JPS5619948A - Method for molding of mold - Google Patents

Abstract

PURPOSE: To make the formation of facing sand layers easy and make material cost lower by coating the self-hardening loam mold sand containing at least a hardener and an inorganic binder on a pattern applied with a parting agent and removing the pattern after ramming up of backing sand.

CONSTITUTION: A hardener such as a hardener used for cement, etc. being essential components and an inorganic binder such as water glass base or cement base are added to aggregate such as chromite sand zircon sand. The amounts of admixture of the latter two are preferably 1W4% and 3W8% respectively, based on the weight of the aggregate. The self-hardening loam mold sand prepared by adding a foaming agent, water, etc. according to need to this is coated thinly on the surface of the pattern having beforehand been applied with a parting agent such as high polymer film (usually minimum thickness lmm). After waiting for this mold sand layer to harden, backing sand is rammed and this so press-contacted with the mold layer as to be plunged thereto. Finally, the pattern is removed and the timing for this may be before the mold sand perfectly hardens, for example, at 70% hardening.

COPYRIGHT: (C)1981,JPO&Japio