Stepper Motor Control??

[The Gresley Luthier]

Hi.
Thanks to members of this site I have decided to build my CNC wood router using NEMA 23 stepper motors. Due to space restraints in my workshop I have decided to build a Floating bed, Fixed Gantry frame, so I need x3 Steppers. I already have several Arduino Uno's I can use, but I understand the Arduino CNC shield can only handle up to 2 amps each, the NEMA 23's will probably be 2.8 amp. Does anyone have any advice on this? I have Googled this problem but things seem a little confusing. Do I use the Steppers with there own Driver, can anyone supply me with a wiring schematic I may study??

Regards.

Ray

[EddyCurrent]

Ray,

I feel you are on the path of building a 'toy' cnc machine.
You need to do more research, start by looking through some of the build logs on this forum, there are plenty of schematics to be found. https://www.mycncuk.com/forums/253-DIY-Router-Build-Logs

[The Gresley Luthier]

Hi, Thanks for the reply. "TOY" maybe to you, but a serious piece of kit for me. I first used a CNC milling machine in 1968, during my apprenticeship, I have been fascinated by them ever since. Its not mechanicals that bother me, but as my thread states I need electronic help, The threads you have pointed me to look mainly mechanical build, Bit I will Plough through them.

Regards.
Ray

[Neale]

We all have to start somewhere - my first CNC router was to a slightly modified version of the JGRO design (details available with a quick Google search). Built from MDF, leadscrews were screwed rod from Screwfix, 3D printed blocks to hold bearings (which were an upgrade from the original design's MDF blocks!) and many other nastinesses. But, despite being thrown together in a hurry to carry out a commitment I had rather rashly made, it worked and taught me a lot. Not least that MDF has the long-term structural integrity of cold-rolled cow dung...

The current Mk2 is all steel, welded construction, Hiwin profile rails, ballscrews, etc. A completely different beast but which drew heavily on my initial learnings. It also reused the Nema23 motors and 2.2KW water-cooled spindle I had rashly over-specced for the Mk1 as I had this vague idea of a future upgrade. Go for it - you can always build a Mk2 if you need it! I described my Mk2 on this forum a few years ago - it's here: https://www.mycncuk.com/threads/11617-AVOR-%C2%96-a-steel-framed-medium-size-router?highlight=avor.

[EddyCurrent]

I certainly don't want to garner any animosity or disrespect by using the word "toy", but the reason for my comment was twofold

1. From your comments I assumed you wanted the cnc machine to do the required job of making guitars. I have made quite a few guitars among other things and I know the amount of rigidity and spindle power that is required to do the job and in a timely manner. You could build a lighter machine that would probably work but you might be dissatisfied with the result so I'm trying to encourage you to avoid that.

2. I'm assuming you want version 1 of the cnc machine to do the job rather than embarking on a version 2 later, why do you think others have had to build a version 2 ?

If you want to build a cnc machine for learning purposes then Neale's reply might be more applicable. Best of luck either way.

A search on the internet for "cnc schematic" produces loads of hits.

[m_c]

To answer the main question, you can use an Arduino to only provide the step/direction pulses to a typical stepper motor driver, although you may need a buffer board to boost the switching voltages (can be done on some basic stripboard).
The CNC shields typically use drivers with limited current and voltage limitations (voltage is needed for speed, and for any decent machine, you'll likely be best with at least 36V)

I'm personally not a fan of arduino based controllers, but they do do the job. Although not likely at the quickest speed.

Ultimately you need something to generate step/dir signals, which are then fed into the stepper motor drivers.
How that's achieved depends on what exactly you're planning on using.