Atmospheric pressure then hardens the sand. When the vacuum is released on the pattern carrier plate, the mold strips easily. Cope and drag assembly form a plastic-lined cavity. During pouring, molds are kept under vacuum. After cooling, the vacuum is released and free-flowing sand drops away leaving a clean casting, with no sand lumps.
Sand is cooled for reuse.
RMS is the norm. Certain details can be held closer. Cored areas may require additional tolerances. Zero Draft Eliminates the need for machining off draft to provide clearance for mating parts and assembly. Provides consistent wall thickness for weight reduction and aesthetic appeal.