Project Director

Elliott, Trevor S.

Department Examiner

Elliott, Louie C.; Margraves, Charles

Department

Dept. of Mechanical Engineering

Publisher

University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)

Abstract

Digital fabrication laboratories have revolutionized project based learning within K-12 STEAM education curriculum. However, classroom utilization of the labs often requires excessive machine hours to accomplish, and this often leads to rapid machine depreciation and disrepair. Many educators do not have the time to repair their equipment while developing curriculum and engaging with their students. This study focuses on building a repair history for common digital fabrication equipment, which includes Prusa i3 Mk2S FDM 3D printers, laser cutters, and CNC routers. Data were collected over a 6 month period to find which machines encountered the most issues. The 3D printers were the only machines that had consistent issues, with a 15 of the 32 printers failing within their first 2000 print hours. Many printers reached 2000 hours within the 6 months, which is concerning when considering the long-term sustainability of the laboratories. The results yielded a 40% failure rate due to jamming, mostly during large-scale prints. Many of the failures suggest that there is a heating issue due to heat creep from the hotend to the heat sink. A rudimentary heat transfer analysis was run, and the results suggest that it is critical to prevent the temperature from the outside of the teflon tube from reaching 136.77oC, which would provide enough energy within 15.86 seconds to cause the PLA to reach its glass transition temperature of 65oC. This issue can be mitigated by installing an additional thermistor into the Prusa’s RAMBo 1.3a board and making a modification to the printer’s firmware that would allow for a temporary cooling process during a large print, which would increase the number of successful large-scale prints in the Prusa 3D printers. This improvement could also be translated to many small-scale FDM printers. An experimental analysis of heat transfer within the heat sink was planned, but due to equipment malfunctions, this analysis could not be performed.

Degree

B. S.; An honors thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Bachelor of Science.

Date

5-2019

Subject

Product life cycle; Equipment and supplies -- Maintenance and repair

Keyword

Additive manufacturing; Digital fabrication; Fab lab; Makerspace; 3D printing; Sustainability

Discipline

Mechanical Engineering

Document Type

Theses

Extent

41 leaves

Language

English

Rights

Under copyright.

License

http://creativecommons.org/licenses/by-nc-sa/4.0/

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