In preparation for a workshop last weekend—I populated the ten bare-bones boards I’d picked up from Advanced Circuits (see my last post). I’ve done a bit of this now, but with Brian’s ever-essential help, I got really cruising. The ten boards probably took about an hour with a few hiccups.
Applying solder paste, using ResEnv’s pneumatic machine.
Responsive Environments, my dear friends and partners in electro-crime, have an extraordinarily well-equipped electronics “pen”. This syringe is connected to an automatic pneumatic dispenser with accompanying footpedal—so you can squeeze out a regular bead of solder paste. This is a QFP package—so not the smallest out there—but pretty damn small.
Throwing down Atmel 168s
There’s also a vacuum lift (I don’t know what they’re really called)—but it’s a mechanical arm that helps you place the chips accurately. Sort’ve like a manual pick-and-place. Actually, that’s exactly what it is. Handy.
Toasting the solder paste under hot air
Once all of the components are down, I ran them through the hot-air soldering/rework station—which streams a jet of balmy 260°C air over the boards and melts the solder. It’s pretty cool to watch. As the solder liquefies, it beads up on the pad and lifts the passive components into alignment. So as you run the boards through, as they heat-up, they wiggle into alignment. This can be an issue—apparently—with smaller components (like 0402s and 0201s) which are small enough to be bodily lifted off their pads by the solder ball and “tombstone.”
Soldering on the alligator clips by hand
Large components need to be soldered by hand. These are the alligator clips for fastening the board to a piece of paper.They’re fairly large so take a bit to heat up.
Programming boards with an AVRISP
A nice little trick: you don’t have to actually solder on an ISP header if you have plated vias on your board. You can just hold the headers in the holes. Works pretty well—though I would solder something on if I were debugging. A small army
Hey, not a bad team.
