2023 ASEE Annual Conference & Exposition

An Undergraduate Research Project in Material
Science for Improved Rapid Prototyping

Fused Deposition Modeling (FDM) is one of the most widely used additive manufacturing techniques. Currently there are a multitude of FDM filaments available. FDM and several other additive techniques can now routinely be found at K-12 schools, colleges, and universities. Not surprisingly, numerous hands on manufacturing projects for higher education make use of Three Dimensional (3D) printers to produce models and working prototypes of designs developed by students. These are routinely used for robotics, mechatronics, control projects and many capstone design activities. Now, instead of expending excess time and money for a complicated first of a kind part; a 3D printed substitution can be created for a fraction of the cost, time, and resources of a machined part. More often than not, users will design a prototype using a CAD package. Then a STL file is created and sent to a slicer program to produce the part using well established FDM techniques. Initially, little concern to the orientations or filament choices (typically out of PLA ) is given. The resulting model or prototype in many cases is easily broken. Much is learned in the process and a new part or redesign is made taking into account the weaknesses and failure locations in the original. The new design might even be accompanied by a Finite Element Method (FEM) or other analyses to support the proposed changes. This process results in a spiral development that continually improves the functionality and survivability of the prototype.
This paper stems from an independent study project that was focused on layer orientation within a 3D printed FDM model. Since many models are created without any regard to their geometric infills, alignment, or the accompanying stress forces, some guidance in 3D model orientation seems warranted. To attempt to uncover the different properties in regard to layer orientation, four of the most commonly used materials were tensile tested. The results are summarized in order to determine their maximum strength, ductility, and modulus of elasticity. This invaluable knowledge will help with initial material decisions, design layups, and orientations. Some of the surprising results are given here. Furthermore, the results contained in this limited offering should prove invaluable for many projects requiring working prototypes. Results and a discussion of best practices are also provided as a measure of merit for this project.
In this paper’s body we lay out the methodologies, in detail, used by the student during this single semester study so that others might duplicate the effort. As this was the third attempt at this particular material based independent study, we also added our observations of the effectiveness of this project’s design and made assessments as to the effectiveness of our approach. A discussion of the figures of merit and why this testing ultimately improves rapid prototyping are included.

1. Computer Aided Design (CAD): https://www.techtarget.com/whatis/definition/CAD-computer-aided-design
2. Standard Triangle Language STL: https://all3dp.com/1/stl-file-format-3d-printing/
3. Polylactic Acid, commonly known as PLA a common FDM printing material: https://all3dp.com/1/best-pla-filament/