EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Soft robots are a key to a safe and “natural” interaction between machines and humans. The replacement of stiff metal parts by flexible elements with the ability to bend and expand predestines them for applications in a fragile and sensitive environment.
A promising approach for this purpose is the use of bioinspired materials systems and mechanisms. The adaptive or reactive behavior, especially of plants, typically is based on materials systems with a complex hierarchical structuring and interaction of highly integrated stiff and flexible elements. Transferring these principles into technical products requires a fabrication method that can handle various substances with a wide range of chemical properties.
As a step towards this goal a low cost multi-material 3D-printer with on-demand tool-change was developed. The device is able to switch between tools on the fly and use them to print specific parts of a structure without interference. The core XY geometry of the printer moves a carriage equipped with a coupling mechanism, which can pick up a tool from its standby position and place it back there after usage. Such a tool can be a filament print-head, a syringe for pastes or other tools that fits to the specific task. This novel system allows us to embed flexible membranes directly into a stiff structure or to create highly expandable pneumatic elements with a wall thickness of just 500 µm. A newly developed continuum actuator printed with our multi-material 3D-pinter allows the user to customize the aspired behavior after the printing is completed. By modifying single sections to bend or expand linearly the same basic actuator design can perform a wide range of movement.
With this fabrication technology new combinations of materials and more advanced biomimetic materials for soft machines can be produced in the future.