Die Casting’s Blog

Investment casting, also called lost-wax casting, is one of the oldest known metal-forming techniques. From 5,000 years ago, when beeswax formed the pattern, to today’s high-technology waxes, refractory materials and specialist alloys, the castings allow the production of components with accuracy, repeatability, versatility and integrity in a variety of metals and high-performance alloys.

The process is generally used for small castings, but has produced complete aircraft door frames, steel castings of up to 300 kg and aluminium castings of up to 30 kg. It is generally more expensive than die casting or sand casting, but can produce complicated shapes that require little rework or machining.

Investment casting offers high production rates, particularly for small or highly complex components, and extremely good surface finish (CT4-CT6 class accuracy and Ra1.6-6.3 surface roughness) with very little machining. The drawbacks include the specialized equipment, costly refractories and binders, many operations to make a mould, and occasional minute defects.

Investment casting is used in the aerospace and power generation industries to produce single-crystal turbine blades, which have more creep resistance than equiaxed castings. It is also widely used by Sturm, Ruger among other firearms manufacturers to fabricate firearm receivers, triggers, hammers, and other precision parts at low cost. Other industries that use standard investment-cast parts include military, medical, commercial and automotive