Abstract: 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.

Abstract: 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.

Abstract: A fugitive pattern, such as wax or other meltable pattern material, residing inside of a refractory mold, which can be unsupported or supported in a particulates bed, is removed by discharging steam or other condensable vapor that may include a surfactant inside the mold to contact and melt the pattern while an exterior of the mold is subjected to a non-condensing gas atmosphere such as air outside of the mold. Regardless of whether the condensable vapor includes surfactant or not, the mold can be tilted relative to gravity and rotated while it is tilted to improve the pattern removal. Condensable vapor is condensed inside the mold where the vapor has contacted the pattern while the exterior of the mold remains free of condenate. The condensed vapor and melted pattern material are drained out of the mold with the surfactant, if present, improving drainage.