초록 ▼

If the surface of metallic mold should not be highly transcribed to the surface of product in injection molding the plastic products, the transcription defects such as weld, shrinkage, etc. are caused to the surface of product. Further, if the resin should be exposed to the surface of high temperatu

If the surface of metallic mold should not be highly transcribed to the surface of product in injection molding the plastic products, the transcription defects such as weld, shrinkage, etc. are caused to the surface of product. Further, if the resin should be exposed to the surface of high temperature metallic mold more than necessary during the molding, the filler and the like of glass and so forth are contained into the resin, and in this case, they are left over on the surface of metallic mold, resulting in the transcription defect. These problems can be solved by heating the surface temperature of metallic mold higher than the glass transfer temperature of resin if the resin is non-crystal and higher than the fusion point temperature if the resin crystal, with the temperature raising speed of more than 2.degree. C. every second, maintaining this temperature during the resin charging, and by cooling at the lowering speed of more than 2.degree. C. every second after the completion of charging. This temperature control shall be conducted with the feed back control while detecting the surface temperature of metallic mold by the temperature detection sensor mounted at the position close to the surface of metallic mold.

대표청구항 ▼

[What is claimed is:] [1.]closing the metallic mold;injecting a plastic product resin material into the closed mold;subsequent to said step of injecting, maintaining the pressure in the mold at a fill level for a period of time;cooling the mold;opening the metallic mold;removing the molded product f

[What is claimed is:] [1.]closing the metallic mold;injecting a plastic product resin material into the closed mold;subsequent to said step of injecting, maintaining the pressure in the mold at a fill level for a period of time;cooling the mold;opening the metallic mold;removing the molded product from the opened metallic mold;controlling the temperature of heating the metallic mold within a short time and in high speed with the metallic mold surface temperature, in contact with the product, being raised more than 2.degree. C. every second until said metallic mold surface temperature is at a level higher than the glass transfer temperature of the resin if the resin material is non-crystal and being raised more than 2.degree. C. every second until said metallic mold surface temperature is at a level higher than the fusion point temperature of resin if the material resin is crystal;maintaining said metallic mold surface temperature during said step of injecting, subsequent to reaching one of said level higher than the glass transfer temperature and said level higher than the fusion point temperature; andafter the completion of injecting, cooling down said metallic mold surface temperature within a short time and at a high speed with the temperature lowering speed of more than 2.degree. C. every second.