Tool not machining where I think it should

Hey guys, I’m trying to cut some acrylic and, I’ve got my origin in my gcode as the center/top of the stock. I then go to CarbideMotion and set the origin for the machine to the center/top of the stock.

When it starts it’s movements, it’s above the stock (not cutting at all or just barely cutting) when I expect it should be cutting through the entire stock (1.3mm).

Any ideas what I’m missing?



Hi Lon,

How did you zero it? If you set the zero too high it will cause the problem.
If you set the stock size too thin it can cause the same problem.


Hey Jim, thanks for responding. I did set the zero right on the stock, so I don’t think that’s my issue. I’m currently suspecting that my Z “travel per revolution” is off.


Did you check that Z0 touches stock in multiple locations? If the bed is not level it acrylic sags easily and may not be actually the same height everywhere.

When you load the file into CMotion what does it show for the Z tool path extents?

Can you post the gcode file, I could review it and check if it has good depths set in it.
If Z “travel per revolution” is off you should be able to measure it fairly easily by jogging the machine. Set it to Inch, and 1 and jog it up and down. You can measure it by using a ruler on the side of the bracket holding the spindal. If it is not even close then yes you should look into it, if you need a more accurate test you can measure a cut depth in a soft material and use a high resolution measurement device.