Publication Date
2025
Document Type
Thesis
Committee Members
Ahsan Mian, Ph.D. (Advisor); Sheng Li, Ph.D. (Committee Member); Daniel Young, Ph.D. (Committee Member)
Degree Name
Master of Science in Mechanical Engineering (MSME)
Abstract
Polyamide-12 (aka PA12) is a synthetic thermoplastic polymer that has been used in various applications, including the electronic and electrical, oil and gas industrial manufacturing and automotive industry. There are several ways to manufacture parts with PA12 and PA12 based composites. Injection molding, a traditional manufacturing process, has been the standard manufacturing route for polymers for a long time. Recently, however, additive manufacturing (AM) processes, such as powder bed fusion (PBF) and material extrusion (ME) have been introduced. PBF is a manufacturing process characterized by the selective sintering of successive layers of powdered material. It is the most effective AM process to fabricate PA12 and glass fiber composite (PA12GF) parts and the most effective manufacturing method to fabricate complex PA12 parts. This process is free of limitations such as the need for support material or proper flow of molten material over a significant distance. These conditions enable orientation of parts at any angle in the build area, significantly expanding the possibilities for part production. This study will investigate the effect of three processing and environmental conditions such as build orientation, heat treatment and moisture level on mechanical properties of the printed materials. Due to the successive layer-based manufacturing method of PBF, the build orientation of a part has a direct influence on the part’s properties. The more obvious properties include the mechanical performance (tensile strength) and the roughness with respect to the laser position. In addition, other physical properties that may be affected by the build orientation include the relative density and dimensional accuracy of the parts. The five orientations that will be investigated are vertical (V), horizontal 1 (H1), horizontal 2 (H2), diagonal 1 (D1), and diagonal 2 (D2). The next factor to be investigated is heat treatment that is a commonly used post-processing technique to improve the mechanical properties of a part. The effect of heat treatment on surface roughness, dimensional accuracy and relative density will be investigated as well. Finally, the effect of moisture on the mechanical performance of parts will be studied. Unlike the other factors investigated in this study, moisture is an environmental factor. To perform this study, the ASTM (American Society for Testing and Materials) D638 Type 4 standard tensile samples will be fabricated using the Formlabs Fuse 1 printer in the various build orientations. The dimensional accuracy of these specimens will be inspected using the Mitutoyo vision measurement system, the roughness will be inspected by the Keyence VR6000 inspection system and the tensile tests will be performed by an Instron tensile tester. The goal of this study is to determine the best build orientation and conditions to optimize mechanical properties, dimensional stability and surface roughness of parts fabricated using PBF.
Page Count
86
Department or Program
Department of Mechanical and Materials Engineering
Year Degree Awarded
2025
Copyright
Copyright 2025, all rights reserved. My ETD will be available under the "Fair Use" terms of copyright law.
