| 摘要 |
PROBLEM TO BE SOLVED: To prevent a silver streak, a sinkmark or a warp from being generated on the surface of moldings, if a wall thickness is reduced by controlling the surface temperatures of an injection mold on the face side through which moldings are visible, without the use of a high pressure air injection device, so that the surface temperatures are kept close to a glass transition temperature level during the period from the start of packing a resin to the end of packing it. SOLUTION: The adherence between the face of an injection mold on the visible face side of moldings and a molten resin material is improved to make the formation of a solidified layer hardly develop by controlling the temperatures of the injection mold on the visible face side of the moldings to a vicinity of a glass transition temperature level (Tg point) during the period from the start of filling the molten resin material into the injection mold to the end of filling the resin. That is, a high frequency heating-type temperature controller 8 is built, as a heating means, into the back of the front 7 side, kept in contact with the visible face of the moldings, in the injection molds 5, 6. Further, the injection molds 5, 6 are used and the surface 7 temperatures of the injection mold 6 on the visible face side of the moldings are thermally controlled by the temperature controller 8 so to the vicinity of the Tg point during the period from the start of filling the molten resin to the end of filling it. After the completion of filling the molten resin, the surface 7 of the injection mold 6 on the visible face side of the moldings is cooled to obtain the moldings. |
