investment casting is used with almost any castable metal,however aluminium alloys,copper alloys,and steel are the most common. In industrial usage the size limits are 3 g (0.1 oz) to about 5 kg (11 lb). The cross-sectional limits are 0.6 mm (0.024 in) to 75 mm (3.0 in). Typical tolerances are 0.1 mm for the first 25 mm (0.005 in for the first inch) and 0.02 mm for the each additional centimeter (0.002 in for each additional inch). A standard surface finish is 1.3–4 micrometres (50–125 μin) RMS.
The advantages of
investment casting are:
Excellent surface finish
High dimensional accuracy
Extremely intricate parts are castable
Almost any metal can be cast
No flash or parting lines
The main disadvantage is the overall cost. Some of the reasons for the high cost include specialized equipment,costly refractories and binders,many operations to make a mould,a lot of labor is needed and occasional minute defects. However,the cost is still less than producing the same part by machining from bar stock; for example,gun manufacturing has moved to
investment casting to lower costs of producing pistols.