20 cnc machine

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$20 CNC Machineby Techbuilder on April 16, 2009 Table of Contents $20 CNC Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Intro: $20 CNC Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 1: Find recycled material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 2: Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 3: Linear slides of fun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 4: X,Y,Z tables for your brunch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 5: Motor mount time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 6: Thread me please . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 7: Gluing time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 3 4 5 7 8 9 9

Step 8: Where's the Z axis :( . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Step 9: A piece from the heaven's . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Step 10: Tall posts oh my! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Step 11: Are we done yet! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Step 12: Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Related Instructables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

http://www.instructables.com/id/20-CNC-Machine/

Intro: $20 CNC MachineI got inspired for this instructable when I viewed the Easy To Build Stepper Controller instructable .When I read the instructable I knew I could make a decent looking and functioning cnc machine for under 20 dollars with a recycled twist, Not to mention I did this in under a week. I expect you to have basic knowledge on power tools and hand tools and of course this instructable requires you to have a rotary tool such as a dremel. Even if you don't have knowledge on power tools or hand tools I advise you to try this instructable because you will learn a lot about hand and power tools and you can build this for less then 20 dollars so if you mess up it's no biggie and it would not cost to much to replace a part. Let's Build! Update 02/01/10 {Hi everyone just thought I would give you an update on this instructable since Ive been getting a lot of emails and messages and such. I'm getting really close to completing the electronics for the CNC, as stated in a comment the steppers I found in the printer were bi-polar stepper motors which the circuit would cost quite a bit more if you went this route. If you were lucky to find some Unipolar stepper motors then you could build the electronics for under 3 bucks however unipolar motors have less torque. I will be selling CNC kits soon and they will be of better build quality as well as a cheap price tag because I know how it is to be on a budget and not have the tools I need to create simple things and even complex things and this world needs more DIY builders. The CNC kits will be available roughly 1 to 2 weeks after the electronics Instructable has been released their will actually be a video showing this CNC working when the electronics Instructable is completed}

Image Notes 1. Electronics Instructable soon to come!

http://www.instructables.com/id/20-CNC-Machine/

Step 1: Find recycled materialNow this is the most enjoyable part of building the cnc machine which is trying to find garbage that people want to throw away. Here's what you need to locate Flat bed scanner Old printer These two items are going to have your juicy stepper motors and the beautiful harden steel rods, that's not the only thing you can get out of these green machines. You will find gears, bushings, cold cathodes, capacitors, buttons, parallel ports and there is so much more.

Image Notes 1. The victim

Image Notes 1. So much fun

Image Notes 1. Harden steel rod Could be used for axis if you can locate 2 alike 2. Cold cathode Could be used for a light box

Image Notes 1. Parts

http://www.instructables.com/id/20-CNC-Machine/

Image Notes 1. Stepper motor or aka the holy grail 2. Bushings

Step 2: ToolsNow I tried to build this with the bare necessities so I could show you that it is possible to make a cnc machine with very little. Required Tools: Drill Screw drivers Tap and Die set Rotary tool Hack saw Vise or some form of clamping device Pliers Drill bits File Center punch Recommended Tools: Band saw Table saw Lathe Bench grinder Bolt cutters

http://www.instructables.com/id/20-CNC-Machine/

Image Notes 1. Hack saw 2. Drill 3. Vise 4. 3ft aluminum rod

Step 3: Linear slides of funThe center core of your cnc machine is your tables so read carefully and follow the instructable. Required materials Quantity Type Cost 4 2"x6"x1/2" Expanded PVC 2.00 2 2"x4"x1/2" Expanded PVC 1.00 2 10" 3/8" Aluminum rod 0.75 2 12" 3/8 Aluminum rod 0.75 2 8" 3/8" Aluminum rod 0.50 1 11 1/4" 5/8"-24 threaded rod 1.00 1 9 1/4" 5/8"-24 threaded rod 0.75 1 7 1/4" 5/8"-24 threaded rod 0.50 Now this is just the run down of everything I of course cut everything up, you can purchase everything you see here from your local hardware store and plastic store for really cheap. First step Stack 2 of the expanded pvc pieces that are the same size and drill a whole in the center and two holes each three quarters of an inch from the edge from the center line. Now cut your aluminum rods to size and stick them through, now you should have a comparable piece down below Repeat for all Axis

http://www.instructables.com/id/20-CNC-Machine/

Image Notes 1. Expanded PVC

Image Notes 1. This is what it should look like after you are done

Image Notes 1. X and Y axis

Image Notes 1. Holes for the aluminum rod 2. Hole for motor

Image Notes 1. Z axis

http://www.instructables.com/id/20-CNC-Machine/

Step 4: X,Y,Z tables for your brunchAlright now here comes the most time consuming part making the tables for the slides but once they are made it really feels like the project is taking off. Required Materials Quantity Type Cost 1 6"x12"x1/4" Acrylic sheet Scrap 1 6"x10"1/4" Acrylic sheet Scrap 1 5 1/2"x5"x1/4" Acrylic sheet Scrap 15 1 1/2"x1 3/4"x1/2" Acrylic sheet Scrap Now what you are going to want to do is stack 4 pieces of the 1 1/2"x1 3/4"x1/2" and drill dead center with a 3/8 drill bit After you have done so feed 2 pieces on each rod and line them up and place your sheet on top and flip it over now glue. Repeat for each axis For your Y axis now would be a good time to drill your holes so you can mount things you wish to cut.

Image Notes 1. 1 1/2"x1 3/4"x1/2" Square blocks

Image Notes 1. Square blocks with the rods through them

Image Notes 1. Acrylic Sheet flipped over and aligned straight 2. Square block ready to be glued 3. Use acrylic glue for maximum strength and clean look

Image Notes 1. You should end up with something like this. Repeat this step to make all three axis.

http://www.instructables.com/id/20-CNC-Machine/

Image Notes 1. Grid paper is a good way to get your holes in parallel.

Image Notes 1. Pretty

Step 5: Motor mount timeNow depending on where you get your motor from they are all going to be different so they will require special mounts I recommend printer stepper motors because they are easy to mount but scanner steppers motors will work just fine. Now in step three you should have drilled the motor hole and now all you have to do is mount it in The coupler that attaches from your stepper to your threaded rod is going to be different based on stepper you have. I made one out of aluminum but you can make one out of plastic just as long as it is wide enough. All you have to do is drill in the center of a little piece of rod to the size of the stepper then on the other side drill 5/16 for the threaded rod. After that tap the 5/16 side And glue

Image Notes 1. Recycled Printer stepper motor attached

Image Notes 1. Screw that attaches stepper motor 2. Aluminum coupler I made The one I made use's a set screw but you can glue it in but it will be permanent.

http://www.instructables.com/id/20-CNC-Machine/

Step 6: Thread me pleaseNow once you have made your coupler it's time to attach the threaded rod and glue a threaded coupler to one of the 1 1/2"x1 3/4"x1/2" square blocks You have to make sure that the center on the threaded coupler matches the center of the threaded rod. After you should get something like down below Required Materials Quantity Type Cost 3 5/8"-24x1" threaded coupler 0.60 Repeat for each axis

Image Notes 1. Just a piece of rod I used to mark the center

Image Notes 1. Thread coupler glued in place Sorry I didn't take a close up shot

Step 7: Gluing timeSo now you should have all three axis completed and now it's time to line them up and glue. The base I used was a 20"x12"x1/4" piece of white acrylic I found at the plastic store You could use smaller but I wouldn't recommend it Once you have found a base, glue your x axis to it and then your y axis to your x axis acrylic top, then you should have something like down below. use acrylic glue for this step it will glue expanded pvc as well if your wondering After that Glue your z axis to a piece of 8"x4"x1/4" acrylic sheet. Required materials: Quantity Type Cost 1 20"x12"x1/4" Acrylic sheet scrap 1 8"x4"x1/4" Acrylic sheet scrap

http://www.instructables.com/id/20-CNC-Machine/

Image Notes 1. You should have something that looks like this 2. Base I used

Image Notes 1. Glue here using acrylic glue 2. Glue all the expanded pvc to the acrylic sheet but make sure it's parallel

Step 8: Where's the Z axis :(Don't worry I didn't forget about that Moving along Now we want to add a mount for are rotary tool to the acrylic sheet on the z axis I used a pipe holder and a screw clamp, you can buy both these items at a local hardware store for really cheap. You have to cut a little lip to attach to the acrylic sheet because the pipe mount isn't going to be flat once you slide the rotary tool in because it expands. Place the pipe mount on top of the acrylic lip and glue. Required Materials Quantity Type Cost 1 Pipe mount 0.40 1 Screw clamp Free

http://www.instructables.com/id/20-CNC-Machine/

Image Notes 1. Bent in

Image Notes 1. Acrylic lip I used my dremel to make this piece

Image Notes 1. Acrylic lip the shape of the pipe mount 2. Leave a 1/16 or more gap for the screw clamp. 3. Glue together using epoxy or super glue

Step 9: A piece from the heaven'sNow that you made your z axis rotary mount it's time to set up the posts and the acrylic sheet that connects them. You need a square hole in the center of the 10"x16"x5/16" acrylic sheet to feed your z axis through After you have cut that out it's time to attach a thick piece of a acrylic to support the z axis on. After you have done that you should attach you z axis to it and make sure the acrylic piece is sticking out at least 1/16" off the edge so you can have a flat side. Required materials: Quantity Type Cost 1 10"x16"x5/16" Acrylic Sheet Scrap 1 1 1/2"x5"x1" Acrylic Sheet Scrap (aka thick piece)

http://www.instructables.com/id/20-CNC-Machine/

Image Notes 1. Used a dremel with a cutting blade then cleaned it up with sanding attachment

Image Notes 1. 1 1/2"x5"x1" 2. Glue to the bottom of the piece you just cut out 3. Then glue your 4"x8"x1/4" to the block

Step 10: Tall posts oh my!Now it's time to glue the 1 1/2"x16"x1" posts to the z axis acrylic top and then after your done with that, you then glue it to the base. Required Materials : Quantity Type Cost 4 1 1/2"x16"x1" Scrap

Image Notes 1. Applying pressure after I set the acrylic glue in.

Image Notes 1. Glue the post to the sheet 2. Glue the post to the base

Step 11: Are we done yet!The answer is no but we do happen to be mechanical done now because of the short amount of time I had I could not add the electronics part to this instructable, so I am going dedicate an entire instructable just to the electronics part some time this week as well as a video. So turn that frown upside down Word of advise this is quite a bit of work even though it may not look like it so by the time you have this finished the electronics instructable will be beyond finished. I will most likely add it on Tuesday or Wednesday of this week. Part list: Quantity Type Cost

http://www.instructables.com/id/20-CNC-Machine/

4 2"x6"x1/2" Expanded PVC 2.00 2 2"x4"x1/2" Expanded PVC 1.00 2 10" 3/8" Aluminum rod 0.75 2 12" 3/8 Aluminum rod 0.75 2 8" 3/8" Aluminum rod 0.50 1 11 1/4" 5/8"-40 threaded rod 1.00 1 9 1/4" 5/8"-40 threaded rod 0.50 1 7 1/4" 5/8"-40 threaded rod 0.25 1 6"x12"x1/4" Acrylic sheet Scrap 1 6"x10"1/4" Acrylic sheet Scrap 1 5 1/2"x5"x1/4" Acrylic sheet Scrap 15 1 1/2"x1 3/4"x1/2" Acrylic sheet Scrap 3 5/8"-24x1" threaded coupler 0.60 1 20"x12"x1/4" Acrylic sheet scrap 1 8"x4"x1/4" Acrylic sheet scrap 1 Pipe mount 0.40 1 Screw clamp Free 4 1 1/2"x16"x1" Scrap ? Scrap from Tap Plastics 12.00 Total= 19.50 I got all my plastic from tap plastics scrap bin and I got the rest of the pieces from home depot and a local metal supply shop.

Image Notes 1. Almost all done!

Image Notes 1. Electronics Instructable soon to come!

Step 12: RecommendationsNow the stepper motors you find in a printer would do just fine but after a while I would highly recommend to upgrade to some bigger stepper motors. As for the expanded pvc I would replace that with Acrylic but do to the fact that I had a budget and the short amount of time I had no choice but to go with expanded pvc but I would really recommend you use acrylic.

http://www.instructables.com/id/20-CNC-Machine/

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Comments50 comments Add Comment view all 120 comments

randhee says:What kind of glue?

Jan 8, 2010. 11:16 PM REPLY

Groszek64 says:CH2CL2

Mar 6, 2011. 10:55 AM REPLY

moondoongoo says:I'm from Argentina... My problem is that acrylic here is so expensive! it's about U$D 130 the board of around 1 m^2 I really like it project, i wanted to do it 1 year ago, but... so much money

Feb 10, 2011. 4:57 AM REPLY

rpicivil2011 says:

Feb 15, 2011. 2:48 PM REPLY For the slides I would suggest that you replace the acrylic parts with UHMW Polyethylene. You may or may not have a supplier near you. But you could get a 1/2in x 3/4in x 1ft piece on mcmaster for USD 2.98, I don't know how much shipping would be but it is a place to start, pricing materials in your area. I would also replace the 5/8"-24 with something smaller like 5/16"-18. Or since you are in the metric world I would suggest a M8 with a Pitch of 1.25 . Of course for this I would buy what ever rod was least expensive down to that diameter, I wouldn't go much smaller though, due to whipping effects. The 1/2in x 3/4in x 1ft bar is enough to make 12x 3/4in x 1in x 1/2in thk slides (They are smaller but still adequate) plus 3x 3/4in x 1in x 1/2in thk threaded pieces. You could actually thread the UHMW instead of inserting couplers which would have a couple benefits:

http://www.instructables.com/id/20-CNC-Machine/

1) less backlash (assuming you make a tap using the actual rod that it will slide on) 2) less friction between the threaded rod and the threaded piece, which translates to less torque needed from your steppers, and less racking of the slides. 3) UHMW is softer than the steel rod, the threaded piece will be the one to where, instead of both parts, so when you start to notice a lot of backlash you only need tor replace the one part instead of both. Though because of the super low coefficient of friction for UHMW, it will take a very long time to wear out. The remaining parts made of acrylic and expanded PVC could be made with MDF. I recognize there will be expansion issues, but it really doesn't matter for a machine this small built with this quality of components. Please let me explain why, before I get flamed. Please note this only applies to std. all thread, with regular couplers and nuts. General purpose ACME rods and nuts will have much higher tolerances. But unless you salvage them from an old machinem you won't come near $20 for just those components, let alone whole machine. Especially if you use precision ACME rods (Over USD 100 for just the parts for this machine_, yes there is a difference between, all-thread, general purpose ACME, and precision ACME, a difference other than the price. A) Precision Odds are the steppers used on this project are going to be 7.5deg per step, or 48 steps/rev, Unipolar or Bipolar motors, probably with only full step mode. Yes, going half step, eighth, 1/16, etc... will improve the precision, but we are pretending that the builder doesn't have the circuitry for such things. As even building your own board from scratch, to handle that functionality will cost a couple dollars each at a minimum, if parts need to be purchased. And as you can see below, fractional stepping won't really help for this machine other than part motion acceleration. Now with the recommended threaded rod of 5/8"-24, that is equilalent to 24 revs/in * 48 steps/rev = 1152 steps/in which is 1/1152 in/step = 0.000868 in/step or 0.868 mil/step or 0.868 thou/step depending on how you like to think about it, (this is an estimate, I will explain why under the Accuracy header) Now consider that the typical backlash on a plain threaded rod using a regular nut or coupler (from my own experience and measurements) is on the order of atleast 1-10 mil (Making a custom nut, would greatly improve this number). With this in mind our effective precision is now 0.868 +/- 5 mil/step being very generous. Then factor in that the nut will occasionally stick to the rod, torquing the whole slide mechanism. This will impact precision in that the theoretical distance traveled in this case 0.868 mil/step will in fact be 0 assuming it did not move at all. It is unlikely that it will stick for more than a few steps, but that is still a couple mil precision lost. A low friction nut would help in this case as well. Now we are 0.868 +/- 7 mil/step. Not to mention the pitch along a rod may vary to some degree. Thrust deflection in the screw/stepper, can also be a major headache. If you have ever pushed or pulled on the spindle of a motor, you will have noticed there is quite a bit of play. This will translate into additional backlash (not technically the correct term, but the motion is similar). This can be eliminated through the use of thrust bearings. Unfortunately this project doesn't include any. The play on average in many of the steppers I have pulled out of printers and scanners is on the order of a 1/16th or 32nd of an inch or 62.5 and 31.25 mil respectively. That is huge. So we are left with 0.686 +/- 35 mil/step. Does MDF expand yes, I am not going to contest this fact. However, it is _never_ going to expand to such a degree over the course of a single session (barring spilling something on it on it, or generally introducing it to a 100% relative humidity environment) that you will be able to measure an appreciable deformation from start to finish. Next because of how it is formed and used, it is probable that any expansion that does occur will happen proportionately along the x and y axis of the machine. The z dimension (typically the thickness of the base) will expand more but still at an extremely slow rate. MDF if exposed to a 30% to 90% relative humidity environment will expand ~0.3% in length and width, and in thickness up to ~5%. However, this often takes weeks or months to occur. for a 24"x24" piece that ends up being little more that a 1/16th of an inch change over the whole machine. B) Accuracy Accuracy on a CNC machine comes down to a few things. The theoretical distance traveled, 0.868 mil/step in this case, vs the actual distance traveled. The squareness or orthogonallity of the axis'. There are other accuracy points but for our purposes they are inconsequential, if I ever get around to writing this whole thing up as an instructable, I'll include them there. As far as 24 rev/in on the 5/8"-24 rod, you should be skeptical as to that value. Precision ACME rod has a tolerance of +/- 9 mil travel per foot, not to mention the tolerance between each thread. This stuff is extremely expensive in relative terms and is far more accurate. I have seen regular all thread that was nominally 5/16"-18 with 18.1 or 17.9 threads per inch. That works out to be a difference of ~ +/- 66 mil travel per foot. This can be accounted for over the lenght of the whole machine by telling the machine to move a set number of steps then measuring how far it actually went to calculate a steps/in or in/step, Depending on what the cnc program you use. However, there is no easy way to account for the fact that while it may be 18.0 tpi in one area it could be 18.1 in an other area. I have see this happen on a 2 foot section of rod. Right angles are very important when doing cnc, I'm sure someone could write a program that allowed you to enter the relative angles of your axis' and it would calculate the g-code to account for the skew. But as far as I know functionality for this is almost none existant. Now it seems that the main concern for using MDF is its propensity to expand. Warping on this scale, with a reasonably thick piece of material is for practical purposes non-existant. Now one way to handle this issue is to simply only attach each axis slide assembly on one end and allow the other to be free. You could also have a slot and bolt on the other end that would allow for it to be secured while cutting and when need be it could be adjusted. The Z access is suspended, and can easily be calibrated for each different job (usually it would be anyway), so as long as the 4 legs supporting the top are identical they should in theory have expanded/contracted at the same rate, thuse only lifting and lowering the z axis slides. Any deviation from vertical that occurs is going to be less than the runout of the tool and spindle. This really belongs under precision but it has components here as well. The finally runout on the tool and spindle assembly, which in this case is the dremel and z axis slide. Because of how the z axis slide is supported. A cantilever beam for any engineers out there. There is a propensity for the whole assembly to deflect/bend. So when the cutter is moving through a piece force is exerted against the arm and it moves. _Conclusion_ At the end of the day MDF for this type of project should be perfectly acceptable. The only structural parts that wood or mdf couldn't replace is bearings, bushings, and rods. As there is simply too much friction. Yes it will expand, and maybe warp a tad, but it won't happen while you are using it. And if you build your machine with that in mind you should be able to adjust the frames and and slides to acount for it, when the humidity changes. There is always sealing the MDF also which essentially lock your machine to one size within tolerances for motion I listed above. I hope this is helpful, good luck with your project.

http://www.instructables.com/id/20-CNC-Machine/

natman says:i might have missed this some where but how do you connect it to the computer to actually use it???

Jan 16, 2011. 2:56 PM REPLY

KungFuChicken says:You mentioned you was selling this as a kit? Is it available now?

Jan 9, 2011. 10:12 PM REPLY

Pizzapie500 says:What materials can this cut through?

Jan 8, 2011. 7:42 AM REPLY

Z.K. says:

Jan 2, 2011. 10:03 PM REPLY Where can I get this expanded PVC? I found some at http://www.budgetrobotics.com/shop/?shop=1&cat=103, but the thickest they have is 6mm which is about 1/4". I suppose I could bolt two together and use it that way. I really doubt this will be a $20 project though unless one already has all the materials. Still, this is a very good instructable and gives me some good ideas.

Techbuilder says:Hi Z.K. I get this a lot and people don't really believe it but i did this under 20 dollars.

Jan 2, 2011. 10:14 PM REPLY

Expanded PVC is extremely cheap at a plastic shop however not online. I did everything around my house and ordered nothing online because with the shipping alone it would be over 20 dollars. Most plastic shops will have scrap pieces of acrylic for 1.70 a pound and pvc for even cheaper, just call around. This is the type of project that requires you to search and put effort in, if you didn't then everyone would be making a 20 dollar cnc machine. My advice to you is to do a lot of calling and don't be afraid to look around and stay away from the internet if you want to cut costs. If you happen to live in an area that doesn't have these resources then go on machining forums and see if anyone has any scrap material there willing to sell to you for dirt cheap. Best regards, Techbuilder

Giorgiodeste says:

Dec 30, 2010. 4:55 AM REPLY YOU ARE great ! I don't know if it works, I can't see how it works, BUT let me tell you, this is a GREAT machine, Yes, my personal congratulation for your ideas and for the simplicity you are able to use during the project....you are a great DIY GUY - BRAVO Congratulation Dec 7, 2010. 8:42 PM REPLY Intriguing new CNC startup on kickstarter.com. Interesting way to go, but looks like a good source of parts for this project. One of their controller/motor kits could work well with this design.

hondaman900 says:

microwizard says:It would be nice to have so much acrylic sheets as "scrap" :-P

Apr 9, 2010. 7:36 AM REPLY

medalhead says:Yeah :D

Dec 3, 2010. 1:18 PM REPLY

hinow41 says:you needn't use acrylic. steel, al, wood, pvc, would all make do

Jan 5, 2010. 4:57 PM REPLY

Minifig666 says:Wood can be a problem though as over time it can warp and become less accurate.

Oct 10, 2010. 12:52 PM REPLY

paulsayles says:Well sealed mdf would be a good alternative

Nov 20, 2010. 10:24 AM REPLY

hightekrednek2396 says:

Nov 25, 2010. 6:36 PM REPLY or if you really had the money tand time and paetiense you could try and make carbon fiber parts but that would defeat the 20 dollar purpose

http://www.instructables.com/id/20-CNC-Machine/

wii552 says:could wood be used instead of plastic for most things?

Dec 19, 2009. 6:21 AM REPLY

NewB007 says:

Dec 31, 2009. 9:40 AM REPLY Wood expands and contracts with humidity (and non-uniformly depending on grain), so you wouldn't maintain the tolerances needed for most CNC machines. That said, if you live somewhere with a constant (or complete lack of) humidity, such as in the desert somewhere, wood that has been fully cured (and/or fully weather-sealed) may work just fine. For anywhere else, I suppose if there were enough play between the wood parts and the rods, then you may be able to make it work with a sacrifice in quality of the finished product and the risk of binding up of the threaded rods and couplers. If you aren't after high quality reproduction of your design (accuracy), then wood may be fine there, also. Basically, this is a M-16 vs. AK-47 argument. One has tighter tolerances and higher accuracy, and the other has looser tolerances and lower accuracy. In the end, if it is good enough to do the job, that is all that matters. Binding would be the only risk here.

tanmanknex says:in Utah it means yes!!!

Jan 3, 2010. 7:58 AM REPLY

sssssbooom says:

Mar 21, 2010. 10:44 PM REPLY I disagree, In the past 2 weeks we have had snow, rain, wind, and 60 degree weather. And my doors lock is harder to lock in the winter. So I don't think the humidity is constant at all.

CharMio says:disagreeing with a scientifically proven fact, i like your style! (wood takes more than two weeks to expand)

Jun 30, 2010. 6:55 AM REPLY

3DMHuff says:

Oct 9, 2010. 1:49 PM REPLY So, if I hang a piece of oak and an equal size piece of balsa from the ceiling of my (partially insulated) shop and measure it daily, it will take two weeks to notice any change and each piece will be the same? I would think the balsa would start showing a change within a few days and the oak would take several weeks. Someone with more time on their hands should try that, then make an instuctable so I can figure out how to measure the moisture content in wood.

NewB007 says:

Oct 12, 2010. 5:33 PM REPLY Well, to be precise, the expansion of wood due to changes in moisture content due to humidity is a dynamic process. The variables include: wood variety, surface area of exposed grain, grain orientation, and the difference between the moisture content of the wood and the humidity of the air (and therefore the diffusion rate), among other things. Putting any sort of "time until" label on this would also require stating a coresponding % increase or reduction in length/width/thickness (whichever dimension is desired--they may not expand the same amount). In short, this all depends on how accurately you want to (and can!) measure the changes.

3DMHuff says:

Oct 12, 2010. 6:52 PM REPLY This subject is bothering me. I know a lot of people that that are master craftsman in woodworking and they all have different opinions when I ask about this. Some say if I lay the wood with the grain in the same direction as much as possible, it will be fine. Others say if I build it with grains criss-crossing it will work fine. So I asked the best wood craftsman I personally know, my Grandfather. He said, "What the hell do you need a CNC machine for?" I fear he is right.

sssssbooom says:

Jun 30, 2010. 9:55 AM REPLY The two weeks is only explaining how often the weather changes. "if you live somewhere with a constant (or complete lack of) humidity, such as in the desert somewhere," Utah is not one of those. I never stated that wood expand faster then 2 weeks.

tanmanknex says:

Jun 30, 2010. 10:17 AM REPLY I don't know what I was thinking when I wrote that so... Yeah. Anyway, the humidity where I live usually is pretty constant, though today during Marching Band it felt like Louisiana. Or Georgia. Or some other southeastern state where it's really humid. Humidity is the one thing I can't stand, weatherwise.

sssssbooom says:

Jun 30, 2010. 9:51 PM REPLY You wrote it 6 months ago, I barely remember replying. Well until CharMio misunderstood my reply lol. :)

socalcovey says:In Washington it means NO!

Mar 3, 2010. 3:55 AM REPLY

http://www.instructables.com/id/20-CNC-Machine/

69fordf100 says:where do you find a pipe mount?

Oct 2, 2010. 11:57 AM REPLY

sadiablo says:

Sep 8, 2010. 6:37 AM REPLY Nice ible :) I'm in the planning and budgeting stage at the moment and have my steppers and controllers on order. Just a couple of quick queries on the construction of your magnificent machine. 1. With the measurements you have used what is the useable cutting area? And 2. Is there any reason you couldn't screw and glue the joins for extra stability and strength? Any help would be muchly appreciated

simon661 says:

Sep 5, 2010. 4:58 PM REPLY BTW To all canadians that live in toronto. I got 4 stepper motor for $10. I bought it from Active Surplus. They have a lot of tools you will need to build this cnc machine.

mman1506 says:go active

Sep 5, 2010. 7:28 PM REPLY

simon661 says:I need the PDF file :( To bad im not a pro member.

Sep 5, 2010. 3:59 PM REPLY

kyle brinkerhoff says:

Sep 1, 2010. 9:12 AM REPLY hey really cool idea for you ! write a plugin for sketchup that will translate a sketch into a depthmap and use that to control your cnc machine! thats what i did and it made it super easy use my own cnc machine.

livingbios says:

Sep 3, 2010. 7:40 AM REPLY Could you explain this? Is this plugin for sketchup literally sending the step sequences? I'm really not understanding how this would play out.

kyle brinkerhoff says:

Sep 3, 2010. 11:31 AM REPLY this method of control works like this: ruby script---->export to external aplication(self written)---->commands sent via serial-----> interpretation by microcontroller----> MOVEMENT | V feedback of position to app via serial

treflip says:Did you ever offer the kits?

Aug 30, 2010. 9:21 PM REPLY

nazgults says:Which type of the scanner is this?

Aug 5, 2010. 7:21 AM REPLY

filjoa says:Hi nice project... what hardware you use? best regards

Jul 11, 2010. 3:27 AM REPLY

pyrorower says:If you attach the proper tip, couldn't you also use this for metal part fabrication?

Apr 20, 2010. 10:07 AM REPLY

amdivoff says:? what tool would you guys recommend to use to get clean cuts on the sheets

Mar 21, 2010. 8:34 AM REPLY

Bowtie41 says:

Mar 26, 2010. 12:49 PM REPLY I reverse the blade on either a circular or table saw with good results.Don't forget to put it back right when you are done!!!

http://www.instructables.com/id/20-CNC-Machine/

socalcovey says:

Mar 3, 2010. 3:47 AM REPLY hey..now don't panic...but you may want to read the sentence again...it says "two holes each three quarters of an inch from the edge from the center line" not "a half of an inch" ? Jan 8, 2010. 6:28 PM REPLY This is a wonderfull peace of work and I am a model airplane maker and a finish carpenter and also facinated by cnc machines. yours is state of the art. I only wish that I could have been able to communicate with you and get help going through building it completely with the electronics. But I still would like to thank you for all the information provided. I shall be looking for more info. if you should post them in future. Great work.

frmco says:

dpsilver says:

Mar 1, 2010. 6:56 PM REPLY the electronics are simple for a 5 wire motor set up ive built my own and tested all three axis now im making the actual machine

fruitkid101 says:Hey guys I dont have any stepper motors but will the small $6 ones from adafruit industries work?

Feb 15, 2010. 11:45 AM REPLY

Techbuilder says:

Feb 27, 2010. 8:37 AM REPLY Sorry to inform you but those don't have nearly enough torque to drive anything really other then something as light as foam. You have to either find some old printers with some large sized steppers or you will have to purchase them.

jamesshin10 says:

Jan 9, 2010. 6:03 AM REPLY umm u said here that we need to locate a old printer can u indicate a specific type cause i have a hard time finding a 5 pins stepper motor.. plss help..

electrotech says:

Feb 26, 2010. 4:28 PM REPLY The five pin stepper motor is unipolar, the four pin motor you have is a bipolar. These are easy to run using a L293D IC. You can download the data sheet on line.

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http://www.instructables.com/id/20-CNC-Machine/