Estratégia de deposição com variação de largura do filamento para geração de estruturas porosas com manufatura aditiva por extrusão de material

Abstract

Through Additive Manufacturing (AM) based on material extrusion, it is possible to manufacture porous media (PM) with planned structure by varying the process parameters. Several studies have been carried out to obtain lattice structures using raster filling with constant width beads. This work proposes a deposition strategy to obtain a unique porous structure, using variable-width beads. These beads (nominated here as segmented) are divided in thick and thin segments, according to their width, generated through combined variation of printing speed and extrusion rate parameters during deposition. An algorithm capable of generating the proposed filling was developed and implemented in the process planning program called RP3 (Rapid Prototyping Process Planning), allowing the control of the parameters in segments of the filling lines. Preliminary tests were carried out in an open-source printer, in PLA, to analyze the equipment’s behavior in response to the variation of parameters during the deposition of segmented beads. These tests made it possible the definition of parameters to manufacture PM with different configurations, which were geometrically analyzed by computerized microtomography (μCT) and characterized through porosity and permeability tests. A configuration generated with traditional raster filling (with constant bead width) served as comparison to proposed filling. The results showed that the 3D printer was able to reproduce the proposed deposition pattern and that pores dimensions and density can be controlled by the parameters of the segmented deposition. The porous structure obtained, when compared to the traditional structures, presents pores with higher aspect ratio and less interconnectivity on the structure. The configuration with the proposed filling presented 27% less porosity and 55% reduction on permeability when compared to the traditional raster filling. Since this is an innovative strategy, which obtains a unique porous structure, the work opens field for new opportunities of studies and applications.