Comparative study on 3D printing of glass fiber-reinforced polyamide 12 re-entrant structures by selective laser sintering and multi jet fusion

• Main Author: Mohammad Nazarul Syarafuddin Bin Zalani
• Other Authors: Zhou Kun
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Engineering; Selective laser sintering; Multi jet fusion; Glass fiber-reinforced polyamide 12; Re-entrant structure
• Online Access: https://hdl.handle.net/10356/181787
• Institution: Nanyang Technological University

In 3D printing, Selective Laser Sintering and Multi Jet Fusion are 3D printing technology within the powder bed fusion family. In powder bed fusion, printed parts are produced from the vat of powder material. The powder material is spread onto the printing bed where the uses of various energy sources are applied to promote the fusion of polymer particles into a homogenous mass. Polyamide 12 (PA12) is the most common material due to its unique combination of strength, flexibility, and environmental resilience. Incorporating filler materials have been a common method of improving the performance of the resulting printed part. This study aims to compare and evaluate the mechanical performance of SLS and MJF when used to print glass fiber-reinforced PA12 re-entrant structures, focusing on metrics such as strength and Young’s modulus. Additionally, specific strength, specific modulus and energy absorption were also considered to characterise the results. Samples are printed using both SLS and MJF in various orientations for the study, and their strength and durability are then evaluated mechanically. The parts were configured having the glass fibers aligned to the X, Y and Z axes. Parts underwent compression testing, loading the specimens in relation to the glass fiber alignment. Results show that the high localised energy used throughout the process gave SLS products a strength advantage by strengthening interlayer bonding. Because of the fusing agent, MJF parts used less energy but still had comparable structural integrity. CT scan images revealed the porosity within which led to brittleness in the SLS parts. Although SLS samples exhibited brittleness because of porosity in fiber-reinforced sections, glass fibers oriented in the Z axis produced the highest strength for both techniques.