A few months ago there was a tweet discussing printing solder paste stencils on a 3D printer. Someone suggested we should try it on an SLA printer. After two months I did the experiment.
First of all, I struggled a little to get the 3D model of the stencil. There is a service https://solder-stencil.me/ which is supposed to generate the models of the stencils from gerber files. Unfortunately, when I uploaded the gerbers of my board, the model I got was completely broken. So I decided to write a custom tool. The easiest way was to use OpenSCAD (and finally an opportunity to learn it!).
So I wrote a short OpenSCAD script which takes two DXF files on the input – one for the outline and one for the holes. It also takes information on whether to generate a front or a backside stencil. You can also supply custom thickness, frame thickness, etc. If you use KiCAD I also wrote a simple Python script to export all the necessary files (which allows you to use Makefile to generate all the manufacturing data!) For the reason to me unknown, sometimes OpenSCAD produces corrupted STL files. Therefore I use admesh to post-process the STL files.
