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Problems with Aluchrome process on a aluminium tray

Q. My company is currently manufacturing a aluminium tray which has high requirements on its appearance. Its surface finishing must be done by "Aluchrome", which gives us a light golden colour and is conductive. However we have a little problem with it, as the finished product could not be touched by hands without wearing gloves, otherwise the plating colour will fade off. I would like to know why and what cause this, besides it is also very difficult to have uniform colour during Aluchrome process, is there anything we could do to improve it? As the process is really slow, and we would like to increase our production rate. Thanks

Sandy Lin
Production supervisor - Manchester, UK
2003

A. Hi Sandy. The process tank needs good agitation for uniform color; is it equipped with air agitation?

You say the process is "really slow" but you give us no timing so we don't if the process is operating wrong or your expectations are for an instantaneous reaction. Please try to tell us what you mean by really slow, and whether this is a spray or dip operation.

Chromate conversion coatings must be dry and set before handling. Gloves are necessary inside the factory. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003

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Q. Thank you for your response. Well, at the moment, our supplier works 24 hours to chromating these metals, and they are only able to produce 50 pieces per day, not including the NG ones. I understand it requires time to process, especially to have a good piece of work. However, the chromated piece which could be used only 30 out of 50, thus I would like to know if there are better methods which could increase the production capacity.

Sandy Lin
Production supervisor - Manchester, UK
2003

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Your first posting didn't indicate that a vendor did this process for you as opposed to you doing it in house. It is perhaps possible that you can help a vendor improve the process, but it would have to start with a highly detailed understanding of exactly what they are doing. So my previous questions would remain open.

But an option, and maybe a better one, is to try to find an alternate vendor who can produce good work at the production rate you require. Best of luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003

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Q. Dear sir,

Our company manufactures ceiling fans. The motor cover and blades are pre-treated in aluchrome before painting.
This operation is usually outsourced. But the quality of the pre-treatment coating remains questionable as some paint peel off problems are reported. Also there is an issue of rusting, if the pre-treated material is kept for more than a month.

Sir, please provide us with any information regarding how to control the quality of pre-treatment and also methods to evaluate the coating quality easily.

Thejus B
- Cochin, Kerala, India
November 17, 2012