At 14:21 18/08/98 -0400, you wrote:
>To TechNet Forum Members,
>        We are a contract manufacturer who assembles boards in a high mix
low to medium volume environment.
>Questions:
>What PWB manufacturing process could be causing this?
>There is no evidence of measling which is usually evident after gross
Z-axis expansion, is    there something we can do during the assembly
process to help minimize Z-axis expansion?
>        How would you proceed with this situation?

Mark ,
From our own experience , as PCB manufacturer , this is not your foult . The
problem exists allready in the boards .
First of all , locate the open via and perform crossection . It will give
all answers .
There are a lot of reasons for such opens .
The most important point to your consideration : opens in small  vias found
after assembly are indicating , that reliability of finish boards is not
good . You might be in situation , that there are a lot of opens in copper
and only solder inside the hole create electrical connection .
Send the boards to inspections .
Good lack

Edward Szpruch
Eltek Ltd - Israel
Tel  972 3 9395050
Fax 972 3 9309581
E-mail :  [log in to unmask]

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