Greeting everyone.
I would like to build a “Hybrid 3d printer / CNC mill” with 4-axis’.
I have designed the mechanics for the machine, but I am struggling to find the “best” controller for my design.
I would like to run 4x NEMA 23 Steppers for the : X, Y, Z & A - axis, plus an extruder stepper.
I do believe that the design of my machine is unique, and I don’t mind spending a bit to make this machine “The ultimate desktop-rapid protoyping machine”, so any suggestions would be great.
Any advice would be appreciated.
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Hi,
you may want to look at the RADDS board and also the XLNC project for some details on going down this route. Are you only interested in low cost boards? Or would you be willing to spend to get something like the TInyG line of boards?
regards,
AlltechM
I honestly wouldn’t bother. The long and short of it is that a 3D printer and a milling machine have very different requirements in their construction. A 3D printer needs to have as light a moving platform as possible to remove the chance of artifacts appearing in the print or to have to reduce the speed to a crawl.
With a milling machine, mass is king! There’s a good reason commercial milling machines are made from cast iron. It’s heavy, it’s stiff and it gives you a nice rigid platform. Sure 3D prints need the same rigidity ideally but a milling machine doesn’t operate at anywhere near the same speeds. Mills create a lot of mess as well, coolant and swarf are a nightmare to clean up at the best of times. Throwing that into a 3D printer and asking it to work to high tolerance? Not going to happen I’m afraid.
As someone that is a keen user of both bits of tech, I wouldn’t waste your time. Several similar attempts have been made in the past.
Perhaps consider using a raspberry pie loaded with linuxcnc for your cnc operation and some other software for printing.
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I couldn’t disagree more. Depending on the construction and application for the milling these techniques are more than possible to put in the same machine (which I have done). However you can’t just build a 3D printer and expect it to work as a milling machine or vice versa. But if you put some thought into it it is absolutely possible to get a machine that does both. What I did was to put a cnc style tool changer on my machine to easily swap between printing and milling meaning that I can print my parts a millimetre or so oversized and then mill them down. However, I wouldn’t ask it to mill steel as it is deigned only for light duty. But take for example a real cnc mill (think high end stuff) you could easily get the speeds needed for 3D printing while still having the power needed for metal machining. It all depends on the construction of the machine.
“However, I wouldn’t ask it to mill steel”
It isn’t a mill if it can’t handle anything tougher than plastics or wood. That’s a router. A very different machine and one that you could feasibly combine with a printer if you found an effective way to take care of the wood shavings.
“But take for example a real cnc mill (think high end stuff) you could easily get the speeds needed for 3D printing”
I don’t doubt you could but seeing as OP is looking at small nema motors and not high end servo motors I assumed they weren’t looking to drop five figures on a machine center.
If the defining factor of a mill is that it can handle materials tougher than plastics or wood, then yes, my machine is a mill (it cuts softer metals with ease and could theoretically cut harder metals but as that is outside the scope of my machine I’ve never tried). If you don’t believe me, please come to my garage and see for yourself.
For the machine discussed in this thread I would recommend OP to ditch the steppers and go on eBay to find some good industrial servos in the 200-400W range. Those would give plenty of both torque and speed to accommodate milling and printing.
And for the high end cnc that could be converted to mill, you probably don’t need a five figured high end machine, something along the lines of a tormach would probably outrun the capability of most extruders on the market today anyways. Just because there isn’t a cheap, off the shelf solution today doesn’t mean that the combo doesn’t make a good product.
Thank you for your response.
I believe my machine design is quite different from anything I’ve seen. It’s awesome how quickly everyone responds and how helpful everyone is, so thank you again.
You’re welcome:) I started the XLNC in an attempt to test the same concept you are thinking about. Everyone above is correct in their own right, but at the end of the day if you are simply learning and don’t care too much for the high specs of commercial systems, then a custom low end low cost/DIY solution is going to be your best avenue. I opted to keep the RADDS board’s firmware standard (no modifications other than pin directions were changed). Obviously you’ll need to offload most complex functions not natively supported by your selected controller onto a PC, hence the need for a custom panel in Repetier. All said and done there isn’t a one sock fits all solution to this problem:(. good luck though, I’m curious what route you take, keep us up to date.
I am not too worried about the cost of the board. Thank you very much for your help. I will look into it. 
Apparently the RADDS board is able to perform the functions I need it to, it does involve a lot of coding - 
The TinyG CNC Controller Board v8 is more than likely what I am going to end up going for.
Yeah, someone commented that it’s a waist of time. Mate, if I am learning while I build this machine then it’s not a waist of time. I’ve spent a lot of time thinking about the buid, and how to make it strong enough to perform CNC (Non-ferris metal) tasks, as well as 3d printing tasks. And believe me, there is a trick My strengths lie in my design, not so much the electronics side of things
