New 4D Printing technique developed by TU Delft researchers has potential to improve bone implants
Researchers at TU Delft have combined origami techniques and 3D printing to create flat structures that can fold themselves into 3D structures (for example a tulip). The structures self-fold according to a pre-planned sequence, with some parts folding sooner than others. Usually, expensive printers and special materials are needed for that. But the TU Delft scientists have created a new technique that requires only a common 3D printer and ubiquitous material. Among other applications, their research has the potential to greatly improve bone implants.
In recent years, Amir Zadpoor of TU Delft has become somewhat of an origami master. His team’s work combines the traditional Japanese paper folding art with the more novel technology of 3D printing in order to create constructs that can self-roll, self-twist, self-wrinkle and self-fold into a variety of 3D structures. In 2016, the researchers already demonstrated several self-folding objects. ‘But there were still serious challenges we needed to address’, says Zadpoor.
A lot of manual labour is usually involved in the fabrication of shape-shifting devices. Also, the material the researchers normally use is neither ubiquitous nor cheap. But in this recent project Zadpoor’s team have used an Ultimaker, which is one of the most popular 3D printers, and PLA, the most common printing material available. ‘At about 17 Euro’s per kilo, it’s dirt cheap’, says Zadpoor. ‘Nevertheless, we created some of the most complex shape-shifting ever reported with it.’ The process is also fully automated and requires no manual labour whatsoever.
Programming time delays
What makes the team’s shape-shifting objects so advanced is the fact that they self-fold according to a pre-planned sequence. ‘If the goal is to create complex shapes, and it is, some parts should fold sooner than others’, Zadpoor explains. ‘Therefore, we needed to program time delays into the material. This is called sequential shape-shifting.’