| 摘要 |
PURPOSE:To prevent inferior goods having a sink and weld due to an abnormal temperature of a molding mold from generating, by controlling automatically a temperature of the molding mold through action of a spring made of a shape memory alloy provided on a movable core. CONSTITUTION:A stationary mold 2 is fixed to a fixed head die plate 1, a core 4 faced on a mold impression 12 is fitted in a stripper plate 3 facing on the mold 2 for fixation, and a movable core 11 is freely movably inserted into the core 4 by interposing a spring 13 made of a shape memory alloy within the core 4. The spring 13 is under a contact state as it has received predetermined heat equal to the transformation point or lower. Then when molten resin is pressed in the mold impression 12 from a gate 10 as per the arrow, the mold is heated gradually and arrives at a high-temperature state. At the time when the spring 13 arrives at the transformation point which has been stored by the spring 13 beforehand, the spring 13 is deformed into a stretched state and the core 11 is ejected within the mold impression 12. Then a gap A becomes gap B, a resin passage is narrowed and a passing speed of the resin becomes fast. With this construction, a temperature of the mold is controlled automatically so that the mold is kept at a predetermined temperature.
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