Picture of Arduino Controlled CNC / 3D Printer Hybrid

Mother Nature Makes ... We Build.

BuildersBot Fuses 3D Printing & CNC Milling Into One Builder’s Dream ""

The BuilderBot is an Open Design machine, that uses Open
Software and Open Hardware. It is a product of open projects such as the RepRap, Arduino and Repetier .

The objective of this instructable is to guide your way throw the entire making process of building a BuildersBot machine. An open design Arduino Controlled CNC Router that can also perform 3D printing.

The instructions will cover all areas such as design, mechanics, electronics and software.

But before you go any further take a look at machine's concept design:

And also the machine build photos and the machine in action:

Finally check out the insane effects of the RGB led's on BuildersBot:

Warning Viewer Discretion Advised (Strong Language)

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Step 1: The BuildersBot OpenDesign (Sketchup)

Picture of The BuildersBot OpenDesign (Sketchup)

To view the the machine in 3D just Download the attached sketch file and access the BuildersBot OpenSource Design (in metric system and is in 1 by 1 scale).

Use this design as much as possible for guidance during this instructable.

NOTE: Use trimble/google sketchup to open the file.

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aldricnegrier (author) 12 days ago

Check out the Buildersbot in action:

mellontiko3 days ago

Hi Aldric!

How do you stretch timing belts? Ι have enough oscillation

aldricnegrier (author)  mellontiko3 days ago

Hi Mellontiko,

You need 1 more person to help you tighten the belts. I can do it by my self now that i have some experience.

I do it by my self using a rope on the small pulley shaft, lock the belt in place, and using the rope stretch the small pulley shafts into place using the rope.

It is a bit hard to explain.

After you do this you can put a tensioner on the belt, for extra tention.


Do you suggest any e-shop to find this article?

Actually im using a 16mm wide belt....

aldricnegrier (author)  mellontikoyesterday

Mine are 15mm, i got the item off a pair of clothe pegs, not your regular clothe peg (they are too small), i found nice strong ones in a dollar store.

Just have a look in a dollar store to find big cloth pegs.

Keep in mind, you need to tighten the belts first by hand, strong and tight, then you attach the pegs. Just using the pegs wont do you any good, if the bets are not tightened.


Hi, I am having CNC milling machine. I am planning to convert it into a 3D printer. I am going to use a quad extruder, I am looking for a control board for the quad extruder, can you please help me?

aldricnegrier (author)  ragav.ramesh.93 days ago

Hello ragav,

I dont know, i dont have experience with multiple extruders. Sorry.


I have a Prusa I3 3D Printer which use Arduino Mega 2560 and Dremel with Flexible shaft. I want to convert my 3d printer to cnc router as you told on step 17 I Configuring the Repetier Firmware for CNC functionality,

But i don't know how to generate g-code from STL , DXF or any other image file(SVG) to use with these type of cnc router.

aldricnegrier (author)  ankitvaid19904 days ago

Hi ankitvaid,

You need to use a CAM software.



mellontiko what is the manufacturing cost ?

Hi Aldric :) thank you for the help so far, in the 15th page you said that the precision will b calculated later, have you done it? could you tell us what it is?

Thank you :)

maddig13 days ago

Hello Aldric, thank you for this fantastic guide! I have a question for you. At the base frame, should I take the measurements from SketchUp or from the manual? In the manual, the lengths of the upper frame are indicated with 750mm, but when I take a measurement in Sketchup there are two 760mm and one 720mm piece. I hope you can help me. And sorry for my bad english, I'm from Germany.

aldricnegrier (author)  maddig12 days ago


Follow the sketchup file, i am sorry for the mistake.

I will correct it as soon as possible. Thank you.

derah0414 days ago
AliGee21 days ago

Hi, I try to build a similar project in a little bit bigger workspace size (1200x1000mm). Now I'm looking for the right motor sizes (Nema 23 / 34).

My problem is that I don't know what motor torques are needed for a 20mm miller (for wood) and the right accelerations of the x and y axes for 3D printing.

Why did you choose this kind of motors and how much micro steps you use? Are you satisfied about your 3D printed objects quality or resolution?

A video about workspeed milling/printing would be very nice to suggest how fast it works.

Sofiadelfi28 days ago
La cama caliente para la impresora 3d se puede tener una medida de 800x800milimetros
aldricnegrier (author)  Sofiadelfi23 days ago

Yes it can. Just scale it that way.

dj_freakout1 month ago

How many amps for the 36V power supplies each?

aldricnegrier (author)  dj_freakout1 month ago

Power supply-----350W--36V, 9.7A

Hi aldricnegrier,

can I know as to where you connected the LCD display?

Does the Ramps 1.4 Breakout Board support the SD card system out of the box?

aldricnegrier (author)  dj_freakout1 month ago

Yes it does, it supports LCD and SD card.


Hello Aldric, i was wondering what you mean with "drill pecking".... i am looking to build a CNC to route and drill PCB's and enclosures for my hobby projects. You think that this is possibke with the builderbot?

aldricnegrier (author)  koen.peeters.3591 month ago

Hello Koen,

You can mill PCB's with the buildersbot with no problem.

There is a GCode (G83) for Drill pecking in normal CNC's, what it means is that your CNC for example will drill a 10mm hole by pecking the hole several times,

-2mm first, than retract to 0mm,

-4mm than retract to 0mm,

-6mm than retract to 0mm

-8mm than retract to 0mm

-10mm than retract to 0mm

This allows for chip removal and drill bit cooling.

Because repetier firmware in not 100% CNC compatible, the GCode for pecking holes will not be recognized. So you need to do drill pecking using G1 gcode instead of G83 by editing your gcode. It is not a problem, it more an inconvinience, because normal CAM softwares offer drill pecking, you can chose drill pecking, and than you need to change the gcode manually from G83 to G1.

It is mostly used in metals and long holes in wood and plastics.

Have a look here:

JacoBez1 month ago

Hi Aldricnegrier,

I've noted that you are using 2 motors on the Y axis and a single on the X axis. That would mean that the force on the Y is twice that of the X. Can you please share with me the behaviour of the machine that you are experiencing when you are cutting for instance a circle or any other shape where the X & Y is travelling simultaneously?

aldricnegrier (author)  JacoBez1 month ago

Hi JacoBez,

2 motors on the Y axis is a widely used technique in the cnc industry, it avoids unbalanced tensions on the corners of the working area.

have a look at these machines:

You can control the power/amps to the motors by adjusting the microsteping drivers. So you can balence the torque this way, or not. it does not matter. As long as your motors don't jump steps.

mellontiko1 month ago

Repetier-Firmware-Buildersbot VERSION 0.92.2 (TESTED and fully working with current project)

Enabled Retraction and Filament Change (for filament change send M600 gcode)

Requirement: LCD Screen

aldricnegrier (author)  mellontiko1 month ago


How many amps for the 12V power supply?

aldricnegrier (author)  lucian.rajac1 month ago

Hi Lucian,

The 12V power supply is 16A, it is for powering the extruder motor and an eventual heat bed.

Do you think I should build the Mega Prusa i3? I would of course like to have the milling function as well.. but at this point I am living in an apartment. I am not sure how to get the plastic parts though... Not many enthusiasts out in the open here in Romania. There are some 3D printing shops.. maybe I can try there...
aldricnegrier (author)  lucian.rajac1 month ago

Hi Lucian,

You should start with Prusa i3 rework for example, it a great overall 3D printer from the reprap project. If you need very big parts than you can go ahead with the Mega Prusa i3. If you can not find some material, contact our store, reprapalgarve, i can send you a Prusa i3 kit to Romania.

Thanks for the reply and for this great project. I haven't built
anything since college and I wanted to make a 3d printer. Thought to do
some research and saw that for most printers out there you need plastic
parts. I wanted the first to be made from scratch and saw your project
here. Have to tell you that it's awesome and that I will build one
myself. Already had the RAMPS + Arduino and display shipped and now
saving money to buy the motors, which are the more expensive part. Also I
am a little bit confused regarding the custom aluminum parts and the
plastic one... don't know how i'll manage to make those but I am hoping
to find a chop-shop with the proper tools. After I finish I will have it
installed in my living room. Thanks again one more time and I will ask
again if I have other questions.

aldricnegrier (author)  lucian.rajac1 month ago

Hi lucian,

I would think twice before building a CNC and having it "installed" in your living room :)

CNC are noisy, create dusts and particles, you can reduce this using a vacuum cleaner (that adds even more noise).

I don't want to des-encourage you, i just want to let you know about these "dirty" details.

A 3D printer on the other hand is a great machine to start , apartment friendly, non toxic (melting PLA), no dust, almost no noise.

Just my thoughts.

Well I know about the CNC part and considered it as well.. But I will mostly do 3d printing with it. The milling will be done only during normal hours and I am considering moving (maybe get a house with garage)

aldricnegrier (author)  lucian.rajac1 month ago

The BuildersBot is a CNC that can 3D print, 3D printing with the Buildersbot is slower than a conventional 3D printer, because of the mass. Do as you wish, if you need help let me know.

mellontiko1 month ago

Hi Aldric!

Couldnt find the problem, so im using 3 stepperdrives one for both Y motors(normal and inverted), X, Z!

Now i build the heater bed so next week i will send you final pics!

PS: did you try the new repertier firmware 0.92.2? (Repetier-Firmware 0.92.2 support volumetric extrusion and filament change).

jpmasse31 month ago


Great project! I am interested in building it myself, would you be able to provide the electronics p/n's you used for it?


aldricnegrier (author)  jpmasse31 month ago

Hi jpmasse3,

Thank you for your comment. I wish i could help but i did not know meaning of "p/n's" :)

Haha. Sorry. Do you know the part numbers and manufacturers for the electronics?



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