Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Anodization being stripped from enclosure body but not end caps

Anodization being stripped from enclosure body but not end caps

Anodization being stripped from enclosure body but not end caps

A device recently came back to our repair department with anodization missing off the enclosure, as shown in the photo below. On the right is a new enclosure, on the left is the enclosure in question.

It almost looks like part of the coating was wiped off with someones fingers, given the fingerprint like smudged areas. This made me initially suspect some chemical on the handlers hands... However, the valleys between the fins are also missing their coating, ruling out this theory.

If the process wasn't "applied" to the surface, it should have affected the entire enclosure. However, the front and rear end caps, supposedly anodized in a identical manner to the body, are completely fine.

The different parts are made by different suppliers, so right now I am suspecting a manufacturing defect. Am I on the right track? Does anyone with more experience with anodization know of a process that could do this? Just today I heard that another unit is coming back with the body almost stripped to completely bare aluminum... I'm hoping to get out in front of this problem, but I just don't have a lot of materials science experience.

Thanks in advance!

RE: Anodization being stripped from enclosure body but not end caps

Anodization is an electrolytic process which uses an electrical current to convert the surface of the aluminum to a protective aluminum oxide. Color is created with a dye that is absorbed into the pores of the aluminum oxide. It looks like a highly alkaline cleaner was used to "degrease" the part. This dissolved the anodizing but was not left on long enough enough to completely remove it. So you are seeing variations in the residual thickness of the anodize. The tips of the fins have a thick anodize because that is where current will concentrate, while shielding the troughs, which get a thin anodize. Oils in fingerprints will protect the anodize from the cleaner for a short time.

Also, sealants may be used on anodized parts to provide more corrosion protection. This, as well as simple thickness differences may explain the differences between parts.

That is my guess, anyway.

RE: Anodization being stripped from enclosure body but not end caps

Thank you for that info! Unfortunately the equipment these devices are installed on moves all of the country and is commonly serviced by shops with no relationship to the main maintenance facility... tracking down whether a cleaner was used will be difficult. Do you know whether a chemical test of the surface could detect the presence of alkaline substances?

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Research Report - How Engineers are Using Remote Access
Remote access enables engineers to work from anywhere provided they have an internet connection. We surveyed our audience of engineers, designers and product managers to learn how they use remote access within their organizations. We wanted to know which industries have adopted remote access, which software they are using, and what features matter most. Download Now
eBook - Managing the Context of Product Complexity Using the Digital Twin
Keeping track of changes to complex products is difficult—think Aerospace & Defense equipment, new generations of commercial aircraft, and software-based automobiles. A new way to managing the digital context of the physical product is required and the answer is the Digital Twin. This ebook explores the opportunity available for Operations and Maintenance for the Digital Twin. Download Now
White Paper - Trends in Industrial Filtration
Substantial progress has been made in filtration technologies in recent years. New filter media materials, designs and processes have led to filters that are more efficient, reliable, compact and longer lasting. This white paper will discuss the various trends that are impacting operational responsibilities of MROs today and the resources that are available for staying up-to-date on the latest filtration solutions. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close