Investment casting

Investment casting

Investment Casting

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

Disadvantages

– Many processing steps are req uired

– Relatively expensive process