Vacuum casting also called vacuum moulding or vacuum sealed molding, which is invented by the Japanese as a new molding process in seventy’s of the last century .It is the third generation of modeling process without binder ,namely physical modeling method.has got rapid speed of development in recent years because of its good appearance quality of castings and low running cost.
The basic operation principle of vacuum casting is to filled anhydrous quartz sand without binder in special sand box.Then we can get the casting after sealing the sand box with plastic film and vacuumizing it to make the casting mold without binder sand compacted and molded by the differential pressure inside and outside of the casting.
Castings produced by vacuum method have not only good quality , smooth surface, high dimensional precision , but also low comprehensive cost. Though the vacuum casting method make use of disposable plastic film, the sand mould without binder ,high recovery rate and low cost of casting cleaning have reduced the machining allowance and improved labor productivity. The cost of vacuum castings is lower than hardening sand, sodium silicate sand and tidal sand mold.