Influence of Build Direction and Post Processes on the Material and Part Attributes of Hard Resins Fabricated by Photopolymerization Based Additive Manufacturing

This study aims to contribute to the scientific knowledge by investigating the influence of build direction and post-curing on the material and part attributes of acrylonitrile butadiene styrene (ABS-like) like resins by photopolymerization based additive manufacturing (AM). Specimens were manufactured in different build directions with the parameters that offer the highest density. Two groups of specimens, one as-built and the other post-cured, were subjected to dimensional inspections, surface characterization, fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), hardness measurements, tensile tests, bending tests, Charpy impact tests and the obtained values were reported and benchmarked. It has been observed that the change in the build direction significantly affects the surface roughness and the average surface roughness of the samples produced in the vertical plane is much higher than those produced in the horizontal plane. It was demonstrated that post-curing has a negligible effect on part dimensions and density. It increases hardness, tensile modulus and flexural modulus while reducing elongation and impact resistance. The effects of post-curing on chemical and thermal properties were also compared and it was determined that it improves the thermal stability. In the absence of post-curing, vertical as-built specimens were observed to have higher strength than their horizontal counterparts.

Keywords:
additive manufacturing; vat photopolymerization; post-curing; mechanical testing; surface roughness; thermal characterization