Hi Lou! Yes, unfortunately you must sacrifice a number of printed wiring 
assemblies to destructive metallographic cross-sectional analysis to 
determine what frequencies/transducers parameters can be used for a given 
set of board characteristics (i.e. thickness, layer count, etc.) to fully 
utilize CSAM as a tool for pwb delamination analysis. Sound metallographic 
preparation techniques (such as the use of cut off wheel) must be followed 
so that  you don't alter the delamination region of interest as you 
mentioned.   If you don't have actual product available for testing, then 
I would recommend that you use scrap assemblies to assist in the 
development of the analysis technique. It should also be noted that CSAM 
isn't going to find fine detail, very small delamination instances - the 
technique lends itself to the larger macroscopic type of delamination 
defects. Some folks have argued that the CSAM is not providing any 
additional information that a good metallographic cross-section would 
provide which is a true statement. However, the application of CSAM 
analysis is much faster than metallographic analysis so I view CSAM 
analysis as another very useful tool in the my analysis methods toolbox. 
One of my mentor's once told me that you can never have too many tools in 
your analysis toolbox!

Dave



Louis Hart <[log in to unmask]> 
01/05/2009 06:22 PM

To
TechNet E-Mail Forum <[log in to unmask]>, "[log in to unmask]" 
<[log in to unmask]>
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Subject
RE: [TN] PWB Delamination Detection by C-SAM






Dave, to get the metallographic cross-sections, am I correct in saying 
that the PCB and delamination region must be cut with a cut-off wheel to 
minimize disturbance to the region of interest?  Louis Hart

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman
Sent: Monday, January 05, 2009 8:45 AM
To: [log in to unmask]
Subject: Re: [TN] PWB Delamination Detection by C-SAM

Hi Vlad - sorry but there are no tricks. We figured out the limits of the
CSAM and frequency/transducer selection the old fashioned way - confirmed
what we thought the CSAM was telling us by conducting metallographic
cross-sections.

Dave




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