Investment casting is also known as the lost wax process. 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.

The mold is made by making a pattern using wax. This wax pattern is dipped in refractory slurry, which coats the wax pattern and forms a skin. This is dried and the process of dipping in the slurry and drying is repeated until a robust thickness is achieved. After this, the entire pattern is placed in an oven and the wax is melted away.This leads to a mold that can be filled with the molten metal. Because the mold is formed around a one-piece pattern,very intricate parts and undercuts can be made. The wax pattern itself is made by duplicating using a stereo lithography or similar model-which has been fabricated using a computer solid model master.

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.

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.

Tolerances of 0.5 % of length are routinely possible, and as low as 0.15 % is possible for small dimensions. 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). 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 types of materials that can be cast are Aluminum alloys, Bronzes, tool steels, stainless steels, Stellite, Hastelloys, and precious metals. Parts made with investment castings often do not require any further machining because investment casting can control the close tolerances itself.

Investment Casting:

• Material: 304 (L), 316 (L), heat-resistant steel, carbon steel
• Process: Silica sol, ethyl-silicate, sodium silicate, colloidal-sodium silicate complex
• Delivery of Samples: 30-60 days
• Casting weight range: 0.1 ~ 10 kg