Many graphite molds are customized and processed according to specific customer requirements. To ensure high-quality completion of order tasks, it is necessary to handle the details of the processing process carefully, especially to avoid cracks. What are the reasons that can cause cracks in graphite molds? Today, the editor of Qingdao Sanhe Yongchang Machinery Co., Ltd. will explain in detail to help you avoid unnecessary problems:
1. If the amount of binder used in the paste is too small or the loading temperature is too low, the plasticity of the paste is poor, and the bonding force between the pastes is small, making it difficult to compact and prone to cracking.
2. Excessive use of adhesive in the paste or high loading temperature can cause significant elastic rebound and slow stress disappearance after the paste is extruded, all of which may lead to cracks. When the loading temperature is high, the smoke cannot be completely discharged, and the smoke is trapped in the paste, which can also easily cause cracks.
3. During the cooling process, the paste is not cooled evenly, and sometimes even the paste that has been cooled into hard blocks is added to the pressing chamber; The heating of the pressing chamber is not sufficient to achieve uniform temperature of the paste in a short period of time, and in this case, extrusion is often the cause of surface cracks on the graphite mold.
4. The temperature of the extrusion nozzle and the pressing chamber is too high, and the paste adjacent to the extrusion nozzle and the inner wall of the pressing chamber is excessively heated, resulting in a large temperature difference between the paste and the pressing chamber. After compression, the extrusion speed of these two materials is different, and the product after extrusion is prone to cracking due to inconsistent surface and partial swelling coefficients. On the other hand, if the heating temperature of the extrusion nozzle and the pressing chamber is lower, and the temperature of the paste in the area is higher, the same consequences will occur.
5. After leaving the extrusion nozzle, the graphite mold should be supported by a semi-circular (for circular section graphite molds) or horizontal plate (for square section graphite molds) receiving platform. If the position of the receiving table is improper, the graphite mold will bend and sag too much after being pressed out, which can also cause transverse cracking of the product.
The above five points need to be noted when processing graphite molds. Qingdao Sanhe Yongchang Machinery Co., Ltd. specializes in processing and producing graphite molds, graphite boxes, and other graphite products. If you also have such needs, please feel free to come to our factory for detailed information.