Jumping on the 4D train

4D printing is the next big thing, and promises the following: Damaged water pipes repair themselves instead of having to be dug out; smart clothing warms or cools the wearer according to air temperature; and prostheses for children grow along with them. For now, these are simply visions of the future, but the acoustic waves can already be heard — with cochlea implants which mold themselves into shape.

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When Skylar Tibbits, a researcher at MIT (Massachusetts Institute of Technology) and pioneer of 4D printing demonstrates liberation from the physical hardships of the construction industry, this is what it looks like: He places a strand of a substance in water — it looks like a string of pearls made of differently shaped links. After a few seconds, the strand shapes itself into a cube as if by magic. Another strand folds itself to spell “MIT”. Nice, but not exactly the huge wow effect one might expect. Naturally, the researcher has more important uses in mind — self-erecting buildings, water pipes which autonomously manage their rate of flow, and even a self-unfolding IKEA closet are all conceivable. Could the Swedish company one day actually eliminate the use of its legendary Allen wrench because Billy shelves and other pieces of furniture are able to build themselves?

The 4th dimension

4D printing is without a doubt an innovation, but is it really yet the next revolution after 3D printing (see ALPORA Insights on Innovation No. 2 / 2016), the disruptor in the construction industry, or perhaps simply the illusion of a few gifted researchers who are more at home in the laboratory than on a construction site?

The fourth dimension in 4D printing is time: 4D printing is 3D printing plus time. A 4D printed object can systematically modify its form over time. In principle, this works in the same way as 3D printing and with the same devices, but with other materials. Upon the input of energy — e.g. heat, movement, and water — programmed material can transform itself into a new, previously defined state.

But as fascinating and innovative as this appears to be: Whatever researchers can do, nature has long been able to. Every tea rose unfolds in water, and so does basically every seed as soon as it falls to the earth, as does a fertilized egg cell which grows into a human. Therefore, using nature as a model (“biomimetics”), researchers at Harvard University were in fact able to create structures similar to those in plants which transform exactly according to plan under the influence of water. For this purpose, they developed a printing material made of a gel containing cellulose, which is the principal component of plant cell walls, as well as an algorithm which allowed the desired shape to be calculated. In this manner, they got a printed “orchid” to bloom with the help of water, almost as if it were the real thing. Biomimetic 4D printing is the name of this process which enables the creation of objects with integrated biological functions. This could be an important step towards tissue engineering, a method which allows biological tissue, body parts, and entire organs to be reproduced.

Hope for patients and companies

A potential goal of biomimetic 4D printing is, above all, its use in medicine. Researchers the world over are working on manufacturing organs which adapt to the body and, for example, are able to grow along with children. Researchers at Laser Zentrum Hannover are using 4D printing to mass-produce cochlea implants: Once they are placed in the cochlea, they mold themselves into the desired shape and perfectly adapt to their wearer. Using this method, a team of researchers from the Georgia Institute of Technology has developed innovative prostheses which are designed to help persons who have lost limbs in accidents or wars. In 2016, doctors at Xijing Hospital of the Fourth Military Medical University in Xi’an succeeded in implanting an innovative breast implant in a cancer patient; the implant allows human tissue to grow into it and ultimately replace it entirely. While silicone implants completely replace the organic breast and are not (permitted to be) biodegradable, the implant of the future should break down completely over time when the breast tissue has regrown.

Growth is desirable not only for human tissue, but also for the use of this technology in various industrial sectors. In the near future, 4D printing will revolutionize the corporate landscape, according to a prognosis by the consulting company Frost & Sullivan. The experts predict that apart from healthcare, the aviation, military, and automobile industries will also be using this new printing process, followed by other industries. 4D printing is vastly superior to conventional production methods when it comes to performance, efficiency, and quality, and allows for the manufacture of new products with improved characteristics, explained the consultants. Therefore, they accelerate the process while simultaneously reducing the amount of work and costs.

Better, more cost-effective, and faster, is the premise, although they are initially significantly more expensive, as is the case with all new technologies. But investing in this innovation is expected to pay off over the long term as soon as the procedure is suitable for mass use. This is because the costs of 4D printing will then fall, and other industries will also jump on the 4D train. The development is being driven by the favorable funding environment; associations, research laboratories, universities, companies, and other investors are poised to invest in this highly promising technology. At the moment, 4D printing is at the threshold between research and development. For successful, particularly innovative companies, the path to finding the silver bullet begins with crossing this threshold.