A rotary extrusion system with a rectangular-orifice nozzle: toward adaptive resolution in material extrusion additive manufacturing

Material extrusion additive manufacturing (MEAM) has revolutionized the production of complex designs while minimizing the amount of effort required due to its simple production pipeline. However, MEAM naturally comes with a well-known trade-off; higher build resolution often tends to enhance the product quality at the cost of a slower build rate. Nozzles, the standard tool for thermoplastic extrusion in MEAM, have evolved into a crucial component of the process for controlling the product’s build resolution. The purpose of this study is to investigate the details of a novel extrusion system that makes use of a rotating nozzle with an unconventional aperture, in contrast to its typical (i.e., circular-orifice) counterparts. The unique nozzle configuration that lacks axial symmetry allows for precise control over the effective dimension of the extrusion via rotational guiding. By positioning the oblong orifice at intermediate orientations, the presented approach seeks to provide continuously variable intralayer and interlayer resolutions for MEAM processes. This paper explores the distinctive characteristics of this new nozzle design as well as the potential uses of the novel extrusion system. The outcomes of the conducted tests demonstrate the proof-of-concept for creating variable bead width within the layers, in addition to adaptable layer heights throughout the 3D objects. Possible limitations of the new approach and future perspectives are discussed in detail.