Stepper Motor Control??

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

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-D...ter-Build-Logs

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

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/1161...highlight=avor.

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.

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.

Hi again, no animosity taken.

Has previously stated, I am not a novice at CNC, my first CNC was a converted "HOBBYMAT BFE65" desktop milling machine, this was about 12 years ago, may be more. I fitted Steppers to this machine, X.Y & Z Axis, it ran on MACH3 and a Desktop PC, a DELL if I remember right. It worked perfectly well, only used it a few times, small parts made. I was then given an offer I could not refuse. I was offered double the money I had spent, a no brainer at the time, as my hands and skeleton where then OK, and I could still use hand tools, since then of course Arthritic has set in in both hands and I now find it difficult to use them, with hindsight I wish I had kept the machine, built another with the money I made, and simply learned more about programming etc; then I might not have to ask many questions.

What can you recommend m_c ?

Regards

Ray

The stepper motor break out board I used is made by Planet CNC. Being an Apple and Linux user I had to find a board that not only worked with Windows. The great thing about this board is the fact DWG files can be sent directly without a toolpath generator . This board works really well with Kirimoto CAM toolpath (freeware) software for STL files.
I assume you need a 3 axis controller for your project.
Planet cnc make boards for 3 to 9 axis machines!

Quote:

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Originally Posted by The Gresley Luthier

What can you recommend m_c ?

Regards

Ray

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For which part specifically?
Controller, or drivers?

I am sticking with NEMA 23's on X,Y & Z Axis. so I was thinking either TB6600 or DM556T Drivers, I am unsure about control side, ie, Mach3, Arduino + Shield ???? I have a fair knowledge of Arduino IDE. connected to my Laptop, or should I go for a stand alone controller?

Regards

Ray

DM drivers are definitely a step above TB drivers.

Given that prices have dropped quite a bit, you might also want to consider using closed loop stepper motors, as you can use the drivers error signal to stop things, should something go wrong, and you don't need to tune the system quite as conservatively, so you can push them that little bit harder to maximise travel speeds.

Controller wise, I personally wouldn't use Mach 3 for any new builds, unless you already had a controller or a license for it.
You can always start with something Arduino based, and leave enough room/cable in the control box to swap it later if needed.
My main concern with anything Arduino based, would be any pulse speed limitations. Microstepping and higher travel speeds can easily hit the limitation of lower performing controllers.

However, depending on budget, for simpler machines, I'd probably be looking at something like UCCNC ( https://cncdrive.com/ - their controllers are pretty good, and if it suits your requirements/budget, the AXBB-E is a nice package).
Centroid Acorn is worth a look as well - https://shopcentroidcnc.com/acorn-cnc-controller/ but it gets a bit spendy if you need any of the features not included with the Free software.
There are quite a few other options, but those are probably the most popular two, unless you go for something Mach 3/4 based, which if you did, there are quite a few other options, but I've not really kept up with them.

A note is generally Ethernet based controllers are more reliable.

Standalone wise, I'm not a fan of them for routers/mills, as I find them a bit limiting, however I do have a DDCV (I can never remember which version!) on a little Roland engraver, and it does the job.

All I can suggest, is spend some time looking at youtube videos of various controllers, and make sure any have any features that you require, but for a fairly basic router, most should be able to control it.

Thanks m_c more bed time reading.

Regards.


Ray