| 摘要 |
PURPOSE:To decrease sinkages generated in the molding part of a boss, a rib or the like by a method wherein a pin, attached to a thin sheet tube, is arranged detachably at a predetermined position in a cavity. CONSTITUTION:The shaft 2 of a ceramics pin 15 is penetrated through the center of a thin sheet tube 14 made of copper while the thin sheet tube 14 and the pin 15 function as one set of a pin P for a mold. The thin sheet tube 14 and the pin 15 are contacted closely with each other within a range permitting slip in accordance with the difference of the amounts of thermal expansion and are embedded into the mold 12 detachably. Resin, heated to the temperature of about 200 deg.C, flows into a cavity 13 through a runner 11 and is kept in a pressure. The resin is cooled through the surface of the mold from an instance when it is poured into the mold while the heat of the resin in the molding part Q of the root of a boss, in which heat is most readily reserved, is released efficiently into the mold 12 through the copper thin sheet tube 14 provided with a heat conductivity that is about 14 times of the same of iron. On the other hand, the deformation of the thin sheet tube 14 is restricted by the head of the ceramics provided with a thermal expansion coefficient of about 1/2 of the same coefficient of steel, therefore, the pin P for the mold itself may be extended only about 1/2 of the thermal elongation of a conventional pin.
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