*If you have boards with a tiny BoM consisting of large parts not rotated from their original position in the tape - and have a vacuum pump!
Selling Lixie displays full-time for the last year has made me desperate for a PNP machine to help automate assembly a little bit. I've purchased the $150 Monoprice MP i3 Mini on eBay and printed out accessories to convert it into a rudimentary pick-and-place machine!
As I mentioned above, this only really worked because my board design only uses one type of part, which happens to be fairly large and also all have the same rotation, allowing for assembly by translation movements only.
The vacuum also never turns on and off like it would in a proper PNP, it is just set to be strong enough to lift an LED, and weak enough to drop it once the tacky solder paste has a hold on it.
Since there isn't even vision alignment on this basic machine, (no visual check of parts or calibration using fiducials) alignment of the tray is crucial, though easy to do. A problem I've accounted for here is that LEDs may be sitting crooked or at an arbitrary location in their tape tray. The visionless fix for this was to drop the vacuum onto the LED, then slide it diagonally into the corner of it's tray to get it in a known position/rotation.
There is a small 3D printed "pin" on the print head cover as well, which advances the tape a known amount (to access the next LED to be placed) which was also crucial to consistent alignment.
G-code was manually written for my Lixie board's part positions, no Centroid X/Y data here like a real PNP would have.
That G-code and that jig model only make Lixies, it was all manually designed just for these, so unfortunately there isn't much useful info to open source for you guys that I can think of, but let me know if you want any of the STLs or original Sketchup files to mess with!
17 июн 2018
