Continuous Robotic Spatial 3D Printing of Topologically Irregular Space Frames

Abstract

Spatial 3D printing via robotic extrusion can offer advantages over conventional layered additive manufacturing, both in speed and strength. However, spatial 3D printing comes with its own challenges such as collision avoidance and sequencing. Overcoming these issues means that a topological path finding problem must also be addressed.

Prior examples of spatially printed space frames, although sometimes forming curved surfaces, have been made up of repeating units arranged in regular grids. This consistent topology ensures simple path planning and sequencing but offers limited scope for geometric freedom and structural optimisation.

For structural reasons it can be advantageous to locally vary the density and topology of a space frame in response to the stress distribution. This generally leads to space frames with an irregular topology which makes efficient sequencing for printing purposes difficult. In contrast to previous work, our novel method allows for topological variation while still ensuring printing in a continuous path is possible. As a proof of concept, we successfully printed a two-metre tall prototype that demonstrates the efficacy of our method.