Quantifying Surface Morphology of Additively Manufactured Plastics
Open Access
- Author:
- Harbinson, Bevan
- Area of Honors:
- Materials Science and Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Bryan D Vogt, Thesis Supervisor
Amy Carol Robinson, Thesis Honors Advisor - Keywords:
- Additive manufacturing
- Abstract:
- The applications for the additive manufacturing of plastics are currently limited by the inferior and anisotropic mechanical properties additively manufactured materials possess compared to materials manufactured by traditional subtractive or formative methods. Improved quality assurance and testing standards are necessary to minimize the impacts of poor material properties. Optical profilometry is a promising nondestructive method to measure the surface morphology and inter- and intra-layer contact of plastics additively manufactured by material extrusion. Acrylonitrile butadiene styrene tensile specimens were printed with 0° and 90° raster angles and 0.2 mm, 0.25 mm, and 0.3 mm layer heights. Surface morphology measurements were made with focus variation microscopy and converted into amplitude spectra using fast Fourier transforms. These spectra were analyzed to identify the wavelengths present in the surface morphology. Parameters describing the height variation, noisiness, and sinusoidal nature of the surface were calculated from the spectra and correlated with tensile testing results, providing the elastic modulus, ultimate tensile strength, and elongation at break of each specimen. The ultimate tensile strength of the specimens printed with a 90° raster angle was found to correlate positively with the amplitude of the two fundamental waves (R2 = 0.929), positively with the mean absolute deviation of one of the fundamental waves across the width of the specimen (R2 = 0.785), and negatively with the total harmonic distortion away from a sinusoidal morphology (R2 = 0.604). No statistically significant correlations were found for the elastic modulus or elongation at break.