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Molding process and dimensional accuracy of zirconia ceramic mold

May 29, 2019

The molding process of the zirconia ceramic mold by grouting includes a physical dehydration process and a chemical coagulation process, and the physical dehydration removes the moisture in the slurry through the capillary action of the porous gypsum mold. The chemical coagulation process is caused by the dissolution of CaSO4 on the surface of the gypsum mold. The Ca2+ increases the ionic strength in the slurry, causing flocculation of the slurry. Under the action of physical dehydration and chemical coagulation, ceramic powder particles are deposited on the wall of the plaster mold. Grouting is suitable for the preparation of large-scale ceramic parts with complex shapes, but the quality of the blanks, including shape, density, strength, etc., is poor, workers are labor intensive and not suitable for automation.

The hot press injection molding of the zirconia ceramic mold is to mix the ceramic powder with the binder (paraffin) at a relatively high temperature (60 to 100 ° C) to obtain a slurry for hot die casting, and the slurry is under the action of compressed air. The metal mold is injected, the pressure is cooled, and the wax blank is obtained by demoulding. The wax blank is dewaxed under the protection of an inert powder to obtain a green body, and the green body is sintered at a high temperature to form a porcelain. The hot injection molded green body has accurate size, uniform internal structure, small mold wear and high production efficiency, and is suitable for various raw materials.

The zirconia ceramic mold casting is to fully mix the ceramic powder with a large amount of organic binder, plasticizer, dispersant, etc. to obtain a viscous slurry that can flow, and the slurry is added to the hopper of the casting machine. The blade controls the thickness, flows out through the feeding nozzle to the conveyor belt, and is dried to obtain a film blank.www.yxhgmould.com