Ok, I have satisfactory method for hand printing solder paste and reflow soldering for my prototype lab. See
https://www.eevblog.com/forum/manufacturing-assembly/beta-layout-reflow-kit-first-try/. I have done my first real board on that, and my process definitely needs some development.
First, placing the stencil could be easier, but I don't think that is a real problem. My next board will have two small holes on the PCB and on the stencil in opposite corners. Then I'll put same size of pegs trough the holes and tape the stencil down. That should do it. Of course, if you have a better idea, please share!
The real issue is placing the parts. I did pretty much what Mike suggested in his video (
), but it was still a chore. The board had 460 components, and besides a couple of connectors, all SMD. For this old guy, that took way too long and became difficult towards the end. My hand started shaking (not much, but with SMDs, you don't want any!) after an hour or so, with two more hours to go. The paste also started going dry (the final board turned out to be fine, though). Definitely something that I'm not looking forward doing again!
Right now, I can't think of anything to improve the manual method. Thank you Mike! You have more or less perfected manual already. Or is he? If you have any tips, hints or ideas, please share!
But I can't help thinking about a machine for this. A hobbyist/prototype pick and place machine could be very simple, basically doing what the manual method does. No automatic feeders are needed. I envision guide slots with the part strips (equivalent of those cardboards (see the video)) and for this purpose, it would be perfectly ok if the control program would do first 40 (or whatever length of the slots are) bypass caps and then ask "please peel 24 more from slot 1". Also, it would be ok if the control program says "First tray finished. Please reload slots: Slot 1: part type xxx (470pF, 0805 capacitor) 24 pieces. Slot 2: ...." The ICs or special components I could place by hand, if the 400+ chip parts would be done by a machine. Or maybe place them pre-oriented to a jig or something.
I would think that with something like this, the 4-5 hours of assembly (with preparation of those cardboard plates) would have been less than one. Not good enough for about any level of production, but a tremendous help for hobbyist or a prototype lab. Not to mention the easy part of it...
I searched, and found some videos and info for DIY projects, but none documented enough to just build one. On the other hand, the videos show that in principle, something like that is feasible. I didn't find any affordable commercial units. Seems to me that this only needs a simplest CNC machine, modified head unit and some software. This project would not pay back to me in time, but it would be so fun.
So, why should't I? Ideas? starting points? (Best starting point that I found with one night searching is
http://www.shapeoko.com/). Or if you know something like the above commercially available (say, less than 1000€), let us know, too.