4D-Printing
Research group '4D-Printing'
With 4D printing, previously static 3D-printed components can change their shape or function over time. To realise this, special materials are required that enable such a change. Therefore, at its core, 4D printing involves the use of intelligent materials in additive manufacturing. These intelligent materials are also known as smart materials. Smart materials are materials that react to an external stimulus in a useful way. This means that the properties of smart materials can be directly influenced by environmental factors. These influences can affect the shape, volume, colour, tension and other properties of the materials. It is this property that forms the basis for 4D printing.
Potential future applications of 4D printing technology include the medical sector and soft robotics. As this technology is still in its infancy, it is likely that more applications and potential will emerge in the future.
The '4D Printing' research group is currently conducting experimental investigations and simulations on the topic of '4D printing'. The focus is currently on smart polymer materials and polymer composites with magnetic properties.
The following video illustrates the process of 4D printing a soft gripper from a magnetically responsive material. Firstly, the creation of the 3D drawing and the actuation of the printed body are illustrated and described in detail. This is followed by video sequences of these steps. At the end of the video, the actuation is monitored for flow density by placing a Hall probe directly under the soft gripper. Connected to a teslameter, the magnetic flux density output is displayed in the bottom right-hand corner of the screen in units of mT.
The video below shows a simple positioning and gripping system made from a shape-memory polymer (SMP). This material can change shape in a targeted manner when heated. Combined with a polylactide and magnetic particle composite material, it is used to retrieve the marble from the bottle.
The direct programming of a stent-like prototype for biomedical applications is shown in the following video. A flat lattice structure from the 3D printer serves as the basis, which is filled with water-soluble PVA to ensure the individual cavities in the lattice structure. The special feature here is that the desired shape change is already imprinted in the 3D printed component during the printing process and no subsequent programming is required. This lattice structure is then heated in an initial water bath (T1) and then thermomechanically preformed into a hollow cylinder. The grid is then deformed under the influence of heat in another water bath (T2>T1), whereby the outer diameter of the hollow cylinder increases.
Further Information
Current research focuses on magnetic polymer composites and magnetic-mechanical simulation. Materials consisting of an elastic polymer with embedded magnetic particles, such as neodymium, are analysed, tested and simulated. To enable targeted movement, the important requirements of the material are first identified and analysed experimentally. In parallel, COMSOL multiphysics simulation software is used to simulate targeted movement in response to an external magnetic field. The knowledge gained should enable targeted, simple movements of the composite materials to be reliably realised and simulated.
Summer term 25: Additive manufacturing workshop for students on the topic of 4D printing of soft robots — development, design and production of a soft robot in the form of a bionic muscle.
If you are interested in writing your thesis in the field of 4D printing, please contact us! Simply get in touch with one of the contacts in the right-hand column.
Enclosed you will find some interesting topics that could be considered for a thesis:
- "Development of an actuator with dual deformation behaviour using 4D printing with magnet-responsive behaviour (torsion-contraction actuator)", contact person: Daniel Kehret, M.Sc., start possible from summer semester 25. (PDF)
- "Selection and application of a Helmholtz coil for activating a magnet-responsive soft robot", contact person: Daniel Kehret, M.Sc., start possible from summer semester 25. (PDF)
- "Investigation of the application and magnetisation of magnet-responsive material", contact person: Daniel Kehret, M.Sc., start possible from SoSe 25. (PDF)
- "Setup of a measurement of magnetic characteristics of a material according to the IEC 60404 standard", contact person: Daniel Kehret, M.Sc., start possible from summer semester 25. (PDF)
Publications to the research field '4D-Printing' so far:
- Kehret, D., Junk, S., Einloth, H., Rapp, B. E.: 4D printing of magnetoresponsive soft gripper and phenomenological approach for required magnetical actuation field. The International Journal of Advanced Manufacturing Technology. 2024. Springer Link. https://doi.org/10.1007/s00170-024-14605-5
- Junk, S., Einloth, H., Velten, D.: A Methodical Approach to Product Development in 4D Printing Using Smart Materials. In: H. Almeida et al. Progress in Digital and Physical Manufacturing. ProDPM 2021. Springer Tracts in Additive Manufacturing. Springer, Cham, 2023, https://doi.org/10.1007/978-3-031-33890-8_12
- Junk, S., Kehret, D., Einloth, H., : Application of Magnetoresponsive Materials in 4D-Printing, Hrsg.: Bernhard Müller: Fraunhofer Direct Digital Manufacturing Conference DDMC 2023 Conference Proceedings, 2023, Berlin, Germany, ISSN: 978-3-8396-1895-0
- Junk, S., Einloth, H., Velten, D.: 4D Printing: A Methodical Approach to Product Development Using Smart Materials. Machines 11, no. 11: 1035. 2023. https://doi.org/10.3390/machines11111035