PRODUCTION OF WAX PATTERN FOR PRECISION CASTING

PURPOSE:To produce a wax pattern for precision casting which decreases surface shrinkage and torsional deformation by heating the powdery wax packed in the cavity of a metal mold and melting the same near the inside surface of the mold then cooling the wax to solidify. CONSTITUTION:Powdery wax 3 is packed into the cavity of a metal mold 1 through a wax packing port 2. A heating medium such as an aq. soln. of ethylene glycol is admitted into the fluid passages 5 formed in the thick walled part of the mold 1 to heat the mold 1 and to melt the wax 3 near the inside surface of the mold 1, whereby a liquid layer 4 is formed. The thickness of the layer 4 is preferably about 2-5mm.. After the layer 4 is solidified by cooling the mold 1, the mold is opened and the wax pattern is removed. It is preferable for tight adhesion of the layer 4 to the inside surface of the mold to apply gaseous pressure of 0.2-10kg/cm or the like upon the cavity inside in the stage of cooling the mold 1 and it is also possible to form a hollow pattern by removing the unmolten wax.