Cut Path Not Following Gcode

I have finally had some time to get the plasma cutter hooked up to my new setup using plasmaC and was able to make my first cut. Thanks to all that helped me get it going.

I immediately noticed that there was a problem after my first cut and I'm not sure what is going on here. I have attached an image that shows what is happening. If you look at the image you can see the white line that shows the gcode drawn out and the red line that is the path that the torch took. If you look inside the wrench on the right you can see the the mouth of the wrench was not cut square like the white line shows. The red line shows that there was a shortcut taken and the mouth of the wrench is rounded. This is clearly a software issue because LinuxCNC is showing the correct gcode drawing but the cut path is not the same. Is this a setting that I need to fix, or is there something else going on here?

That is due to low acceleration/fast feed rate and can be eliminated by using G64 P0.1 if using mm.
Just put that at the top of gcode file.

That is due to low acceleration/fast feed rate and can be eliminated by using G64 P0.1 if using mm.
Just put that at the top of gcode file.

I'm not using mm, I'm using imperial measurements.

MakingStuff wrote:

That is due to low acceleration/fast feed rate and can be eliminated by using G64 P0.1 if using mm.
Just put that at the top of gcode file.

I'm not using mm, I'm using imperial measurements.

In that case
G64 P0.005 should be enough for plasma. That is basically the tolerance that the machine should follow, so nothing would go farther than that set tolerance from the actual tool path.

It's part of path blending and you can set it to your liking.

More info here:

linuxcnc.org/docs/html/gcode/g-code.html#gcode:g64

G64 P0.005 fixed the problem.

I have one more question. Why do I need this on my new setup, but it wasn't required on my old LinuxCNC 2.7 machine? Is this something new for LinxCNC 2.9?

Can we use G61 or G64 in lathe mode?

MakingStuff wrote: G64 P0.005 fixed the problem.

I have one more question. Why do I need this on my new setup, but it wasn't required on my old LinuxCNC 2.7 machine? Is this something new for LinxCNC 2.9?

That was changed during 2.7 when the new trajectory planer was implemented. It is in later versions of 2.7, 2.8 and 2.9.

That was changed during 2.7 when the new trajectory planer was implemented. It is in later versions of 2.7, 2.8 and 2.9.

Ok. Thanks for your help!

Bob

Oops, that is my fault.

There is a file called imperial_startup.ngc (or metric_startup.ngc) that sets G64 P0.04, it should have been G64 P 0.004. The metric version is correct at G64 P0.1

I will fix this.