Fabricating Porous Structures using Robotic Hotwire Cutting

With an increasing interest in fabricating complex structures in architectural design, the concept of porosity has become a vital topic, opening up new avenues for tectonic thinking and functional demands in architecture. Porous structures typically consist of minute interstices or modular structural grids that allow fluids to pass through and are typically present on a micro scale. By adopting a biomimetic approach, which moves from the micro to the macro scale, the application of digital tools has enabled the design of functional building elements. For example, the 30 St Mary Axe tower by Foster and Partners imitates the shape and porosity of a Venus Flower Basket Sponge, resulting in enhanced endurance capabilities. Furthermore, porous structures can improve the building's thermal, light, and air circulation conditions. However, porous structures have a highly complex topology that poses a challenge for the fabrication process, and is primarily limited to 3D printing and CNC milling manufacturing approaches, with the addition of casting and chemical processes depending on the material. In this research, we propose a novel design and manufacturing approach for porous structure fabrication that uses a hot knife tool with an industrial robot to cut expanded polystyrene materials. This approach offers a faster and more efficient way to fabricate porous structures than additive or milling techniques, with an integrated design approach that enables a range of design scenarios to be explored. Additionally, our method provides hands-on experience and practical testing of a large-scale prototype.