Mar 7, 2017 | By Benedict

Researchers at Saarland University in Germany have developed Hotflex, a computer-controlled, 3D printable composite structure that allows 3D printed objects to be precisely bent and deformed after printing.

Consider the following statement about 3D printing: “After printing, the 3D object is static. You can no longer change it or adapt it to your needs.” Whether you agree with that statement or not probably depends on how you define “change.” After all, 3D printing does allow you to print an object, see how it functions, and then print a new version (or several new versions) if necessary. This iterative process could easily be seen as “changing” a 3D printed object and adapting it to your needs. Considered in that sense, isn’t 3D printing actually pretty great for changing and adapting objects?

Well, not if you ask Daniel Gröger, a doctoral student at Saarland University, and the man behind the contentious statement. He says that, because 3D printed objects—even those printed in relatively flexible filaments—cannot be physically altered after printing, they aren’t really adaptable at all. And since a 3D printed design might require countless iterations before it is perfect, 3D printing can actually be quite wasteful too. All this might seem a little harsh on a technology that is known for its prototyping prowess, but Gröger does have a point: individual 3D printed objects, on the whole, can’t be radically altered. Machined into something smaller and neater? Yes. Remade altogether? Easily. But bent into a completely new shape? Rarely.

Gröger and a team of researchers at Saarland University want to change 3D printed objects to make them both malleable and adaptable, and they’ve come up with a pretty interesting way of doing so. Hotflex, their new creation, is a flat composite structure made up of several individual layers that can be controlled electronically with an Arduino. When the Arduino activates a “heating” layer at the center of the structure, the 3D printed object becomes deformable in an instant, allowing its maker to make physical changes to it using their bare hands.

Although it is the central heating layer of Hotflex that is controlled by the Arduino, each layer of the device plays an important part in its function. Outside the heating layer lies a “moldable” layer, which consists of a biodegradable plastic. If this layer reaches a temperature of just under 60 degrees Celsius, it becomes deformable. After it has been reshaped by hand, it will stay that way once it cools down. Outside the moldable layer is an external layer of flexible plastic, the “base” layer, which gives added stability and protection.

To create their tri-layered, computer-controlled structure, the Saarland researchers used both consumer-level 3D printers—a Makerbot Replicator 2 and Leapfrog Creatr HS—and a cheap inkjet printer that could print with conductive inks (for the electronics). The researchers found that the outer “base” layer could be made from ABS, PLA, and TPE, with the flexible “moldable” layer made from PCL (polycaprolactone). The heating element is a printed resistor, laid out in a serpentine pattern.

The Saarland researchers say that Hotflex can be used for a number of purposes. As well as making static 3D printed objects bendable, it can also be used to make touch-responsive sensors and information-displaying surfaces. Thus far, Gröger and co have used their creation to make an adjustable bracelet, a jewelry box that opens with a touch-sensitive lock, and a computer mouse with an ergonomic thumb rest that can be adjusted to the user’s preference. “We are presently integrating our flexible heating structures into the workpieces during the printing process,” Gröger says. “But this will soon also be done automatically.”

While we would have some doubts over the structural integrity of a 3D printed part that has undergone multiple deformations, the Saarland study nonetheless shows an interesting new way of approaching 3D printable materials.

“This is an entirely new style of modeling,” added researcher Jürgen Steimle. “You no longer have to click around in a digital 3D model, but can work with your own hands and receive a completely different kind of feedback. At the same time, you reduce the number of iterations and waste less material and time.”



Posted in 3D Printing Technology



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BoozeKashi wrote at 3/7/2017 8:21:16 PM:

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