Strange milling behavior when milling out

can anyone tell me why the edges are milled out during CNC milling (a shape 7.5mm deep is to be milled only vertically) in such a time-consuming way as shown in the viedeo, instead of going around the contour once. This would save a lot of time.
Since I can’t upload videos as a “new guy”, here’s the link to it:

I simply don’t understand the point of retracting the milling cutter vertically along the contour.
Is it possible to change this?


Without knowing what software or model/image you’re using it’s hard to say. What it looks like to me is whatever software you used to generate the gcode generated small taps/loops along the edge (slightly pixelated image?) instead of a smooth contour. There should be options to smooth edges to reduce things like that in the cam software.

Edit: If you don’t mind uploading the model and gcode?

thanks for the feedback. …sorry for that.
Sure I can upload the “model”. It is basically just a vector curve that I want to mill 7mm into the wood with the option “fill” to put something in a board in this recess.

It is a .SVG which I had generated in Corel Draw from an image (outline of an stl file).
It’s not more than this: (The rest of the message is a complete image, because as a “newbie” I am not allowed to upload more than one embedded image. I hope you can see everything. )

It’s apparently a bug in Luban… :confused: I just copied your settings for a simple oval (using Luban’s add shape tool) aaand… it does the same thing. It does this (I assume) to remove the cusps left over from sweeping left and right, this was on the latest 4.3.0. However, on Luban 3.15.2, it only sweeps back and forth, it does not go back to do the outline, but you don’t get a fine edge, unless you do a secondary path to follow the outine, which actually gives you the result of sweeping back and forth to clear, then running along the outside in a smooth contour.

Your best option would be to use a different CAM software, a popular one is Fusion360, I have a two-pass guide here:

While it’s specifically for multi pass 3d engraves, it does have a section good for setting up Fusion for the snapmaker. You would simply want to import the SVG, then use the 2d pocket operation to fill it instead of all the other nonsense. :slight_smile:
Another option would be Kiri:moto, while I have not used this personally, I’ve read about others using it, and TeachingTech mentions using it in their review of the snapmaker. It’s free and browser based:

There’s other CAM software out there, but those are the ones I know of offhand. Sadly, it’s your best option, as Luban is just… sort of junk. You COULD install the older version, 3.15.2, do a fill operation, then add another for outline or on the path to do the edge and it would be a lot faster than the odd dance Luban 4.3.0 is giving you.

Luban just isn’t very smart at it’s toolpaths. It’s not seeing it as continuous but as a bunch of small sections and it then tries doing a plunge on each.
Fusion 360 has choices for toolpaths so that you can tell it how you want to approach a cut and create the path.


Thank you all for your responses.
@ Skreelink: …and for your instructions. Is this doable with the free version of Fusion?
I’ve been working with OnShape so far, but will now take a closer look at Fusion 360 and also take a look at Kiri:Moto.
Now I have at least a direction in which I can go and know that Luban is rather suboptimal. :frowning:


There are a few limitations with the free version of Fusion but nothing that there aren’t workarounds for (or don’t actually apply to SM)

The main one is it doesn’t include rapid moves but you can edit the g-code manually and just do a find & replace to put them back in.

The other one is that you can only have 10 editable projects going at one time, but you can easily toggle them between readable only and writeable.

The biggest is that it no longer supports 4th axis, but if you don’t have the rotary module it doesn’t matter.


Too bad, because I also have the Rotary module.
But I will try to get something going with Fusion in the first place.


You can use (the free version) of Fusion360 with the rotary module and a little bit (ok a lot) of effort if you’re using it to do multi-side milling. It’s not using the full potential of the 4th axis, but it can be helpful depending on what you need:

(the above is for cnc only)

I’ve made a post-processor that allow us to specify our own speed for rapid moves… It’s on GitHub.
And there is also a tool library and a machine library available.

Check it out here:

Thank you a lot for this source!

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