Ever since witnessing the magic of the first MakerBot, I’ve been captivated by 3D printing. As an engineering student, the hefty price tag of professional 3D printers – ranging from $800 to $2500 – felt out of reach. Driven by curiosity and a desire to create, I embarked on a journey to build my own, starting with readily available materials. My initial attempts using Arduino with easy drivers and parallel ports were met with roadblocks, often requiring specialized tools or parts I couldn’t easily access. That’s when inspiration struck from a familiar source: my old box of LEGOs.
This project, a LEGO 3D printer, has been a year-long endeavor. It utilizes hot glue as its printing material and is constructed almost entirely from LEGO bricks. Its design draws inspiration from the early MakerBot models. While it technically prints, I consider it more of a proof-of-concept or prototype than a polished, finished product. Currently, it relies on four separate power supplies – 3V for the extruder motor, 7.2V for the NXT brick (the “brain” of the printer), 12V for a cooling fan, and 115V for the hot glue gun itself. Operating the extruder is currently manual, requiring me to switch it on and off, although automating this is a planned improvement.
The biggest hurdle has been my limited programming skills. Every movement of the printer is painstakingly programmed manually through the NXT software, as I haven’t yet discovered a compatible G-code interpreter for the NXT brick. For the next iteration, my goals include reducing the height of the printing platform, minimizing wobble, and enabling G-code compatibility for more streamlined operation.
In the meantime, I’m sharing a Lego Digital Designer (LDD) file of the complete printer design. The Technic parts in the digital model closely mirror the physical printer, while some structural elements have been simplified in the LDD for faster digital construction. However, the overall structure and dimensions remain accurate. To balance the weight of the motors on each axis, I incorporated suspended blocks under the X and Y axes, weighted down with coins. For the extruder motor, I repurposed a low-speed, high-torque lens adjustment motor from an old VHS camera – a perfect fit for the task. In the LDD file, you’ll find a green box attached to the extruder gears; this represents the custom case I designed for the motor, which works effectively.
While hot glue serves as a functional printing material, its rubbery nature limits its practical applications. Thin, single or double-layer prints can adhere to glass, creating window stickers, but the resulting objects lack rigidity and sturdiness. Future experiments will explore printing with wax and heat-melting resins to achieve more robust and versatile prints. Currently, I’m constrained by the materials I have on hand, and 3D-printed parts could significantly enhance the printer’s accuracy and performance. Initially, I lacked sufficient gear racks, so I sought assistance from someone with access to a professional 3D printer. They generously printed around 30 gear racks for me. While these printed racks are functional, their imperfect compatibility with LEGOs is the primary source of wobble in the printing platform.
If you find this project intriguing and want to see more innovative LEGO creations, please consider supporting it by voting in the 3D printing and LEGO contests!
Thanks,
Matt
UPDATE: My LEGO 3D printer project has gained recognition on prominent tech news platforms including Technewsdaily and Gizmag! Huge thanks to Randal Marsh and Elizabeth Palermo for their fantastic articles! It’s also been featured on Hackaday, Dvice, and numerous other sites!
