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.

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

News

 

Informative international exchange

Prof. Victor Neto from the University of Aveiro (Portugal) visits Offenburg University of Applied Sciences and the 4D Printing research group.

Exploring Gengenbach's old town, from left to right: Prof. Victor Neto from Portugal, Daniel Kehret, Prof. Stefan Junk, Marvin Henkel
© Hochschule Offenburg

Prof. Dr. Victor Neto from the University of Aveiro (Portugal) visited Offenburg University of Applied Sciences on Wednesday, December 10, for a professional exchange on the forward-looking topic of 4D printing. The visit provided an opportunity to learn about current research activities and bring together different scientific perspectives.

The program began with a visit to the scanning electron microscopy laboratory at the Center for Learning and Teaching (CeLT) in Offenburg. Dr. Pascale Müller provided insights into modern analysis methods currently being used in ongoing research projects. This was followed by a tour of the laboratory for additive manufacturing in medical technology at the Peter Osypka Institute for Medical Technology (POIM) under the direction of Prof. Dr. Peter Quadbeck.

After visiting the historic old town of Gengenbach, the next stop was the rapid prototyping laboratory of Prof. Dr. Stefan Junk, head of the 4D Printing research group in Gengenbach. Prof. Dr. Junk presented current projects and research priorities as well as the possible printing processes in the rapid prototyping laboratory. 

The meeting focused on an intensive scientific exchange on the topic of 4D printing, which was greatly enriched by different experiences and international perspectives and created a good basis for further cooperation.