Investment casting also known as the lost wax process, is one of the oldest manufacturing processes. The Egyptians used it in the time of the Pharaohs to make gold jewelry some 5,000 years ago. Intricate shapes can be made with high accuracy. In addition, metals that are hard to machine or fabricate are good candidates for this process. It can be used to make parts that cannot be produced by normal manufacturing techniques, such as turbine blades that have complex shapes, or airplane parts that have to withstand high temperatures.
Investment casting is not a new technique. The basic technique of investment casting, or lost wax casting, has been in existence for well over 6,000 years. The origin of the process is a matter of some doubt and various claims have been made as to where it was founded. Beeley and Smart report that archaeological investigations have indicated that around the years 3000-4000 BC, societies in Mesopotamia possessed skills in engineering and metallurgy (17).
English: An investment cast turbocharger turbine.
English: Investment casting shell for a turbocharg...
English: Interior view of an investment casting sh...These societies were able to produce a range of gold, silver and copper artifacts made by the lost wax casting process. Beeley and Smart write, "the Chinese were using the technique from 2000 BC onwards and the Egyptians from around 1400 BC"ÃÂ (18). Early castings were produced from a wide range of patterns. Production of identical wax patterns was achieved by the use of dies of carvable stone, cast bronze and carved wood. The lost wax casting process reached its highest artistic expression in Renaissance Italy. Benvenuto Cellini produced many memorable pieces using investment casting (Ezra Kotzin 40). Investment casting continued to be used for artistic expression, however, around the 1900's the use of the process was extended to the manufacturing of gold fillings and false teeth by B.F. Philbook of Iowa (Diamond 283). According...