Many parts can't be recognised visually. Capacitors are the obvious example.
On Sat, Jun 25, 2016 at 6:11 AM, Chris Albertson <[email protected]> wrote: > The ideal hobby use pick and place machine would be very different > from a commercial machine. Lets say I want one board made. What I > want to minimize is my time. With a conventional machine by FAR most > of my time is spent setting the machine up. In fact setup is so slow > that for smaller PCBs I could do it with tweezers in a fifth of the > time needed to set up the machine. > > So a hobby machine must be designed such that you could get it going > in nearly zero time. In the ideal case you drop the parts all mixed > up, (but right side up) in a small tray. They are mixed and in random > orientation. then you give the machine your PCB design file (not a > special pick and place file) and then a vision system IDs the parts. > Today vision is dirt cheap. > > But the 3D printer needs one more degree of freedom. It must be able > to rotate the part (or the PCB) as it is unlikely the part on the tape > or tray only needs translation to the PCB, likely ration is required > in almost all cases. > > I think a hobby machine would only be successful if it could reduce > the setup time to nearly zero and for that it would need a really good > vision system that could hunt down randomly placed parts. It would > have to work pretty much like you or I would do the job manually. But > we have software like openCV and good "board cams" with M7 > interchangeable lenses for $35. A vision system actually saves a ton > of money because the machine need not be so precise as vision closes a > feedback loop. > > Also how many hobbyists are going to have reels of parts? I might buy > some parts by the dozen but most no more than about 4 or 6 at a time. > I don't want a large machine. It should have a working surface, a > white melamine table about 12 inches square and I place the PCB to be > stuffed and all the parts on the same foot square table at any random > location then press the "go" button. The camera scans the table. > This kind of machine would be horrible for production work but a one > foot cube machine that required zero setup is what most of us want. > > Going a little farther. I'd like this SAME machine to actually make > the PCB too. A 3D printer could route the copper and drill holes and > print the solder resist plastic too. > > On Fri, Jun 24, 2016 at 8:56 PM, Attila Kinali <[email protected]> wrote: > > On Fri, 24 Jun 2016 13:59:58 -0500 > > "Graham / KE9H" <[email protected]> wrote: > > > >> Lots of problems to be solved... > > > > Most of these problems are easy: > > > >> How do you take loose parts or cut tape or tape reels > > > > You don't. No loose parts with any kind of pick&place machine. > > As for cut tape, these can be taped on an empty reel to make > > them compatible. Everything has to be in a tray, reel or similar. > > > >> and get the right > >> part out, and into the chuck, oriented in the right direction? > > > > Orientation is defined by the reel/tray the parts come in. > > This is also documented in the datasheet, usually. > > > >> How many different kinds of parts, sizes, shapes, pin counts, IC > >> footprints, can you handle at once? > > > > As many as there is space around the machine :-) > > > >> How do you know it is the correct part? > > > > You put it manually in the right feeder and double check that it > > fits the programming. > > > >> How do you know where the "+" end, or "pin 1" is? > > > > This comes with the orientation of the part in the reel/tray. > > > >> How do you know that there actually is a part in the chuck? > > > > Your trays are guaranteed to be non-empty by manually loading them. > > > >> How do you know the part in the chuck is oriented the way you expected > it? > > > > The manufacturer guarantees that the reels/trays are loaded correctly. > > > >> How do you know where the footprint on the circuit board is located? > (to a > >> few thousandths.) > > > > This is provided by the pick&place file. Usually its 3-5 digits after the > > decimal point, when using mm. But as I wrote before, you don't have to > > place part hyper exact. Being within 0.1-0.3 of the pitch of the part > > is usually enough. Surface tension does the rest. > > > >> How do you know the part left the chuck and ended up where you intended > it > >> to be? > > > > You dont :-) > > > > The way how this is checked is either a pre-solder and/or post-solder > visual > > inspection. This is either done manualy or using a camera system where > > computer compares the PCB to the picture of a known-good PCB. > > As this is ment for a small volume and hobbyist system, doing the visual > > inspection manualy is good enough and more than fast enough. > > > > Attila Kinali > > -- > > Malek's Law: > > Any simple idea will be worded in the most complicated way. > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > -- > > Chris Albertson > Redondo Beach, California > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
