Pottery shell mode method

Pottery shell mold castings are mostly produced in a small amount, not easy to mechanization, automation, high cost, therefore, its scope of application is quite limited, mainly for images:
(1) This is for welding and it can be cast in one body
(2) Materials with poor cutting ability can greatly reduce the processing amount
(3) Complex shapes of art, arts and crafts
Compared with dewaxing casting, it can be made into large casting or thick meat parts, or in the number of dewaxing casting method is too little. The applicable products are:
(1) All kinds of metal molds: die-casting, plastic forming (shot forming, hot press forming) for glass products, rubber products, and forging.
(2) Blade: large steam turbine, various moving impeller
(3) Parts: electronic guide wavetube, aircraft stabilizer, valve body, etc
The ceramic shell mold method uses silica gel solvent as the binding agent, mixed refractory powder filler and gelatinization
Ineding, as a slurry. The slurry with full fluidity is poured on the surface of the model, condensed, molded, dehydrated at 700℃, dried, burned at 1000℃ to improve the strength, and make the ceramic shell mold. The thickness of the ceramic shell mold is 3~20mm. When pouring a large casting, the back of the ceramic shell mold should be padded to support the weight of the bearing metal melt.
Model material in less amount use surface treated material, mass production of metal or resin, filler using high purity, high melting point refractory to prevent the reaction with molten metal, the material of cast metal, the particle size distribution of refractory is large particles mixed with small particles, can obtain moderate strength and surface, gelelling is used to accelerate the curing of binder, generally use alkaline substances such as ammonium carbonate.
The weight percentage of the filler and the binding is adjusted to control the fluidity of the slurry, the strength and air permeability of the mold. The amount of filler makes the volume of the slurry 1.5 to 2.5 times of the joint volume.
The back support of the ceramic shell mold can be dry, oil sand, carbon dioxide, or permanent metal mold. The mold must be preheated before casting, 500℃, 200℃ low melting point metal, 200℃, preferably in inert gas to prevent oxidation or decarbonization.