In a message dated 12/7/2006 6:24:44 A.M. Central Standard Time,
rwskinner@... writes:
What do you reckon a person could build there own PCB Drill for, if they had
to buy all the components?
If you have the TIME to read through hundreds of "ad pages" in magazines and
buy and try steppers and hardware offered, and have patience to live-over
having wasted much money, and you are a VERY good hunter of such goodies, you
might cobble something almost-useful for $1000. But if you want to have SOME
success within weeks of beginning, so buy KNOWN-USEFUL steppers and good
drives like the Xylotex or Gecko drives, and can design a decent buffer PCB with
at least a 74HCT541 and preferably a 74HCT02, etc., for "motor-on/off latch,"
etc., and want it to WORK well, you will need at least Bishop-Wisecarver
rails and ball-bearing "V-wheels", and/or Thomson or equiv. linear ball bearings
and hardened round-ways, and know HOW to mount all that properly. You will
also need some decent quill-motor like a Proxon, or, if you are creative, a
400 Hz. 3-ph. motor with 1/8" collet/nut on its shaft, VERY precisely mounted
to that shaft, and a 400 Hz. inverter circuit to power that. But this
high-freq. approach DOES take some experience with things-electronic, though the
result is FAR superior to a "brush motor" (aka "universal motor"). Also, you
can get away with GOOD ACME screws and PRELOADED Turcite (glass-filled
Teflon) nuts from one of the "precision screw makers" like Ball Screws and
Actuators or a couple of others, names I cannot recall as I have never actually used
other makes of screws.
Plan on using excellent cabinetmaking expertise and Baltic birch plywood for
the carcass, and preferably light-colored Formica for the top, so
double-stick "poster tape" will work well thereon, without doing damage. It takes some
years of fiddling with such to be able to cobble something that works OK, if
you are just beginning to brew your own such machinery.
After all that, if you do not waste and build efficiently, you might do it
for less than $2000. I am envisioning "about what I have in MY PCB drill",
and what I'd do differently, were I to do an all-new one, and I am CERTAINLY
not including all the "learning expenses" of 35 years of home-brewing.
Carbide PCB drill-bits INSIST upon slop-free movement, and logic that
ENSURES the drill is UP and STEADY before moving to the next X,Y begins, and STEADY
for drilling. Jan Rowland
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