Mark,

The restriction on the use of ultrasonics for cleaning of populated boards
is related to the concern that bond wires and other sensitive structures
could be subjected to resonance.  Resonance imparts an extremely large
amount of mechanical energy into the structure, resulting in outright
fracture - or worse, latent damage which doesn't degrade the performance to
a detectable level before the hardware is shipped to the customer.

Ultrasonic cleaning is usually restricted to bare boards, boards only
populated with terminals and connectors, and mechanical parts.

Regards,

Robert wm. Cooke

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Mark Austin
Sent: Monday, April 18, 2005 8:15 AM
To: [log in to unmask]
Subject: [TN] Ultrasonics

Technetters

I seem to remember somewhere that ultrasonics shouldn't be used to clean
populated PCB's. I have believed this to be due to damage inflicted to the
wire bonds within IC's and Xtals.

Is this the case can someone clarify what components (if any) cannot be
cleaned using ultrasonics?

Cheers

Mark

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