4D Printing

Additive manufacturing (AM) is a promising technique for fabricating 3D complex shapes, which are difficult to be fabricated by the traditional manufacturing processes. Currently, most AM processes are layer-based. However, such approach has drawbacks such as fabrication speed is slow and the built parts have anisotropic stiffness. Recently, inspired by Origami, a new AM technique based on self-folding structures has been developed. Instead of directly fabricating the 3D shape, this new manufacturing method fabricates a 2D self-folding structure. The self-folding structure fabricated by AM can be automatically folded into a demanding 3D shape by actuation mechanisms such as heating. This approach is called 4D printing. Models fabricated by this method have reconfigurable shapes, and the procedure of fabrication is fast since only a few layers need to be made by AM. However, 3D surfaces can only be fabricated by self-folding structures when they are flattenable. To fully utilize the technique of 4D printing, the shape of a non-flattenable surface has to be optimized to a flattenable shape, while keeping the shape as-similar-as-possible and without introducing many artifacts. In this talk, the design and the fabrication process of 4D printing will be discussed. Some related topics in design for additive manufacturing and its applications in biomedical engineering will also be covered.