What, exactly, is “Investment Casting”?
Investment casting is an industrial process based on and also called lost-wax casting, 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.
Investment casting is generally used for small castings, but has been used to produce steel castings of over 600 pounds and aluminum castings up to 60 pounds. It is generally more expensive per unit than die casting or sand casting, but has lower equipment costs. It can produce complicated shapes that would be difficult or impossible with die casting, yet like that process, it requires little surface finishing and only minor machining.
Investment casting is not a recent technology, having been used as early as 1,800 B.C. and beyond to produce beautiful bronze works of art. Yet this method of casting fine ferrous and non-ferrous components is even more useful today than in the ancient times. Why? Because it can still do so many things so much better than many alternatives.
The process involves a number of intricate steps resulting in components which feature considerable design flexibility and economy. The method competes to some degree with machining, forging, die casting and other processes, but is the only means which combines many of the benefits into one. It can, for example, produce a part which previously required several steps, several parts, and was not as strong nor as cost efficient as the investment casting. The net shapes made possible frequently require only minimal finishing.