Cracking is a relatively common forming problem in silicon-carbon ball production. Even when a binder is used, improper raw material proportions, mixing methods, pressing conditions, or subsequent drying procedures may still cause surface cracks, internal cracks, or complete ball breakage. Therefore, solving this problem requires examining the entire production process rather than focusing only on the binder itself.
The amount of binder added directly affects the bonding condition of the balls. If the addition ratio is too low, the particles may not form sufficient connections, resulting in weak areas inside the balls. These areas may develop cracks during demolding or handling.
However, adding too much binder does not necessarily improve ball strength. Excessive binder may change the forming characteristics of the raw materials, cause uneven moisture or component distribution inside the balls, and affect the drying process and subsequent processing performance. Therefore, the appropriate addition ratio should be determined according to the raw material characteristics and binder properties.
If the silicon-carbon powder and binder are not mixed thoroughly, some areas may contain excessive binder while others receive insufficient coverage. Areas with weak bonding can become structural weak points inside the balls and develop cracks during pressing, demolding, or drying.
To address this problem, manufacturers should inspect the mixing equipment, mixing time, and feeding sequence to ensure that the binder is distributed evenly throughout the raw materials. Localized clumping should also be avoided because it can affect the internal structure of the finished balls.
Moisture is another important factor affecting powder briquetting. If the mixed material is too dry, the particles may not come into sufficient contact or bond effectively, resulting in insufficient ball strength after forming. If the moisture content is too high, the balls may contain excessive internal moisture. During subsequent drying, uneven shrinkage may occur and lead to cracking.
Therefore, moisture should be controlled according to the binder type, raw material properties, and production process. The material should have suitable forming characteristics while remaining appropriate for subsequent drying.
Pressing pressure directly affects the arrangement and bonding of particles inside the balls. If the pressure is insufficient, the internal structure may remain loose. Uneven pressure distribution may also cause differences in density between different areas of the same ball.
In addition, equipment operating conditions, mold wear, and feeding consistency may influence forming quality. Manufacturers should inspect the briquetting equipment and ensure that the raw materials enter the forming area continuously and evenly.
If the silicon-carbon balls require drying after forming, the drying conditions are equally important. When moisture evaporates too quickly from the outer surface, the surface may shrink before the interior has dried sufficiently. This difference in shrinkage can create internal stress and cause surface cracks. The problem may be more noticeable in balls with relatively high initial moisture content.
Therefore, drying conditions should be selected according to ball size, initial moisture content, and binder characteristics. Excessively rapid temperature changes should be avoided.
In addition, different binders have different bonding mechanisms, application conditions, and thermal characteristics. If the selected product is unsuitable for the silicon-carbon raw materials or cannot meet downstream processing requirements, adjusting the addition ratio alone may not produce stable ball quality.
Therefore, manufacturers should systematically examine binder compatibility, raw material proportions, mixing conditions, pressing pressure, and drying procedures. Conducting small-scale production trials to determine suitable operating conditions is generally more effective than simply increasing the amount of binder used.
