General-purpose polyethylene injection molded products uneven surface gloss（Variant: Strengthened Measures）

The gloss of different areas of the product surface differs significantly, with locally darkened or high-gloss areas appearing, affecting appearance consistency. Uneven gloss is usually related to the melt flow direction and differences in cooling conditions, and is especially common in large flat plate products.In particular, extra attention is needed on top of the original basis, this problem is more prominent and requires key attention.

（1） The mold cavity surface finish is inconsistent, with local wear or uneven polishing\ （2） Melt temperature is uneven; temperature differences at the flow front cause different surface replication effects\ （3） The mold cooling system design is unreasonable, with large differences in cooling rates at various parts\ （4） Improper injection speed, the melt flows unstably in the cavity, forming different surface textures\ （5） Too much or uneven mold release agent, affecting product surface gloss\ （6） On top of the original basis, extra attention is needed: process parameter fluctuations or equipment status changes aggravate this problem

（1） Check and re-polish the mold cavity, ensure consistent surface finish, roughness Ra≤0.4μm\ （2） Optimize barrel temperature settings, ensure uniform melt temperature, temperature difference controlled within ±5°C （160-260°C range）\ （3） Improve cooling water channel design, ensure uniform cooling at all cavity parts, temperature difference not exceeding 5°C\ （4） Adjust injection speed, adopt multi-stage injection, make the melt fill the mold smoothly\ （5） Reduce mold release agent dosage or switch to silicone-free release agent, ensure uniform coating\ （6） And strengthen process monitoring; on top of the original basis, extra attention is needed, paying special attention to parameter stability

Uneven gloss reflects inconsistency between the mold surface state and melt flow, and needs improvement from three aspects: mold polishing, temperature uniformity and injection process.Targeted preventive measures need to be taken in different production scenarios.