diy cnc router : 30 steps - instructables
This instructable will show you how to construct a CNC Router that will allow you to cut 3-D shapes out of wood, plastic and aluminum using a standard hand held router. Recently I have noticed that more and more projects on instructables have involved the use of some sort of CNC machine, be it a laser cutter, 3d printer, milling machine, etc. I wanted to join this revolution of digital fabrication and start making my projects even better using these tools. So about a year ago I set out to find a way to make this possible and came to conclusion that a simple 3 axis CNC router would be the best option to get things going. I started doing some research and decided to design and build my own machine. This instructable steps though all the parts needed to build the machine I have designed and the reasoning behind why I built the machine the way I did. It also includes an explanation of CNC technology and would be a great reference for anyone looking to learn some metal fabrication skills. My hope is that someone might use these plans to build this router for themselves or at least draw some inspiration from my design. I have created 2d drawings of all the parts with complete dimensions and specs, details on how to build each part, a complete parts and tools lists with prices and links, a basic wiring diagram and an explanation of the design.
I have designed this router to be very versatile and hope to also use this same machine as a 3-D printer and a hot wire foam cutter in the future. This machine is constructed from rectangular steel tubing and aluminum plate and was fabricated using a small horizontal band saw, bench top drill press and flux core MIG welder. There is no need for high precision and expensive tools to build this machine. Using the techniques I have listed in this instructable for marking, centering, drilling and tapping anyone with the desire to build something well, will be able to complete this project. There are no angles to cut or parts that seem impossible to get right, just straight cuts and holes to drill. The machine bolts together and can be adjusted for square and levelness on each axis.
Travel: X-Axis 23in Y-Axis 13in Z-Axis 6inLinear Guide: Fully Support Round Linear Rail and Mounted Bearings (20mm, 16mm, 12mm)Linear Drive: 1/2-10 5 Start Precision ACME Screws and DumpsterCNC Anti-Backlash NutsDrive Motor and Controller: Gecko G540 Controller with Gecko 280oz-in NEMA 23 Stepper MotorsConstruction: Welded 1x2 Steel Tubing and 3/8 Thick Aluminum PlateSpindle: Bosch Colt Trim Router Rapid Speed: 200ipm (inches per minute)Cutting Speed: 1/4" end mill, full width cut, 0.100" depth of cut, 50ipm, material - hardwood (This is a fairly easy cut and is probably less than half the true cutting capacity)
Lets 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 smallslices 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, lets 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 its a CNC "router" it means a machine made to cut wood, plastic or other soft materials. This instructable will show youhow 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 websitecncroutersource.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 ofthe 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.
You now know my decisions and hopefully understand my reasoning. I think I have a pretty good combination of parts that has exceeded my expectations. If you decide to build a machine based on my plans I have everything laid out in the following steps.
Attached are all the drawings with complete dimensions and specs in "DIY CNC Router Drawings.pdf" The parts list pdf contains all the parts and tools listed in the instructable. I have also included a 123D file of the entire assembly of the router. You can open and view the model as well as all the individual parts using the free software 123D. Here is the DIY CNC Router in the 123D Gallery.
The stepper motor mounting plate is a clever name for the plate that mounts the stepper motor. This part has been designed to be universal for the machine and you will need to make 5 of these parts. This part is made from aluminum flat stock that is 2.5" wide and 1/4" thick. This is a great starting point for this project because you have to use all the tools needed for the construction of this machine and its a fairly simple part. First cut 5 pieces to a length of 4" Then you need to lay out the holes using dykem, a scribe and a combination square. I did not do this for this part because a friend, who converted a small mill to CNC, made a jig for me. Even if you don't know someone who can do this I would recommend making a jig first. To do this just lay out all your holes and drill them all the same size, a size that you have a transfer punch for. That will be your reference for all 5 parts and you'll just transfer punch all the hole locations for all the plates. This will save you a lot of time and effort. Once all the holes are located with the transfer punch drill them to the sizes indicated on the drawing, following my good hole drilling guide lines. For the counter boring bit set the depth on you drill press using the stops on the machine. Do a test counter bore hole first and check the depth with an M5 low head socket head cap screw. You need the head of the screw to be below the surface of the part. All five parts are basically the same except for the plate that mounts the z axis stepper. That plate needs two extra holes to mount it to the z axis plate, which are shown on the second drawing. As a side note, at this point you should also make the jig for the gantry mount, step 16. This will help with many of the parts as you build.
Let me start off saying that making your own standoffs is not worth your time. These parts can be purchased for less than a dollar a piece and will be made with much better tolerances. I would recommend Mcmaster carr part #91780A063 This standoff uses 10-32 screws so you need to us that instead of M5, but the 10-32screws are cheap because they are more common. I made these standoffs but will most likely replace them soon with the Mcmaster part. I made a jig to hold the tube with a set screw which allowed me to drill the ends with the drill press and hold the part while tapping. My results were not the best but close enough, and that's why I recommend just buying these parts.
The x-axis frame is made from 1x2x0.065" steel tubing. The side rails are taped to allow for the mounting of the 20mm linear rails. YOU MUST BUY THE LINEAR RAILS BEFORE YOU START MAKING THESE PARTS. The rails I got had the mounting holes drilled but it looked like someone with a hand drill just went to town drilling these holes. They were not drilled with much precision so you will need to transfer punch all the locations for each rail. Use the drawing as a reference but mark the locations based on your actual parts. The ends match the hole pattern on the stepper motor mounting plate so just use your jig to transfer punch those locations. Four 3/8" holes are also drilled in the corners to mount the machine to the mdf base. The frame was welded together using a right angle clamp from Northern Tool. This was my first time welding with a clamp like this and I was impressed with its accuracy and ease of use.
This part is made from 2"x1/8" thick steel angle stock. The cut outs on both ends were done with my band saw in the vertical position. I used a sandpaper disc on my angle grinder to get a smooth finish after cutting. I marked all the holes with the scribe and the combination square. Clamp the part down well when drilling the 5/8" hole in the center, just a safety precaution.
These parts are fairly simple but involve a lot of drilling and tapping. All of the holes on the vertical tube are to allow the gantry to be mounted higher or lower on the machine. This allows the machine to to be optimized for the different materials that you may want to cut. For example if I'm cutting primarily sheet material I can lower the gantry and space out the bearings on the z axis more which will make the machine more rigid for cutting thinner material. Make sure to drill and tap all the holes needed in each piece before welding them together. I used a jig I made for the gantry mount plate to locate and transfer punch all the tapped holes.
If you've made it this far its time to treat yourself to a little CNC action. Bolt everything together as shown in the drawing. Check out the z axis assembly, step 22, for a picture of how the drive screw is assembled. Once its together, turn the screw by hand and watch as the gantry uprights slide down the linear rails, its a beautiful thing. Enjoy this for a moment and then get back to work on the rest of the machine.
The pictures shows how I marked the holes for the jig, which I made at the beginning along with the motor mounting plate jig. This was then used to make the 4 actual plates for the machine and to locate and transfer punch many holes on other parts.
This part is made from 1.5"x 1/8" thick aluminum angle stock. I marked all the holes using the scribe and combination square. I placed this part in a vice when drilling the holes. For safety clamp the part down well when drilling the 5/8" hole. This is a big drill bit for my little drill press and was probably spinning to fast even at the slowest speed. This caused a lot of vibration which can lead to disaster in a hurry. Be careful when drilling with large drill bits on bench top drill presses.
At first glance it might seem like a daunting task to make this part by hand, but it can be done. The drawing shows dimensions with three decimal places but don't think it has to be exactly perfect, maybe two decimal places would be good enough. To make this more reasonable, break up the holes into sections and do each set individually. The counter bored holes go to the y axis bearings, start there. Once that is good move on to the tapped holes for the z axis rails, you should transfer punch these so it shouldn't be that hard. Then do the center tapped holes for mounting the drive parts. Finish off with the holes in the top edge of the plate. I had to spin the head of my drill press around and hold the plate with a separate vice in order to drill these holes. You'll probably have to do some thing clever like this unless you have a larger drill press with more clearance.
Like before just mark, center punch and drill to finish this part. Note the extra holes in this part are not needed, follow the drawing and you'll be fine. Also you'll have to cut an 1/8" wide section off one side for this part. I did this with the band saw in the vertical position.
If you have built everything up to this point, you are a master hole driller and this part will come out perfect. At least thats what I thought when I finished this part. Use those newly acquired and quickly mastered skills to finish off the precision parts needed for this machine.
This is pretty easy too, get a piece of 3/4" MDF from the hardware store and have them cut them cut it or cut it yourself. The 4 threaded rods are each 4" long and bolt this base and the x axis frame together. They are also used to level the frame. I used 3/8"-24 NF fine thread but normal coarse thread work work just as well. I used a 1" spade bit to counter bore the holes in the mdf. You should go deep enough to allow the stud and nut to sit below the surface of the wood.
There are two table support bars that bolt to the x axis frame. They are made from 1"x1" steel tubing and 1"x3/16" steel bar. You should cut the 3/16" thick bar into four 3" long pieces and drill and tap the M6 holes first. Then drill the holes in the x axis frame(I built these parts after welding together the x axis frame) Now bolt the plates to the frame and measure for the tubing, it should be 32-5/8" but you should fit the tubes as needed. Then with the plates still attached to the frame weld the tubes to the plates. By doing this you ensure that the finished part will be able to be removed and bolted back in place on the frame. You don't have to weld the entire end of each tube the plates, just put four good tack welds on the corners at each end. Then you can unbolt the support bars from the frame and fully weld the tubes. Also when drilling the three holes in the tube be sure to drill through both sides. You will only need to tap the top side on the tube but the through holes will allow you to transfer the hole locations on tho the work table.
The work table is a piece of 3/4" MDF and is bolted to the table support bars. This is the surface that the material will be clamped to. I chose to use MDF for this purpose because it will be a sacrificial piece and can be cheaply replaced when needed. I will be screwing down work to this and can cut into it if needed. The hardware in the picture is 1/4"-20 x 1.5" long screws, nuts and washers. The screws need to be fully threaded. The six screws are used to mount and level the work table to the machine. The counter bored holes allow the screw heads to sit below the table surface so material can be attached easily.
The electronics for this router consist of main power switch, power supply, stepper motor controller, power relays, stepper motor cables, outlet and an e-stop. I plan to adding limit switches and cable carrier(e-chain) soon. I purchased a 10ft piece of 12/3 stranded power wire and a male outlet plug. This is wired to the main power switch which has a red indicator light. When switched on the 110v AC is feed to the power supply and relays. The power supply is a 48v DC 12Amp supply from Mean Well. This is wired to the Gecko G540. The relays are used to power the Bosch Colt router and a shop vac to suck up the shavings when running. The relays are controlled by the G540 which takes commands from the computer, so they can be controlled by the code you run. The DB9 connectors on the G540 connect to the stepper motors. Each stepper needs a resistor placed between pins between 1 and 5 to control the current to the stepper. Gecko provided the proper resistor with the steppers motors I purchased from them. The resistor needs to be wired to the connector that is connected directly to the controller. The stepper motor is wired to pins 6-9 of the connector. I made extension cables for the stepper motor with DB9 ends and the cat5 network cable from the parts list. The network cable has 8 conductors but i soldered pairs of wires together to get four connections for the stepper motor. The enclosure I used is an outdoor electrical box which I decided to use after seeing Building an Electronics Enclosure. The switches are mounted in a standard outlet box and the relays are bolted to the side of that box. The power supply was mounted in the box to the bottom side and the G540 was placed on the top panel. The e-stop switch was also mounted to the top panel. I made all the connections using using 14 gauge stranded wire and crimp on spade connecters. The wiring picture is basic but does include all the needed connections.
I am using Mach3 to control my router. Mach3 is CNC control software that takes G-code and outputs signals through the parallel port on a computer to the G540. It is highly recommended that you use a desktop computer to run mach3 and your cnc. I bought a "off lease" desktop from tigerdirect for $120 and plan to use it as a dedicated CNC computer. You will also need a CAM software to convert your designs into G-code or you could learn the G-code language and write your own programs in a text editor. Take a look at this information from Probotics, CNC Software it has lots of links for many different CNC software options. The picture is a screen shot of Mach3 which will take some time to learn but there are many videos on the Artsoft website and this software is well supported.
HI, 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? 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....
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.
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.
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.
Hi I am in Australia , cannot get a Nema 280 oz in , they have Nema 387 oz in rated at 3.5 amps, which is also matched to a Gecko G540 controller. Do you think this motor would be suitable for a CNC built to router wooden signs , boxes etc .. Thank you Gordon Johnson
This is one of the best instructables I have ever seen. I will be using a lot of your ideas and parts references to build my own. Thanks again for all the effort you have put in, and the attention to detail.
I really love it .. Here i'm trying to make my own CNC ..the school would pay for it as long it's costs less than 300$So here i'm making my own plans ..already have the code ( almost done ), materials but still confused if wood gonna be okkay for building this device ..notice that i will use 4.3kg stepper motor for the three axis ..and 15cm for the X axis and the same for y axis and the body is made from wood and dremel with extender chaft connected to external power supply ..IDK if it's going to be strong enough to hold it , if i needed some help , can u give a little ?