Development of volumetric additive manufacturing technology and the capability assessment of post processing methods

Abstract

ract newlineThe layering approach and serial repeating procedures result in inferior mechanical and surface characteristics of the 3D printed objects, anisotropy and long duration. In this thesis, a novel 3D printer able to volumetrically fabricate objects within a spinning container is developed. Centimeter scale 3D models are manufactured within seconds using less viscous commercially available Anycubic Eco UV resin through tomographic reconstruction. The dimensional changes of fabricated 3D geometries from the CAD model are less than 5%. The volumetric 3D printer produced a cylinder of 1 cm height and diameter in 30 seconds, whereas FFF and SLA 3D printing technologies required 54 and 46 minutes, respectively. The effect of post-curing time and temperature on the ultimate tensile strength of Phrozen resins is investigated. Beige resin resulted in a 46.62% boost, whereas Aqua-Gray showed a 78.63% increase in the tensile strength values after UV curing using a pre-heated chamber at their respective heat deflection temperatures. Thermal annealing as a post-processing method to boost the mechanical properties of the fused filament fabricated thermoplastics is also studied. Annealing PLA samples at 95°C for 1 hour resulted in a maximum tensile strength of 38.27 MPa, representing a 23.02% increase. Similarly, annealing PLA-CF samples at 95°C for 2 hours resulted in an ultimate tensile strength of 42.49 MPa, representing a 14.01% increase. The crystallinity index of PLA increased from 3.91% to 28.7%, whereas PLA-CF increased from 5.93% to 30.86% after the annealing process. The ultimate tensile strength of PC-ABS increased by 20.39%, from 32.39 MPa to 38.99 MPa after annealing at 180°C for 1 hour. XRD analysis of annealed models revealed a maximum crystallinity index of 32.56%, compared to 6.58% for non-annealed samples. newline