Analysis of Causes of Color and Gloss Defects of Injection Molded Products Under normal circumstances, the gloss of the surface of injection molded parts is mainly determined by the type of plastic, colorant, and finish of the mold surface. But often due to some other reasons, the surface color and gloss defects of the product, the surface dark color and other defects.　　Other reasons and solutions are analyzed as follows: 　　(5) The mold finish is poor, the cavity surface has rust, etc., and the mold exhaust is poor.　　(6) The gating system of the mold is defective, the cold slug well should be enlarged, the runner, the main runner, the runner and the gate should be polished.　　(7) The material temperature and mold temperature are low, and local heating of the gate can be used if necessary.　　(8) The processing pressure 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.　　(9) Plastics should be fully plasticized, but the degradation of the material should be prevented, the heating should be stable, and the cooling should be sufficient, especially for thick-walled ones.　　(10) To prevent cold material from entering the workpiece, use self-locking springs or lower the nozzle temperature if necessary.　　(11) Too much recycled materials are used, plastics or colorants are of poor quality, water vapor or other impurities are mixed, and lubricants used are of poor quality.　　(12) The clamping force must be sufficient.