Modern Manufacturing Finds A Home

Manufacturing is one of WPI’s oldest educational and research disciplines, dating to the Institute’s founding and the noisy, gritty world of machine tools and metal foundries within the Washburn Shops. It is also among the university’s newest, most cutting-edge fields, occupying an emerging area where computer models, sensors, robotics, and new ways of custom-designing raw materials and custom-building complex structures layer by intricate layer are transforming how products are produced, repaired, and even recycled.

The interdisciplinary world of modern manufacturing at WPI has found a home in the new Advanced Manufacturing Center, which, appropriately enough, is housed in a former manufacturing building a short walk from the WPI campus on Sagamore Road. After WPI acquired the building, an idea emerged to use it as a new research center to address the significant growth of research in additive manufacturing at WPI and the need for specialized space for conducting it. Provost Wole Soboyejo championed the idea and, with Bogdan Vernescu, vice provost for research, secured the funding from WPI to undertake the design and construction.

“Manufacturing and materials are among the most active and well-funded areas of research at WPI,” Vernescu says, “accounting for over 30 percent of our research funding. The Washburn Shops is where this research has traditionally taken place, but that 150-year-old building is not an appropriate place for today’s advanced manufacturing research.”

The Advanced Manufacturing Center places WPI within the upper echelon of university manufacturing programs in the United States, which, in addition to burnishing the university’s reputation, will help attract outstanding faculty members and graduate students, along with additional research funding, notes John McNeill, the Bernard M. Gordon Dean of Engineering. “It is going to enable large, interdisciplinary, multi-institution awards—some really high-impact grants,” he says. “To me, this facility is a sign that WPI is growing up and taking its place among top research universities while continuing to do relevant, real-world work.”

Of the 20,300 square feet of space in the Sagamore Road building, about 6,000 consists of shared areas and 7,300 has been left unfinished to accommodate future expansion, leaving 7,000 square feet for active laboratories. The largest of these is the lab of Danielle Cote, assistant professor of materials engineering, whose work for the U.S. Army Research Laboratory first prompted the search for an off-campus location for advanced manufacturing research.

To date, WPI has received about $40 million in funding from the Army to pursue work related to a cutting-edge additive manufacturing process known as cold spray, which uses pressurized gas to accelerate powders to near-supersonic speeds. The powders adhere tightly to any metal in their path, making the technique an excellent way to repair broken parts—helicopter engine casings, for instance—or make new ones.

Much of Cote’s research has focused on the powders themselves, as their characteristics and quality greatly affect the success of the cold spray process. Her team has developed and extensively studied new powders made from aluminum alloys, refractory metals like titanium and tantalum, and copper, which can be used to apply antibacterial coatings to metal surfaces. They have also pioneered heat-treating protocols that increase the strength of the finished powders.

To support those studies, a 2019 award from the Army, plus other awards from NASA, has allowed Cote to purchase over four million dollars of specialized analytical equipment, including a scanning electron microscope, scanning calorimeters, and indenters, devices that can apply pressure on samples as small as individual powder grains to test their mechanical properties at the micro- and nano-scales.

“With only 300 square feet of lab space in Washburn, we simply didn’t have the room for all of this equipment,” Cote says. “But the biggest reason for moving here is to have space for actual 3D printers.”

Currently, a cold spray printer, controlled by a robot arm, sits inside a large metal box designed to shield researchers from flying metal particles and the noise of the cold spray process. Beside it is a concrete pad that will soon support a new wire arc 3D printer, which can produce large parts quickly using metal wires and an electric arc to deposit metal layer by layer.

“This is where the funding has been pushing us,” Cote says about working with metal wires. “We’re getting our feet wet and are excited to do with metal wire some of the same work we’ve done with powders.”

With its most recent funding award, Cote’s team is moving into a new domain: cybersecurity. Typically, information for 3D printers is transmitted to the machines wirelessly, making the process vulnerable to hacking. If part designs are intercepted, they can be altered in subtle ways. All but undetectable though normal inspection, the flaws could make the parts subject to catastrophic failure. “We are looking at ways of preventing such attacks,” Cote says, “and detecting them should they occur.” The work is being carried out in partnership with cybersecurity experts at WPI and other universities.

Additive manufacturing is also the focus of research in the Sagamore Road lab of Lin Cheng, assistant professor of mechanical engineering, who joined the WPI faculty in the fall of 2021 in part because of the availability of the facilities in the Advanced Manufacturing Center. His work explores what he calls smart materials, which are metal powders and other metals that are carefully designed to meet specific manufacturing requirements.

Cheng develops additive manufacturing models that employ artificial intelligence to teach the computer models about the underlying physics of the manufacturing process. That education begins with the governing equations for a host of physical phenomena related to material properties and the behavior of metals when they are, for example, melted by lasers in an additive manufacturing printer.

Since the governing equations provide only a partial picture of the additive manufacturing process, Cheng collects reams of data in his lab, which includes a 3D metal printer that uses metal powders as starting materials. Multiple sensors and cameras can be installed to collect data as a part is made, and an attached computer drives the machine using Cheng’s models.

“We cannot just do simulations and data-driven computational work,” says Cheng, who notes that experimental validation helps fill in the gaps in the models and increases their accuracy and predictive power. In an iterative process, the improved models are tested in the lab to generate new insights that further refine the computational tools. He calls this approach physics-informed artificial intelligence. “We integrate the data we have collected,” he says, “and let the models discover the governing equations—to discover underlying mechanisms from the complex physics. This is a kind of scientific discovery.”

Cheng’s physics-informed models will permit the design and manufacturing of complex structures that have, heretofore, been impossible to make. These include items whose microstructure varies from location to location or from the macroscale to the microscale, to precisely meet the requirements for a particular part. They may also include new classes of active materials that respond to changes in environmental conditions, such as a wing surface that alters its shape in response to changing stresses.

Cheng is also interested in using his AI models to optimize the way parts are made using additive manufacturing. The goal is to minimize or even eliminate imperfections that can impair performance. “If we can understand the physics of the manufacturing process,” he says, “we can optimize the microstructure—to essentially have programmable microstructure.”

Additive manufacturing “is more efficient and less wasteful than traditional manufacturing techniques, so it is naturally sustainable,” notes Cote, who says the Advanced Manufacturing Center’s emphasis on sustainability sets it apart from similar endeavors at other universities. The work of Jamal Yagoobi, George I. Alden Professor and head of the Mechanical and Materials Engineering Department, exemplifies that focus.

Central to this mission is a drying research test bed designed by Yagoobi and his colleagues in CARD and currently under construction at RBS (Redding Bakery Systems) in Redding, Penn. Funded by a $4 million award from the U.S. Department of Energy, the 10-meter-long machine can be augmented with cameras and custom-designed sensors that will monitor samples as they move along a conveyor belt and are dried by technologies developed by CARD research teams. “It will all be driven by artificial intelligence algorithms to achieve optimal drying conditions,” he says.

Technologies to be tested include noncontact ultrasonic wave dryers and a dielectrophoresis-based drying system that is an outgrowth of a multi-year, multimillion-dollar NASA contract for work in Yagoobi’s on-campus Multi-Scale Heat Transfer Lab, work that will help keep electronics cool in space.

“The beauty of these technologies,” Yagoobi says, “is that they will not only reduce energy consumption, they will also deliver optimum properties; a better product, with minimal energy consumption—that’s what this test bed will make possible.” The testbed will arrive in time to be featured at the 2022 International Drying Symposium, which will bring industrial drying researchers from around the world to the WPI campus in June (the first time the meeting has been held in the United States since 1986). “This will be an opportunity to showcase this system, which is the only research tool of its kind anywhere in the world,” he says.

Traditionally, the manufacturing process ended with the delivery of finished products, but today it is becoming a closed loop, where used products are recycled to become the raw material for new products. This stage in modern manufacturing is represented by three Sagamore Road labs. The first is that of Brajendra Mishra, professor of materials engineering and director of the Center for Resource Recovery and Recycling (CR3), an NSF I/UCRC run jointly by WPI, the Colorado School of Mines, and KU Leuven Belgium. CR3 conducts a broad range of recycling research, including the recovery of rare earth metals from electronics and red mud (waste from aluminum smelting). A second lab is being established by Yan Wang, professor of materials engineering, who invented a revolutionary process for recycling lithium-ion batteries. The patented process generates raw materials for new batteries, which outperform the originals. Wang’s research has been translated into a company, Ascend Elements (formerly Battery Resourcers), that is building a full-scale battery recycling plant in Georgia.

In his Sagamore Road lab, Berk Calli, assistant professor of robotics engineering, is applying his expertise in vision-based robotic manipulation and his interest in developing socially responsible technological solutions to recycling though two projects. In work funded by a $2.5 million award from the NSF’s Future of Work at the Human-Technology Frontier program, he is leading a team that includes co-principal investigator Jacob Whitehill, assistant professor of computer science at WPI, and experts on sustainability and industrial ecology at Yale and Boston universities. Their goal is to improve the accuracy and efficiency of recycling centers that sort and process paper, plastics, and other household recyclables.

In another project, funded by EMR Group as part of an NSF I/UCRC called ROSE-HUB, Calli is working on the world’s first robotic system that will aid workers involved in ship breaking, in which large ships are cut up to recycle their metals. The goal is to develop a mobile robot that can operate an oxygen- and propane-fueled torch to make cuts with guidance from a human expert, freeing the human from often dangerous work.

The human worker will determine the best location for each cut. The robot will then observe the desired pathway and compute the series of movements it will need to make to successfully complete the cutting operation. Testing prototype robot systems requires a large open space and a place to safely store oxygen and propane gases for the torch. When no suitable locations could be found on campus, the Sagamore Road building, which has an outdoor storage shed adjacent to a roomy parking area, offered the perfect spot, Calli says. “Without the Sagamore building, there is no way we would have been able to conduct these experiments safely.”

In addition to producing new knowledge and innovative technology, the Advanced Manufacturing Center contributes to the future of manufacturing, locally and beyond, in a number of ways. First and foremost, it is helping educate future manufacturing professionals with the most up-to-date experience, according to McNeill.  “Companies know,” he says, “that whatever they have worked on at WPI, our graduates will be conversant with cutting-edge technology.”

She says the availability of the Advanced Manufacturing Center has opened up her team to exploring new partnerships and new projects. “I don’t know what is coming next,” she says, “but having this space has removed a lot of barriers and opened the way to try new things.”