If you look through all the Technet archives, you may find an answer, 
but the two answers you will certainly find on this subject are:
"It depends!"
"How long is a piece of string?"

I apologise if you think it unhelpful, but this is the best I can do.

Brian

Todd, Richard wrote:
> Technet,
> 
> I am receiving questions about the allowable limits of ionic contamination on our finished assemblies.  I believe that J-STD-001D indicates that the allowable limit is 1.5 ug/cm2.  Is this the same for both leaded and lead-free assemblies?  Is there any other specification that details what the maximum acceptable limits for ionic contamination should be for finished assemblies?
> 
> My customer won't take my word for it; I must provide industry-recognized evidence.
> 
> Thank you in advance.
> 
> Regards,
> 
> Rick Todd
> Senior Engineer
> Panasonic Automotive Systems
> 
> 
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