Light Distribution in 3D-Printed Thermoplastics

Daylight distribution is an essential performance parameter for building facades that aim to maximize user comfort while maintaining energy efficiency. This study investigates the feasibility of using 3D-printed thermoplastic to improve daylight distribution and transmission. To identify how geometry influences light distribution and transmission, 12 samples with various patterns were robotically fabricated. In a physical simulation of spring, summer, and winter, a robotic arm was used to direct light onto the samples in both the vertical and horizontal print pattern directions. In addition, three samples of conventional facade materials, including a polycarbonate panel, a polycarbonate sheet, and a single sheet of glass, were compared with the 3D-printed samples. All samples were examined and compared using high dynamic range imaging to qualitatively characterize luminance. The data analysis demonstrated that 3D-printed geometry can successfully generate customizable diffusive light distribution based on the needs of the user. Furthermore, the results showed that the vertical pattern direction had higher light transmission values than the horizontal pattern direction.

In-Crease: Less Concrete More Paper

Concrete is one of the most used materials after water. Largely owing to this, its environmental impact is substantial, although its embodied carbon per unit volume or mass is low when compared to most alternatives. This, along with the broad availability, good strength, durability and versatility of concrete means that it will remain a material of choice, although more efficient ways of using it must be found. Structurally optimized building components are a means to do this as they can save about 50% material. Unfortunately, however, such elements are presently too expensive to produce owing to them requiring non-standard formwork. It is an objective of digital fabrication to propose solutions to this issue. In this con-text, Digital Casting Systems (DCS) have advanced material control strategies for setting-on-demand in digital concrete processing. Thereby, the formwork pressure is reduced to a minimum, which opens possibilities of rethinking formworks as systems that are dynamically shaping, millimetre thin or weakly supporting the material cast inside. In this paper we present a brief overview of millimetre thin formworks and summarize the first realization of concrete elements that utilizes the mechanics of paper folding to make millimetre thin formworks up to 2.5 meters high. Such formworks could initially be flat packed, erected into shape, and eventually peeled-off and recycled in established material streams. This would reduce waste and transport cost, while offering a surface finish that meets the expectations for exposed concrete surfaces.

Eggshell Pavilion: a reinforced concrete structure fabricated using robotically 3D printed formwork

This paper discusses the design, fabrication, and assembly of the 'Eggshell Pavilion', a reinforced concrete structure fabricated using 3D printed thin shell formwork. Formworks for columns and slabs were printed from recycled plastic using a pellet extruder mounted to a robotic arm. The formworks were cast and demoulded, and the finished elements were assembled into a pavilion, showcasing the architectural potential of 3D printed formwork. The Eggshell Pavilion was designed and fabricated within the scope of a design studio at ETH Zurich. The structure was designed using a fully parametric design workflow that allowed for incorporating changes into the design until the fabrication. The pavilion consists of four columns and floor slabs. Each column and floor slab is reinforced with conventional reinforcing bars. Two different methods are used for casting the columns and floor slabs. The columns are cast using 'Digital casting systems', a method for the digitally controlled casting of fast-hardening concrete. Digital casting reduces the hydrostatic pressure exerted on the formwork to a minimum, thereby enabling the casting of tall structures with thin formwork. The floor slabs are cast with a commercially available concrete mix, as the pressure exerted on the formwork walls is lower than for the columns. In this research, 3D printed formwork is combined with traditional reinforcing, casting, and assembly methods, bringing the technology closer to an industrial application.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41693-023-00090-x.

Digitally fabricated ribbed concrete floor slabs: a sustainable solution for construction

The concrete used in floor slabs accounts for large greenhouse gas emissions in building construction. Solid slabs, often used today, consume much more concrete than ribbed slabs built by pioneer structural engineers like Hennebique, Arcangeli and Nervi. The first part of this paper analyses the evolution of slab systems over the last century and their carbon footprint, highlighting that ribbed slabs have been abandoned mainly for the sake of construction time and cost efficiency. However, highly material-efficient two-way ribbed slabs are essential to reduce the environmental impact of construction. Hence, the second part of this paper discusses how digital fabrication can help to tackle this challenge and presents four concrete floor systems built with digitally fabricated formwork. The digital fabrication technologies employed to produce these slab systems are digital cutting, binder-jetting, polymer extrusion and 3D concrete printing. The presented applications showcase a reduction in concrete use of approximately 50% compared to solid slabs. However, the digitally fabricated complex formworks produced were wasteful and/or labour-intensive. Further developments are required to make the digital processes sustainable and competitive by streamlining the production, using low carbon concrete mixes as well as reusing and recycling the formwork or structurally activating stay-in-place formwork.

Robotic Plaster Spraying: Crafting Surfaces with Adaptive Thin-Layer Printing

Embedded in a long tradition of craftsmanship, inside or outside building surfaces, is often treated with plaster, which plays both functional and ornamental roles. Today, plasterwork is predominantly produced through rationalized, time-, and cost-efficient processes, used for standardized building elements. These processes have also gained interest in the construction robotics field, and while such approaches target the direct automation of standardized plasterwork, they estrange themselves from the inherent qualities of this malleable material that are well known from the past. This research investigates the design potentials of robotic plaster spraying, proposing an adaptive, thin-layer vertical printing method for plasterwork that aims to introduce a digital craft through additive manufacturing. The presented work is an explorative study of a digitally controlled process that can be applied to broaden the design possibilities for the surfaces of building structures. It involves the spraying of multiple thin layers of plaster onto a vertical surface to create volumetric formations or patterns, without the use of any formwork or support structures. This article describes the experimental setup and the initial results of the data collection method involving systematic studies with physical testing, allowing to develop means to predict and visualize the complex-to-simulate material behavior, which might eventually enable to design with the plasticity of this material in a digital design tool.