3D Printing in the Materials Science and Engineering Lab Courses - Project Summary Lorraine F. Francis and Michael Manno Department of Chemical Engineering and Materials Science University of Minnesota – Twin Cities Background 3D printing (3DP) is both an important manufacturing technology and an exciting vehicle for promoting student learning in Materials Science and Engineering (MSE). Traditional manufacturing methods, such as injection molding and die compaction, involve fixed molds or dies that are expensive and present restrictions on the shapes of the fabricated parts. In 3DP, parts are designed using a computer automated design (CAD) program and then a digital file of the 3D object is used to create the part using a 3D Printer. The process flow from idea to printed object is fast and inexpensive, which opens the door to creativity and multiple redesigns. In 2013/2014, 3D printing was introduced into the senior MSE labs: MatS 4221 (Materials Performance) and MatS 4301W (Materials Processing). The Experiments in Learning Innovation (ELI) grant allowed us to expand the 3D printing technologies available to undergraduates studying MSE and develop a more comprehensive series of lab experiments (targeted explorations that are carried out in a 2-3 hour lab session) and design projects (open ended projects that span 5-10 weeks). Before the start of the ELI project, we had successfully launched design projects in MatS 4221 and MatS 4301W, and had developed one 3DP experiment for MatS 4301W. The design projects were made possible by the donation by Stratasys of a Fused Deposition Modeling (FDM) 3D Printer (Dimension SST) and our acquisition two lower-end FDM printers (MakerBot Replicator2 and MakerBot 5th generation). The 3D printers are located in the new MSE Undergraduate Lab facility, which is used by MSE juniors and seniors. Students design their parts using SolidWorks, a computer-aided design (CAD) software, which is available for student download and also in the College of Science and Engineering computer labs. An introduction to SolidWorks was added to MatS 4221. The project in MatS 4221 is based on design for mechanical performance, and in MatS 4301W, the project focuses on the 3DP process, including achieving shape complexity and dimensional tolerances. As described below, during the course of the ELI project we added equipment and developed new experiments and design projects to create a more comprehensive experience in 3DP and solid modeling that starts in the junior year and develops in the senior year. Experiment and Project Development The bulk of the 3DP experiments and projects take place during the senior year in MatS 4221 (Materials Performance) and MatS 4301 (Materials Processing). In MatS 4221, the senior MSE students design a part or assembly based on mechanical specifications and functional performance using SolidWorks, print their projects and test mechanical functioning of the projects. In Fall 2014, the students designed portable ice scrapers, taking into account the engineering properties of the 3DP materials and physical design requirements as well as the aesthetics. In Fall 2015, we made several advances in MatS 4221. First, we developed a set of two lab experiments in which students first 3D printed standard specimens, called ‘dogbones,’ using a variety of parameters, and second, characterized the mechanical properties of the specimens. See Figure 1. To analyze their mechanical property data, they used the simulation package in SolidWorks. The use of SolidWorks for simulation broadened the students’ experience with the program significantly and improved their understanding of structure-property relationships. Another existing lab experiment on failure of electrical heaters was also modified to include



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a SolidWorks simulation to predict thermal performance. An ambitious 3DP mechanical design project also took place in MatS 4221 during Fall 2015. The students first 3D printed and assembled fullyfunctioning prosthetic hands using an open source design from the e-NABLE organization. In this exercise, students learned about printing, Figure 1. Left: Photo of a 3D printed dogbone undergoing a tensile test, assembly, and the functioning Right – result from SolidWorks simulation, which shows a range of stress of the hand. Then, they were levels in color with the faint color variations in the center of the specimen challenged with creating their due to internal structure of the 3DP part. own design for a thumb-only prosthetic device. The students had to design a mechanism for motion of the thumb and the infrastructure for attachment to the existing hand structure. The design was completed in stages, allowing students to explore concepts and create prototypes. Sixteen teams of students designed, printed, and tested 16 unique designs (see Fig. 2). Given the high demand for printer time, we were happy to have purchased a second MakerBot Replicator2 with the ELI support. While the complexity of this project definitely stretched the students, they all developed functioning thumbs and more importantly they learned the concepts of design and redesign by experience. Notably, the students’ first designs were often not the size or shape that they anticipated based on their CAD files and calculations. Having the actual physical object, which is possible with 3DP, was a key part in their learning process. By making and testing the first design, they were able to see the path forward to a more functional redesign. A video synopsis of this project, created from student PowerPoint presentations, is under construction.

Figure 2. Student prosthetic thumb design projects from MatS 4221, Fall 2015.



MatS 4301 (Materials Processing) emphasizes an understanding of process fundamentals. To enable a broader understanding of 3DP, we used the ELI support to purchase a FormLabs Form1 Stereoligthography (SLA) 3D Printer. The Form1 printer (see Fig. 3) uses a laser to polymerize a liquid monomer layer-by-layer to create a 3D object. This is a different mode of printing compared to our existing fused deposition modeling (FDM) printers, which use extrusion of molten polymer to create the object. In the Spring 2016 offering of MatS 4301W, the 3DP experiment was modified to include a comparison between FDM and SLA, including an exploration of process fundamentals and an economic analysis. In the experiment, students printed Lego bricks to assess resolution

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qualitatively based on the fit of the brick to a standard board. To make the structure and resolution characterization more quantitative, we used the ELI support to add a stylus profilometer and a digital optical microscope, which the students used to measure features in their 3D printed parts. The students’ experience with the factors that influence 3DP resolution and structure is then used in a team design project. In Spring 2015, the students created unique designs, focusing on fit and aesthetics, with each student team creating a Lego brick character in a message to future MSE students (see Fig. 4). In Spring 2016, students are creating objects of significance to the field of MSE or to the University of Minnesota to be attached to a Lego board. This year’s project also challenges the students to learn a new technology – 3D scanning.

Figure 3. FormLabs Form1 Stereoligthography (SLA) 3D Printer in MSE Undergraduate Lab.

Figure 4. 3DP project from MatS 4301W, Spring 2015: “Lego Message Print Challenge”.

This academic year we also began to add 3DP experiments to the junior labs. The two junior level labs are MatS 3801 (Structure Characterization Lab) and MatS 3851W (Materials Properties Lab). These labs cover a lot of ground and are designed for students who have just started taking courses in the major. Hence we have been exploring adding activities that enhance the student experience without burdening them. In the Spring 2016 offering of MatS 3851W, we added 3D printing and mechanical property testing of 3DP dogbone specimens to an existing mechanical properties lab experiment. In this experiment, students are exposed to the 3DP process and the interesting structure-property relationships that result. The students compare materials properties for specimens made by traditional methods with those made by 3DP. Additional Impact and Future It is also worth noting that the developments in 3D printing for the MSE lab courses have had additional impacts on the students. The Material Advantage (MA) student group has been using 3D printing to make forms for creating ceramic parts. In this case, the 3DP form is used to make a gypsum mold, which is then used to create a ceramic mug. The MA team successfully fabricated a mug and competed with other MA chapters from Universities around the country in a mug drop contest, which was held at the Materials Science and Technology Conference in Columbus, OH in October 2015. Recently, our MA group has also joined forces with another student organization to provide a ceramic part for a rocket, again using 3DP in the process. In MatS 4400 (Senior Design Project), seniors in their last semester complete a ‘capstone’ engineering design project in collaboration with a mentor from a local industry. While these projects usually do not use 3D printing, instructors of MatS 4400 have noticed that student teams routinely use SolidWorks for CAD model development and simulation. As an example,



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one student team in MatS 4400 used SolidWorks to design the frequency and placement of the pneumatic vibrators in a paint tank. Lastly, discussions with seniors have provided anecdotal evidence that adding their experience with SolidWorks and 3D printing has had a positive effect on their career prospects. We look forward to continuing to develop 3D-printing-based experiments and design projects in the MSE lab classes. In 2016/2017, we will look for an opportunity to incorporate 3DP materials into MatS 3801 (Structure Characterization Lab) in a way that does not add to an already busy lab class, and to further refine the comparison between the mechanical properties of 3D printed parts with conventional polymer parts in MatS 3851W (Materials Properties Lab). In the senior lab classes, MatS 4221 (Materials Performance) and MatS 4301W (Materials Processing), existing experiments and design project approaches will be refined and also better assessed. We would like to develop questionnaires to give to students before and after MatS 4221 in Fall 2016 so that we can learn more about the impact that the project has on their learning of the design process and to help us refine the project experience. Acknowledgements We are grateful to Kim Wilcox and Mary Jetter for providing support and encouragement throughout this project and to Paul Baepler for giving ideas on project assessment. We thank Colin Holgate for developing the operating procedures for the Form1 SLA printer and the digital optical microscope, and for exploring lab experiment ideas. We also thank Robert Lade for developing the SLA portion of the 3D printing lab experiment in MatS 4301W.



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