help with circles

[phe259]

hi all

could somebody point me in the right direction.

whenever i try to cut a circle it always comes out as an oval this happens with the vcircle in turbocnc sample files so i guess its a setup prob and not a cad cam prob

starting to pull my hair out now

[Bubba]

Sounds like backlash in your system! You MIGHT try to setup the backlash in your config file, but even then, sometimes it only helps but does not correct the problem if backlash is significant.

[phe259]

thanks bubba after 10 hours of tinkering i can now cut perfect circles

on the subject of circles what the best / easiest way of cutting circles in tcnc or whats the best cad/cam software for cutting circles

[Bubba]

I just draw them in cad and run it through Sheetcam to handle the G-code for me!
about any cad/cam software should be able to handle that function as G02/03 are amongst the staple G codes along with G0 and G1.

I know that sounds like a smarta$$ answer, but it works. From what reading I have done though, it seems the use of I,J works better than the R function for G02/03 as sometimes, I have heard the controller software may get confused and cut a circle in the wrong direction if using R function.

Any cad program that can output dxf files is usually suitable for the cad portion, however some (like possibly Corel Draw) will break arcs (including circles) up into short straight line segments and this is possibly a setup issue. I cannot verify that part as I do not use Corel.
For cam, as I said, I like SheetCam; but again you can download the ACE converter to do the conversion for the G-code. The big difference is that in Ace, you have to your own tool path offsets, whereas in a program like SheetCam, you draw it, tell the cam what size tool and it figures it out.
One of the things I like about both TCNC and SheetCam is that an owner has the ability to customize the processes to suit your own pleasure!

Hope this helps, but if I can provide more info, just let me know.