Plans for a CNC



  • I'm wanting to build a CNC to use with the Due.t To be honest I do not want to start from zero so I was wondering if anyone may share some designs
    to start from for my build. A printer I could do from zero but this is different and I don't want to waist time. I have a general idea but it would be better
    to see something that is using the Duet.
    Thanks for anything.



  • Are you thinking of the physical construction, or wiring and configuration? The former I think the cnc zone forum or something may be a good resource, the latter is loosely covered in the wiki by saying its about the same as a printer without extruders.

    I've been on the fence to convert my CNC router because it would need higher stepper motor currents than currently offered (3rd generation Duet boards will offer more motor current), and I would very much like to have some of the planned features in version 3 of the RepRapFirmware available, mostly relating to probing. General motion controll will work just fine with the current version of the firmware.



  • I was was looking for the physical plans not wiring or configuration. I would be any thing big 50 x 50 max.



  • @synapsis I am planning a CNC myself, and the first decision is which material you want to CNC: wood or metal (aluminium, steel). This leads to different requirements for construction. I will build two CNC machines, because it is so different. Wood for big things like doors, not to be so precise (mm), spindle requirement not high, stepper/other motors not much current. Metal for small things, high spindle requirement, high stiffness of construction (expensive linear guides, steel frames, heavy), high qualitiy motors, high precision (1/100 mm). Wood CNC is easy with Duet IMHO, metal could be realized by attaching motor controllers to the external interfaces of Duet (leadshine etc.). It is also important which software is planned (Mach3...).

    I am a big fan of Möderl's CNC machines, you find a lot of instructions on his homepage and youtube. (only helpful if you know german language)



  • Then you'd need to decide on capabilities like JoergS5 points out, without any idea of what you want to use it for or how much time and money you want to put into it its hard to give specific advice. CNC Zone is a gold mine for more serious stuff, Thingiverse has a few low end options like MPCNC and Root CNC



  • This is not a simple undertaking right now. I suggest that you start with the mechanical kit version of this:

    https://openbuildspartstore.com/openbuilds-workbee-1010-40-x-40/ along with NEMA 23 stepper motors consistent with the Duet2/TMC 2660 current supply.

    Then incorporate a Duet2 as the controller. This will be the upper end of low performance, but it will get a job done. As noted above you could wait for the Duet3 and have enough current supply for bigger NEMA 23s, but you'll be limited in voltage necessary to deal with the motor inductance.

    Personally, I went this route and selected a Mesa Electronics 5i25 FPGA, Geckodrive G540, and LinuxCNC. I use hardware stepping from the 5i25. You'll need a computer with a 25 pin parallel port for the 5i25. I run the motors with a 48V unregulated power supply. This setup is kind of the lower end of professional performance, IMO.



  • Thanks for the replys, First I'm looking to do mostly aluminum small parts then some small parts in plastic, PVC and a little wood.
    So I really do not need anything big, Max Nema 23 motors. I have seen many CNC on Ebay etc but most with parallel ports and a couple with USB but the controllers are ?????
    So I would maybe want to change it to a Duet. I seen the workbee and also saw rawcnc.com with the RAW 1,5. Some new is always hard until you know it. 🙂



  • If you want to cut Aluminium you need rigidity which means $. The typical eBay cnc couter will have far too much flex to give good finish, I have a "3040" CNC, and straight off the bat the controller, spindle and power supply was replaced ... roughly doubling the intial cost and still the hardware has too much flex to do any real cutting.

    Worth noting that anything with USB on eBay will not work with LinuxCNC, it'll either be Grbl or something bundled with a pirate copy of Mach3/4 which means no support or updates. Really can't recommend the latter, even though the Gecko G540 still is a parallell driver it worked so much better with LinuxCNC than the original stuff with Mach3



  • Could be of interest https://forum.duet3d.com/topic/11161/duet-3-first-generation-prototype-giveaway

    I'm currently getting my 3040 chinesium CNC router up and running on a Duet (quite unexpectedly!), and all I can say is just, wow. It runs faster, smooter, and easier compared to the Gecko G540 with linux cnc. I guess the pros so far, far outweigh the cons with respect to g-code support from LinuxCNC, Duet has them beat on all other areas, and as long as the Fusion post processor can generate code that works with the RepRap firmware and the Duet board can deliver the current you need then its happy days.


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