Spherical slicing method and its application on robotic additive manufacturing

This article presents a spherical slicing method for additive manufacturing (AM) which is used to lay additive layers on a spherical surface, thus removing the stair stepping effect, increasing structural integrity and tensile strength. A toolpath is required to guide the extruder in the three-dimensional space and deposit the material in the desired locations. These tool paths are computed using slicing algorithms. The well-established method in AM industry is the planar slicing. In this method, the Computer Aided Design model is sliced using planes and as a result, two-dimensional tool paths are formed. With the introduction of multi-axis AM machines, development of new non-planar slicing algorithms has started. In this article, a novel non-planar, spherical slicing, is introduced. In the proposed spherical slicing method, the model is sliced by spherical shells such as that of an onion. These spherical slices are then used to generate the appropriate tool paths for guiding the robotic manipulator in three-dimensional space together with the corresponding orientation to lay the spherical layers on top of the previously manufactured planar base. Results are verified by manufacturing a model using a six-axis robotic serial manipulator by fused deposition modeling.