Effects of Post-UV-Curing on the Flexural and Absorptive Behaviour of FDM-3D-Printed Poly(lactic acid) Parts

Abstract

In this study, the effects of the post-ultraviolet-curing process on the flexural, absorptive, and morphological properties of poly(lactic acid) specimens produced using a fused deposition modelling technique 3D printer were experimentally investigated. In this direction, 15, 30, 45, and 60 min post-UV-curing processes were applied to poly(lactic acid) three-point bending and absorption specimens produced at 190 and 200 °C. Three-point bending tests and morphological analyses were applied after the post-ultraviolet-curing process, and absorption tests were applied by immersing the post-ultraviolet-cured specimens in a distilled water bath for 1-, 3-day, and 1-, 2-, and 4-week exposure times. The changes in flexural strain properties for each experimental parameter were also simulated by the computer-aided finite element analysis and compared with the experimental results. It was observed that the post-ultraviolet-curing process increased the flexural strength of the poly(lactic acid) specimens produced at both 190 and 200 °C with the same increasing trend up to 30 min of exposure, and the most significant increase was determined in the specimens that were subjected to post-ultraviolet-curing for 30 min. Although the flexural strengths of the post-ultraviolet-cured specimens were higher than the non-cured specimens in all conditions, it was detected that they tended to decrease after 30 min.

Post-Ultraviolet-Curing Process Effects on Low-Velocity Impact Response of 3D Printed Polylactic Acid Parts

“…The findings of this study are consistent with the study conducted by Hsueh et al [36], and the 60-min post-UV-curing process causes a decrease in the mechanical properties of PLA parts. In the study by Akderya [38], the effects of the post-UV-curing process applied between 15-60 minutes on the flexural and absorptive properties of PLA parts were investigated. In accordance with this study, it is seen that the mechanical properties of the specimens applied 30-min post-UV-curing have the highest value.…”

“…As a result of the emergence of the photo-oxidative degradation process with the effect of UVirradiation, an irregular, uneven, and variable adhesion success has emerged between the printing fibres. The biodegradable structure of PLA is triggered by the emergence of the photo-oxidative degradation process, and the phenomenon adversely affects the adhesion success of printing fibres that form the material structure [38,50]. In addition, the specimens exposed to the post-UV-curing process for 30 minutes have the highest peak force and energy values.…”

“…In addition, the specimens exposed to the post-UV-curing process for 30 minutes have the highest peak force and energy values. It can be said that the reason for this is that the post-UV curing process applied at certain critical times forms a stronger adhesion between the printing fibres, especially starting from the outermost surfaces of the specimens [36,38].…”

“…Studies examining the effects of post-UVcuring, one of the post-production processes, on the mechanical behaviours of the parts fabricated with the FDM technique are relatively new [36,38]. In the study conducted by Akderya [38], the 405 nm post-UV-curing process was applied to the PLA parts at different exposure times of 15, 30, 45 and 60 minutes, and then how the flexural and absorption behaviours were affected by the post-UV-curing application was investigated. In this study, the effects of post-UV-curing treatment on the impact behaviour of PLA specimens produced by the FDM technique were investigated.…”

Performance Comparisons of Machine Learning Methods of PLA-based Photochromic Material UV Sensor

“…In this study, a new method for UV light measurement was developed. In this method, 3D printable filaments, which are a product of Polylactic Acid (PLA) Photochromic materials that change color under UV light, were used [6]. Although PLA has high mechanical strength and superior thermal processability, using it pure is far from functional [7].…”