View source for Operation Solderable

The electronics industry is moving towards using smaller and smaller packages. Indeed, some components, such as gyros and accelerometers, are only available in [http://en.wikipedia.org/wiki/Quad-flat_no-leads_package QFN packages]. Currently the only way we can solder these types of components is through a rather [[PCB_Manufacturing#QFN_Packages | 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 [http://www.sparkfun.com/ overpriced boards], saving us '''a lot''' of money.

Join the discussion at icrs-operation-solderable@googlegroups.com. Sign up [http://groups.google.com/group/icrs-operation-solderable here].

Below are a few Ideas of what can be done.

== DIY solder paste stencils ==
We might be able to use a [http://www.zblob.com/solder_paste_stencil.html laser] [http://www.buildlog.net/blog/2011/09/diy-solder-stencil-on-a-diy-laser/ cutter], a [http://www.flickr.com/photos/sgk/6290703292/in/photostream/ vinyl cutter], [http://www.instructables.com/id/Making-stencils-for-solder-paste-at-home/ chemicals], a [http://www.youtube.com/watch?v=Mq-JrfIW24s cnc mill] or otherwise, to make our own [http://www.sparkfun.com/tutorials/58 solder paste stencils]. This will enable us to consistently solder difficult SMD components, without the cost of buying professional solder paste stencils.

We have access to the [http://wiki.london.hackspace.org.uk/view/Equipment/LaserCutter london hackspace laser cutter]. However, it has limited precicion. If you know of a better one, please let me know! -- [[User:Madcowswe|Oskar]]

=== CNC Drilling ===
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
* thermistor/thermo-couple
* microcontroller
* 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.