Causes and treatment of uneven color of injection products

Analysis and solution of color irregularity of injection molding products

1.Colorant diffusions are not good, and this situation often causes a pattern near the gate.

2.The thermal stability of plastics or colorants is poor, and the tone of the production should be stable, and the production conditions must be strictly fixed, especially the material temperature, material quantity and production cycle.

3.Of crystalline plastics, try to make the cooling speed of stamping parts, parts for wall thickness difference is big, can be masking off color with colorants, for wall thickness is uniform to fixed parts and mold temperature.


4.The shape and gate form of the making parts have influence on the plastic filling condition, making some parts of the parts produce color difference, which should be modified when necessary.

5.The reasons for the color and gloss defects of the injection molding products are analyzed. In normal circumstances, the gloss of the surface of the injection molded parts is determined by the type of plastic, the colorant and the finish of the surface. However, it is often caused by some other defects such as surface color, gloss defects and dark surface.


Other reasons and solutions are analyzed as follows

1.The mould has a poor finish, the surface of the cavity is rusty, and the mold is not well ventilated.

2.The casting system of the mould is defective, and the cooling well should be increased to increase the flow path, polishing main channel, shunt and gate.

3.The temperature and mold temperature are low, and the local heating method can be used when necessary.

4.Too low processing pressure, too slow speed, insufficient injection time, insufficient back pressure, resulting in poor compactness and dark color.

5.Plastic should be fully plasticized, but to prevent the degradation of materials, the heat should be stable, the cooling should be sufficient, especially the thick wall.

6.To prevent cold material from entering the production, switch to self-locking spring or reduce nozzle temperature when necessary.

7.Using too much raw material, poor quality of plastic or colorant, mixed with water vapor or other impurities, poor quality of lubricant.

8.The locking force should be sufficient.

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