Hello Guest it is August 23, 2019, 01:24:13 AM

Author Topic: Jerky Movement on combined X-Y Movmenet 3 Axis CNC Router  (Read 12706 times)

0 Members and 1 Guest are viewing this topic.

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: Jerky Movement on combined X-Y Movmenet 3 Axis CNC Router
« Reply #10 on: June 14, 2011, 06:51:07 PM »
In fact your Y is even higher at over 100KHz, are you using the parallel port? If you are you are going to have to slow down on Velocity in motor tuning.
Hood
Re: Jerky Movement on combined X-Y Movmenet 3 Axis CNC Router
« Reply #11 on: June 14, 2011, 06:55:25 PM »
Oh! Ok!

I'll ask Pete from CNC Teknix to look at this for me as I have little to no idea how to change that!

The computer is an Basic PC runing Windows 7, so i think it should have the capacity in my humble opinion!

Thank you greatly for your assistance!

Added: - I'm not sure how CNC Teknix have set up the outputs to the machine, I will ask Pete to check this out as a possible cause of the problems!

May i ask, Are we covering up the problem by setting the CV settings differently? I set the "Turn CV mode off on angles>" to 8 degrees this morning and it has made a massive improvement, but it is still not 100% spot on!

Many thanks again, I really appreciate the support you have all shown!

Regards
Rob.
« Last Edit: June 14, 2011, 06:57:46 PM by Signdraft »

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: Jerky Movement on combined X-Y Movmenet 3 Axis CNC Router
« Reply #12 on: June 14, 2011, 07:02:43 PM »
If you are just using the parallel port then you have the axis velocity way too high as you can not get that frequency
If you set the Velocity for X  and Y axis  to 6500 and Z to 2500 and the kernel to 45KHz and see how things go.
You may be able to go faster but just set these for a test.
Hood
Re: Jerky Movement on combined X-Y Movmenet 3 Axis CNC Router
« Reply #13 on: June 14, 2011, 07:07:17 PM »
Thanks for this Hood!

I will ask Pete to have a look at these settings when he gets here to continue the Tuning!

I thank you greatly for giving us the lead on where to look and what to try to resolve the issue!

Regards
Rob

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: Jerky Movement on combined X-Y Movmenet 3 Axis CNC Router
« Reply #14 on: June 14, 2011, 07:08:37 PM »
I cant see how CV settings would help where you are having the issues butthen again if motor tuning and kernel are screwed up then its possible that its helping.

All of the above is of course only true if you are using the parallel port, if you are using something like the SmoothStepper then it can pulse much faster so your motor tuning may well be correct.
Hood

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: Jerky Movement on combined X-Y Movmenet 3 Axis CNC Router
« Reply #15 on: June 14, 2011, 07:11:56 PM »
Ah ok just looked in your xml and you are indeed using the SmoothStepper. I will load the same plugin you are using (17bd) and see if there are problems with your SmoothStepper config.
Hood

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: Jerky Movement on combined X-Y Movmenet 3 Axis CNC Router
« Reply #16 on: June 14, 2011, 07:16:44 PM »
Had a look at the SS config and it seems reasonable, I would however set X axis to 65KHz and Y and Z to 128KHz and the other axis to the min of 32KHz. It likely wont help with your issue but its best set that way to reduce overheads.

Hood
Re: Jerky Movement on combined X-Y Movmenet 3 Axis CNC Router
« Reply #17 on: June 14, 2011, 07:28:25 PM »
Thanks Hood!

Many weeks ago we had a fault on the screen, which mentioned the smooth stepper! I cant remember the exact fault but it was a LARGE dialog box, Some of the warning dialog i had written down was:
"Smooth Stepper V17bd”
“Smooth stepper ran out of data….. blah blah blah…. You should home before proceeding……”


I will discuss this with Pete when he gets up,
Thanks again!
Rob.

Offline BR549

*
  •  6,886 6,886
    • View Profile
Re: Jerky Movement on combined X-Y Movmenet 3 Axis CNC Router
« Reply #18 on: June 14, 2011, 07:28:49 PM »
That looks like badly tuned set of servos. It will look good on lines that are inline with the axis movement EXCEPT at the tail end of the move AND on diagnal  striaght lines you get the scallop effect.

Look at the end of the inline straight moves it has a BIG overun and correction. Same with the diagnal moves , move overshoot correct back.

Just athought, (;-) TP

Offline ger21

*
  • *
  •  6,288 6,288
    • View Profile
    • The CNC Woodworker
Re: Jerky Movement on combined X-Y Movmenet 3 Axis CNC Router
« Reply #19 on: June 14, 2011, 08:13:52 PM »
Quote
Hi Ger,
I'll check those settings, If it turn CV mode off completely the machine is very "steppy" (each line of code has a slight pause before the next begins, which is slow on the engraving as there are so many lines of code!)

Leave CV on, but turn off all the options.

But again, I think it's a servo issue, and Terry seems to agree.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html