Suitable stepper motor drivers for my creation

[chillybo]

26056260572605826059

Please view my attempt at building a roughly 4 foot by 2 foot CNC router for wood plastic and aluminium cutting. I'm already committed to using 2 x low inductance nema 34's (3.4 mH, 4.6Nm, 5.88 amps parallel)) for x and y (belt for X direct drive for Y) and a Nema 23 (3mH, 4Nm 4 amps parallel) for the Z axis. I have built a 52 volt unregulated power supply to power the three stepper motors (750VA, 36 x 2 output in parallel)
My controller is a CS-Labs IP-M.
I am now keen to order more components to get it moving in particular stepper motor drivers. I understand from reading numerous threads on here that digital drivers are the way to go and I will need 20 to 80 volt capable ones rather than 50 volt max as my power supply exceeds 50 volts.
My question is ....any recommendations for stepper motor drivers and are these suitable?
https://www.aliexpress.com/item/2041623058.html?spm=a2g0o.detail.1000060.1.6b3c46a 46GZgH3&gps-id=pcDetailBottomMoreThisSeller&scm=1007.13339.90158.0&scm_id=1007.13339.90158.0&scm-url=1007.13339.90158.0&pvid=c6938efc-605c-428e-8f3f-02c2ccf6a7ad

Constructive criticism about my creation is welcome
Thanks in advance ...Chris

[Lee Roberts]

Hi Chilly,

Yea I think that's a good price for the Leadshine DMA860H drivers and offers room for a bigger PSU output in the future, for the 80v drivers around 70v is a good target for the output of the power supply to get the best performance safely.

The most obvious things that stick out to me about the machine are,

The belt on your bed axis looks a little loose, I would consider designing in a couple of cam roller bearings to act as a belt tensioner, don't actually use a cam roller bearing as they can be expensive, a standard radial type bearing with a built in flange would work just as good, have a look at how others have implemented this in the build logs section, start with routercnc's MK4 machine (http://www.mycncuk.com/threads/9369).

I would consider lowering your gantry height as well, its quite tall and realistically you'll still have more than enough "headroom" for sheet material and quite thick plate, doing this will give better rigidity and stiffness is what its all about.

Be very careful pushing the motors to hard and or fast, those spiral beam couplings you've used don't like taking a lot of abuse, they look great at first and don't cost much which is attractive but I wouldn't use them on anything other than a really light weight machine i.e a 3D printer. I've seen quite a few just simply snap at the spiral, their just far to light weight and really need quite good alignment of the connecting shafts to be reasonably reliable.

Lastly... Get yourself a new Hat rack and move that one because its going to get covered in swarf :joker:

[chillybo]

Thanks Lee, I think the mistake I made with the power supply voltage is that I calculated the stepper motors 'sweet spot voltage' from the one with the lowest inductance thats going to be powered by the supply ( 3mH whereas the two Nema 34's are 3.4mH). I suppose it's now a case of seeing what the performance turns out like and if need be build a separate supply for X and Y.
The gantry will be lowered and the excess extrusion will be cut off to help with weight of the gantry. Ive built it like this so I can work out the best height by actually using the machine when its ready to cut.
I can tension the belt by lowering the stepper motor as it is adjustable. I will be building some kind of springy tensioner though.
I will keep an eye on those shaft couplings and maybe swap them for the Oldham type ones or even switch to using belts.
Im building it in the kitchen dining area at the moment and have to put up with the wife grumbling about it. Its being used mostly as a clothes horse at the moment to justify it being in the house instead of the garage :biggrin:.