> Tom:
> 
> If you are using no-clean flux to solder SOTs (or anything with tall,
> non-solderable body that will repel the wave from reaching the pad,
such as
> tantalum capacitors), dual wave would not work. This is because the
first
> wave (chip or turbulant wave) will kill the flux, resulting in the
poor
> solderability at the second wave (lambda wave). The way we do it
rather
> successfully is to elongate the pad size and solder them with a
vibrating
> wave (omega wave), which has much lower surface energy to reach any
shadowed
> pads. Good luck.
> 
> Regards
> Jauwhei Hong
> [log in to unmask]

Jauwhei Hong,
We don't have any problems soldering SOT's with no-clean flux and
dual-wave (chip & lambda). We get fine results if we only use an angle
of 4 degrees, accurate dwell time for the specific pcb and a "perfect"
preheat profile. We also don't have to elongate the pad sizes, we use
the ordinary sizes the pick & place do.

i don't know, but are we different?

/Jan Merstrand
 Operation Engineer
 Ericsson Microwave Systems
 [log in to unmask]

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