Influência da orientação espacial de impressão nas propriedades de peças de polipropileno produzidas via manufatura aditiva Multi Jet Fusion (MJF)

Abstract

In the additive manufacturing (AM) process using HP's powder bed fusion technology (Multi Jet Fusion – MJF), the main process parameters that affect the performance of printed products are the printing orientation, positioning of parts within the printing area and energy deposition and cooling parameters. Considering that the MJF technology is a relatively new process, in the literature there is still few information about the influence of process parameters on the performance of products manufactured using this technology. Furthermore, the published studies focus primarily on the material Polyamide 12. Little has been published on studies of the other materials available for the MJF process. Of these, Polypropylene (PP) is a polymer classified as a commodity widely applied in industry and, therefore, arouses much interest in several applications. Thus, this work aims to investigate the effects of varying the spatial orientation of printing on the mechanical performance of PP samples printed by MJF and on the performance of the process itself. For this, an experimental design was initially carried out using DOE (Design of experiments) to print samples in different spatial printing orientations according to the response surface method with two variables. Mechanical properties of traction and impact of the PP samples were evaluated, in addition to thermal, porosity and morphological analyses. To evaluate the process, printing vats were simulated according to the response surface method with three variables, evaluating cost, productivity and raw material consumption characteristics under the influence of the printing orientation of simulated vats. The results obtained revealed that, by the applied experimental model, statistical significance was identified for the influence of print orientation only on the properties of maximum tension under traction, elongation, porosity and crystallinity, although variations in properties are low. As for the evaluation of the process, little influence of orientation was identified on factors such as cost, printing time and material consumption, these factors being more dependent on the number of parts contained in the vat and packaging density. The application of the response surface method allowed the elaboration of surface graphics that provide guidelines for optimizing the printing of PP parts via MJF for improvements in productivity and mechanical performance of the parts.