| 摘要 |
PURPOSE:To shorten a time necessary for cast of a core and to eliminate ununiformity of the shape of a hollow part by utilizing the hollow core wherein a tubular body is internally chilled in the inside thereof to perform molding of resin and immersing the molded form of resin in a hot bath and passing a heating medium into the tubular body to dissolve the core. CONSTITUTION:A flexible tubular body 2 made of metal is arranged in a mold 1. Melt M of low-m.p. alloy is filled into the space 8 of a product from a nozzle 7 and a hollow core 9 is cast. This core 9 is arranged into a mold 10 and injection molding is performed by injecting resin material P into the space 16 of the product part from a nozzle 15. The formed molded form W of resin is taken out together with the core 9 from the mold 10. The molded form W of resin is immersed together with the core 9 in an oil bath 19 heated by a heater 18 and heated for a prescribed time. When oil 17 is circulated into the tubular body 2 and the core 9 starts melting, the driving source 22 of an exciter 21 is started to impart vibration to the tubular body 2. Fall of molten metal 24 is promoted. The vibrator 21 is rotated in the direction shown in an arrow A, and external force is imparted in the direction for drawing the tubular body 2 from the molded form W. Molten metal 24 falls and the molded form W is obtained. |
