On 11/27/24 01:48, John Dammeyer wrote:
I was in a discussion with a friend about CNC systems. He's acquired a MASSO
box and commented on the superb documentation compared to his UCCNC system for
his router.
My comment was that a standard PC or Raspberry Pi4 (Pi5?) and a MESA Ethernet
Interface like a 7i95 at the lowest level will run simple CNC machines like CNC
routers without fancy tool changers etc.
And I reminded him that the FPGA's on the MESA products have open source
configuration. The question asked was, and I didn't have an answer, how open
source are they really? If someone wanted to do their own PC board layout
could they build an equivalent 7i92H or is there still stuff that's
proprietary? The rest of LinuxCNC is all open. May be a mine field of very
confusing and difficult to understand information but it's there for the people
who know.
Nice as MASSO looks or some other systems I prefer the MESA and PC (or Pi4/5)
solution. But how does one justify a LinuxCNC solution for a simple CNC
system. Not a major overhaul of old iron that gets the old paper tape stuff
thrown out. But a brand new mill from the far east that is retrofitted with
inexpensive AC Servos?
John
I went thru that several years ago when I bought a far eastern 600x400
gantry mill that was 4 axis cnc with BBLB stuff much of which, like the
vfd, was thrown away because It was only manually controllable. The z
motor was too weak to pick up the spindle, and I needed a 4th B axis
too. So the electronics went in the trash trailer, a decent psu was
fitted and at first enough 2m542's found to move xy at 200 ips. I had
then just converted my sheldon to better 3 phase motors. So I bought two
more, put a 1NM 3 phase, a direct, same physical size on the Z at the
same time the OEM spindle had failed, bearings shot. Z can now lift a
kilogram heavier motor quite nicely at 75ipm.
These 3 phase motors are stepper/servo's. Looking for a B axis, I bought
an RVS30 5/1 worm, printed a stick chuck and printed a base for all that
including the shaft adapter for the 3NM motors 8mm shaft to the 14mm
input on the RVS30. So now I have a B axis that can do 500 rpm while
synchronized to Y. Then, wanting to use buttress threads on the vice
screw I planned to make by syncing B to Y. But the 7 degree taper on the
load face looked like a lot of ticklish code to write so I printed a 7
degree wedge to put under the spindle motor and raise it 20mm while I
was at at. Its still there. Bit is a 1/16" RN with 1/4" DOC. Wrote the
code for that, and have now made 9 screws about 50mm in diameter, with
4mm tall buttress threads on double start for a 12mm feed per rev of the
handle. The screw is hard maple, about 12 threads engage the printed
nuts for a leg vise screw about 21" long. There is not a similar vice
making kit on the market at any price.
Someone needed do it and the only volunteer I could find was me... I
also made an air compressor strong enough to clear the chips off the
screw, which if cutting metal can also serve as a mister. 5 little $12
12 volt thingy's, so quiet I cannot hear it over the spindle motor.
Figuring that bit was fragile, I've now made 9 screws and have only
broken one out of a ten pack.
It can be done, but its been a 5 year trip so far. Now I'm rebuilding
much faster 3d printers to make the rest of it, but with only one
printer, its about 2 weeks a screw to make the rest of it. I'm plowing
new ground there too with the stepper/servo tech. Its capable of
printing a minimum of 5x faster than OOTB.
So this 6040 mill has a shelf above it with all the electronics on it.
But I'm running out of time, 40+ years as a DM-II, And now 90 years old.
Cheers, Gene Heskett, CET.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
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