Ceramic mold casting

Ceramic mold casting, also known ambiguously as

The Unicast process is very similar to the Shaw process, except it does not require the mold to be ignited and then be cured in a furnace. Instead, the mold is partially cured so the pattern can be removed and it is then completely cured by firing it at approximately 1,900 °F (1,040 °C). If a metal with a low melting point is cast then the firing can be skipped, because the mold has enough strength in the "green state" (un-fired).[5]

The main advantages of ceramic molds are: a reusable pattern (the item used to create the shape of the mold), excellent surface finish, close dimensional tolerances, thin cross-sections, and intricate shapes can be cast. For undercuts and other difficult to cast features, part of the pattern can be made from wax in conjunction with a standard pattern; essentially using investment and ceramic mold casting techniques together. The main disadvantages are: it is only cost effective for small- to medium-sized production runs and the ceramic is not reusable. Ferrous and high-temperature non-ferrous are most commonly cast with these processes; other materials cast include: aluminum, copper, magnesium, titanium, and zinc alloys.^[1][2][4]

Weight limits are 100 grams to several thousand kilograms (3.5 oz to several tons). Cross-sections as thin as 1.3 mm (0.051 in) are possible, with no upper limit. Typical tolerances are 0.1 mm for the first 25 mm (0.005 in for the first inch) and 0.003 mm per additional mm (0.003 in per each additional in). A draft of 1° is typically required. The typical surface finish is 2–4 um (75–150 uin) RMS.^[2]

• Ceramic forming techniques