METHOD FOR MAKING INVESTMENT PATTERNS Russian patent published in 2002 - IPC

FIELD: machine engineering, namely casting with use of investment patterns. SUBSTANCE: pattern is made of powdered mixture of pattern composition with fraction size (0.1-1.6)mm and ammonium nitrate with fraction size (0.1-2.5)mm. Relation of mixture components by volume: pattern composition -(20-65)%; ammonium nitrate - (35-80)%. Method comprises steps of metering pattern material to press mold in quantity providing manufacture of patterns with porosity degree (3- 10)%; without preliminarily heating pressing pattern material due to coinciding parting surfaces of press mold; sintering powered pattern material at pressing practically without phase deformation processes at providing open capillary porosity which compensates thermal expansion of pattern at melting-out it from ceramic envelope. EFFECT: enhanced dimensional and geometrical accuracy of patterns and castings. 1 tbl