Re: Freqmod problems

["Shelbyville Design & Signworks" <signworks-at-mcleodusa.net>]

specifics:

Gantry router, 8' x 12' work area
rack & pinion drive
23 frame stepper approx 200 oz-in or so, running halfstep, geared 40:1 with
a 24 d.p. 30T pinion
(step size is about .00025, way to small for routing, but this project
started out with a real small
budget (wife holds the purse strings and we all know how that goes) and the
reducers were already on the machine)
gantry weight is approx 600 lbs +-

(if you've ever seen a Heath/Esab plasma cutter, it's the same machine)

running the table on Turbocnc I can achieve 150 IPM easily,
but no contstant contour.

I am going to be removing the gear reduction and going to gecko 201 drives,
with a 550 oz-in
motor on the x axis, dirctly driving a 20T pinion, it will increase the step
size to approx .0015, this should
help with the speed, but the biggest problem is inconsistent step pulses
(scope confirms this)
with this much inertia, it doesn't take alot to throw things out of whack.


erie patsellis



Shelbyville Design & Signworks
1309 W. S. 7th Street
Shelbyville, IL 62565
(217)774-4444
visit our website at http://216.43.233.169

----- Original Message -----
From: "Hugh Currin" <currinh-at-oit.edu>
To: "Multiple recipients of list" <emc-at-nist.gov>
Sent: Monday, February 11, 2002 6:23 PM
Subject: Re: Freqmod problems


>
> Erie:
>
> What type of machine are you using?  i.e. size steppers and drivers. I'll
bet
> someone on the list has an *.ini file they'd be willing to send you as a
> starting point.
>
> I have freqmod working with 760 oz-in motors, Camtronic drivers half
> stepping, 2:1 reduction timing belts on a bridgeport kneemill size
machine.
> Does this come close? It isn't optimum but may be a starting point. :-)
>
> Hugh Currin
> Klamath Falls, OR
>
> On Monday 11 February 2002 04:03 pm, you wrote:
> > am I the only one who has unsuccessfully tried to use
> > freqmod with steppers? no amount (I've spent at least 8
> > hours on this so far) of pid tuning seems to eliminate following
> > errors. Steppermod.o for now.
> >
> >
> > erie patsellis
>
>