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Lund University team led by Olaf Diegel builds mobile concrete 3D printer to 3D print furniture

Dedicated readers will doubtlessly remember the name of Olaf Diegel, a Swedish professor who became famous in the 3D printing community for 3D printing a wide variety of musical instruments. Last September, he even masterminded a band relying almost solely on 3D printed instruments. However, the professor at the University of Lund in Sweden also dabbles with a number of other applications, as this recent project illustrates. Together with a team of colleagues and students, he has just built the portable concrete 3D printer visible above, and used it to 3D print a chair as a proof of concept.

As the professor explains on his website, this project grew out of a conversation with the Helsingborg city department responsible for housing. ‘[They] were interested in working with Lund University on developing a demo 3D printer machine to print houses,’ he says. ‘However, as with many projects undertaken without a budget, the Additive Manufacturing research team at Lund University had access to a spare ABB robot arm, so they decided to start with a smaller scale proof-of-concept system that was capable of printing street furniture, or public artworks.’

This concept quickly grew into an eye for a 3D printer that is portable and wheeled to quickly move from point A to point B. Ideally, it could be put into position, locked down, 3D print an object and move on to the next location. To Master’s students, Borja Serra and Lars Henrik Anell, were brought onboard the project to transform the ABB IRB140 robot arm into a mobile 3D printer. ‘They divided up the work into two sub-projects, with Borja taking care of the 3D printer frame design, and the software and programming of the robot, and Henrik taking care of the design and construction of the concrete print-head,’ the professor explains.

And the setup they came up with is impressive. The frame for the 3D printer (visible above) was built out of aluminum, and incorporates a removable bottom set that can be used to make the frame rigid and safe during transportation, while removal makes the robot itself more functional. The printhead used for concrete extrusion was based on an earlier design by prof. Diegel (originally intended for the extrusion of polymers in granule form). To keep costs down, Henrik decided to use a 100 mm hole boring auger as the concrete delivery mechanism.

In software terms, this portable concrete 3D printer relies on MATLAB – as any other 3D printer could use – but instead translates it into RAPID code, which is required to control the ABB IRB 140 robot. ‘It also uses another algorithm to keep a continuous flow of concrete during the print. This is important to guarantee a good quality print and get good mechanical properties for the concrete,’ the professor adds.

But obviously the real question is: what is the 3D printing quality like? Well, the proof-of-concept can be seen below, and the YouTube clip illustrates how the 3D printer functions in real life. The professor does add that the clip was filmed at a quite early stage in the process, which is why concrete had to be shoveled in manually. The later system contains an automated feeding system.

This proof of concept definitely suggests there’s a future for smaller scale concrete 3D printers. Other existing projects are all focused on 3D printing actual homes, and are therefore much larger and far more expensive. Transportation alone will be a logistic nightmare for some of them. However, for smaller concrete objects – such a little walls, benches and tables – and art, this Swedish definitely seems to be a fantastic option. Further refinement will focus on improving concrete feeding, adding paddles that can be used to smooth objects and possibly a gantry system. In short, we’ll definitely hear more about this ongoing project in the near future.