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Assembly & Placement Defects -
Component Movement
A component movement or misplacement is all to common
on MELF devices due to their shape. The end terminations lift the
main body off the surface of the board and often out of the glue
deposit. The terminations can vary making it a variable problem
from supplier to supplier.
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| Figure 1: An incorrect volume of glue or incorrect dispense
design caused movement. |
In Figure 1 the problem has been caused by using
the incorrect volume of glue or the incorrect dispense design. If one dot
of adhesive
is to be used then it must contact the body without going on to the
pad surface. If a two dot pattern is to be used the peaks of the glue
dots must
touch
and straddle the part preventing it moving.
Assembly & Placement Defects:
Component Movement | | | | |
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© 2007 Trafalgar Publications
Text and photos courtesy of Bob Willis |