Estudo experimental e teórico das influências dos parâmetros de controle da manufatura aditiva nas propriedades mecânicas de flexão do PLA extrudado

Abstract

Due to the increasing demand of the industry for parts with low weight, high strength, and economically unviable produced by traditional machining techniques (subtractive manufacturing), it is necessary to use new approaches to manufacturing. The additive manufacturing (AM) is gaining prominence for it’s ability to reconcile the production of objects and functional assembled sets of complex macrogeometrias in one step, combining different materials and properties. Despite the increased interest in MA, information on the influence of process variables remain scarce and together with the lack of technical standards for standardization of parameters, generate a lack of reliability and understanding of the mechanical behavior of parts manufactured by MA. In this context, This study aims to determine the mechanical properties of the PLA materials extruded through three points bending tests, and presents new methods of calculation considering the actual area moment of inertia. The print input parameters investigated were the (a) percentage of fill, (b) fill pattern, (c)building orientation, (d)thickness contour, (e)the thickness of the base and top, (f) nozzle temperature, (g) table temperature and (h) distance between layers. The results show that increasing the percentage of fill after 30 % is not accompanied by improved mechanical properties and current analytical methods of bending tests are not consistent with the theory of Hooke's Law due the significant alteration of elastic modulus for the same material. The new proposed method decrease the change of the material’s rigidity and shows a data processing more consistent with the Hook’s Law. The results indicate that dimensional tolerance were affected by the input parameters, whereas the increased of the layer’s number and extrusion temperature were responsible for the tighter tolerance.