Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Hello,

I posted this in the easy bake group, but thought it might be worth
sharing here also. For members of both groups, please accept my
apologies for the double post. (I've edited a bit and andded some
things to this message)

Ballendo

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Alexandre,

Thank you for the reply. I'll be looking forward to your details...

Now, since you brought it up<G>

Pick and place. I'm pretty heavily into CNC, so the xyx stuff is a no-
brainer, and I've got machines already to use to get started. What
I'm trying to find out is how the tape reels are handled?

I recently received a couple of sample SMT parts that were cut from a
reel, and it appears that a tractor feed of some type is used (like
the old dot matrix printers), along with something to peel off the
thin clear plastic cover film that keeps the parts in their "pockets"
until "grabbed" by the vacuum pickup--at least that's what I plan to
use, unless someone tells me otherwise...

Looking at websites of pick and place mfrs. has not helped as they
don't show much detail in their pictures. If anyone has up close
pictures of how the tape reels of a commercial pick and place machine
are arranged and used, I'd sure like to see them!

The other area that has been covered a bit is placing the solder
paste. Commercially it is printed using a stencil. The archive
mentions that these stencils are expensive. A cnc machine can quite
easily cut the thin material that would be used for stencils. The
only problem might be the rounded ends of the "windows" due to the
cutter radius. What do you think? Would the radius ends be a problem?

I think I'm leaning towards using my machines to make stencils,
rather than adding a paste dispenser. But if I could easily(I really
mean CHEAPLY) add a decent dispenser, it might be a better choice?

Getting back to pick and place... The machine I use most for PCB
drilling and front panel engraving has a 15 inch wide travel, so the
reels would need to fit within that area. If I put reels front and
back, I'd have 30 inches of "width" for parts. I also see vibratory
feeders and manual parts trays on some SMT rework stations. Does
anyone have pictures or information on these?

I have c axis capability(for rotation of a part held in the vacuum)
to ensure that a "picked up" part could be oriented correctly, if the
board required a different orientation than the tape reel it was
picked up from.

Thank you for any replies in advance,

Ballendo

P.S. What would you be willing to pay for a cnc machine kit that
assembles like a bookcase(meaning rather quickly--an hour or two--,
with limited tools), was 12" x12" (or 12"x18") in work area, and
could be used as a pcb drill, solder paste dispenser, enclosure
cutout and panel engraving, vinyl cutting, pcb milling. The kit would
be complete, with software and drives and motors included, and just
needing plugged together.

Is this something any of you would be interested in buying? At what
price? Speed will be at least 48IPM, and if the price merits, it
could be as high as 200IPM, with 90IPM a "reasonable" mid level.

What about a different machine? Smaller, and aimed more squarely at
drilling and milling pcbs? Say 6"x12" area, and slower too, at about
36IPM. Still a simply assembled(screwdriver, hex wrench) kit,
complete with s/w, motors, cables and drives. Waht would be a "fair"
price? (That you would be willing to pay!)