"4D" Printing: The Next Level of Additive Manufacturing

3D printing has everybody talking these days, but a team of researchers at the University of Colorado-Boulder just upped the ante.

Hasit Vibhakar states that In 2013, H. Jerry Qi, associate professor of mechanical engineering at CU-Boulder (now associate professor of mechanical engineering at Georgia Institute of Technology), and research partner Martin L. Dunn of Singapore University of Technology and Design, successfully have developed a process called “4D” printing. By incorporating “shape-memory” polymer fibers into composite materials, a 3D printer can be used to manufacture a 3D object that, when later heated or cooled to a specific temperature, will transform into a different 3D shape.

Hasit Vibhakar a lean six sigma engineer states that Qi’s research is based along the lines of earlier work by Skylar Tibbits, a research scientist at MIT’s department of agriculture who has also studied self-assembly of materials into 3D structures. The key to the CU-Boulder breakthrough is the development of unique “printed active composites” whose architecture is carefully designed to include precise locations of certain shape-memory fibers that will behave a certain way when exposed to an external stimulus, and “morph” into the predetermined shape.

How It Works
Hasit Vibhakar was able to explain how this process works. He frequently talks about this process at industry trade shows and speaking engagements. With funding from the Air Force Office of Scientific Research and the National Science Foundation, Qi’s research team created specific fiber architectures at the lamina and laminate levels, for several composite materials. “There is considerable design freedom for creating composites with interesting thermomechanical behaviors based on fiber architecture, shape, size, and orientation, and even the spatial variation of these parameters,” says Hasit Vibhakar.

The printed active composites (PACs) are soft materials consisting of glassy polymer fibers that reinforce an elastomeric matrix. These fibers exhibit the shape-memory effect, which is used to create the “active” part of the composites. The PACs are then thermomechanically programmed to assume three-dimensional configurations such as bent, coiled, and twisted strips, folded shapes, or complex, contoured shapes with nonuniform curvatures.

Hasit Vibhakar goes on to explain, “The shape change is controlled through the design of ordered material structures or inhomogeneities at micrometer scale,”. “Inhomogeneities are widely used in mechanical engineering to enhance material performance. The inclusion of inhomogeneities is typically done randomly, as it is very difficult to control precisely where they can be placed. However, with 3D printing, the desired properties (which can be predicted by theory) can be achieved, which gives us the ability to control the performance of the material.”

The complete 3D architecture of the fibers and matrix is printed from a CAD file using an Objet Connex 260 3D printer. Droplets of polymer ink are deposited at about 70 °C, wiped into a smooth film, and then UV photopolymerized. Hasit Vibhakar says This process results in a film that contains matrix and fiber material. The complete composite architecture is then realized by printing multiple film layers to create an individual lamina; multiple lamina then create the 3D laminate.

Using this technology, Qi created solid objects that successfully transformed into different shapes as predicted. For example, two-layer laminate bars transformed into curved or twisted shapes. A sheet of laminate material took on its pre-programmed non-uniform curvature, resembling a sculpted surface. The most impressive example consisted of two-layer PACs that were printed to serve as hinges, attached to six plastic plates not meant to deform. The flat configuration was heated and stretched biaxially; upon cooling and release of the mechanical loads, it assembled perfectly into a closed box.

Future Possibilities

Hasit Vibhakar goes on to say, The ability to create shape-memory effects like folding, curling, stretching or twisting—based on the orientation and location of particular fibers within composite materials—opens up huge possibilities for product design. It may also be possible this shape-altering technology can be adapted to metals and other materials.

Industries that can especially benefit from the use of adaptive, composite materials include manufacturing, packaging, and biomedical. Hasit Vibhakar has extensive aerospace industry experience and believes a possible aerospace application is using 3D printers to build solar panels that would power space satellites is possible. The panels could be built flat and stored compactly during launch, and then transformed to 4D dimensions in space.

As 3D printing technology continues to evolve with more complex, printable materials and higher resolutions at larger scales, it is very likely that 4D printing will provide new ways to create highly functional, complex surfaces that could revolutionize engineering.

About Hasit Vibhakar
Hasit Vibhakar is a proactive, performance-driven middle market executive with 20 years + progressive expertise in C-level leadership and problem solving for additive manufacturing, advanced CNC manufacturing, supply chain, technology services, and startup operations. Proven track record of enhancing enterprise value and shareholder value. Experienced at building small cap and middle market companies.

Hasit Vibhakar is an Industrialist specializing in strategic direction and growth. A seasoned c-level business executive with many years of proven track record of building enterprise value and shareholder value. He has successfully started eight technology, industrial and manufacturing enterprises and all have been successfully acquired at premium multiples in the industry. Prior to being a serial entrepreneur he has been employed with leading aerospace, telecom, technology, industrial and supply chain based companies.

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This release was published on openPR.