Alumina wear resistant ceramic molding method(2)

Molding methods: aluminium oxide wear resistant ceramics have dry, grouting pressure, extrusion molding method, cold isostatic pressing, injection, stretch film, pressure and hot isostatic pressing molding, and other methods.In recent years at home and abroad and develop filter shaping, direct injection molding of solidification and gel injection molding, centrifugal injection molding molding technology with solid free molding method.Products of different shape, size, complicated shape and precision of the products need different molding methods.

Pick the common molding is introduced:

1: slip casting, grouting is aluminium oxide wear resistant ceramics using the earliest molding method.Because use gypsum mold, low cost and easy to forming large size and complex shape parts.Injection molding is the key to the preparation of alumina slurry.Usually with water as the solvent medium, add the glue and adhesive solution, sufficient exhaust after grinding, then pour into the plaster mould.Due to capillary of moisture adsorption, gypsum slurry after solidification in the mould.Wear-resistant plate, hollow grouting requirements in adsorption pulp mold wall thickness, also the residual slurry must be poured out.In order to reduce body for shrinkage, should try to use high concentration slurry.

2: dry pressing molding: aluminum oxide wear resistant ceramics dry pressing molding technology is limited to simple shape and wall thickness more than 1 mm, the ratio of length to diameter is not more than 4:1.A single axial or two-way molding method.Press hydraulic, mechanical, can show semi-automatic or fully automatic forming method.Press maximum pressure of 200 mpa, yield per minutes can reach 15 to 50.Due to the hydraulic press stroke uniform pressure, therefore in powder filling diverge from pressing pieces of different height.Pressure and mechanical press size change because of how much powder filling, easily lead to size after sintering shrinkage difference, affect the quality of the product.So in the process of dry pressed powder particle uniform distribution is very important for mold filling filling.Accuracy for manufacturing filling amount of alumina ceramic parts size accuracy control.Powder particles with greater than 60 mu m, between 60 ~ 200 mesh can be most effective, the free flow of pressure molding best results.Alumina wear resistant ceramic slurry will need to add organic additives to make slurry particle surface formation of electric double layer make slurry stable suspension without precipitation.Also need to join the ethylene glycol, methyl cellulose, alginic acid amine such as binder and poly propylene amide, gum Arabic, such as dispersant, purpose is to make the paste is suitable for grouting molding operation.