Development of a proof-of-concept retro-fit system for multi-material printing in a metal LPBF system

• Main Author: Tay, Aloysius
• Other Authors: Paulo Jorge Da Silva Bartolo
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2025
• Subjects: Engineering; Additive manufacturing; LPBF; Multi-material
• Online Access: https://hdl.handle.net/10356/181917
• Institution: Nanyang Technological University

This report details the development of a retro-fit multi-material Laser Powder Bed Fusion (LPBF) system designed to enhance additive manufacturing (AM) capabilities by enabling the production of parts with multiple materials in a single layer. Current LPBF systems are generally limited to single-material applications, constraining the optimisation of mechanical properties for complex parts, while multi-material LPBF systems face challenges related to feedstock contamination. Contaminated feedstock is generally expensive to recycle, or simply cannot be recycled with current technologies. To address this limitation, a novel method was developed, using a sacrificial material masking technique to selectively deposit different metal powders while minimising feedstock cross-contamination. The proposed system builds upon an existing custom LPBF platform developed in the Singapore Centre for 3D Printing (SC3DP), which originally could only fabricate single material LPBF parts. Key challenges addressed include optimising the the sacrificial material application and ablation methodologies, and developing a repeatable and reliable workflow for fabrication of multi-material parts, starting from data preparation. Extensive testing validated the process, demonstrating the ability to manufacture parts with clear material boundaries and minimal contamination. The designed process and system accounted for the potential of functionally graded structures, which blend material properties for enhanced part performance. Initial testing with 316L stainless steel and copper confirmed the feasibility of the approach, achieving Technology Readiness Level (TRL) 4. The report concludes with recommendations for further automation of the system, including automated sacrificial material application and multi-material powder handling. Future work will focus on refining process parameters, enhancing software integration, and exploring additional material combinations. The successful development of this system sets the stage for more efficient, cost-effective, and sustainable multi-material additive manufacturing solutions.