Vinit

The risks of ultrasonics are manifold, but not necessarily too terrible.
There are several component types that can suffer: MIL style
semiconductors, but not plastic-cased ones, quartz crystals, multilayer
capacitors etc. If you have semiconductor packages which do not have the
bonding wires held in a solid mass of plastic, then you may be at risk,
but this can be minimised (but not eliminated) by choosing the frequency
range and intensity. It is essentially a compromise. There is MUCH
general misunderstanding about ultrasonics.

I personally favour an adequate spray regime over any immersion type
(the bath and shower argument!). If you wish to know more, contact me
offline.

Brian

Vinit Verma wrote:
>
> Hi Technetters,
>
> I am presently evaluating post reflow PCB cleaning machines, both aqueous
> and ultrasonic. I have a concern regarding ultrasonic cleaning. Read
> somewhere that the ultrasonic frequencies can have an effect on the wire
> bonds inside the packaging. Does anyone have any idea of this?
>
> Thanks in anticipation.
>
> Regards
> Vinit Verma
>
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