LEGObot 3D Printer





Introduction: LEGObot 3D Printer

About: I am an engineering graduate who is constantly tinkering, making, and building. I have always enjoyed disassembling old electronics and re-purposing them. I enjoy anything mechanical, electrical, chemical, o...
   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!

Step 1: Instructions

The ldd file will generate instructions for you, if you don't know how to do it, follow this.

1, Open the 3D printer.ldd file in Lego Digital Designer
2. Select "Tool Box"  from the menu bar
3. Click "Generate building guide"  or press "CTRL" and the "M" key together (in windows).
4. Wait for it to generate the building guide
5. Follow the instructions :)

This is not the same gear rack I had printer for my printer, but it looks like it would work better.

For those who can't open the .rar file or don't have WinRAR you can download the LDD file > HERE < from MediaFire
And for those who can't use Lego Digital designer, download the HTML instructions > HERE < from MediaFire

Step 2: Whats Next?

Now that you have a 3D hot-glue printer, what can you with it?

Color your gluesticks

Print your own candy with sugar sticks! (might be a mess)

I'm going to be experimenting with pine resin based glue sticks, it melts in heat and cools hard, so it could be used.

If there are any problems, clarifications, or questions you have, feel free to post them in the comments and I will answer them as soon as I can!

I also am looking for a good name for this, if you have any ideas, or if you like LEGObot please let me know!


Toy Building Blocks Contest

Finalist in the
Toy Building Blocks Contest

3D Printing Contest

Second Prize in the
3D Printing Contest



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    128 Discussions

    This is brilliant, poetic, and generally pretty awesome. Try to find time and finish it because you are a genius.

    Why side lined? Legal or wife...or both?

    Why side lined? Legal or wife...or both?

    Shut me down. Lego making Lego, how perverse


    Interesting project, too bad it's sidelined at the moment.

    Not yet, it has proven more difficult than I first thought. this project has been sidelined for an undertermined amount of time.


    2 years ago

    Has the programming came out


    2 years ago

    Has the Programming came out yet


    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

    Thank you!


    1 reply

    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?



    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.

    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.

    Dude this is so freaken badass!

    It's awesome how you made this with legos and hot gluexD Very innovative!

    Hi, I love this project, I would love to build it for a local school. How much does it cost?