Anodizing

[abrown128]

How often do team anodize aluminum and how much would that cost?

[IndySam]

We get ours done for free here in town. Check around your area and see who does it.

You can also find do-it-at-home-kits for smaller stuff.

[Brandon Holley]

We've anodized every year from 2006 and on...we get it done for free as well

[MrForbes]

We've never had any aluminum anodized, possibly because we don't get it done for free?

[EricLeifermann]

Even if we could get it done for free, we would never get it done because the robot and parts for the robot aren't done in time to be back from anodizing before ship date...

[artdutra04]

Try to find a local anodizing company and see if they'll sponsor your team with free parts. Anodizing can be done in your shop, but you'll need a really powerful DC power supply, as in like 20A+ continuous at 12VDC, as well as an assortment of heated chemical baths, including one with sulfuric acid. It's pretty nasty stuff to keep in your shop when you're trying to build a robot.

The one key thing to either anodizing or powder coating parts is that you pretty much need to have everything designed in CAD and completely machined/fabricated ahead of time. When you anodize or powder coat parts, there really should never be a "oh no, these holes don't line up!" or a "gahhh! the roller chain wants to go through this piece of aluminum!" moment. You should know everything ahead of time, and the anodized or powder coated parts should just bolt together.

Also, when anodizing, surface finish is important. Any blemishes or scratches or marks in the surface will show through.

[abrown128]

Would this change the thickness on critical tolerance parts so that some things are too tight?

[EricLeifermann]

Originally Posted by abrown128

Would this change the thickness on critical tolerance parts so that some things are too tight?

Anodizing parts won't change the thickness, but powder coating will.

[Doug G]

We bought a kit last year and tried it out in the off season. Kinda cool, we used a battery charger from the school's auto shop and did some small pieces of aluminum. We got some unequal coloring, so it is important that the etching process is done correctly. We learned that is something we don't want to be bothered with during the build season, a professional shop can do a much better job anyways.

[sanddrag]

Originally Posted by EricLeifermann

Anodizing parts won't change the thickness, but powder coating will.

Actually, anodizing does ever so slightly increase the dimension of the part. I couldn't see the effect being anything more than negligible in a FIRST robot though. From what I recall, anodizing adds about 0.0002 inch, whereas powder coating can add up to 0.020" I've never actually measured it.

[EricLeifermann]

Originally Posted by sanddrag

Actually, anodizing does ever so slightly increase the dimension of the part. I couldn't see the effect being anything more than negligible in a FIRST robot though. From what I recall, anodizing adds about 0.0002 inch, whereas powder coating can add up to 0.020" I've never actually measured it.

Thats what i meant by not adding thickness. Of course it ads some but it doesn't add enough that it would critically affect a dimension.

[abrown128]

So its essentially insignificant. I'm looking into this for swerve parts. I guessing that these pieces wouldn't cost very much to anodize and an anodizing service could do this in a short amount of time.

[Matt Howard]

Originally Posted by EricLeifermann

Even if we could get it done for free, we would never get it done because the robot and parts for the robot aren't done in time to be back from anodizing before ship date...

We've had things anodized before and had them back well before ship day.
You just have to know what you will need when.

[Brandon Holley]

Originally Posted by sanddrag

Actually, anodizing does ever so slightly increase the dimension of the part. I couldn't see the effect being anything more than negligible in a FIRST robot though. From what I recall, anodizing adds about 0.0002 inch, whereas powder coating can add up to 0.020" I've never actually measured it.

While this theoretically is true, there has been instances for us in the past where we have made parts to very tight tolerances (+/- .001") and then anodized them only to find they no longer fit together. We make sure to anodize parts and then remachine them if they require a tight tolerance (such as a press fit for a bearing)

[sanddrag]

Originally Posted by Brandon Holley

While this theoretically is true, there has been instances for us in the past where we have made parts to very tight tolerances (+/- .001") and then anodized them only to find they no longer fit together. We make sure to anodize parts and then remachine them if they require a tight tolerance (such as a press fit for a bearing)

I agree, this is sometimes an issue.

Another thing to note is there are different types of anodizing. Some hard anodizing processes can add a thickness which must certainly be accounted for.