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Defective nickel-chromium plating
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I work in a consumer product manufacturing plant. Recently, we receive defective nickel-chromium plating part from our supplier. From the attach photo you can see some wrinkle mark on the chrome layer which happen after go thru -20C low temperature preservation test.
The composition is ABS plastic with nickel-chromium plating.
Looks like it is always more severe near the mould injection gate point.
Our supplier until now still does not have any clue to why it happen.
I would like to know what might be causing this problem.
Thank you.
ST LEE- Penang, Malaysia
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This looks like delamination caused by poor adhesion of the metal to the ABS; thermal cycling will really show up the problem! It is interesting it is associated with the mould injection gate, as this could indicate its cause; I am no moulding expert but have seen a very similar problem before and found it to be incorrect moulding conditions. I suggest you peel off the metal and look at the ABS underneath. It is possible you will find evidence of chromic acid in the ABS; this can easily be blamed on bad rinsing, but in my experience it is also associated with bad processing.
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Trevor Crichton R&D practical scientist The Pheasantries - Chesham, U.K. |
October 30, 2008
Dear..
As per my knowledge and experience this problem is due to improper preteatment before processing.
We are also a plater of chrome and doing Chrome plating on ABS Plastic.
We are getting very good yield. Before doing a plating on ABS Plastic it is necessary to plate the component with copper and then chrome. So that good adhesion of chrome takes place on the component with longer run.
- Bangalore-India