G2/G3 issue

[girogiri]

Hello all,

we are having the following issues: depending on "linear error / linear addition" values some arcs (G2 and G3) go completely wrong when Feedrate is at around 3000mm/min.
Even worse, hitting stop or pause button while the machine is in the wrong position, cause a rapid of the machine to the previous ( sometimes) next point in the Gcode: in our case the rapid is 20.000mm/min
This is enough to snap the endmill and creates a safety problem as the machine moves unexpectedly after the stop command.
I have videos and files available for testing.

Thanks
Giorgio

[cncdrive]

Hi,

Which version of UCCNC are you using?
There was an issue found with very high feedrates and very high resolution and with some arcs, this issue was resolved in the latest development release, can you test that please to see if it resolves the issue?

[girogiri]

Hello Balazs,

We are using the .2115 version, same problem as in the previous.
If you want I can send files and configuration to reproduce it

Cheers Giorgio

[cncdrive]

OK, please upload the files.

[girogiri]

Hello Balazs,

pls find attached the .pro file and a stripped down version of gcode. The problem arise if "linear_addiction" is set greater than 5.
When the arc is executing and machine is out of position, if we change Feedrate or pause the execution, the machine goes back to correct position at hi speed.
Feedrate has no influence on this issue.

We also have a similar issue with tangential axis, I sent you a couple emails about that.

thanks
Giorgio

report.nc

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Default.pro

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[cncdrive]

Dezsoe, please test this and report the result to me.

[girogiri]

Hello,

news on the G2/G3 issues?

thanks
Giorgio

[cncdrive]

Not yet, but the problem is probably that an issue in the code optimiser, because the arc code in your g-code program is very unusual, it is a very small part of a vary big circle, so probably the starting end endpoints are so close enough that the software thinks that the programmed circle is a full circle instead of an about null circle.
But we will investigate the issue further soon, we already started working on it, but it takes time...

[girogiri]

why if you change feedrate or pause while executing the whole (wrong) circle, the machine moves very fast to the correct position?
We also have a similar problem when we use the G68.

[cncdrive]

I don't think that I will be able to answer your question, I mean it is probably a bug and we working on finding the reason and eliminating it.