I've got to build at least 50 boards that have 384 LEDs each (a 24x16 array). I've looked at a couple of assembly services like Advanced Assembly and SeeedStudio's Propagate and at qty 50 their prices are just too high. On the other hand placing them manually takes about 45 minutes each and I'm not relishing the prospect of 38 hours tweezing almost 20,000 pieces.
I'm building a CNC Dremel mill right now and am getting a good understanding of stepper motors etc. so I'm thinking it will be possible to build a pick and place machine too. It will only need to pick up 1206 size components and because the placement grid on the PCBs is well-defined I won't have to use any optical alignment, rotation, etc. so it seems like it's doable.
I've seen some DIY pick and place builds on the web and think I can build most of the parts, but I'm having trouble figuring out how to make the component tape advance mechanism. It needs to hold the tape so the head can pick up a part, pull the cover tape off, advance an exact amount to the next component, etc.
If anyone has any links to resources on how to build (or buy and integrate?) a pick and place tape feeder I would appreciate it.
Tape and reel seems to standardize on 4mm sprocket hole spacing (but not sprocket hole shape?) - this matches Super8 film by the look of it - find an old scrap Super8 projector mechanism maybe??
@MarkT - Good idea on the Super8 projector idea. I will check it out, thanks!
@terryking228 - I've seen you post about being in Italy before, I am very jealous. My family is from north / east of you, from a little village near Trento.
Here's a couple videos of what I'd like to build:
I'm only placing LEDs on these boards -- they're driven by TLC5916 constant current drivers and MOSFETs controlled by an ATMega328 on another board.
If you can make a pick and place you'll have no problem advancing the tape. Your going to have to hook up to whatever software your using to run the steppers(emc2 or mach3 I would imagine), use there api and everytime a piece is taken you advance the tape. Also you have to program where the items are in the first place. If you have a little programing experience it shouldn't be to hard or maybey it's time to learn? Plus I'm sure someone has the whole process documented maybey...Also rotating the head is important which adds another axis and when you pick and place sometimes it's not perfectly aligned so a little feedback is needed...usually from a camera but i've seen other ways of dealing with that online.
If you can make a pick and place you'll have no problem advancing the tape.
Haha well then I suppose this is a chicken and egg problem. How do I make the pick and place machine? Specifically, the tape feeder. I don't have access to a 3D printer so I'm looking for help on building the feeder out of readily available parts.
my thought is by the time you make something functional you could have done it by hand Maybe you can get a couple buddies to help out (get pizza and beer)
I feel your pain though, we had to get 10 prototype boards of similar count out at work and our stencils are MIA somewhere from the maker to us, it took two of us 2, 11 hour days to put it together.
the feeder is more or less a gear, and a few wheels, ours are spring loaded ratchet jobs but those are real pick n place machines for high speed and volume
my thought is by the time you make something functional you could have done it by hand
That's what I'm afraid of. I do have a working CNC mill and in the fantasy world of my head I thought I could just replace the Dremel with a vacuum tip, but unfortunately it looks like there's a little more to it than that...
well with a mill there you still might be able to, you just need a way to peel the tape, and hold it in place while the head picks it up ... (sounds simple right lol)
Maybe you can get a couple buddies to help out (get pizza and beer)