Investment Castings

Reliance Foundry Steel Investment Castings provide production of intricate parts and cost effective replacements for many types of sand castings, die castings and metal fabrications.  Steel Investment Casting (aka lost wax process) foundries provide intricate, high quality casting alternatives to sand casting that can eliminate the need for machining.
 
Investment casting can be a less costly alternative to other methods of metal casting work such as die-casting and machined components. Investment Casting is regarded as a precision casting process to fabricate near-net-shaped metal parts from almost any alloy. Although its history lies to a great extent in the production of jewelry, the most common use of investment casting in more recent history has been the production of components requiring complex, often thin-wall castings. It can be used to make parts that cannot be produced by normal manufacturing techniques, such as turbine blades that have complex shapes and would require unusual cores. Intricate parts can also be produced using centrifugal casting, die casting, permanent mold and vacuum (v-process) casting and mold methods; however, investment casting provides the ultimate technique for low weight precision steel casting production.

Stainless Steel Gear Reducer Housing

An investment casting mold is made in foundries by making an impression pattern using wax or foam (lost foam) or some other material that can be melted away from special high pressure dies or tooling. This wax pattern is dipped in refractory ceramic slurry, which coats the wax pattern and forms a skin. After this, the entire pattern is placed in an oven and the wax is melted away. Because the mold is formed around a one-piece pattern (which does not have to be pulled out from the mold as in a traditional sand casting process), very intricate parts and undercuts can be made.

The process uses a one piece mould without joint lines or the need for draft angles, which allows for component shapes that have an aesthetic and uniform finish.  Tolerances of 0.5 % of length are routinely possible, and as low as 0.15 % is possible for small dimensions. Traditionally, investment castings can weigh from a few grams to 35 kg (0.1 oz to 80 lb), although the normal size ranges from 200 g to about 8 kg (7 oz to 15 lb). More often today, higher and higher weight castings are being produced using investment castings techniques. Normal minimum wall thicknesses are about 1 mm to about 0.5 mm (0.040-0.020 in) for alloys that can be cast easily.

The benefits of the investment casting process may be summed up by the four words - accuracy, versatility, integrity and finish. Few, if any, alternative metal forming methods can offer such a unique and broad spectrum of advantages.