Investment Casting
Investment casting produces near-net-shape configurations, offering designers and engineers freedom of design in a wide range of alloys. The process is capable of producing precise detail and dimensional accuracy in parts weighing many pounds or just a few ounces.
Investment Castings use the “Lost Wax Process” to produce intricate castings with very tight tolerances. This method is used to mass produce parts that demand a high quality "as cast finish", which produces a visually attractive finish and also reduces machining cost.
In this process a pattern is made by injecting wax or plastic into a metal mold. The pattern is then coated with slurry (a watery paste of silica and a binder) that will harden to produce a mold or shell. The mold is then turned upside down and the wax or plastic is melted out of the mold, revealing the final product.
The investment casting process is more expensive than the other casting methods, but because of the reduced need for secondary machining, it is more economical to use this process with complex parts. Investment casting is generally used for parts between 1 ounce and 10 lbs., however heavier parts are also occasionally produced. Typical materials that are used in investment casting include aluminum alloys, bronzes, tool steels, stainless steels, hastelloys, and precious metals.
| ADVANTAGES |
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DISADVANTAGES |
•Complex Shapes Possible
•Thin Wall Section Possible
•High Production Rates
•High Dimensional Accuracy
•Can be Used With Most Pourable Metals/Alloys
•Minimum surface Treatment Prior to Plating
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•Castings Generally Limited to 10 lbs. or less
•Expensive Dies for Wax Pattern
•Expensive Unit Cost, Labor Intensive
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