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Is surface material removed during titanium etching/anodizing?

I am looking for information regarding the loss of material during titanium anodizing. Specifically, will the surface of the part be etched away during the titanium anodizing process, and by how much? Also, does the desired colour affect the amount of material removed? The components in question have tolerances in the ±.0002" range, so even slight changes in dimension may be significant. Materials are both 6V 4Al and CP Grade 2.

Thanks much,

John Jans
Medical device manufacturer - Jacksonville, Florida, USA
2004

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2004

What type of titanium anodizing are you looking for, acid or alkaline? We do acid anodizing on titanium fasteners and some material is removed during the etch/activation step (a nitric/HF dip) but I haven't noticed any removed during the actual anodizing.

Typically, we remove one to three tenths, controlled by the length of time the parts are immersed. In our bath the amount of time required is great enough to let us have acceptable control over the etching loss (our customer must maintain tolerances within a range of 5 tenths total, virtually identical to yours).

The color caused by acid anodizing is interference coloring and is dependent upon the thickness of the anodic coating, I've pretty much stayed in the low volt range (brown, purple and blue) and haven't noticed any significant change.

Good luck!

Jim Gorsich
Compton, California, USA