There are many reasons for the surface flow marks of rubber products, and the following are some of the main reasons:
1. The fluidity of the compound is poor and the viscosity is too large.
2. The mold temperature is too low, resulting in reduced fluidity of the rubber.
3. Poor exhaust.
4. Excessive use of powder and release agent.
5. The raw materials of rubber products, such as synthetic styrene butadiene rubber and natural rubber, contain more impurities in themselves, and these impurities are exposed in the process of processing, resulting in the production of flow marks.
6. The raw material formula design is unreasonable, such as uneven dispersion, insufficient vulcanization, etc., resulting in sticky rubber surface, which is forced to extrusion in the subsequent processing process, leaving traces.
7. During vulcanization, the vulcanization material has yellowing phenomenon during the vulcanization yellowing process, resulting in obvious flow marks on the rubber surface.
8. In the mixing process, the dispersion of the compounding agent is uneven or the proportion of the compounding agent is too high, resulting in obvious flow marks on the rubber surface.
9. During the extrusion process, the extrusion speed is too fast or the extrusion temperature is too high, resulting in obvious flow marks on the rubber surface.
10. During the vulcanization process, the vulcanization temperature is too high or the vulcanization time is too long, resulting in obvious flow marks on the rubber surface.
11. The uneven thickness of rubber products will also lead to the production of flow marks.
12. The mold design of rubber products is unreasonable, such as gate, mold structure, etc., will also lead to the generation of flow marks.
13. In the processing of rubber products, defects such as impurities or bubbles are exposed, resulting in the generation of flow marks.
14. The vulcanization formula design of rubber products is unreasonable, such as insufficient vulcanization time and low vulcanization temperature, resulting in insufficient rubber vulcanization and flow marks.