Re: Heck of a time tuning servo motors.

--- In CAD_CAM_EDM_DRO@y..., "Dan Mauch" <dmauch@s...> wrote:

> A shoptask should have a 3:1 ratio timing pulley set up with a

14XL037

> timing belt pulley on the motor.
> Next, it sounds like you have either or both your gibbs and your
> backlash is set too tight. The hand wheels on the XY axis must turn
> freely with no apparent drag.
> Dan
>

Hey Dan thanks for the reply.

Since the servo motors I am using have 3/8" shaft I may have
difficulty getting down to a 3-1 ratio. You mentioned this in a
previous post, but I assumed that my servos would be so powerful it
wouldn't really matter. I think that my backlash is definitely set
too tight. In some experiments I did last night with my Y axis gibs
set more loosely the system behaved a lot better. I think with a
little servo tuning it would work well.

I had set the lash really tight for manual work, and hopefully with
lash compensation in software I will have a workable system with it
set up a bit loose.

The real problem with this approach is in the Z-axis (mill spindle).
There's no easy way to loosen this up without making it useless for
plunging/milling. I think since there is a bunch of room up there I
am going to fashion a second stage of reduction and try to get to 4-1
or 6-1 on my z axis giving me a ton more torque. I'm looking at
timing belt pulleys right now. A little machining on the plate and
an offset bearing mount and it should work.

Of course all of this exercise has gotten the light bulb to go off in
my head why everyone is using ballscrews. Originally I had thought
that they were just "kinda nice" Now I'm convinced they are really
nice and almost required.

Thanks for the suggestions.

-Erik Reikes