Looping: Load-oriented optimized paths in non-planar geometry

Abstract

Effective material utilization in the additive manufacturing of lightweight components is of increasing importance. The Looping (Load-oriented optimized paths in non-planar geometry) method presented in this work enables the translation of desired material orientations into suitable manufacturing instructions. The desired material orientations are derived from the principal stress directions that would manifest for an isotropic material. By employing non-planar slicing, these orientations can be followed by the deposited material beads. The novel path planning algorithm combines load-orientation and path continuity. While this can be beneficial for load-oriented printing in general, it is an especially significant step for load-oriented printing of continuous fiber reinforced polymers. The ability to follow desired material orientations with continuous paths shows particularly high potential for highly anisotropic fiber reinforced polymers. The algorithms are implemented and demonstrated in a complete process chain. However, challenges remain in the optimization of the orientation and manufacturing system for fiber reinforced polymers, which are not the focus of this work. For this reason, the process chain is realized for a neat polymer. In this context, the developed method is computationally evaluated with respect to layer height, unfilled areas, manufacturing time, geometric accuracy, and physical fabrication. The continuous and load-oriented path planning algorithm is tested against a continuous contour parallel approach and planar slicing through tensile testing. The investigations show an applicability of the process chain to successfully produce complex parts with the desired load-oriented paths. The proposed algorithm shows an increase in mechanical performance compared to the contour parallel approach highlighting its potential for non-planar printing. However, it is also found that limitations of the non-planar manufacturing process still limit its potential to surpass optimally oriented planar printing for the investigated geometry.