1.What types of coating appearance defects are there?
Coating scratches/abrasions: Linear marks appear on the surface, and in severe cases, the zinc layer or substrate is exposed.
Coating bubbles/pinholes: Bubbles or tiny holes appear on the coating surface, usually with a diameter of less than 1mm.
Coating sagging/paint accumulation: The coating is too thick in some areas, forming traces of paint flow (common on vertical surfaces).
Coating color difference/color unevenness: The color of the same batch of plates is inconsistent, or the color depth of some areas is different.
2.What are the types of coating adhesion defects?
Coating peeling/delamination phenomenon: the coating is separated from the zinc layer or substrate and can be torn off in pieces.
100-grid test peeling phenomenon: after 100-grid cutting according to the standard, the coating edge peeling area exceeds the specified value (such as >5%).
3.What are the coating performance defects?
Insufficient weather resistance of the coating (powdering/fading): After long-term outdoor use, the coating surface will appear powdery or the color will become lighter.
Defective corrosion resistance of the coating (rust): Rust spots appear in the undamaged part of the coating, or rust quickly develops around the scratches.
4.What are the types of processing-related defects?
Forming cracking phenomenon: The coating cracks along the deformed part during stamping and bending.
Zinc powder shedding (powdering) phenomenon: White zinc powder adheres to the coating surface after processing, and the rough surface is exposed after wiping.
5.What are the other special defects?
Coating contamination/foreign matter inclusion phenomenon: dust, oil, metal debris and other foreign matter attached to the surface, or unknown color spots appear.
Uneven coating gloss phenomenon: The local glossiness of the surface is inconsistent, forming "bright spots" or "fog spots".