| 摘要 |
PURPOSE:To produce balls with good as-cast yield and productivity by superposing and setting a plurality of componental units with spherical product parts made of materials which evaporate by molten metal in a molding flask, molding the same and pouring molten metal in each componental unit. CONSTITUTION:Spherical product parts 3 are integrally formed in plurality and continuously by way of transverse ingates 2 to longitudinal runners 1 and longitudinal vents 5 are integrally formed by way of transverse ingates 4 on both sides of the respective product parts 3, whereby componental units 6 are made. Further, longitudinal, transverse and rise members 7a-7c are made and the member 7c is made into the same shape as that of the runners 1. All these are made of the raw materials such as expanded polystyrene resins which readily melt and evaporate by molten metal. Coat is applied to each unit 6 and sprue 7 and is dried. Next, a samll amount of fluid self-hardening sand 9 is put in the molding flask 8 and the sprue 7 and further plural units 6 are subsequently superposed and set. The sand 9 is then put in and is molded. When molten metal is poured to this through the member 7a, the foregoing raw materials are subsequently evaporated and the molten metal flows in, and in turn the gas is vented, whereby the castings are made. |
