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 powered mixture of pattern composition with fraction size (0.1-1.6)mm and sodium tetraborate with fraction size (0.1-0.63)mm. Relation of components of mixture by volume: pattern composition -(75-80)%; sodium tetraborate -(20-25)%. Method comprises steps of metering pattern material to press mold in quantity providing manufacture of patterns with open porosity (3-10)%; without preliminarily heating pressing pattern material due to coinciding parting surfaces of press mold; at pressing sintering powdered pattern material 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