Generally, the surface of plastic products obtained by this injection molding method has good glossiness and beautiful colors, but in the actual injection molding process, many products produced by Household appliances mould have great defects in color and glossiness. Apart from the hard factors such as plastic raw materials, colorants and the smoothness of the mold surface, what other reasons will cause this situation?
(1) poor mold finish, rust on the cavity surface, and poor mold exhaust.
(2) The gating system of the mold is defective, so the cold well, runner, polishing runner, shunt and gate should be enlarged.
(3) The material temperature and mold temperature are low, so local heating method of gate can be used when necessary.
(4) 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.
(5) Plastics should be fully plasticized, but the degradation of materials should be prevented, and the heating should be stable and the cooling should be sufficient, especially for thick walls.
(6) Prevent cold materials from entering the parts, and switch to self-locking springs or reduce the nozzle temperature when necessary.
(7) Too many recycled materials are used, the quality of plastic or colorant is poor, mixed with water vapor or other impurities, and the quality of lubricant used is poor.