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Causes and solutions for surface color and gloss defects of injection molded parts

date：2023/08/19

   Injection molds are a tool for producing plastic products; they are also tools that give plastic products complete structure and precise dimensions. The injection mold consists of two parts: the movable mold and the fixed mold. The mold injection molding is a processing method used in mass production of some complicated shapes. The plastic material is injected into the mold cavity of the injection mold through an injection molding machine, and the formed injection molded parts are obtained by cooling and solidification.
   Usually, the surface of the plastic products obtained by this injection molding method has a relatively good gloss and brilliant color, but in the actual injection molding process, many products produced by the injection mold factory have relatively large color and gloss. In addition to the hard factors of plastic materials, colorants and the surface finish of the mold, what are the reasons for this? Today, Dongguan Injection Mould Factory has solved this mystery and how to deal with it.
 
(1) The mold finish is poor, the surface of the cavity is rusted, and the mold is poorly exhausted.
 
    (2) The casting system of the mold is defective. The cold material well should be enlarged, the flow channel should be enlarged, the main flow channel should be polished, the runner and the gate should be polished.
 
    (3) The material temperature and the mold temperature are low, and the local heating method of the gate can be used if 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 darkening of the surface.
 
    (5) The plastic should be fully plasticized, but the degradation of the material should be prevented, the heat should be stable, and the cooling should be sufficient, especially thick-walled.
 
    (6) Prevent cold material from entering the part, if necessary, use a self-locking spring or reduce the nozzle temperature.
 
    (7) Excessive recycled materials are used, plastic or colorant is of poor quality, mixed with water vapor or other impurities, and the quality of the lubricant used is poor.
 
    (8) The clamping force should be sufficient.
    
It can be seen that it is necessary to create a high-quality plastic product, which requires a lot of effort, not only good plastic raw materials, but also sophisticated processing equipment and high-precision injection molds, coupled with skilled operators. Adequate patience and care throughout the production process can be finalized.