Characteristics of investment casting :
1) High dimensional accuracy of castings and low surface roughness value. According to the different alloy, the dimensional tolerance level can reach DCTG4-DCTG7, the surface roughness is generally Ra=1.6 ~6.3μm, and the best can reach 0.8μm. Castings with complex shapes and high dimensional accuracy requirements have achieved near-net casting, which greatly simplifies the manufacturing process and reduces the cost. Because the near-net casting retains the dense layer on the surface of the casting, the service life of the casting is improved to a certain extent. Table 2-1 lists some castings. Except for the mating surface, the rest parts can meet the design requirements of geometric tolerances and surface roughness without machining.
2) Can cast complex shape castings. It can cast large complex castings or large assemblies that are difficult to form by other process methods. As shown in Table 2-1, the diffuser is connected by 81 blades between the inner and outer rings, and the maximum outer dimension of the cast titanium alloy casing is 1320mm.
3) Can cast special-shaped complex holes and thin-wall castings. The blades of the aero-engine impels listed in Table 2-1 have a minimum wall thickness of 0.4mm and a minimum aperture of 0.4mm.
4) There is no limit to the alloys that can be cast. Castable alloys are aluminum alloy, magnesium alloy, copper alloy, titanium alloy, cast iron, cast steel and nickel, cobalt, chromium based superalloys and other difficult to process alloys, as well as composite castings.
5) Strong adaptability. It can be used for mass production, but also for small batch or single piece production. Casting profile size is small to a few millimeters, large to thousands of millimeters; Light weight to a few grams, heavy to hundreds of kilograms.
