NEED HELP. Gcode error?

New to this CNC word. I’ve been playing around with it for a few months now and make small plaques for my guys at work. I am currently cutting an image when my CNC machine seems to switch positions in the middle of the cut for the same image. I’ve restarted my Computer… re-selected the image and tried to re-cut it but it always switches position half way… pls ease help.

Usually problems such as you describe are due to a slipping belt or loose pulley set screw:

It’s best to work up to long cuts, testing the machine functionality in stages — even then, never leave it running unattended.

Hi Romy,

To figure out whether the problem is at machine level (e.g. belts/pully as William mentionned) or at G-code level, I suggest you try and visualize the G-code you ran. There are plenty of G-code viewers; for a quick visual check I use this online one:

just click in the G-code text window, Ctrl+A and delete, then paste the G-code from your file, and click “Simulate”
If you see the same shifted feature, the problem is in the G-code, else it is something happening during the job on the machine itself.


Thank you for the link! the problem is in the Gcode how do i fix it?

Hey Will,
Thank you for the suggestion. The pulley all seem to be tight. Thanks


Do you have the design file from which this faulty G-code was generated ? I guess so from your description in your first post where you mentionned you “re-selected the image” ? The problem is most likely there, so probably the design file itself should be fixed (i.e. it is very unlikely that the g-code post-processor itself would have introduced this shifted feature)

If you cannot find the issue, maybe share the source design file here.

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Hey Julien I figured it out. I reset the program and deleted all the tool parths and re-selected them. Thank you for assisting and showing me the link for Gcodes.