The Eiffel Tower recovering its shape using 4D Printing.Unlike 3D printing, 4D printed structures have the potential to transform shape in a pre-programmed way in response to a stimulus (e.g. changes in temperature). These types of structural transformations currently exist outside of additive manufacturing, with research having already demonstrated “shape memory” and “smart material” properties. One of the most popular technologies is known as shape memory alloy, where a change of temperature triggers a shape change. Other successful approaches use electroactive polymers, pressurised fluids or gasses, chemical stimulus and even a response to light.
The additive manufacturing of multi-material SMPs is at the cutting edge of materials, engineering and design research. The work by A/prof Ge and the DManD team presents a new 4D printing approach that can create high-detail (i.e., up to a few microns resolution), multi-material SMP architectures. The approach uses a high resolution projection micro-stereolithography (PμSL) technique, combined with an automated material exchange process to produce multi-material parts made from a family of specialised photo-curable polymers.
A workflow illustrates the process of fabricating a multimaterial structure based on PμSL
The constituents and compositions of the 4D printing polymers have been designed to exhibit high-performing thermo-mechanical behaviour, showing a failure strain much larger than any existing printable materials. A high-fidelity computational tool-chain has also been developed facilitate the design of SMP 3D structures. The tool-chain achieves this by simulating important design considerations including local deformation, shape fixity and free recovery rate. The combination of both material and structure in the 4D printing process has allowed for the creation of some clearly impressive outcomes demonstrated in the recently published paper.
This research by DManD successfully demonstrates the first multi-material 4D printing of active polymers in the world that uses the PμSL technique. The research opens the door to a myriad of new applications beyond those available with current commercial printers.