Ever since I saw the first makerbot, I have been obsessed with 3D printing, I am an engineering student and I don't have an extra $800-$2500, and have been doing my best to create one out of what I have on hand. I tried using arduino with easy drivers, and parallel port, but neither one gave results, I always needed a tool or part that I couldn't get.  So I pulled out my old box of legos and started building.

   This is a project I have been working on for the past year, it prints in hot glue and is made almost completely out of legos. Its design is roughly based on the first version of the makerbot. While it does print, I would call this more of a prototype or concept than a finished project.  I am using 4 power supplies (3v extruder motor, 7.2v for nxt, 12v fan, and 115v for hot glue gun) and having to manually turn the extruder on and off, (although I am working on that one) . Unfortunately,  due to my lack of programming skills, every move has to be manually programmed from the NXT programming software, I have yet to find a g-code interpreter for the NXT.
  Hopefully in the next version I will be able to shorten the height of the platform, reduce wobble, and use g-code files.
But in the meantime, I have included a Lego Digital Designer file of the full printer, just about all the technic parts are exactly the same as in my printer, but for the structure I used different part placements to speed the digital building process, the structure and dimensions are still the same. under each X and Y axis there are 2 suspended blocks that I placed coins in to balance the weight of the motor on each side, for the extruder motor I used a lens adjustment motor out of an old VHS camera because it was low speed/high torque. In the .ldd file, the green box on the right side of the extruder gears is the case I made for it, it works perfectly.

   While hot-glue works, its very rubbery and doesn't have many practical uses, if only one or 2 layers are printed then it will stick to glass to make window stickers, but its not sturdy or rigid, I will be experimenting with printing using wax and heat-melting resins in the future. I am currently limited to what I can make with what I have on hand, some more printed parts could really improve accuracy on this.  I initially did not have enough gear racks so I asked someone who had a 3D printer at work if he could help me out, I was able to get around 30 of them printed, and while they work, they do not connect perfectly to the legos, which is what causes most of the wobble in the platform.

If you liked this and want to see more, please vote for it in the 3d printing and lego contests!


UPDATE: My project is now on Technewsdaily and Gizmag! Thank you Randal Marsh and Elizabeth Palermo for writing those excellent articles! also on Hackaday, Dvice, and many more!

1-40 of 114Next »
AnnaR920 days ago


We're looking to hire someone who owns a LEGO 3D printer for an event. We would pay for services, travel and accommodation. This would be between October 15-18.

If you would be interested, please get in touch at anna.rust@socialbakers.com.

Thank you!


matstermind (author)  AnnaR920 days ago

Thank you for the offer, however I would need to know more information before I can make a decision. What event is it? Where is it? and what makes my project so valuable to have expenses paid for this event?



citylife2 months ago
Could you tell me the detailed list of the tools needed to make this printer?
matstermind (author)  citylife2 months ago

the only tools used was the mini hot glue gun, a philips screwdriver to take apart the camera lens, and scisors to cut the sewing string. The rest is all legos. I did use a soldering iron to make a touch sensor as i did not have enough lego ones, but it functions exactly the same as a lego one.

MSM945 months ago

That is very interesting music. Where from?

its "Animusic"

smartmiltoys6 months ago

I like this project but it's like saying It cost me $0 dollars to build
my car because I made it from the parts I had lying around. I might
happen to have an engine, transmission, suspension, tires, and a frame
lying around but most people won't be able to build a car for less than
they could buy a car already made. Same thing here. Unless you already
have $700-900 of the correct Lego parts lying around most people are
better off buying a 3D printer kit.

divadg1237 months ago
Dude this is so freaken badass!

It's awesome how you made this with legos and hot gluexD Very innovative!
TheTutor117 months ago
Hi, I love this project, I would love to build it for a local school. How much does it cost?
jdzach8 months ago

In your next version you should try mounting a 3d-pen they are around $80 i got mine for $60 so there a fraction of the cost of a 3d printer.

davidbarcomb9 months ago

Excellent project. I love it

jdzach9 months ago

I'm making my own version but I'm having trouble making the glue gun trigger squeezed. Any ideas?

matstermind (author)  jdzach9 months ago

I couldn't figure out an easy way to get a consistent rate of extrusion by squeezing the trigger, so i disassembled to hot glue gun, kept the heater and metal nozzle part, and used to gear assembly on top of the printer to push the glue through from the back.

Do you know when the program will come out by?

matstermind (author)  williamntanujaya10 months ago
I ave no idea how long it will take, i am just starting to learn labview, and a gcode interpreter is a fairly advanced program. So, if I can figure it out, it will take a long time.

You can remove the Lego Mindstorms electronics and replace it with a RAMPS board (It runs Repetier, you can find out more on the RepRap page). You can also replace the servos with basic $7 stepper motors to run with RAMPS. It costs around ~$30-$40 to implement this system. You can also attach a nozzle ($0.50) onto a high temp hot glue gun, and run PLA through it, since PLA's prime temperature is 190C (which is the standard temperature for high temp hot glue guns). ABS melts and can be used at 190C (I've melted lego's before at 70C) but the ABS does not stick to itself well. If you use ABS, it is also recommended to use a heatbed to prevent curling. Hope you have fun with this printer!

jgarza21089 months ago

can you make it less complicated to get instructions on the download

Do you know when the program will come out by?

Crafterkid12311 months ago

could it make complicated cases with holes in the side without having the glue fall into where the holes are? or will i have to use an x-acto or a frame?? this is seriously the best 3d printer idea i've ever seen and it even looks like can make it myself :D. what files does it need to program the printer??

What if it runs out of glue while printing? As far as I know, these glue sticks runs out very quickly( Well, for my glue gun)
matstermind (author)  andytangtsk1 year ago

Ideally, each layer is as thin as possible, so the extrusion rate is set very low, but the size of the object is still limited by the amount of hot glue stored in the extruder. However, The extruder is designed so that it can be expanded to hold more hot glue.

Oh, thanks, great project and i'ble by the way
한민류1 year ago

how can I make lego 3d printer? please tell me my mail. If you want.


XYZAidan1 year ago
Where does the string attach? I can see it is wrapped around the axles connected to the servo, but where else?
matstermind (author)  XYZAidan1 year ago

The string goes over pulleys in the top corners and then are tied to ball joint pegs below the pulleys.

turtleson1 year ago
Damn, nice job, man!
matstermind (author)  turtleson1 year ago

Thanks, i am still slowly working on version 2.

yomanurock1 year ago

how do I put together all the 'non-lego' pieces? I have the lego structure and now i need to put together all the non'lego pieces.

matstermind (author)  yomanurock1 year ago

reply is above. If you can, it would be nice to see pictures of your progress.

matstermind (author) 1 year ago

There are only two non Lego pieces, the motor for the extruder (which actually could be an old rcx motor or power fuctions motor, and the hot glue gun for the extruder. the hot glue gun needs to be taken apart and have the metal heater placed in the lego "jail" to hold it together. I took the printer apart a few months ago so i can't take any new pictures. but these three best depict the placement.

Oh my… You made that?

could you use something like weed wacker line instead of hot glue sticks

How does the hot glue come out and how do u make the extruder
matstermind (author)  someone_6781 year ago

The extruder is simply a hot glue gun with the plastic case and trigger assembly removed. A motor turns gears which pushes down on the back end of a gluestick and forces the glue out the front.

aneeshdua1 year ago

well pls tell me the approximate cost of this project....Thanx

matstermind (author)  aneeshdua1 year ago

I already had all the parts I needed, so I spent a total of $0 on it. I have no idea how much it would cost to purchase the parts new.

ManutoBck1 year ago

Sorry for be wearisome, but i relley need your help, anybody know how to put all the non-lego pieces??... I have all the Lego strucutre, but now, i don't know how to put the extruder and the non-lego pieces! Really thanks to sombody that can helps me... =)

Dude, this is a very nice job! simple programming for the NXT I think, but yes it is very nice. Now, you are an engineer! :)
matstermind (author)  jhardenberg1 year ago
ManutoBck1 year ago
First of all, sorry for my English, i'm Spanish... Second, i like to say, that this project is AWSOME! I'm trying to build for a High School project and i need some help. I have all the structure and the Lego mechanisms,but i don't know how you put the extruder, and all the non-lego pieces... I really need your help... Thanks! =)
1-40 of 114Next »