CNC Mill Build - It Works!

Very quick update, I did finally sort out my electronics problem and was able to mill my first piece.

Behold the power of my machine:

When I shot this video my setup looked like this.

Already I'm not happy with it, the electronics are too close and don't allow the wires enough room so I can't use the full length of the Y axis, also they really need to be covered. 

I'm currently holding work down using push pins, not a great solution.
Already working on changing all that. But for now it works !



See my next stage of improvements here.

CNC Mill Build - eLectronics

The last post saw me putting the finishing touches to my machine build, by adding the belts. Unfortunately that's the easy part over, now I'm tackling electronics.


There are two stages to controlling a CNC machine. The first is a controller which will take a Gcode file* and turn it into step and direction pulses that tell each motor when to turn.
The second is a motor driver which takes these low voltage data signals and sends high power signals to actually drive the motor.

For the driver (the second part) I'm using pololu a4988 drivers along with a stepper shield. After finally sourcing all the parts this is what they look like.

The driver is quite small, you can see one of them in the top left. The rest is just capacitors, to even out power, and connectors, to attach all the motors.

This board is a 'sheild' which is intended to be used with an arduino. You can use an arduino as your controller, but I wanted to use a PC because it gives me more control and a  nice graphical interface.

Which means I had to build a separate board to make it so the signals to and from this shield could be sent via a parallel cable.

This is what I put together. Again not much going on here, the parallel cable is broken out and the signals sent to the right sockets (so they match up when the shield is plugged in on top).

There is also a 5v regulator to supply the logic voltage and all the connections are optically isolated. This means that the CNC motors and the computer aren't physically connected, this means any noise caused by the motors won't affect the computer.

Bart Dring, of Buildlog.net designed this board which does exactly what I want. But he doesn't sell them anymore. So what I did was buy the arduino version (also designed by Bart, but now made by Reactive Substance) and adding in the missing components so that it was functionally the same. It probably would have been easier to just build the whole thing myself from Bart's schematic. But the black boards help with heat dissipation  as well as matching the drivers I bought, and looking badass.
Edit: of course now that the M6 is finished, I could design a new PCB with everything on and mill it on my machine, how ever I'm unlikely to ever get round to this.

Now the shield carrying the stepper drivers, just plugs in on top. Each one of those drivers (now with large blue heat sinks on) controls one of the motors, each motor has 4 wires.

The large silver box off to the left is the 24V power supply, this is the power that is used to drive the motors, the 5V logic is supplied by a small regulator I put on the lower board.


That's most of the hardware set up, the other end is an old PC running Ubuntu, I'm using LinuxCNC to control my machine, it's a very powerful tool (probably overkill for this little thing) but nice all the same.

What came next was lots or testing tinkering and , to be honest, swearing as I tried to figure out why it wouldn't work.

(figured it out eventually WooHoo!)




*Gcode is the end result of designing on a computer, it's composed of simple lines of text that instruct the machine where to go using an absolute positioning system. E.g. g0 x10 y10 would tell the machine to move to that co-ordinate (g0 is just max speed) so kind of like playing Battleships.

CNC Mill Build - Zzzzz

I am slightly regretting this procedural format I've locked myself into now, but I'd better finish it . 

In the previous post I bolted together the X and Y carriages to form the main framework of the machine. Now I'm tackling the Z axis.

The Z axis is different in that it is screw, rather than belt, driven.

The flexible coupler and flanged bearing are attached to a length of M8 threaded rod. The aluminium tape is wrapped round the rod to ensure a tight fit.

The threaded rod is coupled to the final motor and the bearing is sandwiched between the two Z plates.

The black brick is a delrin nut, it is threaded onto the screw and the final length of Makerslide is bolted on.

These are the spindle mounts, once the machine is finished they will hold the Dremel.

That finishes up the Z axis. Now all I have to do is mount it to the machine, 
and add the belts,
and sort the electronics...

CNC Mill Build - Squaring Up

Starting with the two Y motor plates I'm going to build the gantry for the X carriage I built last time.

These are the two X lengths of Makerslide as well as the belt anchors and a belt and pulley.  (I'm going to wait until the end to mount the belts.

The X carriage is now mounted between the two Y plates, completing the Y carriage.

Two more (longer) lengths of Makerslide and the two endplates.

I now have the basis of the machine assembled :D

The mechanics of this bolt together nice and easily, I'm less certain about the electronics :s

Next up is making the Z axis.

CNC Mill Build - X Carriage

This is continuing fromt he last post where I was assembling one of the Y plates.

This time I'm going to put together the X carriage.

X Plate (all plates are identical)

Motor, smooth idlers and fixings.

This starts off similarly to the Y plates, except that here the motor is mounted flush against the plate.

The two X plates get bolted together to create a nice solid box, here you can see what's going on inside (that shot was a lot harder to take than it looks, because nothing is fixed)

The last X plate finishes off the carriage, but in this step the V wheels for the Z axis are also added.

Next I'm going to bolt the motor carriages together to form the basis of the machine. : )

Once it's all squared up you get a much better idea of how the machine is going to work.

CNC Mill Build - Just Like Lego

Last gime I gave a bit more info on how I got interested in CNC and where this kit came from. Now I'm actually putting it all together.



Everything in this kit was so beautifully packaged and labelled it reminded me of cracking open a fresh Lego kit. The sheer delight of all the tiny bags of sorted pieces brought back many a childhood memory.

Anyway all this organisation prompted me to tackle the build in a very measured and precise way, not at all how I usually work.

So for each step, I laid out all the parts and took a picture. 

The first step is bolting one of the Y motors to a motor plate.

Bolt on 2 smooth idler wheels. These just guide the timing belt in the right direction.

Bolt on 4 V-wheels. These are what will actually grip the Makersilde rail. 

Those two small parts in the bottom left are eccentric spacers, they're slightly offset so that you can adjust how tightly the wheels grip the rail. It's this kind of simple problem solving, that makes this design so good.

That's one of the Y drive plates finished (the other is simply a mirror image).

Next time I'll be assembling the X carriage.

CNC Mill Build - Intro

Ever since I found out about computer controlled production, I've wanted one of the machines for myself. 

Start up projects like the MakerBot (my first love) have made it much easier for anyone to get into digital production. But The $1000 price tag was still far too much for me seeing as I was still a student.

Image credit: BrePettis.com

During my time at uni I had access to a laser cutter, which was great, but limited to 2D production, and I used the Shapeways service to get a few 3D models printed. But found the price tag prohibitive and the 2 weeks of waiting between design and product was painful, and ruined one of the fundamental principles of digital production*.

But in my third year of uni I got it into my head that I was going to build a CNC mill. 
I did a lot of research and made a bill of materials. My aim was to build the whole thing for under £200. Long story short, I got the mechanics working (sort of) then ran out of steam.
The beast is currently disassembled in a box and may be worth it's own (rather depressing) post, it just wasn't going to be accurate enough for me.


Jump to October 2012 and for the first time in a long time I have a job and then stumble upon project Shapeoko. An open source kit that aimed to get you up and running for $300.

And just when I started looking at how I would get all the parts in the U.K I found the eShapeoko! Someone in Europe was selling kits, so almost immediately I ordered one.


Because the project was new they were still having problems sourcing all the parts but finally in mid January this rather small, but tantalisingly heavy package arrived at the door.

eShapeoko #23

Individually labelled parts bags. Almost more exciting than the actual machine.

Here's everything that came with the kit. Lots of lasercut steel, several lengths of Makerslide (more on that later) and various other bits of hardware.


I wanted to paint my kit to protect it, but mostly so it would look cool. I had a lot of black spray paint, and only a bit of red (left over from my Red Dwarf phone). I think that dyeing all the nylon spacers may have been a step too far, but I guess I was just over excited.

I may never get it running, but it's damn well going to look sexy!

The only other bit of prep is tapping the ends of the Makerslide. 

Makerslide is a new bit of hardware that was originally a kick-starter project by Bart Dring. It's similar to a standard aluminium extrusion, used in many designs that need to be strong light and inflexible. The key difference is that Makerslide has a set of V rails on it, which allows it to be used as the primary linear motion system as well as the main structural support which makes it ideal for small (or quite large) machines that need linear motion.



Well the colour scheme's all done, now I suppose I actually have to put it together. 

In my next post I begin assembling the kit.



* I think the direct link between designing on a computer and then very quickly being able to hold it in your hand, assess it and make changes is one of the best things about this technology.
However I still think Shapeways is a great service and I've always been really happy with their parts. It's still probably the best way to for newcomers to experience digital production without having to spend hundreds on getting set up. As well as the fact that the machines they use are far better than any home setup and give the option of printing in all sorts of cool materials.