Hitchiner Manufacturing Co., Inc.

Wax replicas of the desired castings are produced by injection molding. these replicas are called patterns.

At Hitchiner (right), complex multi-cavity dies are used to cast ring segment patterns with several part replicas attached to a center ring.

The patterns are attached to a central wax stick, called a sprue, to form a casting cluster or assembly.

Hitchiner's ring segment waxes are simply stacked to form the assembly. The ring is notched so that the optimum spacing is automatically achieved.

The shell is built by immersing the assembly in a liquid ceramic slurry and then into a bed of extremely fine sand. up to eight layers may be applied in this manner.

At Hitchiner, specialized shell building robots are used to build the shell. This automation provides for a consistent build and allows for larger molds than could be built by manual methods.

Once the ceramic is dry, the wax is melted out, creating a negative impression of the assembly within the shell.

Steam autoclaves are used for this purpose. At Hitchiner, the wax is reclaimed, purified and recycled.

In the conventional process, used by most foundries, the shell is filled with molten metal by gravity pouring. as the metal cools, the parts and gates, sprue and pouring cup become one solid casting.

Hitchiner uses its exclusive countergravity processes to cast the mold. In these processes, molten metal is siphoned up into the mold cavity in a controlled fashion, resulting in superior castings. The vacuum is released when the parts and a portion of the gates have solidified, allowing the molten metal in the central sprue to return to the melt.

When the metal has cooled and solidified, the ceramic shell is broken off by vibration or water blasting.

After countergravity casting, the molds are discharged from the casting machine into a special hopper that separates the castings from the process materials. The castings are tumbled, stripping them of all shell remnants.

Traditionally, the parts are cut away from the central sprue using a high speed friction saw.

Hitchiner's countergravity-cast parts do not have a solidified central sprue and therefore do not require this operation. Only a small gate stub remains after casting which is easily removed by a mass production grinding operation.

After minor finishing operations, the metal castings—identical to the original wax patterns—are complete.

Hitchiner Manufacturig Co., Inc. has the capacity and experience to offer complete-to-print machining and subassembly operations, delivering a finished component ready for installation in the finished product.