Extruded polymer instability study of the polylactic acid in fused filament fabrication process: Printing speed effects on tensile strength

Abstract

AbstractIn recent years, additive manufacturing (AM) processes have allowed the building of complex parts and objects with favorable geometric shapes without the need for fabricating special tools. In AM, objects are built layer by layer. Advantages include the possibility of forming complex shapes, reduced waste, no special requirements, and so forth. A critical parameter to consider in AM technologies is the processing (printing) speed, which, if increased, can reduce production (printing) time and expenses. Thus, speeding up the production time in AM has always been paramount. In recent years, fused filament fabrication (FFF) has been extensively developed due to straightforward processing, reliability, and ability to build complex objects and parts from thermoplastic materials. In addition to simplicity, this method has some shortcomings, including low printing speed and instability during the rasters deposition when speeding up the printing process, which is investigated in this study. The results showed that the nozzle height from the work‐piece surface and nozzle diameter play a critical role in the process instability. Additionally, there is a critical limit in the formation of molten instability independent of the printing speed. Furthermore, the effect of printing speed on tensile strength was investigated. The results showed that optimizing the nozzle temperature and the extra extrusion multiplier allows printing a high‐quality part having optimum tensile and mechanical properties by the maximum printing speed.