New Pick and Place design ideas

[jmelson]

About the case of "black component on black tape" (or "white component on white tape").  How do seriously professional feeders that can absolutely, positively move the tape EXACTLY the appropriate distance every time... make sure they can pick up the FIRST of those components after the reel is loaded (to get in sync)?

Well, the feeders on my Philips (made by Yamaha) machine require about 8 mm of tape ahead of the pick-up point to reach the sprocket.  So, you have to spill 3 0805-size parts, or 2 small ICs.  You can put those in a box for later rework, or put them back in the tape later.  This is really not a big problem when you are working with cut tapes of expensive chips, and I never sweat over the couple resistors and caps here and there.

Jon

[jmelson]

That laser component alignment.  I assume that's doing the same job as those "jaws" in the LE40V videos that I posted links to a while back, correct?

Yes, same purpose, but the laser does it better.

I assume that laser alignment means the part gets rotated until the reflection off the side of the component comes back into the open slit (in to a photodiode) under the laser illuminated slit just above... or something like that.  If not, explain how that works.

They use a line-scan chip, as used in old document scanners.  This has a linear array of usually 2048 photodiodes about 25-35 mm long, and a CCD bucket-brigade array to shift out the analog samples.  So, the nozzle is turned until the shadow of the part makes the shortest dark region in the middle of the camera view.  At that point, 2 sides of the part are normal to the camera, the other 2 sides are parallel.  At that same time, the position of the two light/dark edges indicate the offset from exact center.  They then turn the nozzle exactly 90 degrees and again measure the offset.  Now, the chip can be placed correctly, by offsetting the nozzle position from exactly over the pads on the board.

The latest system uses a first-surface mirror that flips down below the nozzles at 45 degrees and reflects a picture of the bottom of all the chips to a number of 2D cameras equal to the number of nozzles.  This allows ID, rotation and  centering of QFN and BGA parts.

Jon

[Kjelt]

You do realize that you are answering posts made over 4 years ago ?

[jmelson]

You do realize that you are answering posts made over 4 years ago ?

Some of them, yes.  But, it puts some info out there.  I'm trying to stir up some new discussion.

Jon