The most commonly used forming technology for alumina ceramics

There are many methods for forming alumina ceramics, such as extrusion, injection, dry pressing, hot pressing, and other forming methods. In recent years, many new forming technologies have been developed at home and abroad, which can develop different forming methods based on different shapes and sizes of products. Below, we will introduce the two most commonly used forming techniques:

Grouting forming method: This is the earliest forming technology for alumina ceramics, which is relatively low-cost and suitable for workpieces with complex shapes and large sizes. The alumina slurry used in this molding method is usually mixed with water as the medium, followed by the addition of binders and adhesives. After grinding, it is discharged and finally introduced into the gypsum mold. If it is hollow grouting, when sufficient thickness of slurry is adsorbed on the mold wall, the excess slurry needs to be poured out to reduce the shrinkage of the body. Therefore, it is necessary to choose slurry with high concentration as much as possible.

Dry pressing forming method: This forming technique is only applicable to workpieces with simple shapes, internal thickness exceeding 1mm, and diameter and length not exceeding 4:1. There are two types of methods: single axial and bidirectional axial. The press is divided into mechanical chamber press and hydraulic press, with fully automatic and semi-automatic forming methods. The maximum pressure of the press is 200MPA, which can produce around 15-50 workpieces per minute. Due to the average stroke pressure distribution of the hydraulic press, the height of the pressed workpieces will vary when there are differences in filling powder. The mechanical press, on the other hand, produces a corresponding pressure with the amount of filling powder, which makes it easier for the size to shrink after sintering, affecting the quality of the product. Therefore, the uneven distribution of powder during the dry pressing process is particularly important for filling, and has a significant impact on the precise control of the size of alumina ceramic parts manufactured.

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