Powder heating temperature, laser power and layer height in SLS 3D printing: impact on physical and mechanical properties of polyamide 12 parts

Abstract

Abstract : "In this paper, physical and compression properties of 3D printed polyamide 12 (PA12) cylindrical parts are evaluated, and the impact of process parameters on these properties was analyzed. Within these parameters, a novel parameter is studied, powder heating temperature before printing, in order to examine its indirect effect on 3D parts. Firstly, compression samples were prepared by selective laser sintering (SLS) with controlled variations in laser power ratio, powder heating temperature and layer height. This preparation is carried out according to ASTM D695 standard of compressive test. Secondly, mass, volume, density and porosity were measured using a precision balance, Archimedes’ principle and 3D scanning. Finally, compression tests are performed to determine compressive young’s modulus, compression strength and fracture strain. The process variables that significantly affected the physical and mechanical properties were identified using analysis of variance (ANOVA). According to ANOVA results, physical and compression qualities are largely affected by the laser power ratio, rather than by layer height or powder heating temperature. High laser power, reduced layer height, and lower powder heating temperature significantly improved density while reducing porosity. Furthermore, the optimal configuration for improving mass, volume, compressive Young’s modulus, and fracture strain is (3, 0.075 mm, 50 °C). However, the compressive strength, strain at break, and porosity of PA12 parts are all negatively affected by the following configuration: low laser power, high powder heating temperature, and medium layer height. Higher porosity, lower density, compression, Young’s modulus, and strength are the result of material degradation. This degradation is attributed to overheating of the powder associated with an elevated laser power ratio and layer height. These findings highlight the importance of precise control of powder heating temperature, laser power, and layer height to optimize characteristics evaluated for polyamide performance."