Inventions ยท Feature
Complex concrete components need not only a good design but also a mould that can be manufactured. The ETH project FoamWork investigates robotically printed mineral foam as formwork. The invention therefore addresses the stage before the actual casting. A documented slab prototype demonstrates the principle without yet providing a universally approved construction method for arbitrary buildings.
The real invention lies in the negative mould
Concrete can take on very different shapes, but its formwork is often complex to produce. Particularly with branching ribs or varying cross-sections, the desired geometry must first be made into a mould capable of withstanding the casting process. FoamWork shifts this step into a robotic printing process. A team at ETH Zurich developed the approach using mineral foams investigated jointly with the company FenX. The printed elements deliberately occupy those areas of the eventual component that are not to be filled with concrete. This makes it possible to create a complex internal structure without conventionally assembling every recess from individual panels. Depending on the configuration under investigation, the foam parts can remain in the component or serve as temporary formwork. The two variants place different demands on materials and processing.
A slab makes the process visible
The publicly documented demonstrator is a ribbed slab measuring approximately two by 1.3 metres. Its rib pattern follows the principal stress directions derived from its structural behaviour. To manufacture it, 24 foam elements in twelve different shapes were printed and arranged by hand within outer timber formwork. It was then cast using ultra-high-strength fibre-reinforced concrete. This sequence shows an important difference from simplistic images of fully automated construction: here, the robot prints neither the finished building nor the entire concrete slab directly. It manufactures specially shaped elements as part of a combined process. Design, foam printing, manual assembly, casting and curing remain separate steps that must be technically coordinated and influence one another.
From demonstrator to dependable manufacturing
The research addresses not only shape but also challenges in manufacturing and combining materials. For wider application, relevant factors include dimensional accuracy, behaviour during concrete casting and the bond between the materials involved. A geometrically convincing sample slab is also no substitute for project-specific verification of load-bearing capacity. Nor can general cost savings be inferred from a single demonstrator. The technical contribution lies initially in making it possible to manufacture complex formwork elements directly from digital designs. This can expand freedom in component design and enable new manufacturing processes. FoamWork is therefore most accurately described as an experimentally investigated manufacturing approach. Whether it is suitable for a particular construction project depends on component size, required properties, local manufacturing and the verification required in each case.
Sources & further reading
- ETH Zurich, Digital Building Technologies: FoamWorkdbt.arch.ethz.ch
- International Journal of Architectural Computing: Foamworkdoi.org
Written in our own words with AI assistance, based on the sources listed above. The text distinguishes research findings, technical prototypes and established knowledge. This feature is not a breaking-news report.