Core Techniques for Metal and Plastic Coating: Enhancing Coating Uniformity and Durability

Core Techniques for Metal and Plastic Coating: Enhancing Coating Uniformity and Durability

The core goal of metal and plastic coating is to ensure uniform and aesthetic coatings while enhancing their adhesion and durability, resisting environmental erosion and daily wear. The quality of the coating depends not only on material compatibility but also on the implementation of standardized process techniques. Mastering targeted skills can effectively avoid problems such as sagging, peeling, and abrasion, balancing decorativeness and protectiveness.

Refined pretreatment is the foundation, directly affecting coating uniformity and adhesion. Metal parts must undergo thorough degreasing, derusting, and phosphating; steel parts focus on oxide layer removal, while aluminum alloy parts require proper anodizing to ensure a clean and flat surface. Plastic parts are treated with sanding roughening or plasma treatment, and hard-to-adhere materials like PP need additional primer application to break the surface inertness. Coating should be performed quickly after pretreatment to avoid secondary contamination, laying a solid foundation for uniform coatings.

Controlling construction parameters is key to improving uniformity. For spraying processes, adjust spray gun pressure, distance, and movement speed to maintain uniform linear spraying, avoiding local accumulation or missing spots. Metal parts can adopt multi-layer thin spraying to reduce sagging risks; plastic parts require controlled coating thickness to prevent substrate deformation due to stress. Stir coatings thoroughly before use, mix thinners in proportion to ensure consistent concentration, and maintain a clean construction environment with stable temperature and humidity to avoid dust affecting coating smoothness.

Curing and coating selection determine durability. For metal parts, use an epoxy primer + polyurethane topcoat combination with dedicated curing agents, and adopt high-temperature baking curing to enhance coating hardness and rust resistance. For plastic parts, select weather-resistant special plastic paints and use low-temperature baking or natural air drying to avoid high-temperature aging. Conduct proper post-coating maintenance: keep metal parts away from acid-base environments and reduce sharp friction on plastic parts to extend coating service life, achieving the dual goals of aesthetics and durability.