Hi Kevin - most XRF systems are capable of measuring ImAg finishes 
provided you have a known good standard for the thickness range you are 
measuring. A number of companies sell the standards for this purpose. We 
routinely measure ImAg finishes with our XRF system without issue.

Dave Hillman
Rockwell Collins
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From:   "Glidden, Kevin" <[log in to unmask]>
To:     <[log in to unmask]>
Date:   10/30/2012 09:17 AM
Subject:        [TN] ImAg thickness measurement / verification methods
Sent by:        TechNet <[log in to unmask]>



Hi everyone,

Hoping all 'Netters in the path of Sandy are safe and sound today.

I am looking for someone who can verify ImAg plating thickness in the 
range of 5 to 12 micro-inches applied over copper using XRF techniques. 
The IPC-4553 specification indicates this might be more difficult to 
achieve for silver than for other finishes, and requires some specialized 
equipment and calibration methods.  I am looking to have this done on 
around 5 or 6 PCBs only.  Offline responses / quotes are OK.

As a follow up, is anyone out there using XRF or other measurement 
techniques to measure thickness of finish platings as part of PCB incoming 
inspection criteria?  If so, what equipment(s) are required and what would 
be the estimated investments?

We periodically see ImAg finish boards that show copper through on the 
second side after only one pass through SMT reflow.  We spec 5-12 
micro-inches, but sometimes measurements have shown we are getting as 
little as 2 to 3.  I am wondering if it is warranted to sample incoming 
lots for verification.

Thanks,

Kevin Glidden


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