Re: Balancing drivers to motors

Don:

I am not familiar with the Parker drives but is seems like you have a
very workable setup now. One can play with motor drives and spend a
lot of time getting the best theoritical waveforms but I doubt you
will see any difference in the the way your mill behaves. When
performance differences get so small they are hard to measure, are
they worth the bother. I think not. I would just make parts and be happy.

Ken

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Don Rogers <Don@C...> wrote:
> I've been following this group for almost a year now and it has been a
> wealth of information.
>
> I have put together a Taig CNC mill. I am using Parker Compumotor
OEM 650
> drivers, and Pacific Scientific Powermax II M22 motors on X, Y, and
Z, and
> a M21 in reserve for A. My interface to the mill is TurboCNC. I have
> varied the acceleration and max speeds to the point that I can
either make
> a 0.0005" move or a 10.000" move and both are dead on with the dial
> indicator after repeated moves.
>
> The Parker OEM 650, and OEM750 to the best of my knowledge, has the
option
> of varying the wave form from a pure sine wave to a negative percent
of the
> third harmonic. In addition, there are tuning instructions for
Phase B,
> and Phase A offsets via trim pots. This coupled with the Microstepping
> ability of the driver up to 50,800 steps/Rev are leaving me some what
> confused. The old mechanic in me the said "if it ain't broke, don't
fix
> it" is clashing with the thought "if I tweaked this, it might be
better".
>
> I have yet to do very much constructive work with the mill, but what
I have
> done so far seems to work well. I have got the backlash down to
less than
> 0.001" and the ways are tight, but not binding. The X will track to
less
> than 0.001" full left to full right. The Y is dead on, and I still
need to
> do some tuning on the Z, but overall it is ready to cut.
>
> My question is about the waveform shape setup, and the Phase A and
Phase B
> offsets. So far, I have been leaving them to whatever the factory
defaults
> were, or in the case of the offsets, what ever they were set to when
I got
> the drivers. Is there some tuning that I should do or should I
follow the
> "if it ain't broke don't fix it" rule?
>
> Don