Step 1: What is CNC

Let’s start with the basics for anyone that is new to this.  CNC stands for Computer Numerical Control, which extends to many different applications but in most cases is used to describe a machine that is controlled by a computer to remove small amounts of material from a larger piece of material.  Most of these machines use a spinning bit with sharp edges to scrape away small slices of material in a very controlled fashion until the desired final shape of the material is left.  Through the use of computers very precise shapes can be cut from almost any material.

So that was really basic, let’s get to some of the specifics on my type of CNC machine.  There are many different types of CNC machines but they are most distinguishable by the type and size of material they are designed to cut.  In general if someone refers to a CNC “milling” machine they are referring to a metal cutting machine and if they say it’s a CNC "router" it means a machine made to cut wood, plastic or other soft materials.  This instructable will show you how to build a CNC router.

If you are learning about CNC and have considered building your own machine I would highly recommend taking a look at this website cncroutersource.com  There is a wealth of knowledge about designing your own CNC router and well as explanations of the different types of router designs and list of terms commonly used in CNC lingo.  When I first considered building CNC machine I was lucky enough to stumble across this site and it helped me make a lot of the basic design decisions early on.

Once you have read though all you can on the cncroutersource.com you can step up to the big leagues and join the cnczone.com forum.  Here you will find a vast amount of information and huge community of active users all doing the things you want to do for your CNC.  There is a specific section of the forum for CNC routers and many build threads have been posted that will make you drool with jealousy.  Have a question about CNC? A simple search of this forum will most likely answer any and all of the CNC questions you have.  Keep in mind though that a lot of acronyms and jargon are used on cnczone but if you have read cncroutersource you should be able to figure it out.
<p>I made this, and have just got to run it once with a temporary handheld router. I am making a box for all the electronics for it as well. Very pleased with the results, but the X travel could be better. Now its only about 210mm travel. All the other black and red parts, I made with my Velleman K8200 3d printer ..Works great ..! Thanks for sharing the project...!</p>
<p>I've started the process of making this with ballscrews, my main issue is bearing to motor mounting. Where did you get those blue standoffs that go around the bearings?</p><p>Thanks!</p>
<br> Hello..! Do you have a 3d printer, or do you know of somebody that have one..? Then you can check www.thingiverse.com ,and find yourself a motor mount. Or I can send you the file I used for my bracket. I use them still, but I would like to make one in aluminum some time. <br><br> Good luck ! <br><br>Kjetil
<p>Great Work! Looks like you used ball screws, is that right? Where did you get them? </p>
Thanks ;) I am really pleased with the rig...but I ordered the wrong size of rails and ballscrews. So I had to downsize all of it a bit. The only drawback is the narrow X axis movement. It might be better to have the rails on the outside to improve this. I bought the ballscrews and rails as a kit from China. Its all right. <br><br> Have you been able to machine aluminium ok with your rig..? <br><br>Kjetil
<p>I only did aluminum once and it was only 1/16&quot; thick. I also recently got an aluminum plate to use as a work surface instead of the MDF. If you do aluminum just make sure its secured really well and the work surface is just as rigid. The small vibrations will limit how far you can go with aluminum. </p>
HI, <br>First i want to say thanks for this write up and the time you've put into it. I'm building this machine and am almost done. I have a question for you on the gantry uprights. It seems like you wouldn't need to drill holes the whole lenghth of the tube as the Z axis has a good amount of travel. Thats alot of holes to drill if there not usefull. Would you say after using the machine that all those holes are a little overkill? <br>Also i added some support plates under the Z axis motor mount plate as it wanted to tilt forward a hair binding the leadscrew. Thanks for all the info and hope to hear back about the uprights....
<p>That's great that your building the machine, please post pictures when its done. The holes on the gantry uprights allow you to adjust the height of the gantry and the clearance between the bit and the work table. I designed it this way but did not fully follow through on the other change that makes this more useful. The idea is that for tall parts you can move the gantry up to get the needed clearance. For shorter parts, like sheet material you could move the gantry down closer to the part. The part I have not done is add a second set of mounting holes on the router mounting plate. The other set of holes would allow you to space the bearings on the z-axis further apart. This does two things. With the bearings further apart the router mounting plate becomes more rigid to resist higher cutting forces but it also reduces the travel of the z-axis. This reduced travel is fine though because you can move the whole gantry closer to the part and because the part is not as thick you don't need the full travel. </p><p>The idea really boils down to, if your cutting short materials, like sheet material, you can adjust the machine to optimize it for the material. Then if you want to cut something thicker you can adjust the machine to get max clearance and travel. </p><p>You are right about the holes though, I could have done less, maybe just enough for a low ,medium and high setting. But the router mounting plate still needs more holes to make this complete. </p><p>I actually plan on doing this soon because I want to use the machine to drill a bunch of holes and moving the gantry lower and gaining some rigidity would make the machine better suited for this purpose. </p>
Here are the pics of my build of this machine. Very straight forward instructions. Also the dust boot i had to make for the machine. <br>
<p>This looks great! Nice job. </p>
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<p>what unit of measurement are you using in the drawings.pdf?</p>
<p>Everything is inches</p>
<p>thank you for all your hard work</p>
How do you stop the bearings from binding on the rail when you tighten the bearing mounting bolts?
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<p>This is a Great Instructable! Thank you very much!</p><p>Only thing I would add is an exhaust fan for the electronics box. Never can be too careful when removing heat from electronic components.</p>
<p>Hi Doug. Thank-you for the guide. I am just about to start on making this CNC machine but just a few quick questions. I am from Australia and I don't suppose you have a set of plans and specifications converted to metric by chance? No so much for the materials, they can be sourced but it would make life easier in manufacturing it all.</p><p> Also, I am a bit concerned about tapping 1.6mm steel. The tube you have as the rails and so forth. Is there a reason why you kept the wall thickness so small an is there any reason why some of the plates couldn't be bolted through (obviously where it won't foul any working mechanism)? If I go up to a 2mm or 3mm tube is weight going to be and issue on the gantry?</p><p>I will try and PM you my email address (still new to 'instructables').</p><p>Again thank you very much. Slick and inventive design, can't wait to make it.</p>
<p>I don't have any drawings with metric dimensions, sorry. On the tapped thin walled tubing it ends up working out alright because there a number of bolts holding each plate. There are about two threads in the tube with the M5x0.8mm screws. I don't thick thicker tubing will create a weight problem so go ahead and use what you have available. </p>
<p>This is an amazing instructable. It is incredibly precise and thorough. I don't know that I will build a CNC - at least not yet, but just reading through this is an education in CNC technology, metalworking and many other processes. Thank you very much. I will be coming back to this.</p>
<p>This is one of the most precise descriptions on a diy cnc. I'm planning my build now and have been doing a lot of reading and it is difficult as a newb to picture all the parts and options. This is really useful. Thanks!</p>
<p>Will you ever have this for sale in a kit form? I&rsquo;ve got some $$ burning a hole in my pocket!! </p><p>Doolie</p>
<p>I know I've been saying I want to offer this machine as a kit and I want to do it right. Start a real business, get a website up, work with suppliers, etc. This is something I want to do but have not had the time to accomplish. I also want to do a little redesign of the machine to improve a few things and reduce the cost. You and the list of people who have expressed interest is now enough to motivate me to do this. Give me a couple more months to get things in place and you can be the first customer. </p>
<p>I would like to know what programming software you use and the motors and controllers you use. Please. Please send back to me at <a href="mailto:paul.bertsch@ngc.com" rel="nofollow">paul.bertsch@ngc.com</a>. Thanks</p>
<p>Great design and very thorough instructions, thanks for posting and sharing. I have a concern though, by tapping the 1/16&quot; (0.065&quot;) steel tubing, did you get enough threads there to hold things tightly? I can't imagine more than two threads present in such thin steel, was wondering how much holding force that actually gave.</p>
<p>Your right the steel is thin and allows for two threads which is enough for the small M5 screws. Plus there are multiple screws for each bolted part. As long as you don't try to tighten the screws with a half inch breaker bar it will be fine, theres no need to really crank down on the screws. </p>
<p>Great design and very thorough instructions, thanks for posting and sharing. I have a concern though, by tapping the 1/16&quot; (0.065&quot;) steel tubing, did you get enough threads there to hold things tightly? I can't imagine more than two threads present in such thin steel, was wondering how much holding force that actually gave.</p>
<p>you are amazing i love to build this router please can you send me the plane and the sketchup drawings</p><p>h.nibso@yahoo.com</p>
<p>This is an awesome project...I want to make one, but am wondering if I have enough projects to do to justify the cost/time. What kinds of projects are people doing with their CNC routers???</p>
<p>Excellent guide. I am using this as a baseline to build my machine. Something which I don't really understand though: How does the acme screw held in place? This is my understanding of it (Let's use the x-axis as an example): On the non-stepper motor side, we have a threaded collar with the bushing. That stops x motion of the screw away from the stepper. On the stepper side, we have the oldham coupler (1/4&quot; on stepper side with the disc then a 1/2&quot; hub) followed by the McMaster collar and bush. These are non-threaded collars so how would they (Both the oldham hub and the collar) grip onto the threaded screw without slip?</p>
<p>Hi,</p><p>Thanks for the wonderful write up. </p><p>In respect of welding and fabricating the frame out of steel, I would like to know about the linearity issue. The linearity (linear accuracy) of the pre fabricated rails will obviously be more precise than the steel tubing used for all the axes' frames. I guess it might affect the parallelism of the finished frame with rails bolted? Any insight into this or any insight to inspect the accuracy of the steel tubing and specific trick to keep the final structure accurate in terms of linearity and parallelism. </p>
<p>yes the frame needs to be welded with as much precision as possible. That why I used the right angle welding clamp. I also purchased shims to place between the rails and the steel but I did not need to use them. I think i just got lucky though. If i ever redesign the machine it will be bolted together to allow for adjustment of the parallelism of each axis. As far as the steel stock, if its bent you may have problems that are not easily solved. The only easy way to determine if the machine is square meaning each axis is 90deg from the rest is the build the machine and cut some part and measure the parts. Adjustments can be made using shims to square up all the axis. </p>
<p>Aluminum plates are important ?? <br>no problem if replaced with another material ??</p>
<p>Aluminum is a good material but other metals would be just as good. HDPE plastic might also be a decent material.</p>
<p>Hello</p><p>I love your project I am planning to use Nema23 stepper motor 425oz-in Dual &amp; <br>DM542A on it hop it fits, Also one important question as I am running out of <br>money and I cannot buy it locally instead of Trapezoidal screw ACME can I use at least for beginning <br>normal screw that I can buy <br>in a store if yes can you tell me whar are the cons. and if not can you at lest <br>tell me why not.</p><p>thanks <br>a lot for the answer as I searched google and couldn&rsquo;t find any answer to this question.</p><p>regrads</p>
<p>You can use normal screw threads. The cons are they don't have high lead and you will probably have more backlash on a single nut. Read through step 2, I put more info about the acme screws there. </p><p>Either thread type will, ACME is just a better choice for CNC. </p>
Great layout!! 1500.00 is good price if it was backed product...warranty..etc. DIY'ER are like the craigslisters....we want it all for little to nothing. If you get busy selling in Dallas area...lemme know if I can help!!<br><br>Dan
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<p>I am hoping to draw a little more of your experience out here... You said accuracy is roughly +/- 0.003&quot;. This is pretty good, but have you found the limiting factors and how to perhaps improve this (still think it is mostly due to runout in the spindle)? You also mention that the motors are plenty sufficient to machine Aluminum, and that the limit is the spindle speed of typical routers. Do you have any experience with actual air-cooled cnc spindle motors? With the proper RPM, do you still think the 280 oz-in steppers are sufficient to properly machine Aluminum? Lastly, and perhaps most importantly, is Gecko the only US based manufacturer you know of for the motors and drivers? I have found some tempting options (http://www.automationtechnologiesinc.com/products-page/stepper-nema23-3-axis-kits/cnc-stepper-motor-3-axis-kit-2) but have been burned by cheap chinese goods so many times I will not risk buying anything unless someone can vouch for quality. Lots of questions here, but thank you so much for your time and help!</p>
<p>Spindle runout is probably the key issue for accuracy on a machine like this. Trim routers are not to designed to the same standards as true cnc spindles. Check out the spindles on Shopbot machines as a possible upgrade. I seen those machines in action but don't have experience. </p><p>For aluminum, I do believe this machine could handle cutting 1/4&quot; thick aluminum plate into shapes but I would not recommend it for billet aluminum machining. A spindle upgrade would probably be required if you wanted to cut aluminum plate all the time. Even then it may take some effort to cut the plate with even a reasonable surface finish. If you want to properly machine aluminum get a milling machine. </p><p>Gecko sells good products but you have to put everything together yourself. I recently found flashcut CNC which another CNA controller maker in the US. They sell whole systems with usb control. A friend of mine got his steppers and controllers from automation tech for his G0704 mill conversion. he got the newer digital drivers and has not had any issues. I don't think you'll get burned going with that 3 axis kit. </p>
<p>I have another quick question. Is there a design issue with placing the x-axis rails facing out rather than in? I can't see one, but wanted to ask. It seems this would gain you ~4&quot; more machining room without making the footprint any larger and the feet are already needed at the corners to elevate and level the entire assembly giving room for the drive nut mount. Your thoughts are appreciated. Thanks!</p>
<p>Your right this would give you more clearance for your your material without increasing the footprint. There is one issue I see with this though. I designed the machine to use only a single 6ft length of ACME screw that I cut to length for each axis. That way there was no waste on this expensive component. The 6ft length is what mcmaster sells. By making the gantry wider you will either need a longer screw for the y-axis or design a new way to hold the shorter screw on a wider gantry. If your not worried about the screw length and will just buy the lengths you need then I see no problems with this change. </p>
<p>All great advice, thank you very much for sharing.</p>
<p>Will make a difference if I have a 425 oz motor for this machine? Mine is six inches longer and six inches wider.</p>
<p>As long as your controllers are properly sized for the motors you should be fine. Is your machine built the same way mine is? If so it would be great to see some pictures.</p>
<p>Yes it is built the same way. Once I have the machine finished I will post some pictures.</p>

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Bio: I enjoy building things more than actually using them.
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