Analysis of the causes of black spots in injection molding and solutions

- Jul 05, 2019-

Analysis of the causes of black spots in injection molding and solutions

  Asia billion uses our experience and expertise to analyze how to solve the black spots in the injection molding process as below for you:

First, we should all start from any source of quality problems. Let's take a look at four reasons for black spots in injection molding:


1. Supplier level: There is a problem when buying raw materials, and there are black spots in the plastic particles.


2. Material degradation: The thermal decomposition of the plastic will cause black spots. The plastic particles stay in the closed barrel and the surface of the screw is too long, which will lead to deterioration and decomposition, so black spots or streaks are generated during the injection molding process.


3. Material contamination: Environmental factors or air dust make it black spots. There is more dust in the production workshop, and there are dust or debris in the feed port or cavity, which leads to more black spots in the injection molding of the product.


4. The screw is not cleaned: it may be that the screw cleaning is not clean, and the dirt with residual dead angle is not cleaned.


4 points to solve the injection molding black spots:


1. Material, using non-polluting raw materials, the material is placed in a relatively closed storage bin to increase the thermal stability of the material.


2, mold design, cleaning the ejector and slider. Improve the exhaust system. Clean and polish any dead corners in the flow channel to ensure no accumulation.


3. Clean the surface of the mold before injection. The injection molding machine selects the appropriate tonnage of the injection molding machine to check the inner surface of the barrel and whether the surface of the screw scratches the accumulated material.


4, process conditions, reduce the temperature of the barrel and nozzle. Clean all aspects of the injection process. Avoid material that has been black spots / black lines are recycled

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