On Thursday 10 August 2017 00:01:38 Kirk Wallace wrote:
> On 08/09/2017 11:33 AM, Dan Bloomquist wrote:
> ... snip
> > You made me look. :) My wheels have no markings so taped a piece of
> > paper and made pencil mark. I mounted a .0001" dial indicator. I
> > can't see any backlash, just my wheel is sloppy. The wheel is 6 1/2"
> > in diameter and to get a .001" move, the outer rim moves ~.075".
> > This is an integrating solution to an accurate setup.
> ... snip
> I'll try to remember to take pictures of my dial setup and post them.
> Each dial is housed in the box where the motor to screw coupler is.
> There is a window on the box for viewing the dial. One problem I have
> is that the stepper drivers are setup for quarter stepping so I have
> 0.00025" jumps. I can see this on the dials well enough, but the DRO
> display increments between these steps and I feel compelled to work
> out the DRO value at the time the last step trips, which wastes a bit
> of time. I replaced the x axis driver with an MA860H which has
> micro-stepping. The MA860H doesn't sing like the old drives and it can
> use twice the voltage. I'd like to change out the other axes when I
> can get around to it.
The MA860H I have has a rather poor step vs current mapping, I cannot
reliably feel the 8th step in a /8 setup. Adjusting the current up or
down one notch should effect it if its iron saturation, but that has no
detectable effect. I've an auto tech drive of the same voltage rating
and a hair more current I've been intending to swap it out for, but I'll
likely put a 960 oz motor in at the same time as that one is the 1600 oz
that was originally on the mills heavy Z. I took it off because the
missing step caused stalls at anything over 26 ipm on the mill. Its
geared down some on the lathe, but the lack of dead weight lets it move
the z almost 90 ipm. The 960 will probably do 150+ ipm. Overkill IMO
when x is stuck at less than 40.
Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
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