Hello,

I need a bit of help to troubleshoot a problem I am encountering. I have built a 3 axis router type CNC running with LinuxCNC, it's really a XYZ traditional router.

When I try to cut my table out of an aluminium plate, I have a strange offset that occur at the back of the cut, on the Y axis. Each deeper pass make it more offset, so I end up with the back of the table tapered.

Where I don't get it, is that this only occur at the back, the front of the table stay good. If I had a problem with my Y axis missing step, I guest I would have the problem on each side, the whole Y axis would be wrong, right ?

The CN code is right, basically my front table cut occurs at Y=2 and the back cut at Y=252. Y=2 seem to stay good but Y=252 offset further and further at each pass..

Can someone give me advice about where I should investigate ? It's my first CNC.

I have attached a picture (sorry for the blur).

Thank you.