Advances in additive manufacturing through binder jetting with fringe research technology

3D printing specialist Phase3D and collaborators from the Illinois Institute of Technology (IIT) have presented a scientific study entitled “Does Selective Shell Printing Advance Binder Jetting Additive Manufacturing?”.

This research, published in the journal Powder Technology, provides valuable insights into the microstructure and mechanical properties of binder-jetted 316L stainless steel components. The fringe research technology developed by Phase3D played a central role in capturing height maps during the binder jetting process, providing insights into the powder deposition and subsequent bonding phases.

The study compared bulk and selective pressure methods in binder jetting and the effects of different sintering atmospheres – vacuum versus hydrogen (H2). The results showed that H2-sintered samples had up to 5% lower density than vacuum-sintered parts, with a final density of 99.7%. The grain size in H2-sintered parts was smaller at about 26 µm than in vacuum-sintered parts at about 33 µm, which is due to remaining pores that inhibit grain growth. Mechanically, H2-sintered samples showed an elongation of 25% and a tensile strength of 460 MPa, while vacuum-sintered parts showed significantly higher elongation (70%) and tensile strength (550 MPa). Fracture analysis revealed that vacuum sintered samples fractured ductile, while H2 sintered parts exhibited a combination of brittle and ductile fracture.

Fringe Research technology was used to capture real-time height maps of the binder jetting process. By precisely measuring the height during powder deposition and after binding, anomalies in the process that could lead to defects in the final product could be identified. This real-time monitoring makes it possible to ensure the consistency and quality of the binder jetting process. Phase3D’s in-situ inspection systems provide objective data of each powder layer and detect process defects with a resolution of 10 µm. This data helped to visualize height anomalies and identify defects during binder-powder interactions.

The findings from this study emphasize the potential of selective shell printing in the binder jetting process. By minimizing binder consumption and accelerating the debinding process, tray printing improves efficiency and is compatible with binder-sensitive materials. The research showed that vacuum sintering in combination with selective shell printing offers better densification, reduced porosity and improved mechanical properties compared to traditional bulk printing and H2 sintering methods.

The integration of fringe research technology into the binder jetting process marks a significant advance in additive manufacturing. By precisely detecting height anomalies, Phase3D enables more accurate and error-free production of complex parts. In the future, Phase3D plans to further refine the capabilities of the Fringe Research technology and explore new applications in other additive manufacturing processes.

Overall, the study shows that selective shell printing and vacuum sintering can significantly improve the quality and performance of binder-jetted components. Phase3D is committed to continuing to push the boundaries of additive manufacturing through innovation and research to deliver world-class solutions for the industry.