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You can build your own CNC machine!


CNC stands for computer numeric control. That means that a computer is controlling the position of the router bit or endmill in 3D space. I use mine for woodworking, prototyping circuit boards, but mostly making crosses. Others use CNC to mill metal, cut parts for R/C airplanes and helicopters, even mill machinable wax for casting jewelry. Think of the possibilities! You can cut some very complex designs. Although there are limitations, with a CNC router you'll have a world of possibilities too.


You can build one and get it operational for as little as $500.00. I did it. Is it easy? I wouldn't say that... But, nothing in life that is worthwhile is easy... Actually, CNC is a lot of work and can get very technical at times. While I am a professional engineer, I didn't learn all these things about CNC in school. Instead, I took several classes at a local community college to learn specifically about Rapid Prototyping, CAD/CAM, and CNC; that's really the fastest and easiest way. Some of my friends chose the hard way... learning slowly on their own, often from expensive mistakes. You don't have to go it alone. A good forum to discuss these machines is www.cnczone.com. The first step is research, research, research. The next step is to get the machine. If you have a lot of cash, no problem - just buying a machine (and please send me a e-mail, let's be friends! None of my current friends have a lot of cash). For around $12,000 you can have a very solid machine and software to run it. If you are like me and don't have an extra $12k, you could choose to build one instead. Build one and I promise that what you will learn will be worth much more than the money you save. Because you'll know the principles and ins and outs, you'll be able to trouble shoot manufactured CNC machines later too. You will really understand CNC, and that's is my kind of fun. CNC will get in your DNA!.   


The CNC has 3 main parts:

1) A computer - you need to draw designs and use special software to convert those designs to code your CNC controller board can understand. The software to draw designs is CAD (or Computer Aided Design) software. The software that writes the code is called CAM (or Computer Aided Manufacturing) software. I use AutoCAD, RhinoCAD 3D, CorelDRAW, Vectric VCarvePro (www.vectric.com), and Mach3 by Artsoftcontrols (www.artsoftcontrols.com).


2) A CNC controller board, electronics, and stepper motors. This part takes the code from computer (via the parallel port or USB) and turns it into signals that turn the stepper motors on the CNC. I built my board from a kit (www.hobbycnc.com). It works great! If you don't want to build a circuit board, another great company is Gecko Drive (www.geckodrive.com/). I recently upgraded my electronics to a G540 stepper driver from Gecko. They make some great controller boards for both stepper and servo motors. The reason I upgraded is my old system runs at 12V but the new one runs at 48V. The higher voltage lets me get faster speeds from my stepper motors so I can make things much faster.

3) The CNC router machine. I'm talking about the mechanics of the machine itself... leadscrews, lead nuts, stepper motors, the router spindle, etc. Most basic machines have three directions of travel an x axis (let's say right and left), a y axis (let's say forward and back), and a z axis (let's say up and down). My first router was from plans at www.solsylva.com. Unfortunately, the website is down. I think they are out of business. When I built mine, there weren't many affordable options. That's not true today. New 3018 CNC engravers from China can be purchased for under $150 from Ebay. I built the 13" x 13" fixed gantry table and highly recommend it as a first CNC router table. It is a great design but won't run fast. I ran mine at about 30 inches per minute. My new CNC is a 24" x 14" machine made by K2 CNC (www.k2cnc.com). Unfortunately, K2CNC is now out of business. But the machine still works great! It will run 80 inches per minute, no problems. I earned the money to buy the K2 by using my home made router table to make and then sell wooden crosses. The K2 router is top quality, extremely precise, and all around excellent American-made product. It did cost 10 times more than my homemade one... but it is all metal and it weighs 160 lbs. Wth the enclosure, it weighs over 300 lbs. Not really very portable.

CNC as a manufacturing technology has some pretty clear advantages and limitations. It can do some truly amazing things, but it will not replace the scrollsaw (fretwork) or hand carving. I've been a wood carver for over 20 years, and while the CNC can make things no person could do... I can make things my CNC can't replicate. Synergy is best (the machine does what it does best, I do what I do best). Among the true advantages of CNC are precision: straight lines are straight and circles are round. Another advantage CNC's are very obedient. They are exceptionally good at following instructions, whether those instructions are correct or not is up to you. A CNC will not argue with you if you tell it to plunge a 3" fly cutter at 20,000 rpm, 5" deep into rock maple, it will do it. Even if it destroys itself. It won't help you dig the metal shards out of the wall or yourself. Another great thing about CNC is that it is hard working. If you teach it right, it will work along for hours while singing its weird little stepper motor song. You can get up and work on other things until it is done. Among the disadvantages of CNC are the dust and noise. It is very good at making both. You'll want to build an enclosure to reduce both and get a good dust collection system too. 
Another big danger that I must mention is the harm it can cause to your wallet: this hobby can go from very expensive to ridiculously expensive even with a homemade router. You'll need new tools you never even knew existed.

My new CNC table.
A KT-2514-09 from K2CNC


To see more about my little crosses, please visit: www.stdwoodworking.com