During the aluminum anodizing process, rack marks are small marks that appear at the points where a part comes into contact with the rack or fixture (jig). At these contact points, the anodized coating may not fully cover the surface, or the color may appear slightly different from the surrounding areas. This is a common and often unavoidable technical characteristic because the part must maintain direct electrical contact during the anodizing process.
Rack marks occur due to two essential requirements:
At Yumoto Vietnam, rack marks are controlled from the order review stage. For anodized products, our sales team informs customers in advance about the possibility of rack marks and confirms fixture contact locations if specific requirements are provided. Yumoto Vietnam then works closely with our surface treatment partners to ensure that the designated contact points are used during processing.
If the customer does not specify fixture locations, we request our anodizing partners to select areas that have the least impact on product appearance while avoiding holes with tight tolerances or functionally critical surfaces.
With extensive experience in precision CNC machining and surface quality control, Yumoto Vietnam helps customers minimize cosmetic risks and ensures that anodized products meet both appearance and technical requirements before delivery.
