Instructables
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This instructable outlines the assembly process of my 2nd generation CNC machine which I designed to be simple to build and quiet enough to be apartment friendly. I have included example projects that I have made in the first two weeks of using the machine to demonstrate its capabilities.

This is the second CNC machine that I have designed and built. My first machine was based off of oomlout’s instructable “How to make a Three Axis CNC Machine (Cheaply and Easily)” (by far my favorite instructable and the one that got me hooked on the site). It was moderately successful, cutting a number of parts from foam (a summary of parts made can be found on my abandoned blog here along with some build photos). The lack of overall stiffness and play in the linear mechanisms meant that plywood and plastics could not be cut effectively. The biggest downfall of the machine was the difficulty to setup and square the axes and lacked the ability to make fine adjustments once set up. The drive pulleys were sandwiched between the gantry sides and if a pulley loosened the entire gantry structure had to be disassembled and put back together and squared all over again (a couple evenings of work).

In reviewing published designs for a 2nd generation machine I revisited Joe’s CNC, a popular design but I questioned my ability to produce so many duplicate parts with enough accuracy. I came across buildyourcnc.com and their blueChick design . What caught my attention was their use of V-groove bearings and how it simplified the design and the ease of aligning the axes. I had previously discounted V-groove bearings due to their cost ($150/ set vs. $12 for skate bearings) but after my first build I had enough experience to fully understand their benefits and to realize they were well worth the investment. The blueChick was simpler than the Joe’s CNC design but was still a bit too intricate for my tastes so I set out to design a new machine based off of the new bearings. I came up with a new design with three main design features that solved shortcomings of my first machine:

1) All of the drive mechanics are exposed. If anything requires adjustment or tightening you can walk up with an Allen key, screw driver or wrench and access everything allowing the machine to be up and running again in a matter of minutes. The axes are easy to setup with the V-groove bearings and can be micro adjusted once installed.

2) The design has a low number of fabricated components and allows for low build tolerances. The precision is based off of the flatness of the plywood and the straightness of the aluminum extrusions. All of the fabricated components can be roughly cut (except two edges detailed in Step 3) and all holes are oversized to allow for slight inaccuracies in drilling. This allows for any inaccuracies in the building stage to be taken up during assembly without loosing any precision.

3) Low operational noise. The machine had to be quiet enough to use in an apartment or I couldn't use it. The rotary tool I used on my last machine worked well but when running at 20k rpm, it screamed too loudly for me to use in my new home. A custom spindle was built as a low noise solution with negligible reduction in performance.
 
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fadel.alif2 months ago

i wonder where you put the usb or any communication cable to communicate between the CNC machine to the PC *i assume this CNC controller is PC-based. and if there is, where di you pluh that cable on the machine? directly to the stepper motor or add an additional built-in controller. Thanks

fkeppler4 months ago

Excelent work

dickda5 months ago
Wow!
hayreter8 months ago

Hi Nick, this is such a good instructable. I have a little question if you don't mind. I noticed that in the plan of left-right gantry sides one of the holes (where you attached limit switch) is missing. Do you get that hole later after installing everything or you just forget to draw it? Or maybe its position is given different on the plan?

yash_p9 months ago

Is this 130 oz-in unipolar rating of the stepper motor? And will the dimensions change if we use any other motors....

nick2334 (author) 10 months ago

Hi everyone, I'm getting a lot of messages asking if I have a 3d model for this project. Unfortunetly I don't. I only have the 2d dimensioned drawings attached in the steps.

blakhachib10 months ago

amazing work

wjap11 months ago
thanks thanks thanks .... so much...
ill try its
leaoaugusto11 months ago
great article!!! very informative!!!
zggtf2112 years ago
Just to let everyone know, i am working on a sketch up of this project (minus the custom sled hardware) to be made with standard length aluminum extrusion, and all 3/4mdf (for ease of construction and rigidity). if you would like a copy let me know
A great project! I would like to have access to your latest mods and CAD drawings.

Thank you,
I'm interested in this sketch up. I'm about to rebuild my CNC.
Here is a list of my modifications so far. I have not finished the mock-up so this is not the final list

Moved mount for y axis motor up 4 inches
changed gantry assembly for moved motor mount
replaced bearing block with alernitive gantry sides
shortened overall gantry height for added clearence
modifed track for easier assembely
modified ider bearings for timing belt security
modified base for new tracks and timing belt tensioner
changed belt tensioner to 3/4 mdf
nick2334 (author)  zggtf2112 years ago
I'm looking forward to seeing your modifications. My one suggestions would be to avoid using MDF if you can. I used it on my first machine for cost reasons and found it to be less than ideal as is its much heavier and not nearly as stiff as ply.
The reason that I wanted to do this in all mdf is because it is half the price of 3/4" ply. This is also just to be able to have a machine that i can use to cut more sturdy, expensive woods, such as the 3/4" ply or other soft lumber (because a 1by is actually 3/4").

These modifications are only for a first machine to make the better machine, not for a really long term use (put it together, make new parts, replace, repeat)

:)
khd.gna1 year ago
thanks
richard971 year ago
i would like to know what type of sepper motor make and model you used and is your roter large enough to use on 1/4 steel if not what would you recumend ?
thank you
richard westerfield
nick2334 (author)  richard971 year ago
Richard, this machine is not even close to being stiff enough to machine steel. If you want to machine steel you will need to use a proper milling machine such as a Sieg mill. There are a number of tutorials online on how to modify one for CNC use and this website (http://www.littlemachineshop.com/Info/minimill_compare.php) has a great breakdown of the different models sold by distributors.
caseyb11012 years ago
+1 for Shigley's!! That's my bible.
amshiv2 years ago
you are too good man. can i use stepper motor with 80 oz in( 0.6 Nm) .will it work or not.
thks
You jump so quickly from hardware to software. Could you give more information how you work to load your designs to the machine. Also which motor drivers do u use?
Thank you so much
nick2334 (author)  rolandcontreras2 years ago
The Instructable was meant to focus on the hardware as software could vary depending on personal preference. In general I used Rhino 3D for the CAD work, exported as an STL which was loaded into CAMBAM. From there I generated G-code which was read by Mach3 and sent to the Hobby CNC driver board. Let me know if you need any more information.
BrianMay2 years ago
Thank you for this instructable! I'm planing on building a similar one with some modifications on the Z axle to have a little bit more depth and I will be using a dremel 4000 as the cutting unit. you mentioned metric units...do you, by any chance, have the metric drawings for this? I am converting everything, but I then have to match it with commercial sizes and if had already done that... ;)

another question...have you tried to cut either copper or aluminium with this machine? do you recoon it is stable enough for that?

once again, thank you for sharing this ;)
nick2334 (author)  BrianMay2 years ago
It shouldn't have any troubles cutting aluminium using a dremel as long as you get a high quality double fluted, spiral, carbide end mill. I have quickly found that the cheap HSS cutter I have are limiting the machine's performance. As for metric drawings all I have are the imperial ones. As long as everything is sized as the closest metric alternative it should all work out with only a few holes needing to be re-bored larger.
that's what I've been doing ;) maybe i'll just cut all the parts in imperial sizes and make all the holes in metric size because it's easier to match with screws and nuts ;)
alienair2 years ago
I want to built a 50"x50"x@5" high routing capacity,what is yiou recommendation regarding the electronic and motor,i built several composit airplanes 4 passenger and i am designing a twin with Mazda rotary rx-8 engine.
First i get quote from several place with a big CNC router and they came up about$11000 to do the fuslage half mould from polystyrene.
This is why i started to look building my own from aluminum rectangular structure.
i do design with Rheno and any recommendation can be appreciated,my experience in router is very limited but i am learning very fast and i dont see any
problem of building the structure
nick2334 (author)  alienair2 years ago
The motors will depend on the weight of the gantry. Cutting polystyrene won't give much resistance at all so as long as the motors can move the machine it will be able to cut. The folks over at gecko drives have a good write up on how to estimate the size motors required (http://www.geckodrive.com/support/choosing-a-drive.html).
Galahir9502 years ago
I was going to build this over the summer with my father, he used to sell CNC machines and he has always wanted to own one. We were wondering if this CNC Control Board would work with your instructable.
( http://www.ebay.co.uk/itm/CNC-Kit-3-Axis-Stepper-Motor-Driver-Nema17-12V10A-220V-/270900965305?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item3f12f4afb9 )
nick2334 (author)  Galahir9502 years ago
The only issue I see with the board is the 62 oz-in steppers. The motors I used are 130 oz-in and I have never noticed them stalling or loosing steps but compared to other builds I have seen, they are on the small side. The axes have a little resistance to overcome but not enough that I wouldn't expect those motors to be able to move the machine so the question is how much torque is left over to do the cutting. If you want to cut platic and wood I don't think it would work but if you're interested in cutting foam and milling PCB's I reckon you could get away with it.

On another note, it is the first time I've seen a diver board being run off of a switch mode power supply without a few hefty caps to smooth things out. I'm not terribly knowledgeable on the electronics side of things but I would imagine that performance would be reduced compared to that if it was run on a beefier linear supply.
After some correspondence with them I was reccomended this model board. This board has 170 oz-in Stepper Motors. Do you think I would run into any problems with a higher oz-in?

http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&isIU=1&item=261029020897#ht_8120wt_946
nick2334 (author)  Galahir9502 years ago
170 oz-in will work well. If I were to do it over I would get steppers in the 150-200 range.
After looking through your BOM, I noticed you bought CamBam and MACH3, why did you feel th need to get CamBam also, was MACH3 not capable enough?
nick2334 (author)  Galahir9502 years ago
There are four steps to getting something made on a CNC machine:

1) CAD software. This is used to draw a 2D or 3D part to represent the desired geometry with lines or surfaces.
2) CAM software. I use CAMBAM. This takes the geometry from step 1 and figures out what tool movements are needed to cut it out. These movements are detailed using G-code which only gives a start and end point and states whether they should be joined with a straight line or an arc and what speed to go in between them.
3) Machine controller. I use Mach3. This takes the start and end points from G-code and figures out how to turn the motors to make the cutting tool follow a straight line, move at the right speed and accelerate and decelerate as required. This information is output as step and direction signals for each motor.
4) Drive board. This converts 5V step and direction signals into current through the motor’s armature making the motor move and by the right amount.

Some of these steps can be combined. For cutting pockets and drill patterns I do step 1 within CAMBAM. Mach3 also comes with a few wizards which can specify pockets and drill patterns and achieve steps 1-3 all in Mach3. To achieve the full potential of the machine to cut 3-d surfaces I required the full Rhino-Cambam-mach3 combination. This is an add-on feature to the software and not its main purpose of machine controller. Artsoft also has a freeware program called Lazycam to do basic cad/cam work which is no longer supported but I have not tried it. The Mach3 documentation is quite good and will give you an understanding of what you can do with the wizards alone (http://www.machsupport.com/documentation.php). The machine is not tied to any particular software/hardware. There are many options for each step and any could be used, some free, some affordable, and some tens of thousands of dollars for use on 6 axis machines.
Okay, I will check those programs out, I think I saw a blurb about them on the Mach3 site. My father used to sell heavy duty CNC machines in the 80s. The ones he sold used to go from $150,000-$1,500,000.
zyh123982 years ago
Thanks for your instructable. It's very good.
wb19782 years ago
Hey huys,

Wondering what software to use. Can it handle Inventor files?
Check this out.

http://www.sorotec.de/shop/product_info.php/info/p2311_usb-cnc-controller-v5-a3.html
nick2334 (author)  wb19782 years ago
I couldn't see much information on that website about the software but I imagine you'll be able to use Inventor. You don't usually use native files types such as Inventor or Solidworks in CAM software but save the files as STL files or similar universal file types.
nic1230982 years ago
that is awesome $1500 compared to over $100,000. lol that is awsome
brian50032 years ago
Have you tried running machinable wax thru this router? I really want to build one but it has to be able to run wax.

nick2334 (author)  brian50032 years ago
I've never dealt with machinable wax. Going by the name alone I would imagine its softer than both plastic and HDPE so I would imagine it would work, just a matter of how aggressively it can be cut.
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