While most investment castings are small, the investment process can produce castings weighing over 1,000 pounds. This capability is limited to relatively few investment casters and requires special handling expertise. Most castings are measured in ounces and weigh up to 20 pounds.
Diverse and complex shapes:
Investment casting provides consistent and repeatable tight tolerances and complex channels and contours. Many of these configurations are impossible to produce. For example, where machine tools cannot reach. Cast parts that achieve final or near final form can significantly reduce post-casting tooling costs.
Investment casting is a good alternative to welded parts or fabrication. Many components can be combined into one casting. The more combinations, the better the manufacturing efficiency. Converting a multi-piece assembly to a single investment casting often improves dimensional accuracy and reduces part complexity.
Accurate and smooth surface:
The ceramic shell used is built around a smooth pattern created by pouring wax into polished aluminium moulds. A 125-micron finish is standard, and even finer finishes are not uncommon.
Investment castings do not contain parting lines because only one mold is used instead of two mold halves (such as in the case of sand casting). Criteria for surface imperfections and cosmetic products are discussed and agreed with the client according to function.
Typically, the "standard" investment tolerance is +/-0.010" for the first inch and +/-0.004" for every subsequent inch.
The design phase may produce drawings that reduce or even eliminate the machining requirements that previously produced the same part.
The cost of any part is directly proportional to the accuracy of its dimensional requirements. Whether it is casting machining parts or manufacturing. Careful design review will allow modifications to tolerances, undercuts, blind holes, etc. to increase yield and reduce part cost. Investment casting will require less machining than traditional castings or fabricated parts if closer tolerances than castings are required.