Blistering between copper-nickel

Hello....(especially Mr.Ted Mooney)
We have a strange problem. Our part's base metal zinc die casting. Our operational process:hot degreasing + rinse + electrocleaning(cathodic)+ electrocleaning(anodic)+rinse+acid dip+rinse+cyanide copper plating+rinse+ acid dip+rinse+bright nickel.When we plate parts,there is some blistering between nickel and copper.When we hit it by a material we see copper layer.How can we explain this?Where is the problem?Who is the guilty?)::::
Thanks.....

The same thing happened to me once. My plater forgot to charge up the acid dip preceeding the nickel. Dumb misteake, but not immediatly obvious. Also you might want to check and see if the load is sitting in the rinse before the nickel for an extended amount of time. I prefer to skip that rinse and go directly from my acid dip (2.5% sulfuric acid) to the nickels. Helps keep the pH down. If that doesn't work you may be experiencing current interuptions in the nickel tank. Try going in live and see if that helps.