Making Things Big: Mechanical Engineering Professor A. John Hart explores the science and technology of nanomanufacturing
Associate Professor of Mechanical Engineering A. John Hart hopes progress in the science and technology of micro and nano manufacturing will enable new technologies ranging from consumer electronics and medical devices to arts and crafts.
“Being in mechanical engineering, in the area of manufacturing, I feel especially motivated to do things that can make a practical impact in how materials are made and how everyday things are improved,” Hart says.
His expansive interests include carbon nanotubes and graphene, 3D printing and other additive manufacturing processes and origami-inspired engineering. He is also interested in images of nano and micro-scale structures as media of art and communication, most famously his “Nanobama” microscopic faces (http://www.nanobama.com) of Barack Obama (2008) that were noticed by newspapers from Japan to Eastern Europe and drew attention from the White House. The tiny carbon nanotube images of President Obama were made from patterned carbon nanotubes and imaged using a scanning electron microscope.
|Nanobama Image. Courtesy A. John Hart|
Hart, who received his Ph.D. at MIT in 2006, moved back from the University of Michigan in July 2013 to join the MIT faculty. His Mechanosynthesis Group has straddled the two campuses during an 18-month transition, but already has grown to 17 members at MIT. Recent projects, done both at Michigan and MIT, include:
- An automated system for high-throughput synthesis of nanomaterials including carbon nanotubes, the Robofurnace (see related article on graduate student Ryan Oliver);
- Understanding of the role of chemical and mechanical coupling in carbon nanotube forest growth (see related article on Postdoctoral Associate Mostafa Bedewy);
- High-speed self-assembly of colloidal systems, in both 2D and 3D.
- A new concept for direct-write printing of solid particles at small scales, funded by the Deshpande Center at MIT.
- Exploration of the folding mechanics of paper, and design principles for achieving folding of paper into small-scale engineered surfaces and structures.
The Robofurnace project, which has its own website and Twitter feed, is being rebuilt at MIT with an improved mechanics. “With our combined expertise, we decided to simply take an engineering approach, an off-the-shelf furnace and mechatronic hardware to achieve two objectives: one, to build a machine that could help out the researcher, so increase the number of experiments that he or she could do per day, and second, enable improved control via the use of automation. I wouldn’t say it’s a breakthrough scientifically or technically, but it’s moreso inspired by a perspective on what tools we can build to improve the outcomes and the pace of our research and to use automation to discover hidden factors in the process,” Hart said.
Hart envisions a day when multiple labs will have automated systems like Robofurnace, automatically sharing data and using software driven analysis.
|Associate Professor of Mechanical Engineering A. John Hart with a folding paper cylinder. Paper's ability to fold and unfold many times and retain its integrity is a motivation for Hart's work on origami-inspired engineering. Photo: Denis Paiste, Materials Processing Center|
Hart was Assistant Professor of Mechanical Engineering, Chemical Engineering, and Art/Design at the University of Michigan from 2007 through June 2013. “I had a great time as a faculty member in Michigan, but it was a wonderful opportunity to come to MIT. I'm motivated to be the best group leader and mentor that I can be, and to chart a vision toward important new materals and manufacturing technologies," Hart says. His team at MIT includes three former Michigan students who who became MIT students, as well as two continuing Michigan students who are visiting at MIT, Ryan Oliver and Sei Jin Park, and seven new MIT graduate students recruited in 2013. Work on origami-inspired manufacturing is led by graduate students Abhinav Rao and Megan Roberts; and digital printing is led by doctoral candidate Justin Beroz. Hart will be teaching a new graduate class starting in February on additive manufacturing; graduate student Jamison Go will be the lead teaching assistant for the course, 2.S998. Hart also plans to teach a professional short course on 3D printing and additive manufacturing over the summer.
Work in the group is supported by several companies as well as the National Science Foundation, Air Force Office of Scientific Research and Office of Naval Research, National, and the Deshpande Center at MIT. The group is affiliated with the MIT Department of Mechanical Engineering, the Laboratory for Manufacturing and Productivity (LMP), Microsystems Technology Laboratories (MTL), the Materials Processing Center (MPC), the Center for Graphene Devices and Systems, and the MIT Energy Initiative (MITEI).
Additive manufacturing, which is also called three-dimensional printing has made an impact in markets as diverse as medical and dental products such as publically traded Align Technology’s Invisalign-brand clear thermoplastic braces to jewelry from sites such as MakerBot, Etsy and Shapeways. Airplane makers are using 3D manufacturing to produce lighter, stronger parts using computational design and taking advantage of the geometric flexibility of the additive process. Airbus, for example, is adopting a 3D-printed metal jet engine hinge that weighs half of the conventionally made part it replaces.
Although overall 3D printing additive manufacturing industry revenues grew to about $2.2 billion worldwide in 2012, Hart still sees that most significant growth is yet to come. “By their nature, additive methods such as 3D printing are not are not going to replace high throughput manufacturing operations. For example, if you wanted to make a large quantity of this remote control on my desk, or something else, out of plastic, injection molding, for example, would continue to be a more scalable method because of what governs the physics of the process. Nevertheless, the emerging capability to "print" pretty much any shape you want, with some limitations, out of plastic and other materials, means that we can think of the small-volume manufacturing of a variety of customized objects and products. These can range from everyday convenience objects such as phone cases, to life-saving objects enabling new medical treatments. For example, I see emerging examples where custom medical implants can be printed from scan data of the patient."
Although he’s keeping details under wraps, Hart says his group is working on improving additive manufacturing at small scales, where materials could be polymers metals or semiconductors. "I'm also interested in innovative concepts for macro-scale additive manufacturing, how do you make the process of 3D printing a polymer or a metal 10 or 100 times faster or how do you make the cost 1/10th of the current cost," he says.
The Mechanosynthesis group includes visiting graduate student Ryan Oliver, left, Associate Professor of Mechanical Engineering A. John Hart, and Postdoctoral Associate Mostafa Bedewy. Photo: Denis Paiste, Materials Processing Center
New additive technologies could be more deployable in small shops than previous manufacturing infrastructure opening new markets for locally made, customized products. “It will be interesting to see how that affects the dynamics of craft fabricationand localized manufacturing, enabled by digital sharing of designs,” Hart suggests. “If you want to get something made, if the process to make it can be completely digitized, does it matter where it’s made or who makes it?”
Hart also is exploring paper folding as a model for using folding as a tool to transform materials into novel structures with functionality. The NSF-funded origami project is collaboration with researchers at the University of Michigan. “It’s also one of these areas at an intersection where I hope our expertise can be useful,” Hart says. “Paper is an amazing material, but what if you could make papers out of other things, paper-like materials, and what if you figure out how to in a real engineered way fold things at a wide range of scales.” Demonstrating a set of complicated folds on a typical letter size sheet of paper, Hart asks, “If instead of being 10 inches on a side, or say 100 millimeters on a side, what if I want it to be 1 millimeter on a side, how in the world do I fold it up like this? I’m not going to do it with my hands; I’m not going to do it with a little robot. I have to program that functionality into the material itself. I’m not saying what we think about what it might be useful for, but let’s just think about the process and if it could be made out of a novel nanostructured material with optical functionality or energetic functionality. I think that’s really interesting, also because of the versatility of folding as a transformational process. It’s easy to make things in sheets at very high speed and to pattern them in 2D. It’s much hard to build in 3D but transformation by folding presents a new opportunity. If you can bring to bear the materials manufacturing process and then mathematics of the performance of the material, then I think there can be a real interesting convergence.”
– Written by Denis Paiste, Materials Processing Center