The steppers that come as an option with the c-beam kit are rated at 2.8A & they won't be drawing anything like that most of the time so a 10A supply should be fine. I'm using a 24v Meanwell that can kick out 14A because that's what I had lying around.

 

Thanks guys!

 

I ran my Ox with xPro controller and a 400W ATX power supply for a while. I did get a 24v power supply for another build that I am working on, and tried it out on the Ox. It doesn't seem to make any material difference to performance. Worked well with either supply.

-- John

 

Stepper motors are driven by pulses of current, the main advantage of a higher voltage supply to the motor drives is that the rise time of these pulses becomes shorter. That's where the increase in power comes from, the motors get up to their rated current faster.
For example the higher current drivers like the Pololu DRV8825 are rated at 8.2V to 45V max. They will work at 8.2V, but there will be problems if you try to drive the motors at high speed. Higher speed means more pulses of current in a given time; at 8.2V the high speed pulses may not get anywhere near the rated current of the motor before they are switched off ready for the next pulse coming along. i.e in simple terms the pulses turn from squares to spikes. This results in the motors lacking power and more importantly, missing steps, even under low load. Drive at 45V and the edges of the pulses at high speed are much steeper, the pulses more square, giving more power, much less chance of missing steps.
Another thing to bear in mind with this type of driver is that ohms law doesn't apply, the motor current is controlled actively by the driver, the current limit needs to be set by the trimmer pot.
I run my c-beam with DRV8825 drivers at 36V, with the speed settings given by Mark in the build video it runs just fine.

 

All good info guys, thanks. So I think my takeaway is to start with 12v using an ATX supply that I have on hand and bump that up to a larger one when I can. My short term plan is to run this with a RAMPS 1.4 board with DRV-8825 drivers that I have as a spare for my printer. Eventually I want to get it onto either an xPro or a smoothie board.

 

ramps is overly complex for a router tbh its the wrong device for the job, xpro runs off atx psu out the box and runs grbl -I foresee headaches and hair pulling with ramps

 

Hello
If you're going down that route, I may be a bit out of touch, but the grbl software used to be based just around the arduino uno rather than the arduino mega that ramps board uses.
I use one of these:
A4988 Driver CNC Shield Expansion Board for Arduino V3 Engraver 3D Printer UKDS
Incredibly cheap, and sits on top of an uno. This lets you use your DRV8825 drivers, and has the advantage of being specifically designed for cnc rather than a 3D printer. All the pins are clearly marked for limits, spindle enable etc etc.. You can get the whole job lot including the uno for less than a tenner on ebay. You just have to note that in the latest grbl software the z limit and the spindle PWM speed pin are swapped.
The DRV8825's need active cooling for bigger motors, I use an old PC CPU fan, and with the nema 23 motors I set the current limit to 2A, and it runs like a dream.

 

I'm experimenting with two other Arduino based GRBL solutions. I already have an xPro, which I'm very happy with.

1. The Arduino CNC Shield Arduino CNC Shield – 100% GRBL Compatable | Protoneer.co.nz. This is the original design of the eBay link above. There is a more current version, which Protoneer also sells on their own on eBay.
2. GAUPS. GAUPS Arduino-compatible Stepper Shield kit - Amber Spyglass Ltd - (Powered by CubeCart). This is pretty cool, in that it auto senses 3.3 or 5v operation, and can also be plugged into an Aduino Due running TinyG (G2) instead of GRBL, so you can experiment with either. It also has nice screw terminals for stepper hook up, which is a bit easier to swap in and out.

Either of these boards take the Pololu stepper modules, so you can also experiment with DRV8825 or A4988 drivers.

I'm planning to start a separate controller thread at some point.

Also building a LinuxCNC rig based on Beaglebone with parallel port shield using conventional stepper drivers. But I really like the simplicity of GRBL.

-- John

 

I've also been using this shield on several CNC machines without ANY problems. Completely happy with only one suggested change to the board. There is a glass fuse that's squeezed in right in the middle of the board. Find it and either jumper around it and place a inline fuse in the positive power lead OR remove the fuse and replace it with an automotive type fuse and holder. There has been some discussion on the protoneer forum about the best choice, but it seems that both methods work fine. Or just forget about it and run the shield as-is. It's really a solid and simple board that will do exactly the job we need on our Ox. Four DRV8825s, a Uno board and this shield and you are in business - it even has spindle control and addresses a full set of limit switches and Emergency switches.

 

Arduino boards are easy to setup with standalone drivers the uno/mega just puts out a 3.3 or 5v logic its just a case of wiring

pololu do breakout boards for the DRV8825 type boards (aka keyes control panel)

Isn't the tinyG just a brother of the gshield with a built in mega but can also run ABC aswell as the XYZ ? it conforms to the gcode standards

 

Alright guys, here it my attempt of containing the dust / shavings etc.

All of the parts are sourced from Lowes / Home Depot. I built the enclosure to fit the new OX type CNC router i am building with my C Beam machine.

Still adding a keyboard tray, monitor etc, however here is some progress.

 

Very nice and based on what I can tell from this small tablet I'm on today, very modern and sleek look. Is it based on a commercial shelving unit that you have enclosed? Or is it built up from bits of "this and that"? How about a few close-ups of the details?

Thanks!
Larry

 

Tropical fish?

Seriously, like the idea, will probably end up going down a similar route, what are you doing for dust extraction?

 

Looks great I don't have the attention span for that....LOL
My ox is on saw horses with a piece of plywood on it.
Just bought an c-beam machine and I will have to get a longer piece of plywood!!! well at least till next summer when I take one of the machines up north to the cottage...
Bob

 

I started an idea / concept thread with some of the details if you want to take a look. It is more of a universal solution so i posed it over there.
My new CBeam / OX Enclosure (Lowes / Home Depot Build) | OpenBuilds

I am going to run the machine without an extraction system at first since i will mainly be cutting aluminum. The coolant mister system will also help keep dust down. If i do need one, i have a ton of LED computer fans laying around and will make a filtered intake / exhaust system much like a computer case.

 

What are you planning on using for coolant for your aluminum cuts?

 

I am going to start with Kool Mist.

 

Does anyone know if the Kool Mist coolant is compatible with components in the Plate Maker, in particular the bearings, the Xtreme wheels, and anti-backlash nuts?

 

I apologize in advance if this has been asked elsewhere.

I am going to build the stock C-Beam and will use the XPro board with it. My question is would I be able to run the G-Code toolpaths saved from Vectric Aspire or V-Carve on my machine? I am thinking of purchasing Aspire or V-Carve instead of using the free CAD/CAM software suggested if it is supported. I will use Universal-G-Code-Sender or GRBL Panel to send the G-Code from V-Carve/ASpire to the XPro.

While I am at it, would there be any advantage of using Mach4 instead of Universal-G-Code-Sender or GRBL Panel, and does Mach4 even support the XPro (it is USB, so I assume yes)?

Thanks!

 

do not use grbl panel with the xpro as it can cause issues with the firmware

you can use and software you like as long as it conforms to the g code standard but be aware the some g code commands are not supported by grbl and you may need to edit the g-code to remove them for it to work correctly

I'm using a mix of sketchup and fusion 360 what are both free - but fusion 360 is a great tool once you learn to use it, I looked at the X-carve and the c beam at the same time

the c beam won as its expandable and just uses standard parts, if you want larger build area look at the openbuilds OX, The benefits of building your own is you get to understand the machine from the ground up

 

I use aspire 8 to generate g code for my machines that run Mach 3 but have had less than satisfactory results going from Aspire to a grbl based firmware. I always allow that the problem may be on my side of the keyboard, so please wait for other responses.

I will be watching for input from our software giants to help us both out.

 

I have an Ox build using xPro. Have the latest version of VCarve (8.x) and no problems with generating gcode for cutting. There is a grbl post processor that you can select for inches or mm.

For control, I have a Raspberry Pi hooked up to the xPro. I started with Universal Gcode Sender, which works well on RPi, and then moved to Chilipeppr (browser running on remote Mac, with the serial port JSON server running on RPi).

Have recently started playing with bCNC, which is by far the most feature filled grbl solution, more like Mach3 in capabilities with macros, plugins, etc. vlachoudis/bCNC · GitHub. It runs great on Raspberry Pi, Mac, Windows, etc. It's one of the few grbl solutions that passed @Sonny Jeon gcode stress test.

I had issues with GRBL Panel initially, and never bothered to pursue.

 

Hi all, first post and would like a little advice on controllers for the C beam machine.

Been thinking about getting into CNC for a while, for milling sheets of aluminium, G10, carbon fibre and brass, and would like precision of 0.1mm or better. It will be a fairly stock build from an Ooznest kit with the NEMA 23 motors. I'll probably change the MDF table for an aluminium T-slot plate and add some splash/dust guards, maybe a dust extraction system too.

The CAD side is sorted (I'm a design/development engineer, using Inventor) so generating the data is easy, but I still need to work out the CAM side of things. Fusion 360 is looking likely at the moment, just need to try it out. I will be using a Mac to control the machine as it will be at home and the plan is to use an Arduino with GRBL, a CNC Shield and Pololu A4988 drivers. This all looks relatively straightforward so far, so some advice on potential pitfalls and tips would very much appreciated.

 

New to the forum, glad I found OpenBuilds. The C-Beam is certainly a nicely designed machine that seems to be getting a good reputation. The fact that it is kitted suits my needs quite nicely.

I'm wondering if this would be a decent choice for the basis of a CNC engraving machine. I'm looking into a machine that can engrave small lettering (.125") and some line artwork (modestly low detail) on aluminum. I've read through the builds, looked at the electronics and software and I'm pretty confident that even with SketchUp, I can achieve the simple text and line art that I want to engrave. The size is about right, I'm engraving small 2" by 4" metal parts. The question for me is about the hardware - is this the right choice for me.

Since my cuts will be light, do I need a full sized spindle setup or can I use something smaller? Any advice by folks that have built metal engravers? I will need to get about 1" more Z height, and there are already examples of folks that have made that mod.

Thanks in advance for any and all advice.

Paul

 

Hello

The 4988 are a bit small for NEMA 23 motors. You need DRV8825s, see my post higher up this page for my set up.
It could be argued that the DRV8825 is not quite up to the job as well, but it's ok with a heat sink and a fan.

Mike

 

There is a newer rev of the CNC Shield (3.10) that adds support for grbl 0.9/PWM. The designer sells on ebay under the name "Protoneer".
Link to details, and other sources: Arduino CNC Shield – 100% GRBL Compatable | Protoneer.co.nz

-- John

 

Hello
This looks just the same as the one I use, which supports grbl 0.9 and PWM for spindle speed.
The pins for z-limit and spindle enable need to be swapped, as the PWM signal is output on Arduino pin 11.
I can't see any difference between the two boards.
Mike

 

Honestly I'm not sure what tweaks were made by the designer. I know there are a couple of versions floating around (3.00, 3.04, and the most current is 3.10). Since Protoneer open sourced the design, it's easy to find a lot of copies cheap! The one you are using may be the most current schematic, but the labeling didn't change.

-- John

 

Thanks Mike. I'm waiting to see if the 8825s are discounted at Pololu later today. Have got the Arduino and a CNC shield (3.10) on the way too, and will look into cooling the drivers .

 

you can get DRV8825 for $5-6 (£4) each, the 8825 comes with the heat sinks, The steppers have a current ratting but rarely do you have both coils energised at the same time, The chip its self has a thermal and over current protection built in,, only if you do something silly, will you blow a driver