Velcro fasteners, the lotus effect and airplane wings are just a few examples of how bionics can solve technical problems. After all, nature offers fascinating answers to everyday challenges. "It is usually very efficient," says Dr. Harald Kuolt, Head of Research Projects at J. Schmalz GmbH in Glatten. "We have been looking for natural suction methods to improve our own vacuum systems."
Vacuum suction and mechanical gripping combined
The company found what it was looking for in leeches. With their two suction organs at the front and rear ends, they have the ability to hold on to different surfaces. Whether slimy or porous, under or above water - thanks to the combination of suction adhesion and mechanical gripping or clinging, they can attach themselves securely to their hosts.
Together with the University of Freiburg, Schmalz launched a project to gain a better understanding of biological adhesion systems. "We investigated the functional morphology and biomechanics of leeches," explains Prof. Thomas Speck. He heads the "Botany - Functional Morphology and Bionics" working group at the University of Freiburg.
After manual pull-off tests, the researchers built rotating systems and determined the centrifugal force at which the leeches detach from the respective surface. "We broke new ground and developed special test setups to measure the adhesive forces of the leeches," explains Speck. In a current research project, the team is investigating the anatomy of the sucking organ, which consists of muscle-controlled sucking, sealing and grasping lips. "Understanding the form-structure-function relationship of the suction organ is essential for further abstraction and implementation steps for new, bionically optimized systems of lard," explains Dr. Simon Poppinga, who heads basic biological research on the model organism at the Technical University of Darmstadt.
Suction pads - from the aquarium to industry
Kuolt goes on to report on the research project: "Our pre-development department then produced a prototype that differs from our standard range." Firstly, the sealing lip runs in a different direction to that of conventional suction cups. Secondly, Schmalz adapted the radii of curvature and combined hard and soft materials. "We were able to reduce the dead volume and therefore evacuate much faster," says the research manager happily. "Our aim is for the new suction cup to perform better than conventional models in terms of holding and shear forces as well as sealing behavior. It should also be suitable for industrial production." And its carbon footprint must also measure up to previous suction cups.
Schmalz is currently focusing on further optimizing two variants. The new models save energy thanks to their short evacuation times. They seal better on rough surfaces and impress with their long service life. Thanks to the new structure of the seal, they should also ensure a secure hold on uneven or sensitive surfaces. "The suction cups must function reliably in standard applications," says Kuolt. This is because the vacuum automation specialist does not want to develop a system for a few special cases.