Letter 18095

Defective nickel-chromium plating [Malaysia]

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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

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.

Metal Finishing Guidebook [link is to book review/sourcing on finishing.com]

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