The focus of BigRep is to find new ways of applying industrial 3D printing with a large 3D printer. Within BigRep’s team of engineers, architects, and industrial designers, there is a plethora of ideas for the BigRep ONE to test.
BigRep’s NOWLAB and creative experts aim to learn from what is already in existence in order to create something which has not been seen before, whether they are in pursuit of innovations in robotics, materials, microstructures, or sensors.
When engineers and product designers meet functional design obstacles, solutions can be found in the problem-solving proclivities of nature. Over the course of millions of years, animal and plant species have evolved to protect themselves when vulnerable, grow taller, run faster, fly higher, and generally survive the elements. Lessons learned from nature are often applicable when designing industrial objects.
The foundations of bionic research can be provided by zoological and botanical research; optimizing technologies and products by drawing on elements within nature. This research focuses on technical development with the use of efficient and sustainable patterns, structures, and builds in the natural world.
BigRep explored the potential of propeller production based on bionic principles in the summer of 2017, with the use of 3D printing technology.
The shapes of products we know today are mostly affected by the production method. In turn, this can really limit the functionality of objects.
Florian Schärfer, Leading Industrial Designer on the Project, BigRep.
Schärfer demonstrated that in a similar manner to how computers have made the calculation and implementation of complex structures more straightforward, biological design elements are now being found in a vast array of products before being easily converted into CAD files for 3D printing.
Propeller Design Principles
A Bionic Propeller model was developed by Big Rep, taking inspiration from a propeller innovation from the Technical University of Berlin (TU). BigRep’s model combined two essential bionic research principles in order to increase the efficiency of a conventional design – even more so given that it was to be 3D-printed.
- The pinions of bird wings inspired the propeller’s loop ends. When splayed out, these pinions allow birds to glide easily and noiselessly through the air. By connecting each propeller blade through a loop, blades without end parts are created.
- Bumps along the fins of Humpback whales inspired the six ridges which are visible on the edge of each propeller. During the rotation of the propeller, air travels through these ridges more quickly with less drag. The principle which allows the world’s largest mammals to storm through the water at unbelievable speeds given their size is also an aerodynamic principle which can be applied to propellers and wind turbines.
All of this creates a propeller which reduces turbulence caused by in-water cavitation or air. Tests using a computer vent which was designed in this manner produced 30% less noise emissions. If tested as a ship propeller, the thrust performance is increased by approximately 19%.
Increasingly, teams of researchers are finding and applying bionic principles in order to increase the efficiency of conventional designs, just like the Berlin-based researchers who developed the loop principle propeller.
Casting the Propellers
In general, propeller designs are sand-casted and frequently they are tailor-made for an aircraft or vessel. Consequently, it is not easy to design and cast these objects on a large scale.
Historically, the positive pattern has been hand-carved and sanded from wood, before being pressed with both sides into sand in order to create a cavity which is filled with metal. This created the mold, which was subsequently filled in order to make the cast propeller. Once it had been cooled, the metal propeller was then milled for the ideal finish.
The process of casting propellers has been revolutionized by the BigRep ONE, as it cuts off enormous amounts of time from the process of producing an initial mold. As Schärfer puts it, “The bionic propeller model can be printed in days instead of being milled and shaped by hand over a period of weeks. The process has traditionally been laborious, but with large-scale 3D printing, the prototype can be created as one single, seamless form.”
This information has been sourced, reviewed and adapted from materials provided by BigRep.
For more information on this source, please visit BigRep.