Greetings All,

I am having my first experience working with an assembly design that
involves 0402 capacitors with underside solderable terminations (vice
wrap-around end terminations)... The reflow process seems to cause the
components to tilt and skew to highly unacceptable levels. Physically it
looks as if the caps floated to the top of the molten solder volume (as if
on pontoons) then slid down one way or the other. The vendor made a few
recommendations including migration to a thinner (4 mil) stencil as well as
some pad design and nitrogen tweaks and... Even after implementing these
recommendations we are experiencing the same problems, just to a slightly
lesser (although still unacceptable) degree... Does anyone out there have
any additional thoughts on how to remedy this sort of issue?

We do build another part [successfully] with a similar style component, but
it is a 1206 form factor and is perhaps massive enough to keep from floating
up the way the 0402 caps do...

Your collective wisdom is greatly appreciated!

Best Regards,

Tom Ochenas
Process Engineering
Maxtek Components Corporation
2905 SW Hocken Avenue
Beaverton, OR 97005
[log in to unmask]
desk: 503-627-3078
fax:  503-627-4651

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