What am I not doing correctly?

I’m very new to this. My setup is:
Precision Plasma 4x4 Table/gantry
Powermax 45 W/machine torch.
Latest version of Candcnc with DTHC.

I drew a very simple plate with 5 holes in it. When I run the simulation everything is fine. I’m using the MP3000-THChighref.post supplied by cadcnc.
When I run the G-code in Mach3 It will cut the lead ins and outs but not the whole circles!

The problem is due to a bug in the post processor. If you send me a copy of the post I’ll tweak it for you.

Here’s the post.

I don’t know if the post does this already or not as I haven’t been able to cut a circle with it yet but can you tweak it so that on holes less than 1.25" diameter it will automatically reduce feed rate to 60%?


This should do the trick. It doesn’t slow down for holes. The best way to slow down for holes it so put them on a different layer then set up a separate cut operation for them, with the lower feed rate.

We are getting closer. I now have circular lemon shapes!

I did figure out the whole layering deal and how to set the feedrate accordingly.

Here is a comparison picture. Another concern that I have is both lower corners. The lower left is not curved like it should be and on the lower right one it looks like it’s switching from an outside offset to an inside offset.
The cut on the left had the start point just up from the corner on the lower right. I moved the start point up about an inch on the right piece.

Here is the Job file so you can see my setup.

That looks like mechanical issues to me. I would say you either have a lot of backlash in the X axis or you are losing steps. Backlash is more likely. If you can’t find a mechanical problem, make sure you haven’t got backlash compensation turned on in Mach.