Investment casting is an industrial process which is closely controlled at every point of production. The process begins with production of a one-piece heat-disposable pattern. This pattern is usually made by injecting wax or plastic into a metal die. These disposable patterns have the exact geometry of the required finished part with allowances made to compensate for volumetric shrinkage in the pattern production stage and during solidification of metal in the ceramic mold.Each wax pattern carries a gate.The wax patterns are fastened by the gate to runners, which is attached to a pouring cup. The patterns, tree and pouring cup form the cluster, commonly known as a tree, which is needed to produce the ceramic mold.The ceramic shell is placed in a high temperature steam autoclave where the wax will melt out of the shell. This will leave a ceramic shell containing cavities of the desired casting shape along with the designed running and feeding system.The ceramic shell molds are fired to burn out the last traces of pattern material, to develop the high temperature bond of the ceramic system and to preheat the mold in preparation for casting.The hot molds may be poured utilizing static pressure of the molten metal heat, as is common in sand casting, or with assistance of vacuum, pressure and/or centrifugal force.After the poured molds have cooled, the mold material is removed from the casting cluster. Individual castings are then removed from the cluster and any remaining protrusions left by gates or runners are removed by belt grinding.