A Methodology for Optimizing Impact Strength, Dimensional Accuracy and Costs of Manufacturing with Three-Dimensional Printing of Polylactic Acid

Among all technologies applied in three-dimensional printing (3DP), fused deposition modeling (FDM) is the most developing one because it is capable of producing parts with geometrically complex figures. Despite its wide applications, there are some drawbacks to its extension, for instance, weak mechanical characteristics and low dimensional accuracy. In this paper, the influence of four FDM process parameters (layer height, printing speed, infill density, and the number of top and bottom layers) on four criteria (impact strength, dimensional accuracy, consumed raw material, and production time) of polylactic acid (PLA) parts is studied. Unlike previous research, this research not only optimizes the properties of produced parts but also minimizes production costs. First, each criterion is analyzed singly; then, in an investigation, all criteria are combined and optimized simultaneously. In other words, a comprehensive decision is made considering both products' qualities and the production costs. The applied methodology for multi-criterion decision-making in this research is also usable in other fields of industry. With the help of this methodology, the best selection of process parameters' levels is attainable. According to the results, layer height = 0.3 mm, number of top and bottom layers = 2, infill density = 60% and print speed = 45.28 mm/s are the best choice while considering all four criteria. Layer height is found the most effective parameter. An increase in layer height leads to a stronger part with a shorter production time but a heavier one with less dimensional accuracy.