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December 2012

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Subject:
From:
Steven Creswick <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Steven Creswick <[log in to unmask]>
Date:
Mon, 31 Dec 2012 14:21:52 -0500
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Richard,

If there is no cavity around the wires, there should be no issue - period!
I suggest that they are drawing inappropriate conclusions.

I absolutely agree that ultrasonic cleaning of sealed, cavity style
components can be catastrophic, but you appear to be speaking of a PEMs
device.


Now then, if there were an air gap in your package, the u/s signal would be
blocked, and you would see nothing on your acoustic image... unless, you
could turn it over and scan from the other side.  Therefore, I doubt that
you have a cavity style device - but you could surprise us  :-)

I had an acoustic microscope from 'the other guys', and would use
transducers of quite tightly fixed frequency, depending on what was being
scanned.  Higher frequency for thin parts, greater resolution.  Lower freq
for penetration, but not necessary fantastic resolution.  I forget what my
low freq transducer was 30, or 80 MHz ....  The highs were in the hundreds
of MHz.  A quickie call to Sonoscan could tell you what frequency they would
use for your device and one could calculate the wavelength and make a
reasonable guess if this would set up harmonics in the wires.  My guess is
the freqs are way too high, but one could check.

Maybe you will convince them easily and the New Year will start out well!

Best regards,


Steve Creswick
Sr Associate - Balanced Enterprise Solutions
http://www.linkedin.com/in/stevencreswick
                         616 834 1883



-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Monday, December 31, 2012 1:48 PM
To: [log in to unmask]
Subject: [TN] Susceptibility of electronics to C-SAM

I have a good understanding of the effects of damage that can be caused by
cavitation when cleaning electronics using ultrasonic wash with the wrong
sweep frequency, but does anyone know if ultrasonic energy from C-SAM
analysis can cause damage to electronics? I recently had a customer object
when I suggested using Sonoscan to inspect some components for die bond
issues, and he said that he had heard ultrasonics could damage electronics.
I explained to him that while that was possibly true of ultrasonic cleaning
(if not done properly), I had never heard of C-SAM harming electronics.
Anyone have any experience with damage caused by C-SAM inspection?

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