PURPOSE: To form a surface skin free of bridge by a method in which a thermoplastic resin sheet fixed to a clamp is heated and adhered to the inner surface of molds by evacuation to vacuum, and all clamping is released at a time when the temperature at which the resin sheet shows maximum elongation is reached approximately.
CONSTITUTION: A thermoplastic resin sheet fixed to a clamp is heated and laid along the inner surface of wooden, aluminum, or steel molds by evacuation to vacuum, and all clamping is released at a time when a temperature at which the resin sheet shows a maximum elongation, or about 20°C, is nearly reached in such a way as to cause the sheet to reach sufficiently even the back side of the molds. In some cases where the sheet is made to go with the molds, a plug is horizontally pushed from side into the lower part of the molds to prevent the occurrence of bridge in the sheet. As the surface skin sheet, various resin sheets of polyethylene, polypropylene, polyvinyl chloride, etc., having a thickness of 0.5W10mm usually, may be cited.
KOJIMA SHIYOUZOU
NANBA JIYUNJI
| JPS5123543A | 1976-02-25 | |||
| JPS5759710A | 1982-04-10 |
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