Towards Layerless Printing in Additive Manufacturing

In recent years, Additive Manufacturing (AM) has advanced from its ubiquitous function of design validation to biomedical and biomimetic engineering, rapid tooling, tissue engineering, the arts and even food manufacturing. Though the corresponding scale reduction of the manufactured models did not coincide with improving two of the most important process characteristics, namely print accuracy and build time. This research aims to formulate a computational framework for computing the maximum build volume for given non-circular aperture extruders and printing machines that have 3, or perhaps higher numbers of degrees of freedom (DoF), and also generate suitable print head motions given heuristic quality constraints. As a first step, the proposed formulation computes the accessible configuration space of a n-DoF AM machine. This subset of the joints workspace corresponds to the geometry which closest approximates the input model (i.e. the maximum build volume), and is instrumental in planning the final (temporal) motion of single or even multiple, collaborative print heads. Additionally, the proposed method allows the ranking of multiple extruder shapes based on their respective maximum build volume deviation relative to the nominal geometry. The second step consists of generating suitable n-DoF trajectories of the material deposition apparatus. The heuristics used in this research pertain to the overlap volume between subsequent traces and the surface quality. This generic trajectory generator offers support for both traditional AM machines with 2.5-axis and circular extruders, as well as emerging AM techniques including robotic 3D printing with arbitrary shaped deposition stencils. Additionally, the proposed motion planning solution is not process specific and can be applied in theory to any multi-DoF Additive Manufacturing technique. The overall formulation makes no assumption about the number of machine DoF, nor about the planarity of the target geometry, making it applicable to future AM technologies such as 6-axis printing with non-planar layers, and layerless Additive Manufacturing