Gaby,

There have been and, I believe, still are several widely accepted
workmanship standards that allowed
50% reductions in conductor width so long as electrical problems do not
exist.  Since you are dealing with 
a multi-layer PWB, I would be more concerned with damage to the inner
layers (if the "nick" was 
mechanical damage).
Consider the following:
"Welding" involves heating the trace near the metal's melt point to fuse
the kovar strip in place.  These 
temperatures are going to locally melt and burn the underlying polymer
(epoxy or polyamide) of the PWB.  
The resulting carbon residue and delaminated trace represent a much worse
longer term reliability problem 
than the nick does.

Regards,
Harry

At 11:07 PM 3/26/96 +0000, gabriela wrote:
>Hello,TechNetters!
>Consider please the following problem:
>Let's say,you have an expensive multilayer board with a nicked 
>conductor.The nick narrows the conductor to 50%,but there is no 
>problem concerning electrical performance.
>Would you cosider repair with a welded covar strip?
>Our supplier suggested the repair,but after seeing the mess around
>it,I would much more prefer to use the board as it is.
>Does anybody support this?
>
>Thank you,
>Gaby
>
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