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Author Topic: "A" Axis Motor Tuning, Varying Loads  (Read 5302 times)

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"A" Axis Motor Tuning, Varying Loads
« on: May 03, 2008, 10:37:22 AM »
Hey Folks,
When tuning the motor for the A axis on a mill for instance, is it common to load the most massive part in the machine prior to tuning ?
Then just suffer from the reduced performance when doing much lighter work ? Or of course loose steps or overload the drive if tuned empty.
Reason I ask: I am contemplating going from a 5lb baseball bat sized part, to a 300lb+ solid wood column.
It seems like the best way would be to "re-tune" for each job depending on its mass.
Any other options ?
Thanks Already,
RC

One other thought, would it be possible/practical to initially tune the motor with no load, then put in the part program something to the effect of : All G0 moves = F### ? That would compensate for the added inertia and would be easy to adjust for varying loads but I have no idea how to implement it.

Another possible option, (but I hope there's a better way), would be to set-up different Mach Profiles for incrementally heavier loads.
« Last Edit: May 03, 2008, 02:01:37 PM by Overloaded »

Offline Hood

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Re: "A" Axis Motor Tuning, Varying Loads
« Reply #1 on: May 03, 2008, 02:50:10 PM »
I am not sure if it is in the latest version of Mach but a while back I was testing out  Rapid Override for Brian, it worked well and was exactly what you were asking about. All you did was set the percentage that you wanted your rapid to be and it would never go above that, obviously 100% was the max.
 However I dont think that would really be the issue for a spindle/A axis, dont really have any experience with that yet but as you are talking AC Servo then I think your drive should manage to keep things on track as long as the motor is suitably sized. If however things do go wrong then the drive will fault and Mach will stop so your work really shouldnt be ruined and you can then slow the acell down a bit or whatever is needed. Suppose really it will just be a case of trial and error. 
Hood
Re: "A" Axis Motor Tuning, Varying Loads
« Reply #2 on: May 03, 2008, 05:39:54 PM »
Hood,
I checked all of the docs I could find and see nothing pertaining to the Rapid Override. But..it would be perfect.

About the servo size....I think a compromise would be OK. I could sacrifice some accel on the big stuff, and be overrated on the dinky parts. That would keep the price down a bit for the components as well as keeping the electrical supply requirements down too.

Any chance of checking with Brian about the Rapid Override? No rush, I'm sure he's busy. I'm just curious.
Thanks Hood,
RC

Offline Chip

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Re: "A" Axis Motor Tuning, Varying Loads
« Reply #3 on: May 03, 2008, 06:04:20 PM »
Hi, RC

It's in ver R3.041, There are no doc's on it, Un-check it to split rapids and feed rate Over ride.

Chip
Re: "A" Axis Motor Tuning, Varying Loads
« Reply #4 on: May 03, 2008, 06:18:28 PM »
Hey Chip,
Thanks for that ! I need to upgrade, 2.62 here and it's not there. Will dwnld tonight. Hideous dial-up takes an hour or 2.
Quick question: Are the 2 sliders totally independent of one another ? Or are they "Locked" together like the checkbox describes ?
Thanks again Chip,
RC

Offline Chip

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Re: "A" Axis Motor Tuning, Varying Loads
« Reply #5 on: May 03, 2008, 06:27:36 PM »
Hi, RC

Un checking splits them up "Independent" of one another, Checked, "Locked" together.

Anytime, Chip
Re: "A" Axis Motor Tuning, Varying Loads
« Reply #6 on: May 03, 2008, 06:49:40 PM »
Doooh ::) Makes sense.
Thanks Chip  :D
Re: "A" Axis Motor Tuning, Varying Loads
« Reply #7 on: May 04, 2008, 06:41:25 PM »
R3.041 finally in.     2hrs 43min
Anyway, The Rapid Override doesnt appear to work with Turn.
The "Lock" option is in config but I dont see how to use it onscreen.
Or am I missing something.....again !
RC

Offline Hood

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Re: "A" Axis Motor Tuning, Varying Loads
« Reply #8 on: May 04, 2008, 06:46:47 PM »
Ah ok forgot its turn you are using, cant remember if I tested it in turn or not, was wuite a while ago. You could try it by adding the slider and DROs to your screenest and see if it works.
Hood
Re: "A" Axis Motor Tuning, Varying Loads
« Reply #9 on: May 04, 2008, 06:55:09 PM »
GOOD IDEA....That thought never crossed my mind.
Would it be possible to duplicate the entire feed control block/window that is in Mill into the Turn screen ?
Thanks Hood,
RC