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1. 3D-Printed Laboratory Equipment for Vibrations and Control Theory Courses: Pendulum, Cantilever Beam, and Rectilinear System

   https://doi.org/10.1115/IMECE2021-69866  

   Garcia, Martin ; Estrada, Benji ; Lucier, Elizabeth ; Tekes, Coskun ; Utschig, Tris ; Tekes, Ayse ( November 2021 , ASME 2021 International Mechanical Engineering Congress and Exposition)

   Learning by doing has proven to have numerous advantages over traditionally taught courses in which the instructor teaches the topic while students remain passive learners with little engagement. Although laboratories give hands-on opportunities for undergraduate mechanical engineering students, they have to wait for a semester for the lab course for instance the prerequisite of the vibrations and control laboratory is the mechanical vibrations course. Since the nature of the dynamics branch consisted of dynamics, vibrations, and control theory courses are highly mathematical, students struggle comprehending the introduced topic and relate the theory to its real-world application area. Furthermore, it’s almost impossible for an instructor to bring the existing educational laboratory equipment to the class since they are bulky and heavy. The advents in manufacturing technology such as additive manufacturing bring us more opportunities to build complex systems new materials.

   This study presents the design, development, and implementation of low-cost, 3D printed vibratory mechanisms to be utilized in mechanical vibrations, control theory courses along with their associated laboratories. A pendulum, cantilever beam integrated with springs, and a rectilinear system consisted of two sliding carts, translational springs, and a scotch yoke mechanism are designed. The main parts of the mechanisms aremore »3D printed using polylactic acid (PLA), polyethylene terephthalate glycol (PETG), and thermoplastic polyurethane (TPU).

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2. Creating and Assessing an Upper Division Additive Manufacturing Course and Laboratory to Enhance Undergraduate Research and Innovation

   Maloney, P ; Li, B ; Zhang, M ; Cong, W. ( June 2018 , ASEE annual conference & exposition)

   This NSF IUSE project is on the Exploration and Design Tier and the Engaged Student Learning Track. It is aimed at better preparing the country’s professional workforce in the renaissance of U.S. skilled manufacturing by creating new personnel proficient in additive manufacturing (AM). AM is mainstream; it has the potential to bring jobs back to the U.S. and add to the nation’s global competitiveness. AM is the process of joining materials to make objects from 3D data in a layer upon layer fashion. The objectives are to develop, assess, revise, and disseminate an upper division course and laboratory, “Additive Manufacturing,” and to advance undergraduate and K-12 student research and creative inquiry activities as well as faculty expertise at three diverse participating universities: Texas Tech, California State Northridge, and Kansas State. This research/pedagogical team contains a mechanical engineering professor at each university to develop and teach the course, as well as a sociologist trained in K-12 outreach, course assessment, and human subjects research to accurately determine the effects on K-12 and undergraduate students. The proposed course will cover extrusion-based, liquid-based, and powder-based AM processes. For each technology, fundamentals, applications, and advances will be discussed. Students will learn solutions to AM ofmore »polymers, metals, and ceramics. Two lab projects will be built to provide hands-on experiences on a variety of state-of-the-art 3D printers. To stimulate innovation, students will design, fabricate, and measure test parts, and will perform experiments to explore process limits and tackle real world problems. They will also engage K-12 students through video demonstrations and mentorship, thus developing presentation skills. Through the project, different pedagogical techniques and assessment tools will be utilized to assess and improve engineering education at both the undergraduate and K-12 levels through varied techniques: i) undergraduate module lesson plans that are scalable to K-12 levels, ii) short informational video lessons created by undergraduates for K-12 students with accompanying in-person mentorship activities at local high schools and MakerSpaces, iii) pre- and post-test assessments of undergraduates’ and K-12 participating students’ AM knowledge, skills, and perceptions of self-efficacy, and iv) focus groups to learn about student concerns/learning challenges. We will also track students institutionally and into their early careers to learn about their use of AM technology professionally.« less
3. Creating and Assessing an Upper Division Additive Manufacturing Course and Laboratory to Enhance Undergraduate Research and Innovation

   https://doi.org/10.18260/1-2--30124  

   Maloney, Patricia A ; Li, Bingbing ; Zhang, Meng ; Cong, Weilong ( June 2018 , 2018 ASEE Annual Conference & Exposition)

   This NSF IUSE project is on the Exploration and Design Tier and the Engaged Student Learning Track. It is aimed at better preparing the country’s professional workforce in the renaissance of U.S. skilled manufacturing by creating new personnel proficient in additive manufacturing (AM). AM is mainstream; it has the potential to bring jobs back to the U.S. and add to the nation’s global competitiveness. AM is the process of joining materials to make objects from 3D data in a layer upon layer fashion. The objectives are to develop, assess, revise, and disseminate an upper division course and laboratory, “Additive Manufacturing,” and to advance undergraduate and K-12 student research and creative inquiry activities as well as faculty expertise at three diverse participating universities: Texas Tech, California State-Northridge, and Kansas State. This research/pedagogical team contains a mechanical engineering professor at each university to develop and teach the course, as well as a sociologist trained in K-12 outreach, course assessment, and human subjects research to accurately determine the effects on K-12 and undergraduate students. The proposed course will cover extrusion-based, liquid-based, and powder-based AM processes. For each technology, fundamentals, applications, and advances will be discussed. Students will learn solutions to AM of polymers,more »metals, and ceramics. Two lab projects will be built to provide hands-on experiences on a variety of state-of-the-art 3D printers. To stimulate innovation, students will design, fabricate, and measure test parts, and will perform experiments to explore process limits and tackle real world problems. They will also engage K-12 students through video demonstrations and mentorship, thus developing presentation skills. Through the project, different pedagogical techniques and assessment tools will be utilized to assess and improve engineering education at both the undergraduate and K-12 levels through varied techniques: i) undergraduate module lesson plans that are scalable to K-12 levels, ii) short informational video lessons created by undergraduates for K-12 students with accompanying in-person mentorship activities at local high schools and MakerSpaces, iii) pre- and post-test assessments of undergraduates’ and K-12 participating students’ AM knowledge, skills, and perceptions of self-efficacy, and iv) focus groups to learn about student concerns/learning challenges. We will also track students institutionally and into their early careers to learn about their use of AM technology professionally.« less
4. High-resolution stereolithography using a static liquid constrained interface

   https://doi.org/10.1038/s43246-021-00145-y  

   Bhanvadia, Aftab A. ; Farley, Richard T. ; Noh, Youngwook ; Nishida, Toshikazu ( April 2021 , Communications Materials)

   3D printing using conventional stereolithography is challenging because the polymerized layers adhere to the solid constraining interface. The mechanical separation forces lead to poor process reliability and limit the geometrical design space of the printed parts. Here, these challenges are overcome by utilizing a static inert immiscible liquid below the resin as the constraining interface. We elucidate the mechanisms that enable the static liquid to mitigate stiction in both discrete layer-by-layer and continuous layerless growth modes. The inert liquid functions as a dewetting interface during the discrete growth and as a carrier of oxygen to inhibit polymerization during the continuous growth. This method enables a wide range of process conditions, such as exposure and resin properties, which facilitates micrometer scale resolutions and dimensional accuracies above 95%. We demonstrate multi-scale microstructures with feature sizes ranging from 16 μm to thousands of micrometers and functional devices with aspect ratios greater than 50:1 without using sacrificial supports. This process can enable additive 3D microfabrication of functional devices for a variety of applications.
5. Assessing the Results of an Additive Manufacturing Course at Three Large Universities on Undergraduates and High School Students

   https://doi.org/10.18260/1-2--32475  

   Maloney, Patricia A ; Cong, Weilong ; Zhang, Meng ; Li, Bingbing ( June 2019 , 2019 ASEE Annual Conference & Exposition)

   Additive manufacturing (AM) is prevalent in academic, industrial, and layperson use for the design and creation of objects via joining materials together in a layer upon layer fashion. However, few universities have an undergraduate course dedicated to it. Thus, using NSF IUSE support [grant number redacted for review] from the Exploration and Design Tier of the Engaged Student Learning Track, this project has created and implemented such a course at three large universities: Texas Tech (a Carnegie high research productivity and Hispanic Serving Institution), Kansas State (a Carnegie high research productivity and land grant university) and California State, Northridge (the largest of all the California State campuses and highly ranked in serving underprivileged students). Our research team includes engineering professors and a sociologist trained in assessment and K-12 outreach to determine the effects of the course on the undergraduate and high school students. We are currently in year two of the three years of NSF support. The course focuses on the fundamentals of the three families of prevailing AM processes: extrusion-based, powder-based, and liquid-based, as well as learning about practical solutions to additive manufacturing of common engineering materials including polymers, metals and alloys, ceramics, and composites. It has a lecturemore »plus lab format, in that students learn the fundamentals in a classroom, but then apply and broaden their knowledge in lab projects and independent studies. Additionally, as outreach, we host field trips from local high schools during which the undergraduates give presentations about discrete AM skills, then lead the high school students through a lab project focused on those skills. This creates a pipeline of knowledge about AM for younger students as well as an opportunity for undergraduates to develop leadership and speaking skills while solidifying their knowledge. We are also in the process of uploading videos and lab projects to an online Google Classroom so that those with access to 3D printers in other areas can learn online for free. We are also self-publishing an accompanying textbook and lab manual. Beyond the course itself, one of the innovations of our project is the assessment strategy. For both undergraduates and high school students, we have been able to collect content area knowledge both before and after the class, as well as information about their attitudes towards engineering and self-efficacy beliefs. This has been particularly illuminating in regards to subgroups like women and students of color. Our research questions include: i) what is the knowledge growth about AM during this course? ii) does this differ by university? iii) does this differ by gender or race? iv) what are the best ways to make this course portable to other universities? Preliminary results indicate a statistically significant improvement in knowledge for all students. This was particularly true for women, which may indicate the promise of AM courses in decreasing the female dropout rate in engineering. Attitudes towards engineering and self-efficacy perceptions also differed after the class, but in varying ways by demographic subgroups and university. This will be explored more in the paper.« less