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Chrome Peel from Plastic Substrates

Assuming the failure mode for chrome peel on plastic is the same for that on metals, namely "improper surface preparation" can you shed some light on what types of in-process checks should be used to assure proper surface preparation (etch) and conversely what post failure inspections can be done to conclude the surface was prepared properly or improperly. We, from time to time (the problem comes and goes with a low occurrence rate) have parts returned from our customers with the chrome coming off the plastic (between the electroless layer, in our process e-nickel, and the plastic substrate) and are told by our manufacturing team (off shore) the problem stems from high parting lines on the part. The problem we have with this idea (we believe it is an adhesion problem) is the plating; is coming off the part in areas that are a good distance from the parting line, and with a good deal of ease.

Regards,

Mark Woloszyk
Account Manager - Detroit, Michigan
September 17, 2008

Hi, Mark. I don't have sufficient troubleshooting experience in plating on plastic to offer much advice. But if the electroless nickel is adhering, the issue is in the electroless nickel process or, more likely, after it.

Electroless nickel goes passive quite quickly, and the major issue may be a delay between the electroless nickel and the next plating step. Try to determine if the plating line is subject to periodic stoppages between electroless nickel and the next plating step (I don't know if you do copper or nickel immediately after the EN).

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
September 22, 2008