

SMT Soldering: It's Easier Than You Think (comic) [pdf] - gnosis
http://www.siliconfarmers.com/smtmanga/SMTMangaFiles/SMT_Soldering_Its_Easier_Than_You_Think_EN.pdf

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AnthonBerg
This video shows how easy it is:
[http://store.curiousinventor.com/guides/Surface_Mount_Solder...](http://store.curiousinventor.com/guides/Surface_Mount_Soldering/101)

Through-hole: Fit part through holes, grab iron, tack solder, put iron back,
flip board, grab cutter, cut leads, put cutters back, solder joints, flip
board back.

SMD: Grab tweezers, pick up part, place, tack solder, adjust fit, solder.

Through-hole sucks. SMD is a bitch with the wrong methods and tools, but very
pleasant with decent tweezers, liquid flux, good desoldering braid, Chip-Quik
super-low-melting-point desoldering solder, and a reasonable tip on the iron.
No expensive stuff needed. But the right methods are, which are easily
learned.

SMD has better electrical properties - less noise pickup and lower inductance,
which is necessary for high frequency work.

Certain chip packages are tricky to solder in SMD, like BGAs I believe.
Possible though. And probably easy with the right tools and technique -
capillary action tends to align everything anyway if you can get heat into the
solder.

Very small SMDis not pleasant ... 0805 is a breeze, 0603 is fine, 0402 can be
a bit tense sometimes. Smaller than that is unpleasant ...

You can do SMD soldering!

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HeyLaughingBoy
I can't tell if you are forcing your point or not, but I have to correct.
You're doing through hole wrong: that way will take forever to do a board.

Stuff the board with the smallest height components. Place a compliant
material on top of the board (e.g., firm foam rubber). Flip board over and
solder all components. Put iron down. Cut leads. Flip board over and repeat
for next highest components.

This minimizes the number of tool swaps and handling and is very fast.

That said: I much prefer SMT soldering and I don't even use an iron anymore,
even for just one board: manually dispense paste on all the pads. Place all
components at once. Put in toaster oven. Bake (I manually adjust the profile
while watching the clock). Remove perfectly soldered boards. But yeah, I won't
do anything smaller than 0805 or 0.5mm pitch QFP just yet :-)

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AnthonBerg
Hahha, forcing a point yes, but also just being a little thick and not
'getting' the foam-pad method. THANK YOU.

In real life, doing many through-hole components at once, I have tack soldered
them top-side - when possible, e.g. resistors, not possible for radial caps.

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DanBC
In production environments you buy special frames for that method.

You can also get "cropping plates" and "cropping machines". A cropping plate
is a sheet of steel with holes drilled for all through-hole component leads.
You place a few PCBs on it, then stuff all components. You then place the
plate on the cropping machine, which has "drop down pins" to hold the
components in place and sliding blades under the plate which scrape / cut the
leads off. You then take the PCBs off the plate and put them through a wave
solder machine.

One potential problem with tacking topside (and this is more theoretical than
real) - sometimes the through hole plating is cracked. On a multilayer PCB
this may mean that you don't have proper connection between all layers. If you
only solder from the bottom of the board you can see if the solder has
correctly flowed. Some high-spec jobs will forbid soldering on the topside.
(Aerospace, etc.)

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AnthonBerg
In Japan, even run-of-the-mill home-improvement DIY stores have SMD soldering
supplies :) Good solder, very nice soldering irons labelled "For SMD Use",
even high-quality liquid flux in 50-100ml bottles with a needle tip.

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gouranga
From experience, its definitely not easy (even with a hot air station).

Bring back though the hole components - much more hackable.

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theatrus2
Really? I'm much happier placing SMT parts than through hole. Granted BGAs are
an issue, but everything else is honestly easier.

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gouranga
0402s and below kill me. I did a bit of time doing rework in the 90s and
controlling solder on such a microscopic scale is an absolute bastard. its ok
placing it first time but if you screw up, life is pain. Never tried a BGA and
never want to. They're pick'n'place territory if you ask me.

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DanBC
I couldn't imagine doing 0402 by hand. For people who don't know, 0402 is 1.0
mm x 0.5 mm (0.039 in × 0.020 in).

Using an oven to solder is nice because it's mostly self-correcting. The
melting solder pulls itself to the shape of the pads and also pulls the
components into correct placement. (With a bit of luck).

Hand soldering SMD components wasn't ever one of my skills. (And my through
hole soldering was, if I say so myself, pretty good.)

