| 摘要 |
PURPOSE:To make one expendable pattern usable as a pattern for producing many castings in the same manner as with a wooden pattern by forming a surface curing agent layer having no solubility with an expendable pattern made of a combustible foamed resin on the surface of said pattern. CONSTITUTION:Foamed polystyrene beads are heated in a metallic mold, expansion-molded or the foamed polystyrene block is machined to manufacture the expandable pattern 10'. The curing agent contg. an adhesive agent of the solvent having no solubility with the foamed polystyrene is coated on the surface of such pattern and is dried to manufacture a pseudo casting pattern 10 having the surface hardened layer 10. The expandable pattern having such surface hardened layer is usable by a plural number of times as a prototype for molding of sand molds in the same manner as with the wooden pattern. The pattern is finally used as an ordinary expendable pattern. |
