Help! CNC 3 axis multiple toolpaths

Hi all,

First of all i am an absolute newbie to this. So maybe this has been asked before and i could not find it.

I have an stl file which i have been trying to carve and learning the settings as i go.

First i did a sample carve with Single toolpath using Carving v-bit. Which took A LOT of time to finish.

So now i started another carve with Double toolpaths, 1st ball-end bit FOR ROUGH, 2nd carving v-bit FOR DETAIL.
Thinking that this will reduce my time and the 2nd toolpath, the carving v-bit will continue from the carving already created by the 1st path by ball-end bit.
But no, the 2nd toolpath is starting “from scratch” and doing ALL the passes from 0. Even when there is nothing to carve and basically same as what i did my first run.

Am i doing something wrong or Luban (or maybe any other CNC?) does not read it the way i am thinking it should?

Please ask any additional details required as i am not well veresed in this.


Luban doesn’t have the features necessary to deal with multiple CNC toolpaths properly. The usual advice is to get a free personal license for Fusion 360 and use it instead.


So the g-code in fusion would count the rough pass and proceed from there correct?

My understanding is that it would (Fusion isn’t Linux-friendly, so I can’t actually run it). @Skreelink has written a step-by-step guide for multipass in Fusion: Fusion 360 Guide For Multi-Pass 3D Engrave

Yes. Fusion360 will work a lot better and won’t do any unnecessary work.

There is a workaround in Luban. Do the first roughing path as you already did. For the finishing pass use a stepdown for the max depth of cut. So if the max depth is 15mm, use a stepdown of 15 mm. Then it will immediately go to the max depth.

But if you compare it to the toolpaths Fusion generates, you’ll see that the toolpaths generated by Luban are very poor. So if you are serious about using the cnc function use different software than Luban, and I can recommend Fusion360.

@ElloryJaye @brvdboss thanks a lot. The help is really appreciated. I shall try out Fusion 360