Luban GCode Question for CNC


I try to relief a big model with my Artisan CNC. I created a toolpath with the double flute flat end mill to cut most of the material. Afterwards, I would like to create a toolpath with the V-Bit to cut the details. So I created both toolpathes which generated a single cnc-file over 90MB. The estimated time in Luban says over 1200h!!! But i thought that’s just a failure in the calculation

After Line 95866, there is the following entry in the gcode:

G1 X11.25 F1200
G1 X-164.25
G0 Z1.00
G0 X-164.25 Y-166.02
G0 Z10.00

;Header Start
;renderMethod: line
;Header End

G0 Z10.00 F1500
G0 X-164.94 Y-166.71
G0 Z1.00
M3 P100

So I interpreted that for the toolchange, but the machine started over again without a stop. It started from the beginning and cuts some air… but I think with the new settings for the new tool, it’s quite slower moving than with the flat end mill.

So what I think what happened:
The Toolchange did not work in the gcode (should stop, go to home and wait till I changed)
Luban didn’t build the second part of the carving based on the work that’s already done. So it starts from beginning, which takes a huge amount of time if the V-Bit wants to cut all the material AGAIN.
So my model is now still on the machine, waiting to get finished but I stopped the cutting.
What can I do now? How can I tell the gcode, that the remaining material is just very little and not the whole wood block???

Please Help, I can’t look at a standing machine which is not working :slight_smile:

Last time I looked, Luban was not able to handle multi-pass milling jobs with tool changes. Admittedly, this is a while ago, but what you describe sounds very much like nothing has changed. That said, you’ll need another piece of software to generate the toolpathes, many people use Fusion 360. Fusion 360 does “Rest machining”, i.e. if desired understands that the previous tool removed a lot of material that does not need to be removed again.
@Skreelink put together a very extensive guide that should help you a lot: Fusion 360 Guide For Multi-Pass 3D Engrave

Hi Hauke

Thank you very much!
I had an Idea now which I am trying; I added a new toolpath with a ball end mill, and set the milling depth (not sure how it is called in english) to 18mm (this is also the max. working depth). So because I know, there is no material, I should be able to finish this toolpath in one try.

And yeah, I tried with Fusion360. But my model is a mesh net, and fusion is HORRIBLE laggy with this model. I converted it in to a body, but it’s still very slow… too slow to work with.
So Luban makes that (and just that) better, as it converts it from the beginning in a greyscale map.

So after the ball end mill, I’ll try the Vbit with milling depth 18mm and hope that the origin doesn’t move :slight_smile:

Indeed Fusion is not very fast with Mesh models. One way to work around this is to use simplify methods that reduce the number of polygons of the Mesh before importing into Fusion. I do this with Windows 3D Builder.

Oh cool, didn’t know that, that’s really simple with windows 3d builder! thank you for that hint!!!
Have you noticed how much the allowance should be in Luban for a first cleanup? I had 0.1, assuming that it does some clearence by itself (for the diameter of the flat end mill). but as it seems, it went in too much on the sides… should I use a bigger allowance ?

At the moment, I’m trying to fix the model with a VBit and set the origin 1mm lower than it should be to clear as much failures as I can from the first steps…

As I said, I do not use Luban for milling, so can not say very much about the settings. In Fusion 360 you have a detailed profile of the milling bits (and Luban must have such profiles builtin, otherwise it would fail to generate any toolpathes that make sense), and uses these data to create precise toolpathes that take the diameter, length, radius, angles etc. fully into account. The task at the beginning of each path is to find the exact same starting point. In X/Y it is easy, since you navigate to the origin once, store it and it will stay the same for each bit. The Z-height is not so easy, as each bit has a different length, and even if you use the same bit twice, it is difficult to clamp it exactly at the same height twice. So you’ll need a Z-reference. This is why I try to put the origin of the work on a piece of stock that does not get milled away. There are more clever ways to do so - including automatic sensors.

However, if you achieve to start every tool path at exactly the same X/Y/Z, all should add up and you would get a nice result.

Last remark: A V-bit is not a good tool to mill away lots of material - it will take ages and wears the bit down. I am certainly NOT an expert here, just fumbling my way around, but so much I gather: Use a flat end mill for roughing, getting as much material away as possible, use a ball-end mill for a finishing path for nice surfaces, and perhaps use a V-bit for tiny details which are too small for the ball end mill to reach. Also, The Snapmaker bits are nice for some first tries, but if you want good and fast results, invest in a few quality bits.