Development of a laboratory module to analyze the effect of 3D printing orientation on material properties

The growing importance of additive manufacturing techniques in the engineering industry makes the discussion of this topic at the undergraduate level increasingly useful. In particular, the significance of the specific material properties of the printed material provides students with an invaluable look at the importance of the orientation of anisotropic materials. In this paper, the material properties associated with the thermoplastic Polylactic Acid (PLA) printed via the Fused Deposition Modeling (FDM) 3D printing method are examined. Specifically, fabricated test pieces are printed at various orientations and then tested for their tensile strength. To determine the optimum number of test pieces for this experiment, ten different orientations rotated in 15-degree intervals on all three axes of rotation are examined. Three pieces are printed for each orientation, and their measured properties are averaged to account for variations caused by unpredictable changes in the printing process. The ultimate strength of each test piece and equivalent moduli of elasticity are calculated and compared to the strength and modulus of an unprinted strand. An experiment is designed with the intent of allowing undergraduate students to repeat a modified form of this experiment in the form of a laboratory assignment for a Mechanics of Materials course. Test pieces with the most representative orientation changes were selected to be given to students for testing. An alternate version of the lab is presented which would allow students to develop their own test pieces in a competition format. The results compiled from a group of undergraduate students at a variety of experience levels that completed the experiment and provided feedback related to the lab's effectiveness at making the concepts of material testing and anisotropic materials clear are presented.