Throughout the evolution of manufacturing, technological innovation has consistently driven leaps in productivity. AFSD, also known as Additive Friction Stir Deposition, is an emerging metal 3D printing technology that is revolutionizing manufacturing in sectors such as aerospace, automotive, and medical devices through its unique advantages.

AFSD enables material processing in a solid-state condition, effectively avoiding defects that may arise during melting and ensuring superior mechanical properties of the material. Furthermore, AFSD features low energy consumption and minimal material waste, aligning with contemporary societal demands for environmental protection and sustainable development. Through solid-state processing, this technology achieves efficient material utilization and significantly enhances component performance, opening new possibilities for manufacturing complex structures.

At the Fourth Aerospace Conference, multiple AFSD-printed components exhibited by Aerospace Engineering Equipment (Suzhou) Co., Ltd. (AEE) were on display. Research indicates that this technology was virtually nonexistent domestically just a few years ago. Today, however, multiple domestic entities are actively conducting related research and have even developed relevant technical equipment. Examples include: - Tianjin University Solid-Phase Friction Extrusion Additive Manufacturing Technology Team - Shaanxi Zhituo Solid State Additive Manufacturing Technology Co., Ltd.

AFSD Overview

AFSD is an innovative manufacturing process that builds complex three-dimensional structures by layering metal materials through slicing and diffusion welding at temperatures below the material's melting point. Unlike traditional fused additive manufacturing, this technology avoids melting and recrystallization, thereby enhancing the material's mechanical properties and density. The core of this technology involves heating and rotating a solid feed rod (printing material) while advancing it downward. When the feed rod contacts the underlying substrate, it adheres through friction. Friction heat then raises the material's temperature to induce plastic deformation without melting. A stirring tool uniformly mixes the heated material, ultimately depositing it to form the target shape.

Patented MELD Solid-State Process, Photo courtesy of MELD

Previously, we provided a systematic introduction to Additive Friction Stir Deposition (AFSD) developed by the international company MELD Manufacturing: AFSD, ten times faster than SLM, with MELD Manufacturing collaborating with universities to advance new technology research. Compared to mainstream laser, electron beam, and arc-based additive manufacturing technologies, the Additive Friction Stir Deposition (AFSD) process offers the following advantages: Low Heat-Affected Zone: Since materials are processed in the solid state, the heat-affected zone is minimized. This effectively reduces material deformation and microstructural changes, enabling the production of metal components free of solidification defects, fully dense, with low residual stresses, and excellent mechanical properties.

• Superior mechanical properties: The strength and toughness of the material after forming typically surpass those of materials produced by traditional fused deposition modeling;
• Wide material applicability: Suitable for various metals including aluminum, magnesium, and copper, expanding application domains;
• Efficient and sustainable manufacturing: Additive deposition speeds are several times faster, with an environmentally friendly process and high production efficiency;
• Open working environment: Requires no protective gas or expensive vacuum systems, enabling printing of oversized metal parts.

AFSD finds extensive application across multiple industries, including aerospace, automotive manufacturing, and tooling production. In aerospace, this technology enables the fabrication of high-strength, high-reliability structural components that meet the demands of extreme environments. Within the automotive sector, its use effectively reduces weight and enhances fuel efficiency while maintaining structural integrity.

Progress of AFSD in China

Several years ago, AFSD technology was virtually nonexistent in China, with only the U.S.-based MELD Manufacturing conducting related research. However, multiple domestic institutions have now successfully developed this technology.

The Additive Friction Stir Deposition (AFSD) equipment jointly developed by AEE and the Institute for the Development and Quality, Macau, is China's first research-grade device, marking a major breakthrough in this field. Featuring a bridge-type structure, the equipment supports both conventional mechanical toolholders and the “Smart Tool Holder” with data acquisition and intelligent closed-loop control capabilities. Using 10mm alloy rods as raw material, it enables lightweight alloy surface modification, coating preparation, and new material development through Additive Friction Stir Deposition (AFSD). This technology facilitates solid-state manufacturing of non-ferrous metals, ferrous metals, heterogeneous alloys, and high-temperature alloys. The equipment has been successfully delivered to the University of Science and Technology Beijing for use in fundamental research and cutting-edge technological exploration within relevant laboratories.

As a nationally recognized “Specialized, Refined, Unique, and Innovative” Small Giant Enterprise, AEE possesses significant technological and service advantages in the field of Additive Friction Stir Deposition (AFSD). Collaborating with the IDQ team, the company has undertaken joint research to deliver customized solutions tailored to client requirements. It has secured over thirty shared intellectual property patents for Additive Friction Stir Deposition (AFSD) and published more than ten SCI-indexed papers. These accomplishments not only advance the development of intelligent manufacturing process equipment domestically but also secure China's position within the global Additive Friction Stir Deposition (AFSD) technology landscape.

In addition to Aerospace Engineering Equipment (Suzhou) Co., Ltd., several domestic institutions are conducting in-depth research and development on Additive Friction Stir Deposition (AFSD) technology. Among them, the Tianjin University Solid-Phase Friction Extrusion Additive Manufacturing Technology Team stands as a pioneer in solid-state friction metal additive manufacturing processes within China: Tianjin University has successfully developed Additive Friction Stir Deposition (AFSD) manufacturing technology and equipment. The team comprises a high-caliber R&D group led by professors and supported by doctoral and master's students, dedicated to advancing the Additive Friction Stir Deposition (AFSD) manufacturing process and providing related premium technical services. The research team continuously optimizes process parameters to enhance material properties and printing efficiency. They independently developed China's first continuous rod-feeding Additive Friction Stir Deposition (AFSD) manufacturing equipment, having fully mastered the core AFSD manufacturing processes for large-scale structural components made from various aluminum and magnesium alloys. This technology is currently in the industrialization phase. The core value of the product lies in overcoming the limitations of current mainstream metal additive manufacturing technologies, which struggle to produce large-scale (meter-scale), high-performance, and high-load-bearing additive structures. This breakthrough particularly paves new pathways for the additive manufacturing of aluminum and magnesium alloy structural components.

Additive Friction Stir Deposition (AFSD) Manufacturing Equipment and Test Work Platform-------(2020)

Shaanxi Zhituo Solid State Additive Manufacturing Technology Co., Ltd. is also an active participant in AFSD, focusing on the practical application and market promotion of the technology: Exposure: Additive Friction Stir Deposition (AFSD) Manufacturing Technology, Shaanxi Zhituo Solid State Additive Manufacturing Technology Co., Ltd. 1200-ton capacity. The company's Additive Friction Stir Deposition (AFSD) manufacturing technology builds complex three-dimensional structures by layered slicing and diffusion welding of metal materials. Its technical principle involves solid-state welding at temperatures below the material's melting point, eliminating the melting and recrystallization process to enhance mechanical properties and material density. Shaanxi Zhituo Solid State Additive Manufacturing Technology Co., Ltd. holds a competitive edge in rapid prototyping through material diversity and cost-effectiveness, demonstrating particularly high cost efficiency in small-batch production and complex product manufacturing. Currently, the company is accelerating the commercialization of AFSD technology through collaborations with multiple research institutions, contributing significantly to the rapid development of related domestic industries.

Conclusion

AFSD is emerging as a key technology in aerospace manufacturing due to its unique advantages. From the successful implementation at Aerospace Engineering Equipment (Suzhou) Co., Ltd. to the active exploration by institutions such as Tianjin University and Shaanxi Zhituo Solid State Additive Manufacturing Technology Co., Ltd., domestic research in this field is flourishing. With increasing research and technological innovation from domestic enterprises and research institutions, the application scope of this technology is expected to expand further. It will play a significant role not only in aerospace but also across multiple industries including automotive and medical. In the future, as the technology matures and its applications broaden, AFSD holds the potential to bring revolutionary changes to global manufacturing.