Jerky movement with UCCNC

[ger21]

Change your error tolerance from .03 to .005.
I think the .03 is for metric setups. That should smooth out what you are seeing.

The plan is cut out of walnut so I know that I need to slow it down some

It depends on your RPM, but with a 3 flute bit, you should be able to cut even faster.
I typically cut hardwoods at 300-350ipm with a 1/4" 2 flute bit. With a 3 flute, you can cut 50% faster.
What works best depends on machine rigidity.

[Beardie7]

Gerry ,

Thanks so much. There are so many parameters to test that I would have been pulling my hair out trying to figure that out. If it wasn't for the several forums that have so many trials and errors, I don't think that I would be able to get it all together.

"Standing on the shoulders of giants".

My rigidity is a bit in question from the spoil board down. I have been planning to get the CNC to fashion up some custom end panels before I then bolt it down to the floor. I plan on cataloging some of my mistakes in design so others can avoid them.

Thank again,
John

[digger]

Heiko. Removing arcs, turning off smoothing, in fusion 360 did the trick for me as well.

Per

How do you remove arcs in fusion?

[Blugreen]

I stumbled across this post while trying to find a fix for this after switching from Mach3 and suffering jerky movements. I spent a few hours making changes and cutting circles to have them all be 40 sided coins.

I use Artcam for my CAM software and was using the Mach3_4 Post Processor. I found that using the Mach4_4-Arcs post processor fixed my issues and I now get perfect circles.

Hope this helps someone else.

[cncdrive]

To resolve this issue, you just have to set the CV tolerances as tight as you want. (linear unify length and linear addition length)
If you set those tolerances loose then the controller has the freedom to make large path errors that is how a circle can become a 40 sided coin.
So, remember that you allowed the software to do that with allowing high tolerances.