3D printed home CNC with Arduino

For a long time I wanted to build a Inexpensive home-made CNCif possible with 3D printed partswith a Arduino as a controller.

In my head I imagined myself doing a thousand and one projects for all my hobbies: printed circuit boards for electronics, wooden parts for my planes model aircraft, and carbon fibre parts for drones, making the machining of crates for electronic projects, panelsetc.

After several years with this recurring idea, in the summer of 2017, I decided to take action and building the CNC (o numerical control milling machine) which I present to you here.

As doing it all in a single Blog article can be very long and cumbersome, and I intend to go into some level of detail, I will include photos and all the tips that seem important to me that I remember from when I built it, I will divide it into several entrieswhich I will be writing about little by little (don't forget to subscribe to the Blog to find out when I publish them):

1. Overview and options
2. Mechanics
3. Electronics
4. Milling machine or Spindle
5. Software
6. Use

In this overview post, I'm going to talk to you about what it is like and of the CNC capabilities in a very generic way.

This is an inexpensive to build CNC milling machine, with a linear motion system fact with bearingsThe skateboards, usually used on skateboards, glide on square aluminium or steel tubes.

The advantage of this linear motion system is that it is sufficiently precise for normal non-precision work (if I wanted to mill a one-euro coin on my CNC I can tell you it would lack precision) and it is much cheaper than the axial bearings on rods or linear guidewaysimportant when you want to getting a cheap CNC.

Overview and options

When I started thinking about building the CNC milling machine, my head was a pressure cookerThe report is full of doubts and questions.

There is a lot of information on the internet, but when you don't have a clue, as I did, you can have it right under your nose and not recognise it.

Things like what I would use it for, the effective job size I wanted to achieve, the general format of the CNC, whether to use professional parts (such as linear slides) or all home-built, etc. I was clear that I was going to use it for milling wood.

There are many options, and I'm going to go over them here because it would be too long, but I can say that after a long time looking - years! I found the design I liked.

The design was called Root CNCa homemade CNC milling machine design with free plansThe electronics were similar to those of a 3D printer: an Arduino, some stepper motors and little else...

Mechanics

The mechanics aspect of the CNC is this:

The mechanical part is made of 20x20mm aluminium or steel which can be purchased at Leroy Merlin or similar, skateboard bearings, 3D printed parts in the 3D printer (many parts, almost 3 kg of PETG filament!) and nuts and bolts (lots of nuts and bolts!).

For the tubes I used 1.5 mm thick aluminium (which you can find at Leroy Merlin) but they flexed on medium hard work, so when I could, I replaced them with 2 mm steel ones.

These would be missing wooden parts which, at first, I made by hand with MDF and, when the machine was already working, one of its first jobs was to machine your own final pieces in phenolic plywood which turned out beautifully.

A tip: if you make them by hand make sure that everything is well squared, when you cut them and when you make the holes (which are many). If everything is not squared and in the right place, then the work you do will be done will not work out well. Ideally, you should have them made by someone with a CNC machine. If not, do what I do, make the first ones by hand, as best as possible, and as soon as it works. "the good ones.

Electronics

The electronics for the Root CNC is also very simple and cheap. It is very similar to the electronics of a 3D printer. 

It consists of a Arduinoas a brain, some driverswhich are the ones that make the Arduino capable of controlling the motors, and a few stepper motors.

The power of the stepper motors and corresponding drivers should be chosen based on what you intend to do with the CNC. The same motors can be used, Nema 173D printers (sufficient for "light" work, engraving on soft woods, printed circuit boards, working with plastics, etc.) or use more powerful 3D printers such as the Nema 23If you want to do things with hard wood, cutting work, work with metals such as aluminium or brass, etc.

In my case I have used Nema 23 motors with DM542A drivers. This set has enough power to work any type of wood, no matter how hard it is, plastic such as methacrylate (also called acrylic), metals such as aluminium, and other materials. 

If you don't want to install such powerful motors and drivers, a good option is to use a CNC Shield board with normal 3D printer drivers such as the DRV8825, which makes the cost much cheaper.

Of course, a power supply and other minor accessories would be missing.

This well-priced kit from Amazon includes the Arduino, the CNC Shield, the DRV8825 drivers and even some limit switches, which can come in handy.

These Nema 17 motors are quite good. They have a power rating of 0.45 Nm. Be careful to get the model QD05 and not QD06 which appears on the same page and which has a lot of less power.

Milling machine or Spindle

The milling machine, spindle, or motor is one of the important parts of the CNC.

Basically we have three main options.

1. Hand Multi-Tool
2. Milling machine
3. High frequency motor and inverter

Hand Multi-Tool

This is the tool type Dremel or similar.

Its main advantage is the price (not that much) but it is not very strong and makes a lot of noise. Nor are they intended to run for long periods of time.

In my opinion not worth much unless what you want to do with the CNC is limited to printed circuit boards, light wood engraving, plastic engraving and the like.

Milling machine

A good milling machine is a workhorsebut it has a big problem: it makes a infernal noise.

I started out, for economy, with a milling machine very similar to the Makita RT0700Ca 710 Watt milling machine and me worked very wellalthough I ended up not being able to stand the noise.

High frequency motor and inverter

In my opinion, what they usually call spindle, the high frequency motor with inverter (VFD)is what a CNC should have, all the rest is just a matter of tinkering.

After two years with the milling machine, I put a spindle of 1.5 kW water-cooled and I wouldn't go back. In the photo you can see the one I bought.

What are the advantages of a spindle?

• No noise. There is very little noise when working under vacuum. The noise that is generated is actually the noise made by the cutter against the material being milled, the engine hardly sounds.
• It is possible to regulate the speedincluding by softwareand that is important.
• Can work hours and hours without flinching.
• It sounds silly, but it's not at all: because it is water-cooled does not expel air (as do milling machines, Dremels and so on), which means that the sawdust does not come outor shavings from the material you are working with, shot all over the garage ?
• Allows you to put a huge variety of types and sizes of strawberries.

Conclusion

Building the Root 3 CNC has been a very nice and interesting projectand it's amazing what you can achieve learn.

It is not difficult toIt's simply a matter of going step by step and with patience.

If you enjoyed the article, I would be very grateful if you could spend a minute to leave a comment below.

One last little trick. I sometimes use a foot pedal, like the one you can see below, to pause the CNC quickly when necessary.