Additive Manufacturing of Shape Memory Polymers: Effects of Print Orientation and Infill Percentage on Mechanical and Shape Memory Recovery Properties

• Author / Creator

  Villacres, Jorge Fernando

• Material Extrusion Additive Manufacturing (MEAM), also known as Fused Deposition Modeling (FDM), is a manufacturing technique in which three-dimensional objects are built. These objects are built by repeatedly extruding thin layers of molten materials through a nozzle in different paths and depositing these layers until the desired object is formed. The shapes are defined by a computer aided design file. This manufacturing technique has become more user friendly and more available over the last decade, thus its uses and applications have risen exponentially. Shape Memory Polymers (SMP) are stimulus responsive materials which have the ability to recover their permanent form after being deformed to a temporary form. In order to induce its shape memory recovery, an external stimulus - such as heat - is needed. The manufacturing of SMP objects through a MEAM process has a vast potential for different applications; however, the mechanical and shape recovery properties of these objects need to be analyzed in detail before any practical application can be developed. As such, this project investigates and reports on the production and characterization of a shape memory polymer (SMP) material filament that is manufactured to print SMP objects using MEAM. To achieve consistent manufactured SMP filament, different parameters of the raw materials were analyzed and a production line for SMP filaments was established. Having a defined filament production line facilitated the manufacture of SMP filaments with consistent characteristics. Additionally, the effects of major printing parameters, such as print orientation and infill percentage, on the mechanical (elastic modulus, ultimate tensile strength and maximum strain) and shape recovery properties of MEAM-produced SMP samples were investigated and outlined. The analyzed shape recovery properties were: recovery force, recovery speed and time elapsed before activation. Results show that print angle and infill percentage do have a significant impact on the mechanical and shape recovery properties of the II manufactured test sample. For elastic modulus, ultimate tensile strength, maximum strain, shape recovery time and shape recovery force an increase in infill percentage increases their value. On the contrary, increasing infill percentage decreases shape recovery speed. Moreover, an increase in print angle decreases elastic modulus and ultimate tensile strength. In contrast, maximum strain shape recovery speed and shape recovery force increased when increasing print angle. Shape recovery time didn’t seem affected the change in print angle. Findings can significantly influence the tailored design and manufacturing of smart structures using SMP and MEAM.

• Subjects / Keywords

  • Layered manufacturing
  • Mechanical properties
  • Additive manufacturing
  • Shape memory polyurethanes
  • Smart materials
  • Fused deposition modelling

• Graduation date

  Fall 2017

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3JQ0T82J

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.