TU Delft Researchers 3D Print “Some of the Most Complex Shape-Shifting Ever Reported” with Ultimaker 3D Printer and PLA

IKEA furniture is, for the most part, pretty easy to assemble. But it could be easier – imagine ordering flat-packed furniture from a place like IKEA, opening it, and watching it assemble itself right in front of you. That’s the vision of Dr. Amir Zadpoor, a researcher at Delft University of Technology (TU Delft). But it’s only part of his vision. Dr. Zadpoor believes that the principles of origami applied to 3D printing technology could be the key to developing better bone implants.

Last year, Dr. Zadpoor and colleagues published a paper on 3D printed self-folding medical implants.

“But there were still serious challenges we needed to address,” he says.

In a new paper entitled “Programming 2D/3D shape-shifting with hobbyist 3D printers,” which you can read here, Dr. Zadpoor along with PhD researchers Teunis van Manen and Shahram Janbaz describe how they used ordinary consumer 3D printers and materials to create shape-shifting devices.

Normally, expensive, specialized 3D printers and materials are required to 3D print shape-shifting objects, but the TU Delft researchers used an Ultimaker 3D printer and some PLA to produce what Dr. Zadpoor describes as “some of the most complex shape-shifting ever reported.” The process is also fully automated.

The shape-shifting objects 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,” said Dr. Zadpoor. “Therefore, we needed to program time delays into the material. This is called sequential shape-shifting.”

The researchers achieved this by alternating the thickness and alignment of the filament, as well as simultaneously printing and stretching the material in certain spots.

“The stretching is stored inside the material as a memory,” van Manen explains. “When heated up, the memory is released and the material wants to go back to its original state.”

So how does all of this relate to bone implants? This technique makes it possible to create implants with a porous interior, which allows the patient’s stem cells to move into the structure of the implant and attach themselves to the interior, rather than just coating the exterior. That creates a stronger, better implant. In addition, nanopatterns that guide cell growth can be created on the surface of the implant.

“We call these ‘instructive surfaces’, because they apply certain forces to the stem cells, prompting them to develop into the cells we want them to be,” says Janbaz. “A pillar shape, for instance, may encourage stem cells to become bone cells.”

Surfaces like that can’t be created on the inside of a 3D structure, however – they’re too complex. That’s why it’s necessary to start with a flat surface that is later instructed to fold into a 3D shape.

A development like this could mean big things for the medical field, but it could also have applications elsewhere – like that IKEA furniture.

“Printed electronics, for instance, can also benefit from our research,” says Dr. Zadpoor. “By using this technique, it may be possible to incorporate printed, 2D-electronics into a 3D shape…Shape-shifting could definitely turn many of our existing 2D worlds into 3D worlds. We are already being contacted by people who are interested in working with it.”

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