Robotic 3DPrinting Earth

Abstract

To cope with the climate crisis, sustainable and eco-friendly buildings are a necessity. To achieve this, we need to change the way we build, this accounts as well for construction materials. For thousands of years, humans have lived in clay and timber hybrid constructions. These hybrids are made of sustainable, possibly circular, highly available and renewable materials with low embodied energy. However, the labour-intensive production makes these hybrid constructions expensive. This was, among others, one reason why modern architecture and construction looked to other, industrial and artificial building materials to satisfy our need for cheap, fast and prefabricated construction methods. The promising, traditional combination of earth and timber has barley been used for prefabricated wall components and façades, despite their huge ecological benefits. On the contrary, questionable and polluting building technologies and materials are used to increase the efficiency within the construction sector.

As designers and engineers, we should start looking back into clay/timber hybrids as one solution architecture can offer as an answer to the climate crisis, despite the high labour cost of this construction type. Digitalisation might be a solution to tackle these high costs. Customized computational design, large-scale 3D-printing and file-to-factory robotic fabrication allow the automatization of certain labour-intensive production steps. It offers new perspectives on production techniques and material usage. The fourth industrial revolution could, in combination with changing legislation and CO2 taxation, lead to a revival of clay/timber hybrid buildings. These hybrids could be made of timber with a density decreased non-structural gradient material infill, such as 3D printed with clay.

Exploring material mixtures, production techniques and building components results in a computational, informative workflow for customized nozzles and the building component. This allows to coordinate and customise the nozzle design according to the limitations of the material properties, the building component and the 3D printing process.

But how can the density of a 3D Printed clay prefab wall component with a 6-axis robotic arm be gradually decreased? Designing a gradient material that is dense on the inside and gets increasingly lighter towards the outside could increase the efficiency by adding another function to the earthen building element. The created cavities reduce the density, the thermal conductivity and the material usage compared to a traditional solid earthen infill. To simplify the toolpath and reduce the cycle time each density class of this stepwise gradated wall system has its customized nozzle. The customization of the nozzle allows to print a complex cross-section geometry with a simplified, otherwise complex toolpath.

Establishing an informative workflow between the building component design, the production tools and the material mixture should lead to a feasible design that is considering the limitations of each input category. Ideally, this approach reduces the necessary amount of adaptations before the earthen component infill can be printed. The nozzles will be customized to reduce the cycle time and shorten the toolpath by creating a gradient material at the same time. This material can be used as an infill for a hybrid wall structure.