Problem with jerky cutting

Androcles

I just recently got my DDCS V2.1 and have been setting it up and doing some test cuts.

I am having some problems with jerky moves when cutting

I have uploaded a video of it here: https://streamable.com/89y5h

I have tried with very low acceleration (100mm/s^2) and high (1000mm/s^2) and some values in between.

It seems as it is en exact stop mode G61 but inputting G64 (CV mode) does not change anything?

Any ideas?

Thanks

Best Regards
Andreas Landsfeldt

Androcles

I am using Solidworks with HSMworks ie. Fusion 360. I have tried a lot of different post-processors including the one listed on here http://www.brainright.com/Projects/CNCController/

I have tried with different pulses/mm - 200, 400 and 800 pulses/mm, and oddly enough at 400pulses/mm one of the points where it "stopped" disappeared but the other ones remained.

Here is a video of the machine cutting the file that I have attached.
https://streamable.com/kaax1

It is very odd how it is in the middle on both sides but not in any other places.
I have disabled circular motion in more than one plane in the postprocessor along with helical moves.

EDIT
I can't see what the problem could be with the toolpath from HSM
I attached an image of it also.

Androcles

Hey
Thanks for all the feedback and the time you guys spent testing it!

So i tried a lot of different things.

Rotated the workplane so that the long side was along the X-axis (Y-axis before). And oddly enough the jerky motion now came at det endpoints instead of in the middle like in the video...

Seems very odd, so I adjusted the closed loop stepper drives and even did a factory reset, still the same.
But I really dont think that something is wrong with the motor or drives but I could be wrong..

I then saw the Feedrate display on the DDCS, and it made a noticeable slowdown when reaching the problemarea.

With low acceleration
https://streamable.com/75l0t

With high acceleration
https://streamable.com/3ntr1

It is almost as if there is som slow feedrate command in the GCode.

I also tried flashing an older firmware, did nothing.

What firmware are you guys running?

Thanks in advance again.

Androcles

71taa

Thanks a lot for your detailed post. It seems identical to what I have tried also our settings a very alike.

I tried installing the newest firmware again, and at first it seemed like it worked a lot better, but the after short time the decelerations came back...

It really seems like it can't handle the code and being able to time the pulses correctly, but it should be more than capable of that with my settings (currently turned the pulses/mm down to 160 as I have been using that always with mach 3 and 4.

Tried bumping up the feedrate, and this is how it behaved
https://streamable.com/n0v3n
A lot more irratic motion

Androcles

"alexwalex"
I just tried using your settings:
"34,35 - 800
45,46 - 1000
263,264 - 2000
99 - 1000"
and oddly enough when i changed the acceleration parameters in manual mode to your values it stopped doing the jerky moves. Those accelerations were far too high for my machine though because of the inertia in the gantry.

But then I reverted and used the following values:
34: 160
35: 400
45 and 46: 100mm/s^2
263 and 264: 100mm/s^2
99: 300mm/s^2

And now it runs the file smooth..
It seems as if there is something weird going on with this controller...

"ytliu"
The file is the same as the one I uploaded earlier. And here are my current settings attached were things are working but maybe you can spot something weird.

Androcles

I am completely at a loss right now...

I just tried the attached file and it was really bad, it looked like the machine could have ripped itself apart.
Here is a video of it.
https://streamable.com/gs4uf

With the settings in the attached pictures.

I also tried lowering all the accelerations to 100mm/s^2 but it was completely the same as in the video I linked to.


What the hell is wrong with this controller, movement with the mpg pendant is smooth as ever and it seems like it is using the parameters for manual control but when excecuting G-code it is just al over the place and troubleshooting is nearly impossible...

Androcles

Okay, it seems to be working now, adjusted the steps so they are the same on all axes.
The weird thing is that I started with it like that, 160pulses/mm on all axes, and it still failed as shown in the first video.

But I will try to post back here if it gives me trouble again.

Thanks a lot for all the help, really appreciate it!

BTW, are there any new functions/features planned for this controller?