Effect of the printing parameters on the tensile strength and surface roughness of a photopolymer resin using dlp 3d printing

The advancement of Digital Light Processing (DLP) in 3D printing has catalysed the production of high-quality parts characterized by their high resolution and swift manufacturing turnaround. Despite its popularity, the detailed effects of specific printing parameters on material properties have not been fully outlined. This study investigated how layer height, exposure time, and bottom exposure time influence the tensile strength and surface roughness of photopolymer resin parts produced via DLP. Utilizing a Taguchi method 9v9 experimental design, the contribution of each parameter to the variance in mechanical properties were explored. The statistical analysis reveals that layer height significantly dictates the surface roughness, contributing to 52.97% of the total variance. Simultaneously, bottom exposure time and layer height substantially influence tensile strength, accounting for 29.64% and 19.00% of the variance, respectively. Exposure time, however, has a minimal impact, contributing just 1.36% to tensile strength and showing negligible effects on surface roughness. Optimization efforts identified a layer height of 0.05 mm and bottom exposure time of 15 seconds as optimal, markedly improving tensile strength and surface finish. Scanning electron microscope (SEM) analysis correlates these optimized parameters with crack morphology, offering microstructural evidence that parts printed with optimal settings demonstrate a more resistant structure to tensile forces, as indicated by the presence of rougher, more tortuous crack patterns on stronger samples. The optimal parameters serve as a benchmark for producing parts with superior mechanical strength and surface integrity, thereby fulfilling the increasing industrial demand for robust, 3D-printed components

Support-free fused deposition modelling printing for overhangs structure

Fused deposition modelling printing utilizes layer by layer printing process. The accumulation of those layers created the 3D object during the printing process. An overhang structure is defined by shapes that extend outward without direct support from a printing base. When printing an overhang structure with a fused deposition modelling 3D printer, the process generally requires support material which may need post processing to remove the support structures. The three-dimensional printing of overhang models without using supporting structures is useful in the current fused deposition modelling manufacturing because it allows to significantly reduce printing time and material usage. In this project, a procedure and algorithm for making a specific toolpath that is capable of printing overhang structures and bridges without using supports will be proposed. The algorithm was tested on three different shapes of models, and it successfully achieved the objective to 3D printed an overhangs structure without support materia