Defective nickel-chromium plating

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.

Trevor Crichton
R&D practical scientist - UK

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.

Rajesh M B
- Bangalore-India

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