I don't mean to cause any undue concern. The issue is fairly simple . . .
You can break glass and ceramic with sound but it is not likely if you are
careful. But ultrasonic cleaning can break wire bonds, and wires, this is
especially true in controls, ceramic ICs and the like were the wires are not
encapsulated and subject to vibration. There are technologies that are
effective in reducing this type of damage. Hope this relieves your fear. If
you are still concerned then you have some homework to do. What frequency
and power does you cleaner work at. What is a construction of the packages
in question . . . stuff like that.
  -----Original Message-----
  From: TechNet [mailto:[log in to unmask]]On Behalf Of Howard Watson
  Sent: Friday, October 26, 2001 11:46 AM
  To: [log in to unmask]
  Subject: Re: [TN] Cleaning paste when misaligned.



  Mike and Guy,

  We routinely clean the second side of misprint solder paste, but from what
you are saying perhaps there could be a problem with damaging some
components.  The components that we clean in the ultrasonic cleaner are
mostly flat chip package, C lead diodes, and some SOT-23 and SOIC.  How do I
verify which components can or cannot go in the cleaner?  Is there any test
data out there to support this issue?  Though we clean very few misprints, I
am a little concerned.  Thanks for your help!

  Howard Watson
  Manufacturing Engineer
  AMETEK/Dixson


       "Barmuta, Mike" <[log in to unmask]>
        Sent by: TechNet <[log in to unmask]>
        10/26/01 09:02 AM
        Please respond to "TechNet E-Mail Forum."


                To:        [log in to unmask]
                cc:
                Subject:        Re: [TN] Cleaning paste when mis-aligned.



  Cathy: This should not be a problem for the bare (unloaded) PCB. However
if
  you are doing a double sided reflow and   misprint the second side you
need
  to verify that the first side components are compatible with the
ultrasonics
  you are using.


  Regards

  Michael Barmuta

  Staff Engineer

  Fluke Corp.

  Everett WA

  425-446-6076

  -----Original Message-----
  From: Cathy Killen [mailto:[log in to unmask]]
  Sent: Friday, October 26, 2001 7:30 AM
  To: [log in to unmask]
  Subject: [TN] Cleaning paste when mis-aligned.
  Importance: High


  Hello All & the mountain dew man.
  Can a mis-printed PCB be washed in a ultrasonic bath to remove all paste
  particles?
  Is there any danger of damaging innerlayers of PCB?

  Thanks in advance.

  Cathy Killen
  Training Instructor
  Smtek Europe Ltd.
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