The electronics industry is moving towards using smaller and smaller packages. Indeed, some components, such as gyros and accelerometers, are only available in QFN packages. Currently the only way we can solder these types of components is through a rather messy approach. What we need is a way to do it more consistently and with a better success rate. If we can, we could make our own versions of overpriced boards, saving us a lot of money.
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Below are a few Ideas of what can be done.
DIY solder paste stencils
We might be able to use a laser cutter, a vinyl cutter, chemicals, a cnc mill or otherwise, to make our own solder paste stencils. This will enable us to consistently solder difficult SMD components, without the cost of buying professional solder paste stencils.
Ask Mike Harbour on lvl 1 how small holes his cnc drilling machine can produce.
You could get him to drill holes in a piece of transparency paper to act as a mask. The mask would have round bits of paste rather than square pads, but it would probably be good enough, and you can probably write an eagle script to convert pad locations to a drill file for him. If he can do 10mil drills, accurate to +-4 mils, that should be good enough. If the transparency sheet melts during drilling, you could buy the mylar sheet the pro's use...
Temperature controlled re-flow oven
All thats needed for this is a:
- small bench-top oven
- mains relay
We used to have a small toasting oven that could be modified to be temperature regulated. This oven has since disappeared. What we need now is either to a) find it, b) buy a new one.
Keep in mind that the oven will be operating at solder-melting temperatures, which needs to be taken into consideration when designing how the thermocouple is wired.