Compensating for Finish

Powder coated bracket. Powder coating is one of the thickest finishes.

Adding a surface finish can change the size of a part slightly. In some designs it is important to consider this when specifying dimensions. Keep the following in mind:

• Mechanical part dimensions apply after non-organic finishes (anodize, electroplate, mechanical etc.) but before organic coatings (powder coat, etc.). For example to make a powder coated one-inch cube your CAD design would need to be a few thousandth's of an inch under one inch in size. But to make an anodized one-inch cube your CAD design should be exactly one-inch.
• You might also want to specify whether threaded holes should be plugged to prevent finish.
• In highly critical cases you might want to specify a tolerance on finish thickness, for example .002" +/- .0005".