1. Unreasonable deformation of formula
A lot of albite is used in the formulation. At high temperatures, the viscosity of albite glass decreases sharply with the increase of temperature, which is easy to cause high temperature deformation of the product, if the calcium oxide content in the green is high, the deformation trend tends to increase, and the use of clay, the shrinkage rate is too large, the product is easy to deformation.
2. Uneven deformation of green density
The density of each part of the green blank is different, so the green blank has a large shrinkage rate in the low density part and a small shrinkage in the high density part, resulting in product deformation. The uneven density of the green blank is caused by the uneven density of the blank and the uneven pressure of each part of the product during the molding process.
3, the deformation of clay sheet in the molding process
When forming a product, the flake clay particles are preferentially oriented so that the shrinkage rate perpendicular to the direction of the clay flake is large, while the shrinkage rate parallel to the direction of the clay flake is small. For example, the shrinkage of the part of the mud extruded by the vacuum mud machine is less than the shrinkage in the radial direction. When the orientation of the clay flakes is inconsistent in each part of the product, the product will experience uneven shrinkage and cause deformation.
4, product weight deformation
When the product contains a variety of glass phases, it has a certain plasticity at high temperatures, and some products may be deformed due to their own weight, which is particularly obvious in large items. For example, due to the gravity of the cup, some products are tilted sideways by the center of gravity of the device, which causes the upper opening of the cup to become elliptical in the direction of the cup. When burned into some large products, the underside will be deformed by friction, which is less than the above. If these factors are taken into account when designing the shape, appropriate compensation can be obtained to overcome the deformation of the sintered product as much as possible.
5. Deformation caused by improper forming or drying before sintering, the deformation caused by unreasonable forming and drying is not obvious. For example, when the rolling mill head is not tightly installed, the machine will not only rotate, the force of the rolling will not be uniform, the amount of water will not be uniform, the thickness of the billet will not be uniform, or the water content will not be uniform. When forming, take mud, and the method of cutting mud is not easy to cause deformation. Uneven drying often causes the product to deform in the plaster mold, and forced release is too early or too late to cause deformation. Sometimes, the green water content is very high, easy to deformation, can be manually corrected, but it will still be deformed after combustion.
Post time: Sep-28-2023