Ceramic mould injection molding principle and plastic injection molding is basically the same. It's just plastic mixed with a lot of ceramic powder. In order to improve injection molding conditions, it is necessary to select organic materials that match the materials used and to select the amount of addition. In order to obtain dense and uniform injection molding, the concentration of ceramic powder should be higher. But too high will make the molding performance worse.
Ceramic mould molding process, the first step is degreasing, is to remove the binder, usually heating speed is 3~5℃/b, about 5 ~ 10 days, but in 0.5MPa pressure under the protective atmosphere, 40 hours can end degreasing. Then sintering, the related thermal parameters can be determined according to the type of ceramics. The line shrinkage rate in sintering is about 15-20%. The work with complicated shape or thick wall is easy to produce cracks in sintering, which should be prevented.
Ceramic particles used in injection molding generally consist of 80-90% powder and 10-20% binder. The binder is removed in the degreasing process, so the added amount is appropriate to the minimum, but it should be noted that if the added amount is insufficient, it will affect the molding effect. In addition, the fluidity of ceramic particles is worse when the particle size is smaller and the shape deviates from the sphere. Therefore, the flow is tested in the simplest possible way.
If the forming conditions are not correct, various defects will occur. One of the most critical is the fusion welding line, if the molding body with through holes or blind holes, it is easy to appear this defect. Therefore, it is necessary to pay attention to the design of the mold, especially the type, position, size and number of openings. At the same time, attention should be paid to the balance between injection temperature and injection speed.
In addition, in order to avoid surface roughness, cracks, long striations, deformation and other defects. In the case of difficult molding, an adaptive controller can be installed in the injection molding machine for fine control.