History of Investment Casting
November 29, 2021
Cast Steel Shot, Metal Abrasive, Stainless Steel Shot
Investment casting dates back thousands of years. Its earliest use was for
idols, ornaments and jewelry, using natural beeswax for patterns, clay for the
moulds and manually-operated bellows for stoking furnaces. Examples have been
found around the world: from Mexico to Mesopotamia, and Egypt to Africa where
the investment casting process produced detailed artwork of copper, bronze and
gold.
The earliest known text that describes the investment casting process was
written around 1100 A.D. by Theophilus Presbyter, a monk who described various
manufacturing processes, including the recipe for parchment. This book was used
by sculptor and goldsmith Benvenuto Cellini (1500 – 1571), who detailed in his
autobiography the investment casting process he used for the Perseus and the
Head of Medusa sculpture that now stand in the Loggia dei Lanzi in Florence,
Italy.
Investment casting came into use as a modern industrial process in late
19th century, when dentists began using it to make crowns and inlays, as
described by Dr. D. Philbrook of Council Bluffs, Iowa in 1897. Its use was
accelerated by Dr. William H. Taggart of Chicago, whose 1907 paper described his
development of a technique and formulated a wax pattern compound of excellent
properties, developed an investment material, and invented an air-pressure
casting machine.
In the 1940s, World War II increased the demand for precision net shape
manufacturing and specialized alloys that could not be shaped by traditional
methods, or that required too much machining. Industry turned to investment
casting. After the war, its use spread too many commercial and industrial
applications that used complex metal parts.
Modern investment casting techniques stem from the development in the
United Kingdom of a shell process using wax patterns known as the Investment X
Process. This method resolved the problem of wax removal by enveloping a
completed and dried shell in a vapor degreaser. The vapor permeated the shell to
dissolve and melt the wax. This process has evolved over years into the current
process of melting out the virgin wax in an autoclave, or furnace.
