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Wed, 28 Feb 2001 16:05:55 +0100 |
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Jonathan
Here what I can say from your picture:
Lead made of copper.
Clipping operation pretty rough. We already had cases, where the clipping operation by hand caused the kind of cracks ( in the intermetallics) as seen on your picture.
However, I believe that you have the cracks before you clip the leads. In this case it looks to me like no wetting.
This could mean:
- Insufficient tinning of the leads --> oxidised copper
- Thin tinning --> Intermetallics
- Old components --> Intermetallics
- Contamination
I suggest you let someone have a look into the solder joint ( microsection ) to find the cause of the defect. Just changing the preheat temperature doesn't seem a good idea to me.
Have a great day
Guenter
Guenter Grossmann
Swiss Federal Institute for Materials Testing and Research EMPA
Centre for Reliability
8600 Duebendorf
Switzerland
Phone: xx41 1 823 4279
Fax : xx41 1823 4054
mail: [log in to unmask]
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