Investment casting produc es very high surface quality and dimensional accuracy. Investment casting is com monly used for precision equipment such as su rgical equipment, for complex g eometries and for precious metals.
This process is commonly used by artisans to produce highly detailed art work.
The first step is to prod uce a pattern or replica of the finished mou ld. Wax is most commonly used to fo rm the pattern, although plastic is also used.
Patterns are typically mass-produced by injecting liquid or semi-liquid wax into a permanent die.
Prototypes, small production runs and specialty projects can also be undertaken by carving wax models.
Cores are typically unne cessary but can be used for complex interna l structures. Rapid prototyping techniques have been developed to produce expendabl e patterns. Several replicas are ofte n attached to a gating system constructed of the same material to form a tree assembly. In this way multiple castings can be pro duced in a single pouring.
Casting with expendable mould: Investment Casting
Parts of grea t complexity and intricacy can be cast
– Close dimensional control and good surface finish
– Wax can usually be recovered for reuse
– Additional machining is not normally required - this is a net shape process
– Many processing steps are req uired
– Relatively expensive process