Uneven surface brightness of injection molded products is a common problem in the production of injection mold factories, which seriously affects the product quality and appearance. So, how to solve it? It can be addressed through various methods. Here are some main solutions:

1、Adjust injection molding parameters
Injection speed: If the injection speed is too fast, it may cause the material to stay for too long, affecting the surface gloss of the product. At this time, the injection speed should be appropriately reduced. Conversely, if the injection speed is too small, the surface of the plastic part is not dense enough, which will also lead to insufficient gloss. At this time, the injection speed can be appropriately increased to improve the surface density and gloss of the plastic part.
Melt temperature: A too low melt temperature will lead to poor fluidity of the plastic part, thereby affecting the gloss. The melt temperature should be appropriately increased to ensure moderate fluidity.
Holding pressure and holding time: Insufficient holding pressure or too short holding time will lead to a too low density of the plastic part, thereby affecting the gloss. The holding pressure should be increased and the holding time should be extended.
Cooling time: For some plastic parts with thick walls, it is necessary to ensure their full cooling. Otherwise, the surface of the plastic part will become hairy, resulting in a decrease in gloss. Therefore, the cooling system should be optimized to ensure uniform cooling effect of the plastic part.

2、Optimize mold design and manufacturing
Mold temperature: A too low mold temperature or too fast cooling speed will form a hard shell when the melt is filled, resulting in a decrease in gloss. The mold surface temperature should be increased, the cooling speed should be reduced, or local heating should be used at the mold gate.
Mold surface finish: A rough mold surface will directly affect the gloss of the product surface. A high-hardness material should be used to manufacture the mold, and the mold surface should be carefully polished to improve its finish.
Mold venting: Poor mold venting will cause excessive gas to remain in the mold cavity, affecting the product surface gloss. The number, size and position of the vents should be reasonably designed to ensure smooth mold venting.
Demolding slope: Improper demolding slope of the mold will lead to poor demolding or uneven force, thereby affecting the product surface gloss. A reasonable demolding slope should be designed to reduce the resistance during the demolding process.

3、Improve material quality
Plastic material: Uneven plastic materials or containing a large number of bubbles and impurities will lead to poor surface gloss of injection molded products. Good-quality plastic materials should be used, and the materials should be fully pretreated to ensure their uniformity and purity.
Additives: Adding an appropriate amount of heat stabilizers or gloss agents to the material can improve the gloss of the product.

4、Strengthen equipment maintenance
Cleaning of injection molding machines and molds: Regular cleaning and maintenance of injection molding machines and molds can ensure that the equipment and molds are in the best condition and reduce the decrease in surface gloss caused by pollution.
Plasticizing property of the screw: Ensure that the plasticizing property of the screw is sufficient to reduce quality abnormalities caused by poor plasticizing.

In conclusion, solving the problem of uneven injection surface brightness requires starting from multiple aspects such as adjusting injection parameters, optimizing mold design, improving material quality and equipment maintenance. Through comprehensive measures, the surface gloss and overall quality of injection molded products can be significantly improved.

Dongguan Shibang Plastic Products Co., Ltd. is affiliated to Shibang Group. The plant area is 27,000 square meters. The main products include molds, toys, electrical accessories, medical device accessories, home appliance accessories, electronic products, small household appliances, and pet products. It provides a complete set of solutions from product design, precision mold manufacturing,injection molding and assembly, and after-sales service for high-end brands.