Effect of fiber length on the mechanical properties of multi jet fusion-printed glass fiber/polyamide 12 composites

• Main Author: Leong, Kah Kit
• Other Authors: Zhou Kun
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/150902
• Institution: Nanyang Technological University

Multi jet fusion (MJF), as a pioneering additive manufacturing technology with a high production rate, has been applied for various powder-based polymers. Like other 3D printing approaches, MJF also allows reinforcement via the addition of fibers. In this project, glass fibers (GF) with different average lengths are employed to increase the mechanical strength of MJF-printed polyamide 12 (PA12) composites. Results revealed that fiber lengths could influence both the printing processes and the properties of the powder as well as the printed specimens, such as the flowability of the powders, the alignment of the fibers, the porosity of the specimens, and the mechanical strength of the specimen. When the fiber length was 226 μm, the ultimate tensile strength (UTS) could be up to 68.69 MPa (22.29% higher than the pure PA12) and the maximum tensile modulus could be up to 5.84 GPa (141.32% higher than the pure PA12). To the best of our knowledge, the GF/PA12 specimens fabricated in our experiments exhibited better mechanical performance over all the ever-reported MJF- and selective laser sintering (SLS)-printed glass bead/PA12 and GF/PA12 composites. Moreover, both the UTS and tensile strength were comparable to the carbon fiber/PA12 specimens fabricated via SLS, which previously was a technique that was able to produce specimens with better mechanical properties. This work can also serve as a guide for researchers to fabricate other fiber-reinforced polymers by MJF.