Researchers unveiled an open-source six-axis robotic 3D printing system that could provide faster, support-free curved builds.
Multi-axis robotic additive manufacturing has long been the domain of pricey industrial providers and proprietary software. This work instead proposes a low-cost, open-source framework that combines a six degree of freedom (6-DoF) arm with FFF technology to print complex, doubly curved surfaces without supports. The nonplanar deposition approach could result in fewer support structures, and potentially higher throughput on geometries that are troublesome when using gantry-style FFF systems.
The researchers integrated classical robotics tools — Denavit–Hartenberg kinematics, analytical inverse kinematics, and Lagrange-based dynamics — with an accessible control stack. A Siemens S7-1200 PLC executes real-time motion, MATLAB handles trajectory computation and iterative tuning, and LabVIEW provides a supervisory HMI over OPC UA. The materials demonstration used only PLA material, but the motion platform is the headline.
An Open Robot For Nonplanar FFF
Against a traditional three-axis system, the robotic arm achieved a measured deposition speed of 128 mm/s versus 65 mm/s and cut printing time down by a whopping 43.7% on selected tests. The researchers also printed smooth, support-free, doubly curved waveforms by orienting the nozzle along surface normals, an application that naturally benefits from a 6-DoF toolpath.
Path planning is where the researchers found much of that gain. An improved contour path algorithm segments post-sliced infill into line units and then applies a bidirectional nearest-neighbor strategy to connect segments in whichever direction minimizes the next travel. On a typical 100 × 100 mm undulating model, printing distance stayed constant but idle travel dropped 77.4% and total path length shrank 34.5%. Across other tests, total path length fell 15–30% and idle moves 40–60%, which leads directly to reduced travel time, lower energy use, and fewer seam artifacts.
Although the mechanical design is intentionally modest — stepper motors with planetary reducers driving belts and a worm stage on one joint — the team reports micron-scale motion increments and practical build quality improvements when tuning steps per revolution and layer height. In PLA trials they ran 205C nozzle, 55C bed, 20% infill, 0.2 mm and 0.1 mm layers at 60 mm/s and showed visibly smoother surfaces at finer angular and layer resolutions.
Mechanisms, Gains And Limits
What is new here is not another exotic slicing kernel, but the fusion of open kinematics/dynamics, low-cost actuation, and realistic path optimization into a cohesive, replicable setup. In 3D printing economics, fewer supports plus less travel time equals lower human touch time and higher throughput.
Compared to commercial software like RobotiDK or ADAXIS, which focus on high-level robotic AM toolpaths, this work focuses on low-level execution physics and parameter compensation. Even with planar slicing, reducing non-extrusion motion and aligning the extruder to local curvature can materially improve surface quality and cycle time.
The researchers call the framework open-source, but a public repository, wiring diagrams, and tuned parameter sets would speed up adoption in design labs and education. Independent benchmarks on larger parts, tougher polymers, and pellet or multi-nozzle extruders would determine the real throughput gains and thermal stability over long jobs. Video of support-free prints on compound curves would be especially convincing.
If all that happens, then this new open source design could become a bridge between standard gantry FFF and industrial robotic AM — without carrying the multi-digit industrial price.
