The causes and solutions of dark color and poor gloss are as follows.
1. The injection mold has poor finish, and there is rust on the surface of the cavity, which is probably due to poor exhaust of the mold.
2. Too many recycled materials are used, the quality of plastics or colorants is poor, water vapor or other impurities are mixed, and the quality of lubricants used is poor.
3. The pouring system of the injection mold has defects, so the cold well, runner, polishing sprue, splitter and gate should be increased.
4. The material temperature and mold temperature are too low. If necessary, local heating at the gate can be used.
5. The plastic shall be fully plasticized, but the degradation of the material shall be prevented, the heating shall be stable, and the cooling shall be sufficient, especially for the thick wall.
6. The clamping force shall be sufficient during the production and manufacturing of injection mold.
7. The processing pressure of injection mold is too low, the speed is too slow, the injection time is insufficient, and the back pressure is insufficient, resulting in poor compactness and dark surface.
8. To prevent cold materials from entering the parts, use self-locking springs or reduce the nozzle temperature when necessary. The above 8 points can be well done to avoid the dark color and poor gloss of the injection mold. Even if this phenomenon occurs in the production process, remedial measures can be well done to minimize the impact on the production progress of the enterprise and increase the production efficiency of the enterprise.