Optimizing the creep response of Additive-manufactured polyethylene terephthalate glycol (PETG) using the Taguchi design of experiment method
Auri, Benjamin (2025)
Auri, Benjamin
2025
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https://urn.fi/URN:NBN:fi:amk-202501221809
https://urn.fi/URN:NBN:fi:amk-202501221809
Tiivistelmä
This thesis investigates the influence of 3D printing parameters on the creep response of Polyethylene Terephthalate Glycol (PETG). The tensile test specimens were designed according to ISO 527-1 and manufactured by Fused Filament Fabrication (FFF). Printing
parameters that are analysed are, infill geometry: cubic, gyroid, tri hexagonal. Infill orientation: 90, -45/45, 0 °. Infill density: 80, 50, 20 % with nozzle temperatures: 250, 235, 220 °C. The Taguchi method was used for the experimental design and testing. After testing, the Signal-to-Noise ratio (SNR) was calculated for each factor. Moreover, the sum of squares (SS) is calculated for each level and factor and an Analysis of Variance (ANOVA) is conducted for determining if the factors and levels are statistically significant. In addition, the creep modulus is calculated and plotted. The results reveal a clear trend of infill density having the largest impact on the creep response of the material, followed by infill geometry and nozzle temperature. The strongest samples, 8 and 6, having 80% infill density with creep modulus values between 1150 MPa-1300 MPa. The weakest samples, 5 and 3, having infill densities of 20% with creep modulus between 690 MPa - 710 MPa. The ANOVA analysis provided a % contribution that each factor had on the creep response. Factor A (infill geometry) had a contribution of 9.7%, factor C (infill density) with a contribution of 85.6% and factor D (nozzle temperature) with a contribution of 4.4%. Factor B (infill orientation) was used as an error term for calculating the f-value and p-values — factor B was considered to have a negligible effect on the creep response. Lastly, the SNR provided the printing parameters which yield the optimal creep behaviour. The printing parameters that yield the best creep response are infill density of 80%, infill geometry cubic, infill orientation of -45/45° and with a nozzle temperature of 235 °C.
parameters that are analysed are, infill geometry: cubic, gyroid, tri hexagonal. Infill orientation: 90, -45/45, 0 °. Infill density: 80, 50, 20 % with nozzle temperatures: 250, 235, 220 °C. The Taguchi method was used for the experimental design and testing. After testing, the Signal-to-Noise ratio (SNR) was calculated for each factor. Moreover, the sum of squares (SS) is calculated for each level and factor and an Analysis of Variance (ANOVA) is conducted for determining if the factors and levels are statistically significant. In addition, the creep modulus is calculated and plotted. The results reveal a clear trend of infill density having the largest impact on the creep response of the material, followed by infill geometry and nozzle temperature. The strongest samples, 8 and 6, having 80% infill density with creep modulus values between 1150 MPa-1300 MPa. The weakest samples, 5 and 3, having infill densities of 20% with creep modulus between 690 MPa - 710 MPa. The ANOVA analysis provided a % contribution that each factor had on the creep response. Factor A (infill geometry) had a contribution of 9.7%, factor C (infill density) with a contribution of 85.6% and factor D (nozzle temperature) with a contribution of 4.4%. Factor B (infill orientation) was used as an error term for calculating the f-value and p-values — factor B was considered to have a negligible effect on the creep response. Lastly, the SNR provided the printing parameters which yield the optimal creep behaviour. The printing parameters that yield the best creep response are infill density of 80%, infill geometry cubic, infill orientation of -45/45° and with a nozzle temperature of 235 °C.