The Fractal 5 Pro is an open source benchtop multidirectional 5-axis 3D printer.

💻 An open-source 5-Axis slicer application was developed to go along with this printer. You can check out the GitHub page for it here to download it for free.

This printer is comprised of a combination of COTS parts, 3D printed parts, and custom machined parts. The BOM lists all required materials with links to purchase them. Excluding taxes and shipping costs, the total materials cost for the Fractal 5 Pro is about $1,900.

Several aspects of the design (such as the CoreXY system and triple lead-screw Z-axis) were inspired by the VORON Trident project, which is also licensed under GPLv3. This project complies with the GPLv3 license and is released under the same terms. I gratefully acknowledge VORON's contribution to the open hardware ecosystem.

Gimbal

• The gimbal assembly includes the heated build plate, adjustable standoffs, A-axis shaft, bearings, A-axis belt drive, slip ring, and B-axis gear drive.

• The slip ring supplies power to and reads thermistor data from the build plate, allowing the A-axis to spin infinitely in either direction without wires getting tangled.
• The A-axis shaft is held in place with a spring-loaded bearing stack with a retention ring in-between the bearings. The bearing stack is centered using locating pins.
• A pulley with adjustable belt tension is used to drive the A-axis. This should be revised as stated in the future work section.
• The large B-axis gear with adjustable pinion placement is used to drive the B-axis.

• The build surface is a magnetically removable PEI-coated spring steel sheet.
• Included with the printer is a leveling bar that can be used to calibrate the build surface to be coplanar with the B-axis. This step is critical to ensure axis alignment when performing coordinate transformations. To complete this calibration, the leveling bar must be placed into the slots on either side of the gimbal as shown above. There are three standoffs that position the build plate that can be adjusted using an allen key. The user should increase the height of each standoff until a slight scratching noise is heard when the build plate rotates past the leveling bar. The leveling bar must be removed when the printer is powered on. This step must be completed after the printer is first assembled, and must be completed again any time the printer is moved.

Z-Axis Elevator

• Similar to the VORON Trident, three independently driven lead screws are used to actuate the Z-axis.
• Spherical bearings are used to avoid binding and allow the elevator frame to pivot for auto-bed leveling.
• Each of the three elevator pivot locations are attached to a carriage that rides vertically along a linear rail for added stability.
• Sensorless homing is used to detect the upper range of motion of each lead screw.

• The range of motion for the Z-axis elevator is such that the printhead can reach any point within the build volume for any orientation of the gimbal with some additional margin in every direction. The image above shows examples of extreme positions with a blue cylinder representing the build volume.

Printhead

• The printhead was designed so that when the B-axis is tilted 90°, the nozzle can move extremely close to the build plate. Designing the printhead this way increases the amount of design freedom the user has over where they can define slicing directions. Due to the differences between multidirectional printing and non-planar printing, the printhead only needs to approach the build plate closely on one side as shown in the image below; the remainder of the printhead does not have any other special geometry constraints.

• The printhead uses a BondTech LGX Lite V2 direct drive extruder due to its compact size and ideal shape for this application.
• An E3D Volcano hotend is used so that the flow rate of the nozzle can keep up with the high speed capability of the coreXY gantry.
• A radial fan and swept duct is used for part cooling and the stock E3D axial fan is used to cool the hotend heat sink.
• An inductive probe is used for both auto bed leveling and calibrating to the center of the build plate. I created an edge-finding procedure by writing custom G-code macros in Klipper for the center calibration process. While the center calibration routine was tested and works, the inductive probe is not ideal for use in this application because of its difficult to characterize electromagnetic field shape. The inductive probe still works great for auto bed leveling, but a different type of sensor should be selected for center calibration as is discussed in the future work section.

CoreXY Gantry

• The CoreXY gantry system is similar to the one used on the VORON Trident with some important differences that are bulleted below:
  • The belt system was adapted to fit the larger 30x30mm aluminum frame extrusions of the Fractal 5 Pro.
  • The belts attach to the printhead on the rear side of the gantry to be compatible with the unique printhead design.
• CoreXY motion systems provide more reliable prints and allow for higher print speeds compared to bedslinger motion systems.

• The tension in each belt can be adjusted using an allen key via the idler blocks on either side of the gantry.
• Cable chains are used to manage wires along the X and Y axes. Wire management for the printhead should eventually be converted to CAN bus as stated in the future work section.

Frame & Enclosure

• The frame uses 30x30mm aluminum extrusions for high rigidity.
• The enclosure features magnetically latched full size doors on the front and both sides for ease of access.
• All enclosure panels including the doors are gasketed with foam tape to help promote a more thermally isolated printing environment.

Electronics

• A Raspberry Pi is used to run the firmware and an Octopus Pro is used to control the circuit elements.
• A 24V, 350W power supply is used to power all the circuit elements while a separate 5V power supply is used for the Raspberry Pi.
• Four fans are used to cool the electronics. This can be reduced to two fans as stated in the future work section.

• The electronics are enclosed separately from the rest of the printer and can be accessed via a removable panel underneath the main printer working volume.

Firmware

• The Fractal 5 Pro uses Klipper firmware.
• This allows the user to interface with the printer wirelessly on their laptop from anywhere on their local network.
• The custom CFG file and saved variables file required to run the Fractal 5 Pro are located here.
• The KIAUH helper can be used to install Klipper.

This project was motivated by the Fractal Robotics vision: To accelerate the development of mechanical solutions. In support of this vision, this project aims to help close the observed gap between some of the limitations of 3-axis FDM and the inaccessibility of current 5-axis FDM.

📋Limitations of 3-Axis FDM

• Overhangs require support structures
  • The process of removing supports often damages or destroys a part
  • Support structures waste material and prolong printing time
• Part strength is limited due to the nature of planar layer deposition
  • Parts are more vulnerable to shear forces applied parallel to layer lines compared to forces applied perpendicular to layer lines

🔒Inaccessibility of Existing 5-Axis FDM

• Options for existing 5-Axis slicer applications are limited
  • Most non-planar slicing requires significant training on advanced CAM softwares
• Most commercially available 5-Axis 3D printers are huge and expensive

🌉Bridging the Gap

The observations listed above prompted an investigation into the needs of 3D printing practitioners across different industries. Two 5-axis FDM methods were considered for addressing as many customer needs as possible while emphasizing ease of use. Those methods were non-planar and multidirectional 5-axis FDM. Each of these approaches has their own benefits and drawbacks. While non-planar 5-axis addresses both the supports issue and the interlaminar shear strength issue posed by 3-axis FDM, that approach typically requires significant training in advanced CAM software and tends to be computationally expensive. By contrast, multidirectional 5-axis focuses primarily on mitigating the need for support structures, but has the potential for providing a much more accessible user experience compared to non-planar 5-axis.

Also, from a hardware standpoint, multidirectional 5-axis 3D printers avoid an important mechanical limitation of non-planar 5-axis 3D printers. Since they don't require the printhead to be long and thin to achieve tight angles, multidirectional printers can achieve much higher print speeds with far less vibration. That said, non-planar slicing is an exciting and evolving area of research, and ongoing developments will hopefully make that method more accessible as well.

The result of this trade study was the development of both the Fractal Cortex slicer and the Fractal 5 Pro printer.

Dozens of potential customers were interviewed to determine 3D printing needs, budgets, and expectations across different industries. This process helped inform and focus design decisions.

🔑Key Customer Needs Translated to Design Decisions

• Reduced post-processing risk, less waste material ➡️ 5-Axis
• Ease of maintenance, clean setup ➡️ FDM, removable build surface, full-size front and side doors
• Reduced training time ➡️ Intuitive multidirectional slicer software, backwards compatibility with 3-Axis 3D printing
• Printing complex parts ➡️ Compatible with any 3D geometry
• High reliability ➡️ CoreXY gantry, auto bed leveling, rigid 30x30mm aluminum frame extrusions
• Expansive material compatibility ➡️ Direct Drive Extruder, heated build plate, fully enclosed
• Large print volume ➡️ 300mm Diameter x 250mm build height

Hi, my name is Dan Brogan, and I spent 3 years (2022-2025) bootstrapping a startup called Fractal Robotics while working part time jobs. Over those 3 years, I developed technical acumen in end-to-end robotics product development, improved my communication skills, and learned a great deal about what goes into running a startup.

My career goal has always been and continues to be to contribute to society through technology in a way that has a positive impact. That goal was translated into the vision of Fractal Robotics, which is "to accelerate the development of mechanical solutions".

At this point, I am unable to continue volunteering my full effort into this project. While I won't be stepping back entirely, I have decided the best course of action is to release both the Fractal Cortex slicer and designs for the Fractal 5 Pro under an open source license so that others can learn from, build upon, and contribute to it.

Open sourcing this project allows me to stay true to the original vision of Fractal Robotics. By sharing my work, I hope to support researchers, developers, educators, and makers exploring similar ideas.

I'm excited to see where others take this work next.

Feel free to connect with me on LinkedIn and reach out to me via email: [email protected]

What does this printer do that others can't?

• It provides all of the following in one product: reduced post-processing risk, less waste material, high reliability, more design freedom, large build volume, intuitive user experience, and ease of maintenance at a relatively affordable price.

What is multidirectional 5-axis 3D printing?

• Multidirectional 5-axis slicing is a technique in which a 3D model is divided into sub-volumes (chunks) and each chunk is sliced in a different direction. This allows users to define multiple slicing directions for a given part. The result is a gcode file with toolpath instructions that include reorienting the part relative to the printhead after each successive chunk is printed. This approach is distinct from non-planar slicing, which modifies the surface of each layer to follow the curvature of the model's shape.

Why Direct Drive instead of Remote Drive?

• The customers interviewed tend to favor printers that are compatible with a wide selection of feedstock materials, including softer filaments. TPU needs direct drive to print effectively since it's so soft. Using remote drive to extrude soft filaments would be like pushing on the end of a string to get the far end to move, which doesn't work very well.

• Redesign print bed gimbal for higher rigidity
  • Use 1/4" thick aluminum sheets instead of 1/8"
  • Rearrange A-Axis bearing assembly to minimize unsupported shaft length
  • Incorporate larger corner gussets
• Change A-axis pulley drive to a high ratio gear drive. The belt system doesn't have enough torque and could use some finer angular resolution.
• Convert cable-chain wire harness system to CAN-bus
• Integrate accelerometer into printhead for input shaping (resonance cancellation)
• Instead of using the inductive probe for centering the print bed, use a sensor that has better defined sensing radii in the X and Y directions
  • The same centering routine can be used, but a different sensor solution is needed
• Create an airtight enclosure for the filament spool
• Reduce number of electronics cooling fans from four to two

If you build a Fractal 5 Pro and want to suggest any other potential improvements, please let me know: [email protected]

The Fractal 5 Pro is an open-source hardware project provided ‘as-is’ without warranty. By building or operating a derivative of this printer, you assume full responsibility for any risks, damages, or safety hazards that may arise.

• Family & friends
• Innovate Newport
• RISBDC
• RIHUB
• Rhode Island startup community

Copyright (C) 2025 Daniel Brogan