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Streaks when Anodizing 3003-H14 Aluminum
I have an aluminum sheet metal part, alloy 3003-H14, that is being outsourced for the coating process. The coating is a hard anodizing with Teflon finish. This part has always been supplied with a nice even finish. Lately we have been receiving the parts with the "streaks" throughout the finish.
The coaters are telling us that this is because of the alloy we are using. Can someone validate this statement?
Product Designer - Moline Illinois United States
September 15, 2011
First of two simultaneous responses -- September 16, 2011
Maybe so, Maybe no. Post some digital pictures.
What is the thickness of the sheet metal? Has it been "work hardened"? Has the anodizer changed his method of "getting the current evenly on the part" (including the middle). Is it streaking between the alkaline etch and the deox during too slow transfer? Does the anodizer have any floating soil on any of his tanks. There are so many possibilities to "mind read" "STREAKS". If the streaks are all vertical, then it is probably NOT "in the metal", Come on back with more data and let's help you decide if "its in the metal" (anodizer's catch-all excuse) or if something else is causing the "streaks".
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina
Almost impossible to say just going by your verbal description. A picture would be very beneficial.
Marc Green
anodizer - Boise, Idaho
Second of two simultaneous responses -- September 17, 2011
Because your supplier always give you a nice even finish, that means the supplier's process is mature. Provided there is no change in the supplier's process or other's (especially during this economy downturn, the boss may replace the experienced with inexperienced), your streak problem lies in mainly in material (strip and re-anodizing to see whether the problem could be reproduced)
John Hu- Singapore
September 20, 2011
Gentlemen, you have valid questions.
The material thickness is .063" and the surface is not hardened in any way. The coater states that no changes have been made to the process. Unfortunately I cannot answer your other questions as I do not have a direct line of communication with the coater.
I am new at this type of forum setup but a photo is attached.
Thank you
- Moline Illinois United States
September 20, 2011
September 22, 2011
From what I can tell, that definitely looks like a material issue. The "streaks" are way too uniform, and evenly spaced for it to be a processing issue.
Did you recently purchase a new lot of material, and that's when this issue arose? Change material suppliers by chance?
Marc Green
anodizer - Boise, Idaho
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