I don't know about the conductive ink part of the fix, but I do know that
those "overcoat" pens are not a very good replacement for an IPC-SM-840
qualified soldermask. Why don't they just use a "real" soldermask for
touch-up over the conductive ink? It would be much more reliable.
My 2 cents.

Timothy Reeves
QA Manager/Process Engineer
ECD Circuit Board Division
13626 S. Freeman Road
Mulino, OR 97042
(800) 228-8198    Fax (503) 829-5482


|-----Original Message-----
|From: Rich Lasko [mailto:[log in to unmask]]
|Sent: Friday, September 01, 2000 7:55 AM
|Subject: Conductive and Overcoat Pens
|
|
|Good morning everyone!
|
|A little background....I am working with a vendor of ours ( that
|manufactures the pcb for electronic assemblies) and we have
|had some issues
|with small artwork opens in the traces.  (The pcb is double
|sided with dark
|blue soldermask and has many small traces throughout the pcb
|which makes the
|almost impossible to see visually).  At this time, the board
|does not have
|an electrical test on it.  Our vendor has advised us that the
|root cause of
|the small artwork opens is either minor dust or scratch on the
|artwork that
|happens at their facility.  The opens are random in nature but are very
|difficult to detect with visual inspection.  Our vendor has agreed to
|implement electrical test (which is fine for future orders) but we have
|approx. (15) fully populated boards that have these artwork
|opens that need
|repair.   Total of the 15 boards are worth $3000.
|
|So.....in order to "repair" the existing assemblies, our vendor has
|indicated to us that they will be using Circuitwork's
|Conductive Pen and
|then the Overcoat pen on top.
|
|My questions to everyone are:
|
|1.) Is this type of repair an "approved" industry standard for
|this type of
|defect?  How many people use it?  Is it reliable - long term?
|2.) Other than IPC 7711/7721, are there any other documented repair
|procedures for this type of defect?
|
|Any help on this would be great!  Peace!
|
|Rich
|

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