Considerations When Ordering Aluminum Anodizing from Finishing Technology

Alloy – Aluminum anodizing can be applied to virtually any aluminum alloy. However, each allow is different, so it is important the alloy is properly designated on the purchase order.

Build-up Per Surface – Hard anodizing can be provided from .0002 to .003”, depending upon the alloy. Like other coatings, hardcoat will change the dimensions of the basic component. Unlike other coatings; however, half of the hardcoat is buildup and half is penetration. On purchase order, be sure to allow for hard anodizing buildup, not plating buildup.

Masking – It is often necessary to mask the coating from being applied to threaded or bored holes, ground points, mating surfaces and other areas. Areas to be masked must be clearly specified on the purchase order. Because of the cost involved in this hand operation, it is usually harder to tap holes to a standard size and make them rather than use oversized taps to compensate for hardcoat buildup. In most cases, it will be less expensive to coat the entire component, even if coating is required on only on one area.

Racking – Proper racking is critical and each component must be racked to maintain firm electrical and mechanical contact during the aluminum anodizing process. Since each rack contact point leaves a small void in the coating, it is important for the contact to be made in a non-critical area. Your suggestions on rack placement will facilitate processing.

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