The concept of building using 3D printing processes is now even conquering the air: Based on the model of bees, swallows and co, researchers have developed flying 3D printers that can construct or repair structures in a sophisticated way. In the future, 3D-printed drones could be used in places that are difficult to access or dangerous – such as on tall buildings or in disaster areas, say the scientists.
Instead of bricks, structures are gradually being made from layers of cement: 3D printing is also becoming increasingly important in the construction industry. Both on site and in the factory, stationary or mobile robot systems are already printing elements for use in construction projects. With special machines, even whole houses can now be built using the 3D printing process. However, these systems must be larger than the structure to be erected, which limits their potential use. Nature's 3D printing master builders, on the other hand, are much more flexible: bees, swallows and the like can fly to their construction sites to gradually build complex structures from applied layers of material.
Based on the example of bees and co
The scientists led by Ketao Zhang from Imperial College London were inspired by these natural models in their development: they developed a concept of cooperatively working flying robots that enables 3D printing technology to be used in the air. The system, known as "Aerial Additive Manufacturing" (Aerial-AM), comprises two units: "BuilDrones", which apply construction material to the intended locations during the flight, and "ScanDrones", which are used to control the process. They continuously record the progress of the BuilDrones and specify the further production steps. Both units act autonomously, but a human also monitors the process and can make adjustments if necessary based on the information provided by the drones.
However, combining 3D printing technology with a flying robot was a tricky task. One of the biggest challenges was achieving precision when printing in hover mode. In order to build up a stable structure, the layers of cement must be applied exactly one on top of the other. However, drones tend to drift slightly when hovering – especially in the case of air movements in the open air. The researchers therefore developed a print head that is attached under the drone by means of a sophisticated suspension. The system can compensate for the slight disturbing movements of the aircraft during the printing process.
Precise construction work in hover
In this way, a millimeter-precise application of the printing material can be guaranteed, the scientists report. It is applied in the form of a sausage and then hardens. After the BuilDrones have applied their storage contents, they fly to a supply to provide supplies - similar to a bee getting new building material for honeycomb construction. The team also developed special building materials that seem particularly well suited to their concept. For demonstration purposes, the scientists used their 3D printing drones to successfully erect an approximately two meter high cylinder made of 72 layers of foam and an 18 centimeter high cylinder made of 28 layers of a specially developed cement-like material.
"At least in the laboratory, we have already shown that our drones can work autonomously to erect and repair buildings," says senior author Mirko Kovac from Imperial College and the Swiss Federal Laboratories for Materials Science and Technology Empa in Dübendorf. The results appear promising with regard to use in construction practice. The special advantage of the concept is mobility. "This scalable solution could make building and repairing in hard-to-reach areas easier," says Kovac. For example, the drones could be used in disaster areas or mountain formations. Building structures could also be erected or repaired at dizzy heights without scaffolding. The scientists believe that their technology can, in some cases, offer cost savings and reduced risk compared to traditional methods. Together with construction companies, they now want to further explore the possible uses of the system and further develop the process.
Source: Imperial College London, Federal Materials Testing and Research Institute Empa, specialist article: Nature, doi: 10.1038/s41586-022-05247-2
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