On Sunday 10 November 2013 09:38:22 andy pugh did opine:
> As I appear to have been ignored...
>
> The problem probably is linked to the limited lookahead, but if you
> only notice it when the rotary is involved, then it may be that the
> rotary acceleration is much too low.
> It is acceleration that limits how fast a particular segment is
> allowed to run, and the lowest-accel axis will dominate.
>
> Angular axis acceleration numbers are relatively enormous as a
> consequence of the units. Tens of thousands of degrees/s/s
I didn't go that extreme, but I am likely too low too, I was considering
that the table has no inertia since its geared down 90 times, and was more
concerned with the added mass of the all steel couplings I had made, which
probably weigh about the same as the 425 motor's armature, and are about
the same diameter. Some day I should make a new motor mount, sized 2"
shorter, and using one of the alu flex couplings which would be ounces
lighter. I bought a pag of them on fleabay when I started on the lathe.
But I would also insert ball thrust washers for worm end play which I do
not now have.
That made a large difference in how much movement power actually got to the
XY tables.
Using those, hidden in the bearing hubs on the xy tables, with factorylike
20 tpi 10mm acme screws, a stalled spindle will break off a 1/4 solid
carbide end mill, ditto if it plugs up cutting dead soft alu. I need more
spindle revs and horsepower, about 10x more, badly. 200 watt motor, 2500
revs wide open, sucks. Its a toy.
Cheers, Gene
--
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-Ed Howdershelt (Author)
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our ancestors.
-- Plutarch
A pen in the hand of this president is far more
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law-abiding citizens.
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