Search results
Results from the WOW.Com Content Network
In casting, a pattern is a replica of the object to be cast, used to form the sand mould cavity into which molten metal is poured during the casting process. Once the pattern has been used to form the sand mould cavity, the pattern is then removed, molten metal is then poured into the sand mould cavity to produce the casting.
Lost-foam casting (LFC) is a type of evaporative-pattern casting process that is similar to investment casting except foam is used for the pattern instead of wax. This process takes advantage of the low boiling point of polymer foams to simplify the investment casting process by removing the need to melt the wax out of the mold.
The Iron Foundry, Burmeister & Wain, by Peder Severin Krøyer, 1885 A Foundryman, pictured by Daniel A. Wehrschmidt in 1899 A foundry is a factory that produces metal castings . Metals are cast into shapes by melting them into a liquid, pouring the metal into a mold, and removing the mold material after the metal has solidified as it cools.
Produce wax patterns: Although called wax patterns, pattern materials may also include plastic and frozen mercury. [6] Wax patterns can be produced in one of two ways. In one process, the wax is poured into the mould and swished around until an even coating, usually about 3 mm (0.12 in) thick, covers the inner surface of the mould.
In 1964, M.C. Flemmings used unbonded sand for the process. The first North American foundry to use evaporative-pattern casting was the Robinson Foundry at Alexander City, Alabama. 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. [11]
The pins are then carefully pulled out of the sand. The critical part of the operation is to separate the cope and drag to remove the pattern. The pattern may be vibrated with a powered vibrator, or the pattern, and maybe the cope and drag flask, will be lightly tapped with a small hammer. The pattern is lifted from the sand, leaving a molding ...
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
The pattern and sand are then inverted so the excess sand drops free of the pattern, leaving just the "shell". Depending on the time and temperature of the pattern the thickness of the shell is 10 to 20 mm (0.4 to 0.8 in). The pattern and shell together are placed in an oven to finish curing the sand.