AutoCAD curves are faceted in CNC

[JoeS09]

I  have drawn a template with one side a radius of 243mm, and saved it to a .dxf file and imported to CNC software Mach3.

To make this a smooth curve, I have switched off any AutoCAD 2018  Snap features and entered Options /Display and set the smoothness to the maximum of 20,000.

But still the CNC software show it faceted, as shown in the attached image, with the discontinuities at 2cm intervals. We tried cutting, and sure enough it cut a faceted curve on the timber , not a smooth one. The machine is quite capable of doing very smooth curves.

I  did a REgen after changing the smoothness setting, and Joined all the 4 sides of the template

 

hoping someone may have some experience with this, so that the curve can be made smooth

Tray Template 5_138 x 42 SQ_revised_smoothed_arced.dxf CNC image.pdf

[steven-g]

In AutoCAD those are only display settings, the actual dxf contains an arc. It sounds like your CNC software is converting the arc to segments I would ask in the Forums for Mach3 if there is a setting that needs adjusting. It sounds like the software that is producing the g-code is causing the problem, is that Mach3 or do you have another piece of software in the middle of the process.

[JoeS09]

Thanks for this good info, steven-g. In the end, the CNC machine owner converted the .dxf file to SVG, loaded it into his Mach3 I  think it is, scaled it to the original dxf size, and it was dead smooth.

so now, all I have to do is use Cloud convert (free) to give him and SVG file, plus a pdf of the dxf showing dimensions, and he is away

Edited March 14, 2021 by JoeS09