Printing Is Poised to Enter the Fourth Dimension
Jean Thilmany | November 03, 2015Although four-dimensional printing with metamaterials remains largely an academic pursuit, the technique is poised to break out of the lab and become available to engineers and designers in the not-too-distance future, analysts and experts say. Perhaps, some say, before the turn of the decade.
In October, around 50 attendees gathered for the 4D Printing and Meta Materials Conference in Amsterdam, the Netherlands, to hear researchers from the Leiden Institute of Physics, the Institute for Complex Molecular Systems, Eindhoven University of Technology and the Institute of Applied Physics, among others, speak about recent 4D advancements and potential applications. The meeting helped signal that 4D is a viable technology, say the conference’s founders.
Time or Shape?
Some research labs refer to the fourth dimension as time while others call it shape change. Either way, the technique is much the same as it involves creating materials that change shape over time, says Marc in het Panhuis. He heads the soft materials group at the University of Wollongong in Australia and is a member of the university’s ARC Centre of Excellence for Electromaterials Science.
The technique involves creating materials that change shape over time, says Marc in het Panhuis.Mechanical metamaterials are defined by structure rather than by composition. They might be elastic and programmable, for example, so a material’s shape -- and thus its function -- may be changed by the application of force, says Jo Geraedts, a professor of new mechatronic design at Delft University of Technology in the Netherlands.
The shape-changing functionality is built into the materials themselves, says in het Panuis, and can be activated by changes in pressure, temperature, current, sound, or other fluctuations in the material’s environment. Structures are printed from the shape-changing material with a 2D or 3D printer and then proceed to take on new forms and uses, he says.
“A 4D printer doesn’t exist, but we can use a 3D printer and with a clever materials design make a 4D printed structure,” he says. In other words, the 3D printed structure changes over time, “like in a transformer toy,” he says. Earlier this year, his soft robotics team demonstrated a valve that opens or closes in response to water temperature.
“So far we’ve printed a valve out of jelly that’s ready right when it comes off the 3D printer. It responds to temperature and turns itself off without you having to do anything,” in het Panhuis says.
Moving Water
Researchers generally credit Skylar Tibbits with coining the term 4D printing in a February 2013 TED Talk, “The Emergence of 4D Printing.” Tibbits directs the Self Assembly Lab at the Massachusetts Institute of Technology. His lab has demonstrated a way to create one-dimensional strands of materials or two-dimensional surfaces that fold themselves into 3D shapes or morph into other 3D shapes when placed in water.
This is like robotics without wires or motors, says MIT's Skylar Tibbits.“This is like robotics without wires or motors,” Tibbits says. “Imagine if water pipes could expand or contract, or even undulate to move the water themselves.”
(Watch a video of a self-folding strand in a demonstration at Tibbits’ MIT lab.)
The Self-Assembly Lab first prints its self-folding structures as strands made of two materials, a synthetic polymer that expands to more than twice its volume in water and a second polymer that remains rigid in water. The materials have varying water-absorbing characteristics that activate a change in shape when they come into contact with moisture, Tibbits says.
The MIT researchers plan to program different material properties into each particle on the strand or surface and then place it in water to activate the self-assembly process. The materials’ qualities also could be coded for color, transparency, stiffness, flexibility and for other properties.
Although the technology has yet to make it out of the lab, applications and markets for the processes and materials involved will evolve as the technology advances, Tibbits says.
Objects already printed with metamaterials, for instance, could also be changed into other objects or adapted to another use, saving money and materials, Tibbits says. Or, the technique could one day be used to embed programmability and simple decision-making capabilities into non-electronic materials, saving manufacturers time and money.
Available by 2019?
And that day could come soon, as some market research firms predict the technology could become commercially available by 2019.
In a June 2015 report, the firm MarketsandMarkets forecasted the worldwide 4D printing market could equal $63 million by 2019 and see a greater than 40% compound annual growth rate, reaching more than half a billion dollars by 2025.
A June 2014 report from analysis firm Frost and Sullivan says 4D printing could have wide-ranging applications such as printing human organs and artificial tissue as well as creating parts for aerospace and manufacturing processes and equipment. The technique also will find a niche in consumer appliances and lifestyle sectors by 2019, the report says.
The MarksandMarkets report segments the global 4D printing market into programmable material markets that include carbon fiber, custom printed wood grain, and textiles. The programmable carbon fiber segment should be the largest contributor to the overall market, with a share of around 62% in 2019.
Programmable carbon fiber enables a range of applications, from morphable airplane flaps to self-regulating air intake valves, adaptive aerodynamics and tunable stiffness structures, according to the U.S. Defense Advanced Research Projects Agency (DARPA).
The military, defense and aerospace industries will account for much of the growth of 4D printing, the report says. It forecasts that the sector will account for a 55% share of the market by 2019 with aerospace making up around 45% of that.
A material’s shape -- and thus its function -- may be changed by the application of force, says Jo Geraedts. That may well happen because, as Frost and Sullivan points out, most of the funding for 4D research and development -- especially in the United States -- comes from government and defense agencies. This trend may change in the next several years as more public and private sector funds flow into the sector.
Until then, military spenders continue to fund 4D printing development. In late 2013, for example, the U.S. Army Research Office awarded a trio of researchers an $850,000 grant to create 4D materials.
4D Materials
Jennifer Lewis of the Lewis Research Group at the Harvard School of Engineering and Applied Sciences has teamed with Anna Balazs, a University of Pittsburgh professor of chemical engineering, and Ralph Nuzzo, professor of chemistry and materials science and engineering at the University of Illinois, at Urbana and Champaign, Ill., to create 4D materials that would be adaptive, flexible, lightweight and strong.
Materials like these will greatly extend 3D printing capabilities. For example, they could become part of a soldier’s uniform, changing color within seconds as the soldier’s surroundings change to better camouflage the wearer, Balazs says.
Beyond military applications, the 4D materials the lab is at work on could be used as an automobile coating that could change structure when traveling over a a salt-covered road or through humid air. The change would be automatic and could help protect the car against rust,, she says.
Through use of a 4D shape-changing material, specific functions like these could be build into the nano or micro levels of a structure or could exist throughout the entire structure or through only a large part, Lewis says.
Meanwhile, DARPA envisions 4D printing shape-shifting robots that can flow like mercury through small openings to infiltrate caves and bunkers, according to its statement.
That image may not be too far-fetched, says University of Wollongong professor in het Panhuis.
“If you think 4D allows us to change shape over time, you can also use it to create materials that just disappear in front of your eyes,” he told the BBC earlier this year. “James Bond can print a secret message that can be activated with the 4D printing process and then disappear before your eyes.”