Obayashi Group: 'Branching Out' with WAAM Metal 3D Printing for Artistic Steel Structure
Japanese construction giant Obayashi Group recently unveiled its latest exploratory achievement—a 3-meter-tall metal 3D-printed installation named "the brænch"—at its Tokyo Technology Research Institute. This is not merely an art piece but a cutting-edge practice of construction-scale Wire Arc Additive Manufacturing (WAAM) technology.
"The brænch" continues its path of exploration. In 2023, Obayashi created Japan's first earthquake-resistant 3D-printed cement building, the "3dpod." This time, a cross-disciplinary team shifted focus to tackle metal 3D printing, aiming to master WAAM as a core competency. This technology offers great promise for the construction industry due to its high deposition rates, lower costs, and capability to handle large-scale components.
The project confronted a core challenge: when applying WAAM to construction-grade carbon steel, issues like slag formation and precision control arise. Obayashi's solution was to develop a proprietary metal 3D printer. By optimizing materials and welding parameters, they successfully achieved stable, high-precision, slag-free deposition, producing components with excellent mechanical properties.
The design process is particularly innovative. The team developed a semi-automated generative design system. This system can automatically generate structurally sound and directly printable path networks from thousands of possibilities that meet WAAM process constraints (such as maximum overhang angle), while also optimizing load distribution.
Finally, the entire structure was divided into 30 unique WAAM-printed components, combined with hollow steel tubes to maximize strength and minimize material usage. On-site assembly utilized Augmented Reality guidance for precise welding. The decorative parasols atop the structure were produced from recycled polycarbonate via robotic-arm FDM printing.
Through this project, Obayashi has validated the immense potential of WAAM for creating complex, high-performance metal architectural elements. The company plans to continue advancing this process to meet the construction industry's growing demand for customizable, high-performance metal components.
