Towards the Design and Manufacturing of Products Using Large-Scale FFF Printers

  • Author / Creator
    Alberti, Devin
  • In this thesis, the challenges involved with large-scale Fused Filament Fabrication (FFF) 3-dimensional (3D) printing is explored through an industrial application in which a cantilever chair is produced as a case study. The chair is designed in SOLIDWORKS® in which easy variability and complex geometry are emphasized to take advantage of 3D printing’s ability for mass customization and economic complexity. The ability to move the process towards creating fully sustainable, recyclable, and biodegradable products is also demonstrated through the use of PLA filament as the 3D print material. The cantilever chair’s mass is reduced using SOLIDWORKS’ finite element analysis tool in which the inclusion of a brace addition was chosen for production due to its reduced material consumption and avoidance of fatigue failure complications. The characteristics of large-scale FFF 3D printers and their connection with slicer settings are also discussed. The poor adhesion performance caused by thermal gradients on the large glass build surface are improved through forced cooling fan profiles and adhesion additions. Significant oozing and diminished feed rate to flow rate responsiveness caused by large heat chambers within large-scale hotends are improved through retraction, travel movement, flow rate, and acceleration settings. Dimensional inaccuracies caused by large translating masses are considered with respect to accelerations, print speed, frame rigidity, and mechanical clearances. After these slicer settings were refined within Simplify3D for a 3DP 300 printer equipped with HFE 300 hotends, the chair was successfully produced. During production, several issues arise including inadequate adhesion, significant warping, and filament degradation. Economic and easily appliable solutions are tested to determine an adhesive substance that would both increase PLA-glass adhesion while at operating print temperatures and reduce adhesion when cooled to ambient room temperature. Of the substances tested, a sugar/ water solution is determined superior in both circumstances compared to a salt/water solution, hairspray, and bare glass. An enclosure is then designed and built to reduce warping by increasing ambient print temperatures and reducing thermal gradients caused by drafts and ambient room temperature fluctuations. Considerations such as future modification, build surface access, and printer access are implemented into its design. Lastly, a filament storage solution is presented to halt filament degradation through the use of desiccant and an airtight pet food container to provide a steady low-humid environment. Complications arouse during the COVID-19 pandemic in which testing of the enclosure and filament storage were not completed. Furthermore, the effects print scale, print parameters, and print material have on mechanical, visual, and economic-based optimization are reviewed from sources using desktop-scale FFF printers. The flow rate limitations of hotends and nozzle diameters, and the relationship between nozzle diameters, extrusion widths, and layer heights are discussed. The geometrical effects of the extrusion width to nozzle diameter and extrusion width to layer height ratios are illustrated and the effect the extrusion width to layer height ratio has on a print’s mechanical properties are reviewed. An equation arelating volumetric flow rate to nozzle diameter, print speed, extrusion width to nozzle diameter ratio, and extrusion width to layer height ratio is then created and used to present optimal volumetric flow rate combinations of varying nozzle diameters, extrusion width to layer height ratios, and print speeds for 3D Platform’s HFE 300 hotend. These combinations are then applied to the braced-cantilever chair case study by observing Simplify3D’s estimated print time and material consumption. From this, it is discovered that larger nozzle sizes could result in significant increases in material consumption and print time due to print parameter settings and print geometry. The affect print parameters have on the mechanical properties of FFF objects are further reviewed with regards to infill density, infill geometry, nozzle temperature, and cooling parameters. From this review, it is revealed that forced cooling and low nozzle temperatures typically effects the mechanical properties of prints negatively through diminished layer bonding. Lastly, the effect of print material color, print post-processing treatments, and wood-based inclusions are reviewed. Significant discoveries include the superior bonding ability of natural PLA, the post-processing radiation treatment to reduce anisotropic tensile strength behavior, and the use of cellulose nanofibers to increase PLA’s tensile strength and elastic modulus.

  • Subjects / Keywords
  • Graduation date
    Fall 2020
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
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