Adaptive Toolpath Generation for Material Extrusion Additive Manufacturing Using a Nozzle with Rectangular Orifice

Material Extrusion Additive Manufacturing has greatly simplified the production of complex designs, but it is often accompanied by a trade-off between build resolution and build rate. A higher build resolution can improve the quality of the finished product, but it also slows down the production process. This compromise can be fine-tuned between production runs via alternative sizes of the primary manufacturing tool (i.e., the nozzle), but, in-process reconfiguration of the nozzle is not utilized in the usual Fused Filament Fabrication (FFF) applications. An extrusion system featuring a rotatable rectangular-orifice nozzle can be employed to tune the build resolution. The effective size of the extrusion can be altered through rotational guidance, where a single nozzle acts as if it possesses various orifice sizes. This method holds the potential to introduce variable bead width and height in the process by employing intermediate orientations of the rectangular cross-section. Nevertheless, the implementation of this concept necessitates the development of a customized tool path planning approach. This paper presents methods for planning the trajectory and spin of a rectangular-orifice nozzle to effectively control the position and width of the printed trace. The intention is to promote rapid extrusion of interior regions and enable the printing of finer details with more accuracy. Due to the critical nature of shell manufacturing and infill generation in FFF, dedicated modes of operation have been developed for these tasks. Versatile test cases are developed for the purpose of evaluating the introduced strategies. The results of these test cases demonstrate the applicability of the proposed method for achieving controllable resolution in FFF.