06.11.2024

Prōtóplasto: Ultra-Lightweight Plastic

NCCR DFAB researchers have developed a novel process for 3D printing with hollow cores (HC3DP). This method is especially useful for building facades as the hollow cores strengthen designs and improve insulation and soundproofing. HC3DP opens up exciting new possibilities for 3D-printed architecture - but what distinguishes Prōtóplasto from previous 3DP plastics in architecture? Marirena Kladeftira and Matthias Leschok present the innovative process.

HC3DP was initially developed during the doctoral research of Matthias Leschok. He was a researcher of the chair for Digital Building Technologies and looked into the application of 3D printed facades due to its superior performance in regards to structure, thermal, and acoustic properties.

Marirena Kladeftira and Matthias Leschok, where does the inspiration for Prōtóplasto come from?

The inspiration for Prōtóplasto derives from the Greek word “πρωτόπλαστος”, meaning "the first formed." This installation was conceived as an experimental platform for us, as researchers, to integrate two distinct 3D printing techniques and explore an innovative tectonic system. By merging the pioneering hollow-core 3D printing with a modular space frame system facilitated by 3D printed joints, our goal was to push the limits of ultralight construction through digital fabrication technologies. This approach enabled us to create ultra-lightweight, self-interlocking components that showcase new architectural possibilities with a mindful use of resources.

With Prōtóplasto we also wanted to provoke a new dialogue about the use of plastics in architecture, particularly given how plastics have been vilified in recent years. By leveraging new technologies, we want to show that plastic can become an efficient and circular material that can help in containing the current resource depletion.

The material is directly extruded hollow during the printing process. Picture: Girts Apskalns

Matthias Leschok, what possibilities does the innovative process of 3D printing with hollow cores offer?

HC3DP offers multiple advantages over traditional large-scale polymer extrusion processes. The key innovation is the ability to 3D print tubular, hollow beads rather than solid ones, using widely available granular materials. This approach not only saves material but also increases production speed. Depending on the printed geometry, HC3DP can reduce material consumption by up to 80% while maintaining structural integrity.

HC3DP improves current 3D printing by allowing the same designs to be printed with less material when used at a high resolution (6mm). It can also be used for larger projects by printing with a wider width (over 20mm). These upgrades make HC3DP useful for more than just standard plastic 3D printing. For instance, HC3DP can be employed in the creation of lightweight installations, furniture, formwork for concrete, and, due to its high thermal insulation properties, it is very well suited for the manufacturing of building envelopes.

A customised nozzle and the introduction of positive air pressure were used for the printing. Picture: Matthias Leschok

Where do you fit in with Prōtóplasto 3DP plastics in architecture? Is there anything comparable?

Prōtóplasto is a new, experimental system using HC3DP technology to 3D print large, strong building parts. The printed lines have hollow cores. This allows for quick printing of big polymer structures —in one test, we printed a 2.2-meter-high piece in under 5 hours, which no other technology can match.

Unlike traditional 3D printing, which isn’t ideal for wide roofs or slabs, Prōtóplasto creates lightweight, strong structures that are easy to assemble and use less material. Instead of metal, which takes a lot of energy to produce, Prōtóplasto uses plastics and bioplastics, opening up new possibilities for recycling and sustainable design. We also wanted to revisit the idea of all-plastic architecture, inspired by the creative, forward-thinking plastic buildings of the 1960s and 70s.

Prōtóplasto was exhibited as a media installation at the ‘Futurama’ innovation centre in Aargau, Switzerland.
Picture: Nijat Mahamaliyev

You have collaborated with participants from the MAS ETH DFAB and created parts for an exhibition in an industrial underground last year. What was the response the pieces exhibited from the crowd?

The response to the exhibition was overwhelmingly positive, particularly for both the surrounding light installation and the free-spanning structure. Attendees were intrigued by the translucent nature of the columns and the filigree cantilevering roof and were eager to understand the technical aspects and opportunities of the system.

Working with the MAS students was also particularly rewarding for both sides. The students were introduced to the new technologies, a different way of thinking about architecture and how to design for new production media, but they also had the space to critically explore their opportunities and limitations in collaboration with us.

In the end, the industrial space provided by Halter AG created a unique atmosphere that really uplifted the experience of our installation. It allowed us to fully explore the interplay between light and material. The pieces feature an unprecedented aesthetic that caught the attention of the crowd. Our work was recently featured at the Fabricate Conference, which showcases only the most relevant and cutting-edge projects in the field of digital fabrication. This recognition highlighted the forward-thinking nature of our approach and the technical achievements behind it.

The spatial frame is being assembled for the exhibition. Picture: Girts Apskalns

Marirena Kladeftira, your research is focused on a new framework for bespoke space frames based on 3D printing. What challenges did you encounter during the design and assembly of the support-free space frames using 3D printed joints?

Space frames are highly efficient structural systems, but existing products typically cater to canonical forms with repeatable modules. Our challenge was to create tailored systems that adapt to specific forms and materials, allowing for greater experimentation, new formal languages, and more efficient construction. This is where 3D printing plays a crucial role. The joints, which determine the system's form and assembly scheme, significantly influence the structure's weight and cost.

Designing Prōtóplasto's roof system was particularly challenging because we aspired to develop a modular radial space frame with varying form that self-interlocks during assembly simply with gravity. This involved creating multiple connector topologies and addressing topologically complex joints due to this modularity, constrained assembly, and the transition from a double-layer to a single-layer space frame inorder to minimise weight and enhance cantilever performance.

How did you overcome them?

To overcome these challenges, we developed a custom computational tool that integrates these parameters founded on my doctoral research. This tool categorised joints based on their position in the structure, the chosen modular scheme, and the required assembly sequence. It enabled us to assign specific geometric details and properties to each joint thanks to the implicit modelling approach I presented in my PHD thesis, resulting in a fully tailored structural system.

3D printing was essential for materialising these components. To be mindful of resource usage and costs, we designed each component to add only the minimum necessary volume to achieve its functionality. Although some joints may appear simple at first glance, their complexity lies in the intricate combination of details within the entire system, rather than in their individual form or aesthetic.

What new perspective does this lightweight plastic bring?

Plastic was originally seen as a way to create lightweight, translucent, and large structures. But today’s large-scale 3D printing often produces heavy, opaque forms. This no longer matches that original vision. Now, with sustainability in focus, material-heavy plastic structures are impractical. Our project, Prōtóplasto, takes a new approach. It’s ultra-lightweight at just 3.8 kg/m². This shows how plastic 3D printing can be efficient and sustainable. We believe there is huge potential for lightweight construction that uses less material but still meets safety standards.

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Prōtóplasto: Ultra-Lightweight Plastic