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New with very slow drive problems
« on: February 12, 2011, 12:48:26 PM »
Hello all

This is my first post on this forum and I have some issues with my mach 3 setup.  I recently bought a small cnc 4 axis mill with a Geckodrive 540 controller.  I have had some success moving the axis but they are moving at a much slower rate than Mach 3 says they are moving.  I have the steps per calculated correctly because the mill does travel the correct distance when I run a simple program but I am not getting anywhere close to the correct velocity.  Mach 3 says I should be moving 37.5 inch per min but I would be surprised if the drives are even moving 1/100 th of that speed.
The second issue I am having is that I can only moving the axis with a written G code program.  I am not able to jog the axis with the buttons on the screen or my keyboard directional keys.

Any help would be greatly appreciated. :)

Offline Hood

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Re: New with very slow drive problems
« Reply #1 on: February 12, 2011, 09:42:24 PM »
Can you please attach your xml file.
Hood

Offline djc

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Re: New with very slow drive problems
« Reply #2 on: February 13, 2011, 04:05:19 AM »
...Mach 3 says I should be moving 37.5 inch per min but I would be surprised if the drives are even moving 1/100 th of that speed.

...I am not able to jog the axis with the buttons on the screen or my keyboard directional keys.

You don't have feed rate override enabled do you?
Is the speed problem the same with both G01 and G0?

You don't have jog disabled do you?
Re: New with very slow drive problems
« Reply #3 on: February 13, 2011, 11:44:31 AM »
Thank you for the replies.  I have the same slow problem with G01 and G00, I also tried with G02 to cut an arc and of course it was still slow.  I was able to get the axis jogging, it turned out I had an absurd number in for the acceleration.  I tried feed override but it did not seem to change anything.

Hood, I will attach my xml file as soon as I find time to go get it.
Re: New with very slow drive problems
« Reply #4 on: February 16, 2011, 10:16:44 PM »
Hood, I have attached the xml file, sorry for the wait.

Offline Hood

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Re: New with very slow drive problems
« Reply #5 on: February 17, 2011, 03:15:03 AM »
You are not likely going to have much luck with the motor tuning you have, steps per may be correct at 40,000 and likewise for Velocity but I think your steppers will instantly stall as you have an acceleration on X Y and Z of 4000
I would think a more likely value for that would be in single figures.

Hood
Re: New with very slow drive problems
« Reply #6 on: February 17, 2011, 01:19:41 PM »
Changing the  acceleration to very low values, below 1000 has a very noticeable decrease in acceleration.  With the acceleration set to 4,000 the motors accelerate to their top speed in about 1 to 2 seconds but yet again the top speed is still very, very slow.  It almost seems like the clock that tells the program what the duration of a minute is, is off.  I think this because both acceleration and velocity are considerably slower than they would be if measured.

The steppers do not stall, they accelerate very slowly when I use an acceleration in the single digits.  The steppers take over 1 minuet to get up top speed with an acceleration value of 4.

Offline Hood

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Re: New with very slow drive problems
« Reply #7 on: February 17, 2011, 02:11:46 PM »
Well that sounds like something is way out of whack in motor tuning or with your drive setup

What micro stepping are your drives set to?
Is there gearing between motors and screw?
What pitch are the screws?
Hood
Re: New with very slow drive problems
« Reply #8 on: February 17, 2011, 02:29:27 PM »
the micro stepping is 10
there is no gearing between the motor and the screw
the screw is 20 tpi.

Offline Hood

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Re: New with very slow drive problems
« Reply #9 on: February 17, 2011, 02:40:50 PM »
Your steps per are correct then, something very weird going on as no way in the world will you manage an accel of 4,000 I/s/s and from what you are saying its definitely not going anywhere near that anyway. Your vel is  if I recal about 70IPM so with an accel of 4000 i/s/s you would get to top speed before you pressed the jog key ;D

Have you tried increase the pulse settings on the motor tuning page? try 5  for both and see if that helps

Hood