elastic modulus of the molding resin, affecting the correlation of the molding resin and molding, the fact is not grasped, currently defects occur such as fold over and whitening of the molding after manufacturing mass-production dies and starting the production, preventing continuous molding. Ž<P>SOLUTION: The resin molding is formed by forming protrusions on the inner face of a shaft cylinder, wherein the protrusion is formed by a core pin of a metal die apparatus, the core pin is linearly drawn out in relation to the shaft cylinder, the flexural modulus of the shaft cylinder is 1,900-3,600 MPa and the elongation of the protrusion is 105% or less. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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