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Anodizing current density calculations / Racking design

I'm designing a small anodizing line for a senior project. When calculating the required current needed, do I need to include the surface area of the racking that is submerged in the solution and the actual part, or just the part. For the time being, I am using uncoated titanium for the racking.

For the rack to become the anode is it best to make the connection where the rack hangs from, or incorporate a some sort of clamping device to the rack while in the anodize bath.

Jeremy Styers
college student - Grand Junction, Colorado, USA
November 17, 2011

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If you're using Ti racks, then no, you do not need to take the rack surface area into account. If using Al racks, then yes, that surface area of the rack must be factored in.

If it's a small line, you'll have a permanent bus bar spanning the anodizing tank, and you'll make your + connection from your rectifier to the bar.

Large/automated anodizing lines work on the same principles, but the bus bar is not a permanent fixture.

Marc Green
anodizer - Boise, Idaho
November 18, 2011