Why isn't there a Thingiverse for CNC?

(Sorry for the spam, I'm not sure why my previous post was deleted, is there a better forum for the topic? PM me if you know)

There isn't a site like Thingiverse for CNC because Rep Rap made slicers so good that STLs can be shared, but slicers could do so much more - they could generate gcode for CNC and so many other machines.

I wrote this article about why this is, how we got here, and how to fix it. Why isn't there a Thingiverse for CNC? Slice Everything!

I'm not selling anything, I'm interested in your thoughts.

D. Scott Williamson
See you at the 2024 Midwest RepRap Festival

“RepRap is about making self-replicating machines, and making them freely available for the benefit of everyone. We are using 3D printing to do this, but if you have other technologies that can copy themselves and that can be made freely available to all, then this is the place for you too.” ~ Andrew Bowyer
These ideas democratize the free and open source automatic creation of gcode (CAM) for any machine that converts gcode to action in order to lower the knowledge/skill barrier to home/hobby manufacturing which, in turn enables innovation, sharing, and iteration by leveraging and extending the amazing work already done for 3D printing.

I feel this is a question wrongly put.

Hardly ever do you share gcode, you share 3d files. Nothing is stopping people from using thingiverse or even github for CAD projects that require machining.

The problem of automatically generating gcode for cnc machining is orders of magnitude harder than 3d printing gcode, which is why many decision during the cam process are made by humans.

Additive and subtractive machining gcode are so different it makes no sense to combine them into one software.

As for a roadmap towards reducing friction for the every-man to turn digital to physical? AI should help quite a lot with that, it has been shown to be able to create 3d files and im sure CAM wont be too much longer.

Hi @DaGameFace, You are correct about gcode not being sharable but wrong about slicers and CADCAM software complexity.

You cannot share gcode because it contains settings for a specific machine, material, and job configuration, but slicers are not simple, CADCAM need not be complex hobby CNC like Shapeoko or MPCNC, and both tools have many of the same internal functions.

The CNC community typically shares 2D DXF files, not 3D files and the process to convert either 3D or 2D to gcode involves the manual creation of 5 simple operations which for desktop CNC are pocket, profile, drill (if not pocket), engrave (includes V carving), and 3D contour. All the parameters (feed/plunge rate, depth of cut, entry angle, finishing passes, etc.) all should be in machine, material, and job presets as slicers have brilliantly abstracted into printer, filament, and print settings.

Automatically generating gcode for 3 Axis desktop machines is simpler than that for 3D printing. Slicers don't naively create layers and profiles, they do complex geometric analysis for the construction of support material and handle nonlinear flow rates that depend on the rate of material being extruded. After slicing a layer, machine operations for perimeters, infill, support layers, etc. are created which bear striking resemblances to profile and pocket CNC operations.

Meanwhile for CNC, bit selection, depth of cut, feedrate, spindle speed are all based on material and machine capabilities for a desired quality level, though parameters are not not organized for automatic configuration CADCAM. 3D part models surface normals identify vertical versus horizontal surfaces, while chamfers all have the same slope, typically 45 degrees. V carving also has the same slope and the vertices in the valley are the actual final 3D toolpath. Determining where profiles, pockets, and engrave operations with V cutters is straight forward for shapes designed to be cut on a 3 axis CNC mill. Roughing versus finishing, conventional versus climb milling, final cut depth are all for finish quality and can be configured based on bit availability and desired quality setting.

As a matter of fact, subtraction and additive are so similar you can use a slicer to generate gcode that can be machined on a 3 Axis mill once Z is negated.

Slicers and CADCAM are extremely similar under the hood. Both generate machine operations, slicers automatically, CADCAM manually, then those are converted to toolpaths, and toolpaths are converted to gcode. Both even have postprocessors for the controller (Mach3, Linux CNC, versus, Marlin, Sailfish)

Slicers could generate gcode for any machine that converts gcode to action to realize a part that can be represented as a 3D model, and an open source tool with the right abstractions and interfaces would be the perfect platform to enable all kinds of consumer and DIY machines : 3D printers, CNC Machines, vinyl cutters (drag knife), laser cutters, EDM machines, hot wire foam cutters, plasma cutters, waterjet, wire benders.

I suggest anyone interested read the article which covers all this in more depth.

Footnote: Kiri:moto (https://grid.space/kiri/) is the closest tool I've seen that has recognized and leveraged the same processes for multiple machines.