Abstract said:
Does anyone here have any "hints" when working with SMT? I haven't tried to
use it yet but I have hundreds of cool components that I'd like to play
around with but I'm afraid that it will just be to much work to do it by
hand. Maybe some of you guys have good hints on how to make it easy to do or
know of a web site that might have some info on it? (I'm also talking about
some of larger pin packages)
Thanks,
Jon
First, Get yourself a nice pair of curved tweezers, especially if you
are planning on doing the work by hand with a soldering iron. This
way, you can lay the butt end of the tweezers on the table, hold them
like a pencil, and press down on the device with the point. This
allows you to avoid holding the device from the sides, which will
result in the part being lifted off the board.
Second, there are a couple of techniques you can practice that will
make it easier. The first, and one I use most often, is to first flux
the board (yes, get yourself a flux pen at least), place the part and
while holding it in place with the curved tweezes, tack one side of a
chip component or several pins of an IC. The other method is to place
a small pad or ball of solder on one of the pads, flux and place the
component, and reflow the solder bump with your iron.
Third, get yourself a good viewer. What you are able to get will
depend on your budget, and they are not cheap, but being able to see
clearly see what you are doing can make a real difference.
Fourth, if you can get a Pace iron and wave tip, do so. With mine I
have put 200+ pin fine pitched flat packs on a board with no trouble
what so ever. The wave tip is also very handy for removing solder
bridges and a lot safer than solder wick which can easilly apply too
much heat to the board.
Fifth, especially if you are using a wave tip, get yourself some good
flux, like an RA or RMA which will make the reflow process much easier
due to the higher level of metal wetting.
Lastly, and VERY IMPORTANT, unless you use an oven with a no clean flux
you MUST clean the board with a chemically compatible solvent. Also
remember, no clean fluxes are NOT no clean in hand processing. No
clean fluxes spread and flow more than any other and unless the flux
gets heated sufficiently, it remains an active acid on the board.
