Thanks to Ryan O'Hara at Ohararp.com for this information, he provides a stencil cutting service and is recommended!
Supplies you'll need:
- A laser cutter
- Kapton film, I like the 2 mil thick 1 ft square sheets from McMaster-Carr
- Solder paste such as Kester No-Clean
Software you'll need:
This is the PCB we'll be making a stencil for. It only has one chip but of course you can use a more complex layout.
Start up Viewmate and File>Import>Gerber one of the Gerber files generated.
Now we'll export to PDF which will allow for easy importing into Corel Draw. The free version of Viewate doesnt seem to permit exporting, but you can print to PDF which is just as good.
Import into Corel Draw and use raster not vector, to burn away the kapton film. For a 35W or 45W epilog, 30% speed and 100% power at 600 dpi made for a nice clean edge. Be sure to gently rub the stencil with water and a paper towel to get rid of the burnt kapton.
I usually use the Dimension layer info to make a jig for silkscreening by cutting out the PCB outline in a 0.062'' (1/16th) clear acrylic sheet
Here is a LFCSP 16 (4mm on each side) cut out of 2 mil kapton as above.