On Oct 17, 2012, at 7:55 PM, Chuck Guzis wrote:
On 10/17/2012 11:24 AM, David Riley wrote:
I suppose. I've had terrible luck with
bridging, but I never
really kept at it long enough to get much good at soldering
fine-pitch parts. My wife got me a pretty decent iron as a
birthday present recently, though (I picked a good one!), so
I may be doing a bit more in the not-too-distant future (more
so if my QBUS board ever gets off the ground, because I don't
really feel like paying for assembly).
Speaking for myself only, soldering TQFP isn't terribly difficult--I could almost
solder an 0.8 mm lead pitch QFP without my glasses. 0.5 mm for me requires a binocular
loupe and careful checking with an inspection microscope. But I've done a lot of it
and had zero casualties, much to my surprise.
Alas, all the QFPs I want to use for my current project are
0.5mm pitch. :-\ But my eyes aren't so bad. And I have an OK
iron now, which should do a fair sight better than my old 30W
Weller firestarter.
I've done 0.8mm QFP in the past, it just required a lot of
cleanup. I moved to a toaster oven for "production" (i.e.
greater than 5 piece) quantities, which worked well enough;
only a bridge every other board, which was easy to clean out.
What I find more of a problem are SMT transistors and
other tiny multi-lead components. It takes a fairly steady hand to get them just right.
For two-leaded components, you can just let the component find its own place floating on
two molten solder pads.
Discretes are something I'm OK with (transistor and other).
They can be a bit of a pain inasmuch as they tend to stick
to the iron for me (or, for 0402 discretes, to the tweezers),
but I've never destroyed one except for maybe a few resistor
arrays.
Hey, if I can do it, anyone can. I started with a
100W American Beauty iron wiring point-to-point (lesson to be learned: Look before you
grab). PCB was a learning experience and SMT yet another one. I still don't know the
right way to handle BGA packages doing manual assembly, so I steer clear of those.
I see a lot about hot air reflow machines, which can be
acquired for right around $100 from SparkFun. The videos
I've seen make it look very effective, and it's probably
the next major piece of equipment I'll invest in. For
the curious:
https://www.sparkfun.com/products/10706
For the moment on my projects, I'm avoiding BGAs because
I'd like to avoid paying for assembly and I don't have
a hot air reflow machine.
- Dave