Post Finishing Techniques to Improve the Functionality of 3D Printed Parts

• Author / Creator

  Salata, Gabriel B. P.

• Generating functional parts using additive manufacturing (AM) has many challenges. These can be material- and/or process-based. This is especially true when the produced part is required to withstand or be sealed for pressure due to the potential air gaps inherent to AM processes that generate weak points within the geometry. Also, due to the manufacturing process, 3D printed parts have an anisotropic behavior, therefore having weaker mechanical properties when compared to regular materials, such as metals. This study aims to investigate and understand how to make 3D printed parts more functional when it comes to sealing applications and whenever better mechanical properties are required.
  The sealing performance will be investigated by understanding the effect of coating on a 3D printed acrylonitrile butadiene styrene (ABS) cylinder and compare its capacity to withstand pressure among three different samples: non-coated (raw), epoxy coated; and spray painted 3D printed ABS cylinders. A unique test procedure has been developed to monitor pressure within the cylinder over an extended period. Preliminary tests were undertaken by using a custom-built pressure vessel designed to fit the cylinder samples while minimizing all the loads other than the prescribed internal pressure. Pressure withstanding capacities of the samples were compared. The results showed that the samples coated with epoxy had improved sealing performance, followed by the spray painted ones. The raw 3D printed ABS samples had the least sealing performance.
  The idea of improving the mechanical properties of a 3D printed part was done by applying the concept of post tensioning technique to samples printed in different orientations, where a metal rod would be added as a reinforcement to the part. To better understand the effect of the reinforcement to the 3D printed parts, tensile and 3-point bending tests were done. There were three different types of reinforced samples for the tensile tests, including 1, 3, and 5 turn, while only two reinforced samples were tested on the 3-point bending, the 3, and 5 turn samples. The different reinforced samples indicated the different amount of compressive load applied into the 3D printed sample. The results, for the tensile test, showed an improvement on both elastic modulus and tensile strength. The elastic modulus had an improvement of 58%, and 48% for the longitudinal, and z-direction samples, respectively, when comparing the raw to the 5 turn samples. The tensile strength had an improvement of 70%, and 97%, for the longitudinal, and z-direction samples, respectively, when comparing the same group of samples. The bending tests showed that when adding reinforcement to the neutral axis, it does not effect on the flexural modulus of the part. However, an improvement of 14%, and 12% could be seen on the flexural strength, for the longitudinal and z-direction samples, when comparing the raw to the 5 turn samples.

• Subjects / Keywords

  • Post processing techniques
  • 3D printing
  • Mechanical Properties
  • Sealing performance

• Graduation date

  Fall 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-ybpz-a621

• License

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