My soldering equipment and methods
Crispian
I recommend using/getting one of these for doing SMD work.:
http://www.ebay.co.uk/sch/i.html?_nkw=rework+station&_frs=1&_trksid=p3286.c0.m359
They are temperature controlled heat gun essentially. Not too
expensive. I have been quite successful in doing SMD soldering - the
steps I use are as follows:
1. pre-solder plate all the pads by first rubbing everything in solder
flux, then using a soldering iron tipped with solder (normal variety)
to go over all exposed pads.
2. reservoir fill all QFN pads by putting lots of flux on them, then
putting pre solder-tipped soldering iron onto the pads using a
"poking" action.
3. Turn on temperature controlled heat gun to around 300 degrees c.
Heat the QFN pads until shiny. Poke with tweezers to check if solder
is molten. DIP QFN package in solder flux, place straight onto the PCB
pads. With plenty of flux, the surface tension should allow the chip
to self align to the board, as well as prevent shorts.
4. Inspect all pads with a high magnification Loupe. The solder should
have a good curved joint with the outer exposed pads of the QFN and
the pad. If not, apply plenty of solder flux on all 4 sides, proceed
to "poke" the pads with soldering iron.
5. Electrically inspect all connections with multimeter.
The method seems to work for me so far. I will be interested to see
what methods you guys have in mind?
Cheers,
Crispian