| 摘要 |
PURPOSE:To reduce flash and consequently improve yield and at the same time external appearance of a product by a method wherein a mold is put close to a nozzle and at the same time the protrusion of the nozzle from the mold is made as small as possible. CONSTITUTION:A flattened circular hole 2 which is produced by connecting two parallel planes opposing to a parison head main body 1 with circular curved surface is bored. A plunger 3 is slidably fitted to the flattened circular hole 2, while the similar hole to the hole 2 is bored to a plunger 3 also, and then a mandrel 5 is slidably fitted thereto. The tip of the mandrel 4 is gradually enlarged downwards in the form of a skirt, the outer shape of the which is similar to the flattened circular hole 2. A nozzle 6, which forms a flattened ring-shaped injection slit 5 together with the tip of the mandrel, is fixed to the lower end of the parison head main body 1. When resin is charged in a space partitioned by the parison head main body and the mandrel, a plunger is pushed in the space by means of injection cylinders 11 in order to inject a flattened tubular parison through the injection slit. |
