Description: One of the newest casting processes; the "V" Process in which unbounded sand is held in place in the mold by a vacuum. In this process the pattern is covered by a tightly conforming thin sheet of plastic which is applied with vacuum after being heated. A flask is placed over the plastic coated pattern, and is filled with free-flowing sand. Another sheet of plastic is placed over the top of the sand in the flask and the flask is evacuated. The vacuum "hardens" the sand so the pattern can be withdrawn. The other half of the mold is made the same way. After cores are put in place, the mold is closed and poured while still under vacuum. When the metal has solidified, the vacuum is turned off and the sand runs out freely, releasing the casting.
Description: One of the newest casting processes; the "V" Process in which unbounded sand is held in place in the mold by a vacuum. In this process the pattern is covered by a tightly conforming thin sheet of plastic which is applied with vacuum after being heated. A flask is placed over the plastic coated pattern, and is filled with free-flowing sand. Another sheet of plastic is placed over the top of the sand in the flask and the flask is evacuated. The vacuum "hardens" the sand so the pattern can be withdrawn. The other half of the mold is made the same way. After cores are put in place, the mold is closed and poured while still under vacuum. When the metal has solidified, the vacuum is turned off and the sand runs out freely, releasing the casting.