Re: deepgroove Z-axis

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Danny Miller <dannym@...> wrote:

>
> I'm setting up a deepgroove CNC kit with the 280oz steppers, the
> deepgroove controller, and Mach3.
>
> I am having some trouble with the Z-axis.
>
> I've got the parallel port pins set up ok. The directions go the way I
> expect.
> I configured it at 32000 step/in and the travel seems to agree with the
> Mach3 location measurements.
> X and Y axis did fine at say 30in/min acceleration 4.
>
> Z, not so much. I was running 5 in/min acceleration 0.5 and it's still
> kinda dicey near the bottom of the travel. It's difficult to get it to
> go up without skipping when it's near the bottom of the travel. Also
> even mid-screw going up you lay a finger on it firmly and you can stall
> it, not sure if that's "reliable". And 5in/sec is REALLY slow, but 10
> is less reliable. At first I wanted to attribute that to the obvious
> weight of the spindle head and motor since it seemed to be a going-up
> problem, but in fact it won't go all the way down without getting stuck
> either. About 3/4" from the table, going down, and it stalls out.

With

> the controlled off, I can tell it's harder to turn the knob in the up
> direction than down as expected, but I don't feel a specific
> obstruction or odd-feeling resistance. Couldn't really compare the

feel

> when it's at the "bottom" vs higher side-by-side because there's so

many

> turns between them.
>
> I played with the freq, no real change.
>
> Next I pulled the motor. It does go up and down freely now. The nut
> can kiss the table. The head can go up and down at 30 in/min.
>
> Is this a normal problem for the z-axis? What can I do about it? Is
> there a break-in procedure I didn't find?
>
> Danny
>

Move the Z motor over to the X or Y axis and jog using that axis and
see if it does the same thing. If so it's probably mechanical in
nature. If not you may have a bad drive or the current limit is set
wrong on Z.