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Scheherazade in Blue Jeans
freelance alchemist
Sindrian Explains it All 
6th-Jul-2011 12:57 pm
Creating Yourself
Originally posted by sindrian at So What is This CNC Stuff Anyway?
It's been pointed out to me that I have yet to really explain what CNC technology is and why it's so awesome.

This post will fix this.

First, the basics: CNC stands for Computer Numeric Control, which simply means that a CNC machine is controlled by a computer using numbers. Technically, this makes pretty much any robot a CNC machine, so let's get a little more specific.

CNC most often refers to machines that move a tool in two or more dimensions or axes. For example, the Kikori is a three-axis CNC router machine because it can move its tool (so far I've only fitted it with a router) in three different dimensions: forward and backward, left and right, and up and down.

Other common CNC machines include laser cutters and 3D printers. Laser cutters move a laser in two dimensions to cut out flat patterns, while 3D printers like MakerBot's Thing-O-Matic move a nozzle that extrudes plastic to create 3D objects (there are other types of 3D printers that work quite differently, but that's another post entirely). CNC routers like the Kikori move a spinning cutter in three dimensions to carve shapes out of solid material. These shapes can be as simple as flat profiles or complex as a detailed relief carving; it all depends on the program and cutters used.

But why are CNC machines so awesome?

Put simply, CNC machines are one of the quickest ways to turn your ideas into physical objects.

When I was little I told anyone who asked that I wanted to be an inventor when I grew up. I would spend hours every day just staring off into space dreaming up everything from pedal-powered airplanes to Nerf-based siege weapons. I got into 3D computer modeling when I was around ten or so, and was amazed by how quickly I could take the images in my head and turn them into 3D objects on my screen. Years later when I entered design school and I was introduced to the school's CNC machines, I realized that these tools could take the 3D objects on my screen and actually make them real.

I was in love.

The only problem was that these machines were fantastically expensive, and I sure as hell didn't want to wait until I had saved up tens of thousands of dollars to get one of my own. I scoured the 'net for other options and found a slew of DIY CNC machines. Unfortunately, they were all much smaller than I wanted: I wanted a machine that could make full-sized furniture, or boat frames, or anything else I could dream up, not just use a Dremel to etch my own PCBs.

Eventually I decided to build the "book" machine from BuildYourCNC.com since it did not need another CNC machine to make its own parts, and the design was free. I had my fair share of issues building that first machine, some of which were my fault, some of which had to do with issues in the design. However, I persevered and after a few months of work I used it to produce a prototype chair for a school project.

At this point I realized that CNC tech was not going just be a hobby for me; it was quickly turning into something more like a calling.

I decided to forgo my last opportunity to get a design internship and instead take a "travel quarter" to spend three months in Boston building a full-sized CNC gantry router. Again, I ended up going with a design from BuildYourCNC.com, this time because they had the only full-sized gantry router design that I could afford to build: the blackFoot. Again, I had my share of trials building the thing (which you can read all about here) but three months later, I had my first full-sized CNC machine up and running.

Problem was, I still wasn't happy with what I had. I liked that the blackFoot was inexpensive and could be built from readily available parts, but it was nowhere near as rigid as I would've liked. Rigidity is important in a CNC router not only because of accuracy, but also in that the more rigid the machine, the faster and deeper it can cut without losing accuracy. I wanted a machine that could accurately cut through 1/2" plywood in a single pass just like the ShopBot machines I saw at the New York Maker Faire, just without the price tag. I decided that for my capstone project for my industrial design degree, I would design a machine that would fulfill my dreams.

Many people I told about my plans were worried that I was biting off more than I could chew. After all, they told me, this sounds like more of an engineering problem, not a design one. When they heard I planned to make it out of plywood, they got even more worried. After all, plywood is not exactly the strongest material out there. How was I going to get the rigidity I needed out of anything less than metal?

I had a few ideas.

For four months I worked on my design, trying different approaches and ideas until I felt I had something that would work. Then I got to building. In about forty-five days I went from a pile of parts to a moving, milling machine. It was great. Then I discovered how accurate it could be, and I was floored. My machine was proving to be everything I wanted it to be. Granted, I did run into a few small issues, but thankfully I found nothing that would've needed a serious revision to fix, just a few small tweaks here and there.

The Kikori was finally a reality.

My next step is to fix all the little issues I found during building before I release the final design. I want the Kikori to show everyone that a production-capable CNC machine is well within their grasp, which is why I'll be making the design files freely available. I know there are people out there who will take the Kikori and improve and adapt it to do even more amazing things, and I want to make sure that they won't be hampered by legal red tape.

Of course I'll be designing improvements and add-ons for the Kikori as well: I've got ideas for both a rotary axis and a 3D scanning module, and I'm developing a couple new gantry designs as well for different applications. After all, one of the reasons I designed the Kikori as a CNC router and not a laser cutter or 3D printer is because I like versatility. Since the structural requirements of a CNC router are much higher than 3D printers and laser cutters, it is possible to turn a Kikori into a laser cutter or 3D printer by simply replacing the router with a different tool. Who knows what else someone will think of to slap into it.

One thing is for sure though: it'll be a lot of fun finding out.

If you'd like to help me please check out my project on Kickstarter!
6th-Jul-2011 06:25 pm (UTC)
You know what's just as awesome? That explanation. So simple even us technophobes can understand :-)
6th-Jul-2011 06:42 pm (UTC)
I know, right?
6th-Jul-2011 07:28 pm (UTC)
Seconded. Part of his strength here is being able to communicate what he's doing, and I think it's going to work very well for him.
7th-Jul-2011 01:44 am (UTC)
That sounds like what Leigh does.
7th-Jul-2011 01:48 am (UTC)
Leigh is...?
7th-Jul-2011 05:04 am (UTC)
Friend of mine. (Well, acquaintance more. She's in that "happy to see me but doesn't answer emails or comments or acknowledge invites most of the time" crowd)

And it sounds more like things she helps other people do, IIRC.

She's big on the hacking and robotics and automatic creation of stuff.
7th-Jul-2011 06:00 am (UTC)
A lot of people are; this is sweeping the world right now. CNC was a major industrial shift in the 1950s thru the 1980s, now it's gotten cheap enough to fuel an entire world-wide subculture of DIY folks, with some people thinking it will have serious effects in the third world (which I'm not sure about yet, myself).
7th-Jul-2011 05:05 pm (UTC)
Yeah, I'm dubious of its actual long-range benefits. The DIY aspect is nice, but a lot of its advantages are of scale. I suspect it will be a nice thing to throw into the arsenal of options, but it isn't going to be revolutionary.

Or rather, it won't be on its own. I could see it being a solid plank of as part of a generalized decentralization of the economies, however.
7th-Jul-2011 10:38 am (UTC)
You should pass this on to her! :)
7th-Jul-2011 05:05 pm (UTC)
I will try to bounce her a link.
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