US Patent 8006744 Method and system for drying casting molds

A system and method of drying casting molds for forming metal parts is provided. In one embodiment, the method includes providing a casting mold comprised of a meltable pattern coated with a ceramic slurry containing a liquid solvent and a binder, placing the casting mold in a chamber, encapsulating the casting mold in a desiccant material, sealing the chamber sufficient to pull a vacuum in the chamber, and applying a variable vacuum to the chamber to dry the mold. In one embodiment, the vacuum is controlled and gradually increased over time from atmospheric pressure to a predetermined maximum vacuum pressure. The vacuum is preferably applied at a rate such that the meltable pattern has a temperature that does not decrease more than about 5 degrees F. from atmospheric pressure to maximum vacuum pressure in one embodiment. In another embodiment, the retained moisture level of the desiccant may be controlled to minimize temperature swings of the meltable pattern during the vacuum application.