Effects of Infill Density, Layer Thickness and Raster Angle on Weight and Tensile Strength of PLA Products Fabricated by Fused Deposition Modeling (FDM)

This paper aims to deliver a study on the effect of process parameters on two objectives as weight and tensile strength of printed products. Experiments are conducted with different 3-level parameters as layer height (0.1, 0.15, 0.3 mm), infill percentage (20, 50, 80%), and raster angle (0 degrees, 45 degrees, 90 degrees). Then, different methods are proposed to optimize process parameters. Taguchi's experimental design is applied in this paper to reduce the number of experiments, helping decrease cost. In detail, the weight and tensile strength of specimens are analyzed by the Taguchi method and ANOVA table. Then an optimal set of parameters is suggested for achieving a product with the best tensile strength and weight. Contribution analysis shows that infill density impacts weight and tensile strength most, with 88.7% and 39.1%, respectively. While raster angle also significantly influences tensile strength with a contribution of 36.2%, it almost has no impact on the weight variance. Layer height also is an influential factor. It affects tensile strength and weight with a contribution of 18.9% and 10.2%, respectively. For single-objective optimization, the best parameter combination for maximizing tensile strength is 0.1 mm layer height, 80% infill density, and 90 degrees raster angles; and the optimal set for minimizing weight is 0.3 mm layer height, 20% infill density, and 90 degrees raster angle. Besides, regression mathematic models for multi-objective optimization are constructed and evaluated for accuracy and reliability. Then, multi-objective optimization with a Genetic Algorithm is studied to identify an optimal trade-off set of parameters as advice to achieve suitable weight and tensile strength of the product according to users' desire.