Low-carbon Surface Finishing for Earth-based Additive Manufacturing
Campaign: Digital Fabrication with Additive Manufacturing – Key for Innovation in Construction
Earth is gaining traction as an alternative material for additive manufacturing in construction because of its sustainable advantages over concrete. However, the hurdles of high surface texture and the need for surface finishing pose significant barriers to large-scale commercialisation.
We aim to tackle this challenge by developing a new surface finishing method to ‘tamper’ and form a surface finish on freshly additively manufactured structures while the material is still formable. This formative process does not need additional material to create high-quality surface finishes and can be integrated during the AM process to demonstrate both ecological and economic benefits. The process is explicitly developed, but not limited to, earth-based AM processes. In contrast to concrete curing and hydration processes, which happen rapidly and are very time-sensitive, the developed AM method has a longer workability window to enable in situ surface finishing and detailing.
In particular, we will focus on developing the tampering method for finishing structures built using the Impact Printing process, an innovative AM approach developed by Gramazio Kohler Research at ETH Zurich. This method involves the rapid and precise deposition of malleable earth-based materials at high velocities, allowing a fast building method with a high surface texture. The custom AM method employs high-yield stress and dense materials, extending the material’s workability for secondary finishing processes.
Preliminary work has been performed at ETH Zurich to support the hypothesis with a prototypical end-effector. However, there are many essential upgrades, including force-based control and vision- feedback, that will enable an industry-grade surface quality. We will collaborate with Marti Engineering AG and Torson Injex to reach a higher level of automation and a greater degree of freedom to achieve finishing on walls with diverse geometric conditions. Finally, the team will demonstrate the potential of this system by building a single-storied wall.
