FESTOFlying lighter with FDR

The BionicBee has to be light. Was 3D printing the intended production method for the complex geometric structure of the frame from the outset?

Mattias-Manuel Speckle: Yes, additive manufacturing offers absolute geometric freedom. Numerous functions can be combined without process-related design restrictions. This saves on components, reduces weight and enables efficient lightweight construction. It is the basic prerequisite for the maneuverability and flight duration of the bee - in other words, for the success of the project. Our development department optimized the design of the support frame step by step and we printed the prototypes in our department. The fifth version weighed in at 12 grams.

Why was that?

Mattias-Manuel Speckle: We had reached the limits of the technology. 3D printing is not just 3D printing. Fine structures are also possible with stereolithography. However, such parts cannot withstand stress. With our selective laser sintering system (SLS), we can produce professional parts with series properties - but only to a certain extent. At some point, the material no longer plays along. We were able to print slightly lighter parts internally for the BionicBee, but they broke on landing at the latest - in most cases they didn't even survive unpacking.

Then 1zu1 came into play with FDR?

Mattias-Manuel Speckle: Exactly. We have been using 1zu1's vacuum casting and 3D printing services for special applications for some time now. As a reliable partner, 1zu1 guarantees high quality and adherence to deadlines - also thanks to good communication. We have already been able to convince ourselves of the enormous performance of FDR technology in previous projects. However, these were small, delicate components. In the case of the BionicBee, however, we were dealing with an element that was 20 centimetres long, 9 centimetres wide and 9 centimetres high.

So completely different dimensions - even for 1zu1?

Stefan Rädler: Such large parts are rare, but just as feasible as the miniature components predestined for FDR. Despite its unusual format, the BionicBee's support frame was produced without any loss of precision and with stable mechanical properties. The project provided proof that FDR is also ready for series production for parts of this size. Of course, Festo's design, which is tailored to additive manufacturing, also played a role: the wire construction requires little mass, which keeps distortion to a minimum.

The material is central to the BionicBee flying object. It has to be light, flexible and robust. Did the FDR technology provide the decisive advantage?

Stefan Rädler: FDR uses the material PA11. The material is tougher and at the same time more flexible than the PA12 known from conventional laser sintering. The elongation at break is around twice as high. This enables more precise and robust components with complex geometric structures.

How did Festo experience the technology change?

Mattias-Manuel Speckle: We were immediately impressed by the results, which significantly accelerated further development. We had the components in our hands just a few days later, were able to test them immediately in the laboratory and further improve the design. The struts became thinner and thinner. Finally, the decorative rear section also disappeared. This is now made of ultra-light modeling foil instead. This gradually reduced the weight from 12 to 3 grams.

The BionicBee was presented at the Hannover Messe in April 2024. Six of them flew through the exhibition hall. Were timing and quantity a factor?

Stefan Rädler: It was sporty (laughs). The final design was ready at the end of February 2024. We had to print 20 parts for the trade fair in a short space of time, which were then assembled by hand. That was only possible with partial deliveries, good coordination and courier services.

What happens now?

Mattias-Manuel Speckle: Maybe we'll take another leap and refine the design further. The potential is there. With FDR technology, even diameters of 0.6 millimeters are possible. So we could save another 1 gram. Apart from the BionicBee, we are also active with 1zu1 in terms of series production in 3D printing - we are currently looking for suitable applications together. It remains exciting!
 

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In conversation: Mattias-Manuel Speckle is head of additive manufacturing prototyping at Festo, where he produces prototypes and series parts using 3D printing processes. At 1zu1, Stefan Rädler accompanies the projects of the global market leader for automation technology. Joshua Köb conducted the interview.

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