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"V'' PROCESS. A Japanese patented process to produce molds using only unbonded sand. The vented pattern plate is covered with a heated plastic film and a mild vacuum draws the film close to the pattern, the flask is located on the plate and loosely bonded sand is added to fill the flask. The plate is rapped to achieve compaction and a second sheet of plastic is placed over the top of the cope. Next a vacuum is drawn through a special port in the flask side. Now the vacuum on the pattern plate is released and the mold is stripped and ready to be assembled to a drag. The mold is poured and the vacuum is released. Clean up and recycling of the sand are simple routines.
VACUUM CASTING. A casting process in which metal is melted and poured under very low atmospheric pressure; a form of permanent mold casting where the mold is inserted into liquid metal, vacuum is applied and metal drawn up into the cavity.
VEINING. A defect on the surface of a casting appearing as veins or wrinkles and associated with excessive thermal movement of the sand, especially core sands.
VENT. A small opening or passage in a mold or core to facilitate escape of gases when the mold is poured.
VENT WAX. Wire or rod shapes of wax placed during making of the core. During baking the wax is melted, leaving an opening through which gases may escape.
VIBRATOR. A device, operated by compressed air or electricity, for loosening and withdrawing patterns from a mold, or for vibrating a hopper or chute to promote the flow of material from the hopper or chute.
VIRGIN METAL (PRIMARY METAL). Metal extracted directly from the ore; not previously used.
VISCOSITY. The resistance of a fluid substance to a quantitative measure flow. A characteristic for an individual substance at a given temperature.
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