| 摘要 |
PURPOSE:To obtain a hollow molded piece with excellent reproducibility without generating the sink mark of a thick section and the warpage of the molded piece by moving at least one part of the compressed section of a molten resin compressed and filled into a mold to the flow side upper than a resin press-fit port, press-fitting a pressure fluid into a mold cavity and holding the pressure fluid until the molten resin is solidified. CONSTITUTION:A molten resin is press-fitted from the resin press-fitting port 5 of a mold 4 with a pressure-fluid inducing path 3a by an injection machine 8. A fixed quantity of the molten resin is press-fitted, and at least one part of the compressed section of the compressed and filled molten resin is moved to the flow side upper than the resin press-fitting port 5 of the mold 4. To be concrete, an injection cylinder 9 is retreated, and an injection cylinder 10 is separated from the mold 4. The injection screw 12 of the injection cylinder 9 is retreated, thus making pressure in the injection cylinder 9 lower than that on the downstream side of the rein press-fitting port 5. A pressure fluid is forwarded through a pressure fluid nozzle 14 from a pressure fluid source 17, and fluid pressure required is applied into the mold 4. Pressure fluid pressure applied into the mold 4 is held until the molten resin in the mold 4 is cooled and solidified. |
