Hello, I am new to the Arduino forums but I am hoping someone could help me out!
I am starting a project where I will be making a small desktop CNC machine for as cheap as I can! I have been doing a bunch of research for CNC machines, how they work, how to build them, ect. But I have found very limited information of Arduino CNC machines and everything that is needed for them to work.
Okay, so the big thing that I am trying to figure out (especially before I buy anything and realize something doesn't work with something and waste money) These are the main electronics I am looking at purchasing:
Now my question is, with all of this connected to my Arduino (Running GRBL) will this be enough to run those motors properly and give me a working CNC machine? (Once connected to the final product of course)
I've seen people mention buying a TB6560 for the CNC, but they not only cost around $40 just for the unit (Without a power supply) but require you to have a PC with an old parallel port. All the components above (Besides the Arduino and Motors) will cost me $35 which includes a power supply, and allows me to use USB.
Now I am completely open to suggestions or criticism on what I should do for controlling and powering the motors! I just need some help and make sure I get the correct things in order to make a proper working CNC.
(Edit: I changed the link the the NEMA 23 Motors, to the set that I own)
Your link does not list the current drawn by the motors or the resistance of the motor coils.
My concern is that a big motor like that would require a lot more current than a DRV8825 can provide. If you need more powerful (and more commercial, more expensive) drivers then they won't plug into the GRBL shield (assuming it is designed to accept the stepstick boards). I suspect GRBL will work with any driver if you figure out how to connect it up.
The power supply must be comfortably able to provide all the current that all the motors require.
I haven't used GRBL but as far as I know it is quite capable of driving a CNC machine.
That is my concern as well, I do not know the motors resistance but they are marked 1.2V 2A. The DRV8825 are rated 1.5A per coil without any heat sink or direct airflow, which I will have so I should be able to bring it up to 2A (Its rated for 2.2A with sufficient cooling)
But I am no expert in this area (which is why I came here for help!) so does this sound like something that can run those motors properly?
RyGuyTech:
they are marked 1.2V 2A. The DRV8825 are rated 1.5A per coil without any heat sink or direct airflow, which I will have so I should be able to bring it up to 2A (Its rated for 2.2A with sufficient cooling)
That should work - but you will be very close to the limits of the driver. I was concerned that the motors might need 2.5 to 3 amps.
You can work out the resistance with ohms law 1.2v = 0.6 ohms * 2 Amps. The voltage is essentially irrelevant.
Make sure you understand how to set the maximum current limit on the driver boards.
This is where I am the most confused, do I just directly connect the 24V 5A power supply to the 2 pins power input (the -+12-34V input) on the board? What do you mean by setting it the maximum current limit?
RyGuyTech:
This is where I am the most confused, do I just directly connect the 24V 5A power supply to the 2 pins power input (the -+12-34V input) on the board? What do you mean by setting it the maximum current limit?
That is probably correct but since I can't see a wiring diagram for the board (because you haven't posted it) I don't want to say YES and be accused of letting the smoke out.
Is your board IDENTICAL to the Pololu DRV8825 ? - they have a good webpage with a connection diagram. It also describes how to set the current.
Then I can attach the Pololu DRV8825 (three, one for each motor/axis) to the CNC Shield, also I can attach the motors and the (from what I understand) the power supply to the shield as well.
I really hope this helps, please ask me to provide you with any more information that I have not given I am still pretty new to all this.
I really hope this helps, please ask me to provide you with any more information that I have not given I am still pretty new to all this.
I think you have got to the stage where you need to rely on your own decisions. On the basis of the questions you have asked so far I don't think I can provide more advice. I repeat what I said, I can't definitively say connect X her and Y there because I might make a mistake or you might make a mistake interpreting what I say.
It would be different if you were quoting a sentence or 2 from complex instructions and asking for advice about how to interpret that small part of the instructions.
Perhaps you can get advice from the board makers.
If you have new questions that I can answer I will certainly try to help.
