The pneumatic hand by Materialise is made up of the palm and wrist area which are printed in polyamide, and the fingers which are printed in flexible TPU by KU Leuven. The hand can grip objects using compressed air. The fingers are designed with an expandable (flexible) side and a non-expandable (rigid) side. When compressed air is applied one side expands and the other stays at the same length. As a result, the finger bends and flexes. The bellows have been designed for optimized flexing and minimized internal stresses. Internal air channels are incorporated into the hand and wrist to distribute the compressed air to the fingers.
The potential of the SLS technology was pushed to the limit in this case, in combination with TPU material. A very thin wall thickness of 1.2 mm is necessary to provide the necessary bending range for the fingers while maintaining air tightness. The pneumatic fingers showcase a flexible thermoplastic elastomer made from powder tuned for Laser Sintering and currently not commercially available for this technique. It shows higher stiffness than currently available Laser Sintering rubbers. Its properties are interesting for biomechanical and orthopedic applications.
Information and use cases:
New materials support the evolution of Additive Manufacturing to an established production technique for parts tailored to form and function. 30 years of experience in research and innovations on the combination of materials, hardware and software for Additive Manufacturing at KU Leuven proves to be a good way to change the manufacturing industry. Beyond-state-of-the-art research results in durable collaborations with industry and continuous innovation in AM. This rubber material is only one example of these tangible results. The flexible fingers are mainly used in industrial gripping applications (gripping parts with industrial automation robots in a factory assembly line) but other possible uses of these actuators include consumer-oriented (household) robots.