Evaporative-pattern casting

[3][4] Proprietary terms included Styro-cast,[5] Foam Cast,[6] Replicast,[7] Policast.

[4] and Lost Foam Sintered Shell (LFSS)[8] The first patent for an evaporative-pattern casting process was filed in April 1956, by Harold F. Shroyer.

He patented the use of foam patterns embedded in traditional green sand for metal casting.

In his patent, a pattern was machined from a block of expanded polystyrene (EPS), and supported by bonded sand during pouring.

General Motors' first product using these processes was the 4.3 L, V-6 diesel cylinder head, which were made in 1981 at Massena, New York.