26-08-2016, 08:56 PM
(26-08-2016, 06:47 PM)Dick.1 Wrote: I'm on the lookout for some scrap boards with these on that I can practice on first as it's been a while since I worked on anything anywhere near this "small stuff"
That's an excellent plan
On some boards, the components will be glued in place before wave soldering, so that makes removal difficult.
Others will have been soldered using "reflow", where the solder paste is applied to the pads, the components are placed on the board, and then the whole lot is put in an oven. It's fascinating to watch (check YouTube), as when the components are initially placed, they aren't done especially carefully. But as the solder melts, the components are brought into alignment by the surface tension of the molten solder. Magic!
Some folk have made their own reflow ovens using small toaster ovens and custom controllers. The hard bit is the "thermal profile", as the temperature has to be carefully regulated as it follows a carefully determined set of numbers during the process. Not something I've tried, but lots of info out there if you're curious...
"Reflow" obviously works best for boards that have the SMT parts on one side. Frequently, that is done first, with the SMT parts on the top of the board, and then the through-hole components are picked/placed and the board then goes for wave soldering.
So it's best to find a board like that, where there's no glue to get in the way...
