What is field assisted additive manufacturing?

Dr. Tan Chaolin from the Singapore Institute of Manufacturing Technology, in collaboration with China University of Petroleum, Shanghai Jiao Tong University, Princeton University, University of Malta, Huazhong University of Science and Technology (Professor Zhang Haiou), University of California, Irvine, Hunan University, and EPM Consulting, published an article titled "Review on Field Assisted Metal Additive Manufacturing" in the top manufacturing journal, International Journal of Machine Tools and Manufacturing. The Singapore Institute of Manufacturing Technology, Shanghai Jiao Tong University, and Princeton University are the corresponding author units.

This' super team 'elaborates on the current progress of field assisted additive manufacturing technology, reveals the interaction mechanism between fields and deposited metal materials, summarizes the correlation between auxiliary fields, microstructures, and mechanical properties, and looks forward to research opportunities in field assisted additive manufacturing.

Overview of Various Types of Field Assisted Additive Manufacturing (FAAM) Technologies

Field assisted additive manufacturing
Additive manufacturing technology provides unprecedented design freedom and manufacturing flexibility for processing complex components. It can manufacture parts that cannot be manufactured by other processes while minimizing processing steps. Typical metal additive manufacturing processes include laser powder bed melting (LPBF), laser energy deposition (LDED), electron beam melting (EBM), and arc additive manufacturing (WAAM), each with their own metallurgical characteristics, advantages, and applicability. The construction speed of LPBF is relatively low, but it has excellent capabilities in handling complex geometric shapes, such as lattice structures, advanced tools (such as mold inserts with conformal cooling channels), customized medical implants, etc; In contrast, LDED and WAAM have lower dimensional resolution and much higher deposition rates than LPBF, making them suitable for large-scale component manufacturing. In addition, the flexibility of material feed in LDED and WAAM has increased, allowing for the deposition of multiple materials within the same layer and across layers. The flexible tool path in LDED can repair large free-form surface parts.

Field assisted typical metal additive manufacturing technology
Therefore, although these technologies have numerous advantages compared to traditional manufacturing methods, there are still some problems and bottlenecks that hinder their large-scale industrial applications. For example, materials with poor printing adaptability may have defects, resulting in larger columnar dendrites with poor anisotropic mechanical and fatigue properties. In order to address these issues and fully leverage the potential of additive manufacturing technology, new methods have been studied for customizing microstructures, innovating equipment and devices, and introducing new concepts. Field assisted additive manufacturing (FAAM) is a new approach that combines the inherent advantages of different energy fields to overcome the limitations of additive manufacturing. Typical auxiliary fields applied in additive manufacturing processes include magnetic field, acoustic field, mechanical field, and thermal field. In addition, there are some emerging technologies such as plasma field, electric field, and coupled multi field as auxiliary energy fields.

The mechanism and advantages of field assisted additive manufacturing
Professor Tan Chaolin's research team has reviewed how the current mainstream magnetic field, acoustic, mechanical, thermal, electrical, and plasma field assisted technologies affect the metal additive manufacturing process. They believe that the assisted fields can affect the convection and dynamics of the melt pool, alter the temperature distribution and thermal history during material solidification, and cause stress or plastic deformation in deposited materials; A detailed review and discussion were conducted on how auxiliary fields affect melt pool dynamics, solidification dynamics, densification behavior, microstructure and texture, mechanical properties, and fatigue performance; We also discussed the research gap and further development trends of field assisted additive manufacturing.

Schematic diagram of using magnetic field assisted additive manufacturing

Schematic diagram of using sound field assisted additive manufacturing

Schematic diagram of using thermal field assisted additive manufacturing

Schematic diagram of using mechanical deformation assisted additive manufacturing

This critical review provides researchers with complete and up-to-date information on field assisted additive manufacturing, which helps to identify the shortcomings and advantages of each field assisted technology and improve maturity and technological readiness.

Field assisted additive manufacturing is expected to have high flexibility in handling high geometric complexity components and good scalability in depositing large or small free-form components. This poses a high challenge for process and system development as it requires a uniform field distribution. The breakthrough of uniform field distribution will improve the flexibility and scalability of field assisted technology, and make its application mature and scalable.

The certification and commercialization of field assisted additive manufacturing systems is another direction of progress, as most of the current field assisted additive manufacturing equipment is experimental and lacks strict testing and certification. The laboratory stage technology may have stability and repeatability issues, which are insufficient to handle reliable industrial products. Therefore, strict system certification is required to commercialize field assisted technology. At the same time, it is necessary to develop and compile system qualification standards to guide and certify qualifications for commercial use. Reliable commercial equipment will attract more researchers to advance and implement field assisted technologies in industrial applications.

Source: AM union Additive Manufacturing Master's and PhD Alliance