ROBOTIK UND MECHATRONIK

As part of the FunkDAF research project, the IGMR is working with the MSE and VCI at RWTH Aachen University to explore the limits of additive manufacturing. Our focus is on multidirectional manufacturing: instead of breaking down components into planar layers as in conventional 3D printing, we generate print paths based on stress data to create load-path-compatible and thus more stable structures.

The kinematics: We use a 6-axis industrial robot in a “robot-guided” configuration. The robot guides the print bed and component under a stationary extruder. This use of all six degrees of freedom enables the printing of complex, non-planar geometries and allows component sections to be manufactured in variable orientations to gravity.

The challenge: Trajectory planning for such systems is highly complex. Unlike static print beds, we are moving a dynamically growing workpiece in space. During the process, the component itself becomes a potential collision object with respect to the nozzle and the environment. To make matters more difficult, the extrusion process requires a minimum working distance from the stationary nozzle. Path planning must therefore not only take extrusion into account, but also precisely calculate how the component volume changes.

The travel paths (empty runs) between individual printing segments are particularly critical. Here, the robot often has to completely reorient the component in order to reach the next section without collision. Our current experiments (see images) demonstrate this impressively:

Helix on cylinder: Requires continuous, coordinated rotation to deposit material on a curved surface.
Orthogonal cuboids: Demonstrate the ability to print overhangs without support structures through a 90° reorientation.

Contact person: Mark Witte
Further information about the project can be found here.