Faculty Mentored Undergraduate Scholarship Program

Taylor University's Faculty Mentored Undergraduate Scholarship (FMUS) program is designed to equip students to answer real–world problems. Students have the opportunity to apply what they have learned in courses and co-curricular experiences to their research.

 

FMUS Summer Research 2021

OCTOBER 21, 2021 · JOSIAH MCCLURG

Summer researchers Addison Johnson, John Pugsley, and Andrew Scherer collaborated with Drs. McClurg and Staritz on a next generation print head for the Martian Environment Printing System (MEPS), as a part of our Summer 2021 Faculty Mentored Summer Research (FMUS) program. Read what 3D Printing Industry has to say here.

Project Summary

Autonomous construction of habitable structures on Mars, from in–situ materials, is one of the key technologies required to realize large scale colonies on the red planet. Robots must be able to reliably build structurally sound buildings, capable of protecting humans from the harsh environment on the surface of Mars. This research sought to build on the current state of the art in additive manufacture of habitable structures for Mars by developing a second generation sulfur concrete printing head that extrudes a constant flow of sulfur concrete. This research focused on improving the power efficiency, extrudate quality, and extrusion automation when compared to prior work. In addition to this, the team sought to reduce the physical size and mass of the print head.

The effort focused on three main areas:

Power Efficiency — Power for future Mars missions will most likely be supplied by photovoltaics or RTG (Radioisotope Thermoelectric Generator) nuclear systems and will be extremely limited. This research examined several methods to improve power efficiency, including improving the thermal path to the unheated materials, improving the mixing approach to ensure more consistent heating, improving sensing to reduce overheating of materials, and improving the insulation of the system to better isolate it from the environment.

Extrudate Mechanical Composition — Building robust structures using 3d printing methods requires well mixed, consistent and continuous extrusions with minimal cracks, voids or irregularities. This is achieved by ensuring that the raw materials are dosed in the correct ratios, mixed thoroughly and extruded at a consistent rate. This research explored a continuous feed system in which the correct ratio of materials are dosed and then progress through a constrained path during which they are heated and mixed, reducing system size and improving power efficiency and mix quality.

Extrudate Thermal Control — Printing consistent, high quality, extrudate requires careful control of the temperature, extrusion rate and back pressure of the slurry. Prior work in sulfur concrete print head design relied on consistent laboratory and incoming material temperatures to ensure extrusions were consistent. This research explored methods to tightly control the temperature of the material, the extrusion rate and the back pressure applied to the slurry, reducing the power required and improving the extrudate quality.

This effort sought to complete the following objectives:

  • Design and manufacture a next generation sulfur concrete print head
  • Test the print head efficiency and print quality (homogeneity, slump, void prevalence, etc.)
  • Involve undergraduate engineering students in research and expand their education
  • Publish at least one article describing the research and findings

    • Methodology

    Organization

    The students and faculty were organized into a team and given the overall objectives and requirements of the project. The project was then divided into subsystems and those subsystems were assigned to each of the students. Responsibility for analysis, design and manufacture was given to the student in charge of the subsystem. Faculty helped guide, organize, motivate and problem solve but allowed the students to drive the interaction. In this way the students were primarily responsible for the project with support from the faculty. To encourage students to remain focused and to provide fast and frequent feedback, Dr. Staritz moved to the Senior Lab (EU228) for the duration of the summer. The project was broken into three major subsystems: Dosing System, Print Head Core, and Power & Control Electronics.

    Research

    Project work began by understanding what prior teams had accomplished or learned. Students reviewed prior designs, analyses, hardware and test results to understand what had been accomplished and how prior work had fallen short.

    Analysis, Design and Testing

    Once the students had a strong understanding of prior work, they began designing their subsystems. Students developed concepts and performed trades and analyses to determine which concept was most likely to succeed. In many cases students had open questions about the viability of various approaches. Students were encouraged to develop prototypes and tests to determine the viability and continue with the design process.

    Manufacture and Assembly

    Students were responsible for the manufacture of the designs and setups needed for testing. Students used the metalworking machines, 3d printers, laser cutter and electronics prototyping equipment to manufacture and assemble parts in–house. Only four student–designed parts required outsourcing for manufacture. Off–the–shelf components were sourced from a variety of vendors.

    Results

    The team was successful in designing, manufacturing and assembling the prototype print head. The assembled unit, shown at right, has undergone subsystem testing, successfully demonstrating the functionality of the electronics, software, extrusion, and mixing subsystems.

    The team conducted system testing, and performed the first extrusion of sulfur concrete on August 17, 2021. Subsequent tests have shown that the system can create a high quality continuous stream of slurry while consuming approximately 50%; less power than the previous print head design. This is substantially better than the team's goal of a 15% reduction.

    The results of this effort position future teams well for additional work exploring the capabilities of the print head and continuous printing of sulfur concrete.

    Mentoring/Training Students Experience

    The mentoring and training experience with our student team has been excellent.

    Teamwork & Communication

    The student team, John Pugsley, Andrew Scherer and Addison Johnson, are all in the rising senior class at Taylor and began this project knowing each other. They already had a strong set of relationships from prior work in classes. They did an excellent job working together, communicating, sharing work, and supporting one another.

    Leadership & Responsibility

    Each of the students took responsibility for their assigned subsystem. The students did an excellent job working with and leading the other students to accomplish their tasks that required collaboration. They advocated for their ideas, organized discussions and guided others through the process of helping with their responsibilities.

    Motivation

    The students were highly motivated and did a very good job of identifying, allocating and performing their tasks. When any of them encountered a delay or problem that prevented them from continuing on their assigned tasks, they sought other tasks to redeem the time.

    Skill & Performance

    Each of the students entered the project with different experiences and skill levels. Their assignments and goals were scoped to their individual readiness and skill. Each student performed their tasks well, was challenged in their assignment and improved in one or more areas. They each applied their training in a real world scenario and brought their subsystem to a functional state.

    Learning

    Each of the students showed an eagerness and ability to learn about the skills they needed to complete their work.

    Impact on Teaching / Scholarship

    FMUS research has been an excellent experience. Through this research I was able to spend dedicated time with the student team working through the details of the project. In the process I learned a number of lessons with regard to both teaching and scholarship.

    Teaching

    In the design process, engineers develop concepts and hash through them as a group to try to find the best solution to satisfy the requirements. Each concept has a champion, an individual that defends that concept. Students need to better understand this process and the preparation that goes into it so that they can take an active role championing the ideas. Students need to be comfortable defending what they believe is the right solution to the problem.

    Having access to a functional CNC mill is an incredible blessing but over the last several years the machine has remained unused. Over the summer one of our students spent several weeks learning the full CNC pipeline, from design to part. This allowed the manufacture of much more complicated parts at a much lower cost. The lessons learned and guidelines on the operation of the machine will be incorporated into the class ENP370 Machine Tool Practices starting this fall.

    Finally, we learned about the incredible value of 3d printing capability on projects. Throughout the design and testing process concepts were developed, printed and tested to evaluate viability.

    Scholarship

    This research accomplished its main goal and positioned us well for future work. The print head design is unique and a clear advance when compared to other work in the area. The team plans to submit a paper for publication on the design and its performance. The results of this work position the Junior engineering class to further explore the capability of the print head and implement additional capabilities like automatic control of heating, extrusion rate and advance rate (for backpressure). The completion of this work also opens the possibility of future experiments several areas, including 3d printed beam strength and print quality monitoring.