More Twitter wisdom..
steve at stevestroh.net
Wed Nov 4 17:17:36 PST 2009
I'm a convert to surface mount... with nearly-50 year old eyes and
hand/eye coordination. Keep in mind in all of this that I didn't learn
surface mount techniques voluntarily - my current job does ONLY
surface mount and so I was paid to learn. But, that said, it wasn't
that hard now that a few lessons learned are past.
1. A stereo microscope was a must for me - made the difference between
nearly impossible and pretty easy. You need one that's on a swing arm
that lets you focus on your work surface rather than an elevated
platform (the kind used for examining slides). Yeah - it'll run you a
few hundred dollars, but surface mount will change from NI to PE if
you have one. I don't have a good source, but once I get my office
area finished with the electronics work area, I'll be in the market
for one too.
2. A number of good surface mount tweezers. These come to sharp points
and are made of tougher-than-usual metal so they don't easily deform -
makes a HUGE difference when you're handling small components under
under the microscope.
3. Very sharp tip for your (ESD-safe) temperature-adjustable soldering
iron... replaced monthly or so. Weller makes good ones and the pricier
units are often available rebuilt for cheap.
4. Fine-pitch solder - maddening to use the big stuff on tiny pads.
5. Liquid flux in a squeeze bottle with a needle tip. Put a tiny
amount of flux on the pad, apply just a touch of solder, and then
anchor one leg of the component down and align it gently. Only once
it's properly aligned (including horizontally), then you can proceed
to solder down the rest of the legs.
6. You can gently clean most PCBs in warm running water, using a small
brush to dislodge the flux residue, as long as you have a source of
(ESD safe) compressed air to make sure you get rid of ALL the water
that might otherwise hide under a component.
My current job doesn't use solder paste / reflow except when it farms
out production-quantity surface mount PCBs. For our engineering work,
we hand-solder everything.
That's it in a nutshell.
Also, we use Eagle too, and you're right - it's great.
On Wed, Nov 4, 2009 at 12:49, Jeremy McDermond <mcdermj at xenotropic.com> wrote:
> On Nov 4, 2009, at 2:07 PM, Jeff Francis™ wrote:
>> Well, and ever-shrinking subset of us still builds...
> The honest truth is that it's getting progressively harder to build. I
> built my Elecraft K2, and it was a great experience. I'd highly recommend
> the kit to anyone looking for a significant project.
> That being said, surface mount soldering is just a pain. The larger parts
> like capacitors and resistors aren't that bad, but soldering multi-lead ICs
> is painful. I recently tried to build an Ozy board from the OpenHPSDR
> project, and the two major ICs on the board were a disaster for me.
> Something about sub-millimeter leads is difficult. There's probably some
> trick to it that I'm not getting, but it is getting more difficult to get
> things built.
> I am playing around with a simple project to do switching of audio, key, and
> mic between my OpenHPSDR rig and the Elecraft. It's an excuse to learn
> Eagle, and hopefully I can build something useful.
> Jeremy McDermond (NH6Z)
> Xenotropic Systems
> mcdermj at xenotropic.com
steve at stevestroh.net
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