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Wave Soldering Defects - Cracked Joint
Cracking of a solder joint on a plated through
joint is uncommon; in Figure 1 the solder joint is on
a single-sided board. The joint has failed due to expansion and
contraction of the lead in the joint. In this case the fault lies
with the
initial design as the board is not meeting the requirements of
its operating environment. Single-sided joints can fail during
assembly due to poor handling but in this case the surface of the
joint shows stress lines which have been produced during repeated
movement.
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| Figure 1: Stress lines here indicate that this crack
on a single-sided board was caused by repeated movement during processing. |
Figure 2 shows a crack around the base of the fillet and
has separated from the copper pad. This is most likely to be related to the
basic solderability of the board. Wetting between the solder and the pad
surface has not occurred leading to joint failure. Cracking of joints would
normally occur due to the thermal expansion of a joint and this would relate
to the original design of the product. It is not very common for failures
to occur today due to the experience and pre testing conducted by many leading
electronics companies.
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| Figure 2: Lack of wetting between the soldre and the
pad surface caused this crack at the base of a fillet. |
Wave Soldering Defects:
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Cracked Joint | | |
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