ETH Zurich Researchers Develop 4D Printed Load-Bearing Polymer Structures

IMTS

Share this Article

There are numerous issues involved with transporting things into space, one being that some of them are just too big and bulky. One solution is to make those items small and capable of being folded up into compact packages which can then be expanded once the destination is reached. 4D printing is frequently used to create these deployable objects; a shape memory polymer will be 3D printed and “programmed” to unfold or expand when exposed to a stimulus such as light or temperature change. There are challenges with this technology, too, however: the energy sources themselves can be bulky, deployment can be imprecise, components can jam, and the objects can lack structural integrity.

Professor Kristina Shea and doctoral student Tian Chen of the Swiss Federal Institute of Technology Zurich (ETH Zurich), who recently used 3D printing to develop an underwater soft robot, have published a study in which they 3D printed a programmable actuator that deploys autonomously and changes shape using temperature change as the catalyst. The study, entitled “An Autonomous Programmable Actuator and Shape Reconfigurable Structures Using Bistability and Shape Memory Polymers,” can be accessed here.

“Using a shape memory polymer as the temperature controllable energy source and a bistable mechanism as the linear actuator and force amplifier, the structures achieve precise geometric activation and quantifiable load-bearing capacity,” the researchers explain. “The proposed unit actuator integrates these two components and is designed to be assembled into larger deployable and shape reconfigurable structures.”

The 3D printed objects were programmed to change shape gradually by tailoring each shape memory polymer to a different activation time. The objects started as flat surfaces that, when activated, transformed into a pyramid or a hyperbolic paraboloid shape, demonstrating a multistate structure. Both showed load-bearing capability during activation and operation.

Shea and Chen used multimaterial inkjet 3D printing technology to fabricate complex designs by selectively depositing photoreactive liquid resins of different stiffness and glass transition temperatures.

“By combining this polymer with a bistable mechanism, called a von Mises truss, we are able to define two distinct equilibrium states that can be precisely achieved,” the researchers explain. “Von Mises type bistable mechanisms have previously been used in active masts, for energy absorption, and more recently to create 3D-printed reconfigurable structures.”

The items were 3D printed using a Stratasys Objet3 Connex500 multimaterial 3D printer. The materials used were FLX9895, a shape memory polymer; RGD525, a temperature-resistant rigid plastic; and Agilus30, an elastomer-like material. The structures were then activated using heated water to simulate a reduced gravity environment.

“The deployment of the unit actuator procedure consists of two phases; the first phase is the programming and assembly of the SMS with the bistable mechanism,” the researchers continue. “The second is the constrained recovery of the SMS and consequently the activation of the unit actuator. In the programming phase, the SMS is heated past and is either stretched or compressed by a distance equal to the stroke length of the bistable mechanism (Fig. 2b, c). While confined, the SMS is cooled and installed in the bistable mechanism (Fig. 2d). The second phase is triggered by raising the temperature of the unit actuator past (Fig. 2e). As the SMS recovers, it triggers the bistable mechanism and achieves the deployed state. Once cooled, this activated state behaves as a rigid structure as the SMS returns to its glassy state.”

The result is an object that smoothly transforms from a flat state into a complex shape, and most importantly, shows load-bearing capabilities both during and after deployment, unlike many other 4D printed objects. The research has the potential to be used for a number of applications, particularly in the field of space exploration.

Discuss this and other 3D printing topics at 3DPrintBoard.com or share your thoughts below. 

 

Share this Article


Recent News

Will There Be a Desktop Manufacturing Revolution outside of 3D Printing?

Know Your Würth: CEO AJ Strandquist on How Würth Additive Can Change 3D Printing



Categories

3D Design

3D Printed Art

3D Printed Food

3D Printed Guns


You May Also Like

Featured

Pressing Refresh: What CEO Brad Kreger and Velo3D Have Learned About Running a 3D Printing Company

To whatever extent a business is successful thanks to specialization, businesses will nonetheless always be holistic entities. A company isn’t a bunch of compartments that all happen to share the...

Würth Additive Launches Digital Inventory Services Platform Driven by 3D Printing

Last week, at the Additive Manufacturing Users’ Group (AMUG) Conference in Chicago (March 10-14), Würth Additive Group (WAG) launched its new inventory management platform, Digital Inventory Services (DIS). WAG is...

Featured

Hypersonic Heats Up: CEO Joe Laurienti on the Success of Ursa Major’s 3D Printed Engine

“It’s only been about 24 hours now, so I’m still digesting it,” Joe Laurienti said. But even via Zoom, it was easy to notice that the CEO was satisfied. The...

Featured

3D Printing’s Next Generation of Leadership: A Conversation with Additive Minds’ Dr. Gregory Hayes

It’s easy to forget sometimes that social media isn’t reality. So, at the end of 2023, when a burst of doom and gloom started to spread across the Western world’s...