How To Build A CNC Machine
If you have no special tools
I am a regular guy. I do not have a huge fancy CNC machine at work. I do not even have a small milling machine or a lathe. My friends do not have them either, so I have nobody to machine some custom parts for me. I have inquired with several shops and individuals who can do custom machining and their prices were out of reach - I estimated that it was cheaper to buy a commercially available machine than to order custom parts for my machine from them.
I was looking for some sort of a kit, or maybe some type of construction where you do not need to make a lot of custom parts. I had come across some kits over the internet, but they were all MDF and thus lack precision and were not rigid enough for machining soft metals. I have also come across several plans for DIY machines. Some of them were very good, but they still required custom machining, or welding, or something else that was unacceptable for me. For example, many plans suggest that the gas pipe should be used as a part of linear motion system. Frankly, I do not think that gas pipe based machine will give sufficient precision and rigidity for working with metals. Furthermore, the pipe will bend (if it is not a short piece of pipe). This means you will have to support it somehow, and such supports restrict carriages design.
My task seemed impossible, but after many weeks of research, I found exactly what I needed. Actually, what I have found was as close to a bolt-together kit as a CNC machine can ever be. The idea was to build a machine around the aluminum extrusion produced by 80/20 Inc. The particular type was fractional 15-series T-slot extrusion. They come in different standard sizes and can be easily connected together. This solved the problem of a base, table and gantry material for the CNC machine.
Now, you can say that yes, there are such types of extrusions, and many firms build their machines out of aluminum extrusion made by Bosh/Rexroth, Isel and other manufacturers, but you still need to fab custom parts that will attach and coordinate the linear motion system to this extrusion. And here is the most interesting thing: you do not need to fab these custom parts yourself! There is a whole set of parts like bearing blocks, ACME nuts, linear carriages and router plates that were designed specifically for 80/20 Inc 15-series extrusion. This means that everybody can take a CAD program and design his or her own machine. It will take quite a bit of time though, because you will have to consider some small but important details and deal with things like choosing motors and lead screws for your machine. But you will probably end up with exactly what you want. If you know what you are doing, of course. Otherwise, you risk loosing a considerable amount of money and not getting what you need.
Keeping all this in mind, I spent literally weeks and months gathering information here and there, justifying critical decisions and designing important assemblies. I started documenting my build from the very beginning to the very end. As a result, I have put up a step-by-step guide that is full of useful tips and tricks. This guide can and will assist you in building your own CNC machine. It will give you detailed instructions and provide clear high-resolution photos for each and every step. 3D models will make understanding the design much easier, and clearly documented Bills of Materials will allow you to order an exact amount of parts and start the build right away. If you have all parts at hand and can devote some time to your new build, you can expect to finish your machine in two or three days. Now this is considerable time saving compared to weeks and months, isn't it? Even if you will be reading this guide thoroughly for a couple of days, time saving is still huge.
This guide is especially useful for hobbyists who do not have much time and cannot justify spending weeks and weeks learning CAD software and designing their own machine. With these plans for CNC machine you do not need to do that. Just check that you ordered everything listed in the BOMs and you are almost there - in a weekend or two you will have your new CNC machine ready to cut whatever you need!
Actually, it is not correct to tell you that this guide is "a set of plans for CNC machine". There are no plans. Yes, they could be included but what purpose would they serve? Since all components are standard, you will never ever need to order any custom parts anywhere. Instead, I have included several 3D models that are much easier to understand by somebody who do not regularly read plans. Each and every step is accompanied with a photo, and as you know, a picture is worth a thousand words.