Jerky Gerbil (Grbl)

I have played with my feed rates but x-controller doesn’t seem to be able to handle curves very well. FR = 100 IPM G-code from V-carve

It looks like it has a buffering issue. Hmmmm

60 IPM FR. 20 IPM plunge for the tool

Check you artwork it looks like a lot of nodes instead of arcs

What is the software tool chain you are using? Easel, Vcarve, something else?

It was designed in VCarve using the x-carve Post Processor. Let me dissect the g-code. If I drop the feedrate down to 20-30 IPM it smoothes out in the corners.

Can you post $$ settings?
Antivirus software running scan in background. Check task manager (if windows), to show processor usage.

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My mchine will do the same thing on occasion. I have shut everything down and rebooted the pc and it usually straightens out and flies right.

It seems something is running simultaniuosly hogging processor time but I have not been able to find it ever.
Quite annoying for sure.

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That was from Easel and Universal G code sender in Windows. I need to retest in Linux. If I can’t fix this I will dump the X-Controller for LinuxCNC and stepper drives. I use that on my Probotix Fireball V90 and it is smooth as butta. I was hoping GRBL could handle the buffering between segments a bit better than that.

Check your post processor. For some unknown reason most of them have the arc commands commented out (G2 and G3). If you don’t have the arc commands set up for grbl then Vcarve generates all the segments to make up an arc and you have to send all of those segments through the serial port. If you have arcs set up then it’s one command for each arc.

Easel does not support arc commands (G2 and G3).

Thanks for the heads up. I’ll double check the PP. I got the recommended x-carve PP on the laptop but I need to check the desktop I use for design work too… I really miss the LinuxCNC interface so I may need to build another controller and sell the X-Controller.

The V-Carving G-Code is just a series of G1’s Is must be too much bandwidth for the USB connection to handle smoothly.

You can test this. Change your PP to allow Vcarve to generate arc g-code (G2 and G3). If you don’t know how to do this I’ll do it for you.

Later versions of grbl support arcs. I think it was somewhere around version 0.9j.

Thanks Larry.
If I remember correctly (not at the system) I am running Grbl 1.0c or maybe 1.0g ? I think it is c tho.
When I booted in Linux Mint, UGS worked almost lawlessly so it is bottlenecking at the usb port and OS CPU hogging resources. ‘stoopid Winders’ I have taken the plunge and ordered 4 drives off Amazon and parallel breakout board so I can set up another LinuxCNC system for the X-Carve… It opens up a lot of possibilities and it is soooo nice to play with feedrates on the fly. You can also start your G-code at a specific line to re-mill a section of code. GRBL doesn’t have enough horsepower to handle my needs.and I LOVE the GUI in LinuxCNC…

Grbl 1.1 supports feed rates on the fly.