Hi Inge

Badly drilled holes
- To fast feeding during drilling
- Old drills

No a priori a bad thing. 
Possible effects:
- Defects in the Cu- plating leading to sponge solder
- Microcracks along glass fibres promoting Cu- filament growth.

Have a great day

Guenter







_____________________________________________________

EMPA
Swiss Federal Laboratories  for Materials Testing and Research
Centre for Reliability
Guenter Grossmann,  Senior Engineer

8600 Duebendorf
Switzerland

Phone: xx41 44 823 4279
Fax :     xx41 1 823 4054
mail:     [log in to unmask]
_____________________________________________________

>>> Hfjord <[log in to unmask]> 10/01/07 7:11 pm >>>
Broken glass fibers caused by poor tooling parameters is my first thought.
The loss of fibers leaves a small cavity that will be filled by Copper,
sometimes even by solder. I assume, that the preparation is correctly done,
so we can exclude smear.

I think you can sleep tonight, this failure can be easily fixed with a fresh
diamond tool in your Excellon. 

If you use laser drilling, the above is not valid.

Inge


-----Ursprungligt meddelande-----
Från: TechNet [mailto:[log in to unmask]] För Jack Olson
Skickat: den 1 oktober 2007 18:56
Till: [log in to unmask] 
Ämne: [TN] Is This a BAD Thing?

I'm not accustomed to looking at reliability issues,
(my designs are usually so perfect... (grin))
so every time I see an X-Ray or a cross-section
I get nervous wondering what I'm actually seeing.

Can anyone explain what the following picture means?

http://www.frontdoor.biz/PCBportal/208what.jpg 

onward thru the fog,
Jack

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