--- In
Homebrew_PCBs@yahoogroups.com, "eeks123" <eeks123@...> wrote:
>
>
> > Tacky enough that I have populated boards on both sides at the
same
> > time then stuck in the oven. The parts that went on the bottom
side
> > were smaller items like 0402 chip capacitors, but they did not go
> > anywhere.
> >
> > Of course if you do that you will need to add feet to the board
so it
> > is not resting on the bottom.
> >
>
>
> amazing! when solderpaste gets liquid components should drop..
that's
> a question i was making myself, is it possible to populate
components
> on both sides when reflow-soldering? i thought you had to hand-
solder
> components on the second side, if not, bad things would happen..
>
Hi Eeks,
Yes! The smaller chip components will not fall off - surface tension
holds them pretty tight. Even if you give the board a little jolt
while the solder is molten, they will generally still not fall off.
You can even put larger components on the bottom of the board, such
as quad flat packs, SOICs, SOTs, SMT electrolytic or tantalum
capacitors etc. but to do that you need to put a tiny little dot of
glue underneath the component before you place it.
It is a bit dicey doing this by hand though, because when you place
the component it needs to be lined up perfectly - you can't use the
surface tension to help you with pulling the component into alignment
in this case.
I've done the glue dot method at a factory before. We made a stencil
just for applying the glue. Then the board went into an automatic
pick and place machine to place the components on top of the glue
dots.
Anthony Burch
http://www.SuperSolderingSecrets.com