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November 2006

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From:
pearl petras <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, pearl petras <[log in to unmask]>
Date:
Mon, 27 Nov 2006 11:02:33 -0500
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Arggghh,
  More delamination. Looks like poor quality PCB's -  a simple quick test adjustment to a component seems to be causing a lot of boards to 'pop' in the same area.  As well, others are popping in the area of a hand-installed edge connector, when they start to solder the center pin.  Even just tinning the pad does it sometimes.
  What would you do with boards like this?
  Would you try to fix it?  How?
  Would you scrap it?  There are some very expensive IC's on this board.
  Do you think it may go deeper than one layer?
  It is a 10 layer PCB
  IPC-A-600 states:
    -The imperfection does not reduce the space between conductive patterns below the minimum conductor spacing. (OK - minimum conductor spacing for low voltage is ~0.1mm)
  -The blister or delamination does not span more than 25% of the distance between adjacent conductive patterns.  (What does this mean?  adj patterns on the same layer as the delam? or do you consider 3-D, if the conductive patterns are on a different layer but the bubble spans underneath them?)
    -There is no propagation as a result of thermal testing that replicates the manufacturing process. (would you try more hand-soldering, or would you try a reflow process, how would you mimic it?)



  Steve, could I trouble you to post another few pics?

  Thanks all.


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