Abstract
Authors have developed a new mold release method by reducing the air pressure of poured green sand mold in a chamber. A moisture-condensed layer, which weakens the mold strength, appears when the temperature of the mold reaches around 373 K after pouring. The mold is placed in a chamber. Water near 373 K in the moisture-condensed layer of the mold starts to boil when the chamber pressure is reduced. Boiling generates a difference of pressure between the inside and outside of the mold, which breaks the mold. In this study, the mechanism of the mold release method using vacuum was investigated through fundamental experiments measuring the temperature and pressure of the sand mold after pouring. The actual phenomenon of mold release using vacuum in the chamber was confirmed. Furthermore, the properties of the green sand after mold release was clarified.
