Help - G-Code Circular Motion for CNC Milling

[Matt Reiland]

Sanddrag,


I think you are getting really close. Couple of things. First, you should be able to download a free version of FlashCut CNC Offline and play around with it.

www.flashcutcnc.com

This is the software that my Smithy CNC runs on at home. It will directly import your .DXF file and convert it to G Code for you. As for bringing down the Z while cutting a circle. Make sure your controller is capable of 3 axis circular interpolation. Mine can only cut 2 axis at a time. Therefore I bring the Z down into the part like your line above then start to cut the circle. If you want you can slightly undercut it then make a final circular path to get a smooth dimension. Now would be a good time to find out about the backlash of the machine you are on also since ANY backlash will show up quickly when you cut circles on a CNC mill since your x & y change direction 4 times in the circle. I got so fed up on mine that I just had new ballscrews made and am putting them on this weekend which should clean up a bunch of slop.

Also the Flashcut manual is available for download which has all of the G codes listed and how they work.