Print Paths Key-framing: Design for non-planar layered robotic FDM printing

We present a method to design non-planar layered print paths for robotic fused deposition modeling (FDM) printing of single-shell surfaces. The advent of robotic arms has created great potential in the 3D printing industry for the realization of non-planar print paths that allow transitioning between different orientations during the print. However, this potential is often not fully realized due to the various challenges associated with the design of feasible non-planar print paths. Inspired by the ubiquitous key-framing technique in animation, where an input of limited degrees of freedom is used to describe a complex behavior, we propose a method to generate non-planar layered print paths subject to the input of the designer, by specifying a series of target curves on the surface of a mesh. Our method generates intermediary print paths with a direction that interpolates that of the targets while respecting the sequence and distances between neighboring paths imposed by fabrication constraints. The resulting print paths have variable layer height, and their realization relies on variable end-effector orientation. We present several examples and fabricated prototypes and make qualitative comparisons to planar slicing, to showcase the capabilities of our method.