Investment casting
Investment casting is valued for its ability to produce components with accuracy, repeatability, versatility and integrity in a variety of metals and high-performance alloys.
Due to the hardness of refractory materials used, investment casting can produce products with exceptional surface qualities, which can reduce the need for secondary machine processes.
Turbocharger products are a common applications for this casting process,[22] though it is also regularly used in the manufacture of silver and gold jewellery.
[24] Its earliest use was for idols, ornaments and jewellery, using natural beeswax for patterns, clay for the moulds and manually operated bellows for stoking furnaces.
Examples have been found across the world, such as in the Harappan Civilisation (2500–2000 BC) idols, Egypt's tombs of Tutankhamun (1333–1324 BC), Mesopotamia, Aztec and Mayan Mexico, and the Benin civilization in Africa where the process produced detailed artwork of copper, bronze and gold.
By far, one of the earliest identified uses of the investment casting process was seen in objects found in the 'Cave of Treasure', discovered in Southern Israel.
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 with the Head of Medusa sculpture that stands in the Loggia dei Lanzi in Florence, Italy.
Investment casting came into use as a modern industrial process in the late 19th century, when dentists began using it to make crowns and inlays, as described by Barnabas Frederick Philbrook of Council Bluffs, Iowa in 1897.
He also formulated a wax pattern compound of excellent properties, developed an investment material, and invented an air-pressure casting machine.
Investment casting is used in the aerospace and power generation industries to produce turbine blades with complex shapes or cooling systems.
[citation needed] Karsten Solheim famously revolutionized golf club design through his company PING by incorporating investment casting for the first time for clubheads.
Other industries that use standard investment-cast parts include military, aerospace, medical, jewelry, airline, automotive and golf clubs especially since the start of 3D printing technology.
With the increased availability of higher-resolution 3D printers, 3D printing has begun to be used to make much larger sacrificial moulds used in investment casting.
Planetary Resources has used the technique to print the mould for a new small satellite, which is then dipped in ceramic to form the investment cast for a titanium space bus with integral propellant tank and embedded cable routing.
