Free 3D (STL) G-code generator?

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zenwebb
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Free 3D (STL) G-code generator?

Post by zenwebb » Wed Mar 20, 2013 2:10 am

I finally got my ShapeOko to move for the first time the other day, and now I'm looking forward to plan some future projects. I really find 2D milling to be pretty boring, so I'm really looking at making smooth 3D cuts. I regularly do 3D printing and find the software to be a little quirky at times, but still gives me exactly what I need. I haven't found any such equivalents in the CNC milling world yet.

What I am looking for is a simple(-ish) program that can generate toolpaths for 3D models (STL format preferably). I've seen other users report success with CamBam and MeshCAM, but I definitely cannot afford either of these. I am a broke grad student, so I really need a free option!

I'd really like to be able to mill objects like this in wood: http://www.thingiverse.com/thing:24897

What software does the community recommend for this type of milling? What types of operations should I research?
Jason Webb
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WillAdams
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Re: Free 3D (STL) G-code generator?

Post by WillAdams » Wed Mar 20, 2013 10:47 am

There was a lengthy discussion on Slashdot, w/o as much opensource as usual:

http://ask.slashdot.org/story/13/03/16/ ... n-software

(tried to capture the opensource stuff in the wiki)
but your example was done using OpenSCAD which is in our wiki:

http://www.shapeoko.com/wiki/index.php/ ... d_Software

I believe HeeksCNC, pycam or freemill would be able to get from openscad to GRBL.

There is a 3D workflow page which should get you started:

http://www.shapeoko.com/wiki/index.php/ ... orkflow_3D

Once you've made the conceptual leap, it should be easier.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets
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zenwebb
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Re: Free 3D (STL) G-code generator?

Post by zenwebb » Wed Mar 20, 2013 2:45 pm

Thankfully, I've been into the 3D printing scene for a little while and have gotten pretty good with 3D CAD tools (OpenSCAD is my weapon of choice :)). It's really just the CAM aspect that is new to me.

In 3D printing, the CAM is relatively simple, I think because you only ever deal with one extruder per job. You don't make multiple passes and the nozzle characteristics generally don't change.

But in milling, it seems like there is quite a bit more inherent complexity because you have to regularly switch out bits and make multiple passes. But right now it is hard for me to separate all of the "extra" stuff from the important stuff - i.e., do I need to know about pocket and profile and contour operations if I already have an STL I want to mill? How do I go from STL to G-code without spending hours and hours fussing with software?

I admit I've been finding it a bit frustrating that the wiki just sort of drops you off at the precipice of making whatever you want, but doesn't really give any help in figuring it all out. It gives some links and some outdated instructions, but it seems like the CAM aspects are extremely complicated and left for you to figure out on your own :(

I've tried HeeksCNC and PyCAM already and found them to be a bit unintuitive and, frankly, a pain to use. They both are quite sluggish and quirky. I've not heard of FreeMill before, so I just downloaded it, and it seems to be a bit faster and more friendly than the others. I will keep tinkering with it.
Jason Webb
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ThatOtherGuy435
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Re: Free 3D (STL) G-code generator?

Post by ThatOtherGuy435 » Wed Mar 20, 2013 3:47 pm

It may help to download the trial of MeshCAM or Cambam and experiment until you understand what the different CAM operations are - that way you'll have a much better idea of what is going on when you try to use PyCAM or HeeksCAM.

If I recall correctly, Cambam has a 40-launch trial and MeshCAM has a 15 day.
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alpha
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Re: Free 3D (STL) G-code generator?

Post by alpha » Wed Mar 20, 2013 3:57 pm

I would guess HeeksCNC is the most powerful FOSS for CAM that exists today. I think the FreeCAD people are working on a CAM module but this is still in it;s infancy. If you come from 3d printing you probably know Skeinforge, by looking through all the settings tabs it looks to me it also supports milling CNC operations. But I never used it that way so I can't tell.

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Re: Free 3D (STL) G-code generator?

Post by WillAdams » Wed Mar 20, 2013 8:01 pm

And that's why I've been hand-coding G-Code.
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zenwebb
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Re: Free 3D (STL) G-code generator?

Post by zenwebb » Thu Mar 21, 2013 2:55 am

If HeeksCNC is the best option out there for free CNC milling, then the hobby community is in trouble! It's not friendly at all, and lacks proper documentation. But I'll keep plugging away with it, because it seems like I may not have a choice.

Skeinforge is an absolute nightmare and I try to stay far away from it if I can :P For 3D printing, I stick to the ReplicatorG front-end and Slic3r. I have yet to see an example of someone using Skeinforge for milling; although it does appear to have options for milling, I don't think anyone has been successful in doing it, let alone documenting it.

Hand-coding G-code is not at all an option for me (or most people), for hopefully obvious reasons.

What I'd really like is a solution that takes less than a week to figure out, without the requirement of me becoming a CNC expert - I have enough other work to do! I also want something akin to the 3D printing approach, where I can slice up a 3D model within an hour and be printing. I may have only have a couple hours a week to spend on working with the mill, so I am hoping for a simple option.
Jason Webb
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WillAdams
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Re: Free 3D (STL) G-code generator?

Post by WillAdams » Thu Mar 21, 2013 11:57 am

I'm not hand-coding G-code 'cause I think it's the best solution --- it's just the only thing which I've found thus far which works for me, 'cause I've not been willing to consider any of the proprietary options and the opensource and other solutions I've found thus far are confusing or limited (still really bummed that the javascript I found to export to G-code from InDesign only does lines).

I hope everyone will put whatever they might learn / discover in the wiki and esp. share their successes --- I'd really like to find some better solution.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets
Nomad 883 Pro #596 (bamboo)

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