Ever wondered how much thickness anodising puts on to your parts or how the anodising process affects dimensional tolerances?

Anodising is a bit different to other finishes in that it actual grows out the oxide layer out of the metal rather than adhering a plating onto the surface of the metal. The amount of anodising put on differs depending on the finish required but as a guide

Clear Anodising – 12um

Light Colours (Red/Blue/Purple/Gold) – 15um

Dark Colours (Black/Green) – 20um

Hard Anodising Clear 25um

Hard Anodising Black – 50um

There can be confusion about how this affects dimensional tolerances as 50% of the anodising goes into the metal and 50% on the surface of the metal therefore for a bore the size will decrease by the thickness stated rather than double the thickness stated as half of the thickness is internal. The attached data sheet shows this more clearly.

the thicknesses stated above are the general guide for those finishes but we are able to put on whatever thickness a customer requires as we calibrate our thickness gauge against each job and measure the thickness during the process.