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Early last week, Lennon Rodgers, director of the Engineering Design Innovation Lab at University of Wisconsin-Madison, got an urgent email from the university’s hospital. Could his lab make 1,000 face shields to protect staff testing and treating Covid-19 patients? The hospital’s usual suppliers were out of stock, due to the spike in demand prompted by the coronavirus pandemic.
After putting his kids to bed, Rodgers went to Home Depot and a local craft store and grabbed supplies, including transparent plastic and a couple of foam mannequin heads. Then he made a hasty prototype at the UW maker space by adapting a construction visor and presented it to his wife, an anesthesiologist. “I was really proud of it, but she put it on and said ‘This is way too heavy,’” Rodgers recalls.
Undeterred, Rodgers devised several lighter prototypes with two friends: Jesse Darley, a mechanical engineer at design firm Delve, and Brian Ellison, business development manager at manufacturer Midwest Prototyping. Rodgers’ wife provided more feedback, and talked the group through infection-control videos showing how to put on and remove face shields.
Last Thursday, the hospital approved the prototype. Rodgers posted the design online for others to use and the ad hoc collective began to ramp up production. They have since sent more than than 1,000 face shields to the UW Hospital. Ford has picked up the open source design, and expects to produce more than 75,000 this week at subsidiary Troy Design and Manufacturing in Plymouth, Michigan. The company plans to send the initial run to Detroit area hospitals.
Shortages of face masks, ventilators, and other medical equipment needed to care for Covid-19 patients and reduce transmission of the novel coronavirus have inspired engineers, makers, and hobbyists around the world. The Madison face shield, dubbed the Badger Shield, is one of the first to bloom into medically approved, mass-scale production.
“We’re filling a niche while the high-volume supply chains have broken down,” says Darley, who took the lead on design and authored the open source technical drawings picked up by Ford. If other manufacturers adopt the design, he adds, “I think we can ramp up production very quickly.”
Medical staff wear face shields over face masks while treating patients to protect against flying respiratory droplets that can transmit coronavirus, such as from coughs and sneezes. Bob Scheuer, director of materials management at UW Health, says protective equipment of all kinds has become hard to find, but face shields are especially critical because staff now wear them routinely.
Scheuer notes that staff disinfect masks between patients and reuse them, but they have to be replaced periodically due to wear and tear. The hospital in Madison doesn’t yet have a rush of Covid-19 patients, but preventing coronavirus spreading to staff is crucial. “It’s a downward spiral if we can’t keep them safe,” he says. “So far these new shields are working well for us.”
'Infection Control Approved'
Darley says engineers would typically huddle together over tools and materials to brainstorm on a new product, but social distancing prevented it on this project. He, Rodgers, and Ellison, who knew each other from design events in Madison, collaborated mostly over phone, FaceTime, text, and Google’s photo-sharing service. “It would have been much easier if we could have met in person,” Darley adds. They placed an order for overnight delivery of items from hardware supplier McMaster-Carr, which donated some materials.
The design work really came together, Darley says, after he contacted a hospital worker he knew from the local dog park and she brought him a face shield that he could measure and disassemble. To make more shields, it first was necessary to destroy one. “The biggest impression was how lightweight it was. It’s featherlight.”
Darley also admired how the shield had cutouts in the foam pad that rests against a person’s head, making it conform better to the curve of a person’s brow. The Madison team tried that too, but later discarded the cutouts to make it faster to manufacture. “We were going for good, not perfect.”
Midwest Prototyping took the lead on assembling prototypes. Rodgers got feedback from the hospital as they worked, and sometimes jumped on his bike to deliver materials or pick up the latest version so his wife could try it. Those comments led the team to lengthen the faceplate, and to switch to latex-free elastic. UW-Madison professor Tim Osswald, an expert in polymer engineering, helped select materials and find suppliers, and a local plastics company created a custom die to punch out faceplates more quickly.
On March 18, the volunteers dropped off the latest prototype at the hospital for testing. The following morning, last Thursday, they received a terse email: “Infection control approved.” Midwest began to prepare larger production runs, and Rodgers posted Darley’s drawings online along with a plea for suppliers, manufacturers, and medical facilities in need of shields to get in touch. “I’ve been fielding calls from individuals up to huge organizations wanting to do this,” Rodgers says.
Ford is the largest company to respond. A company spokesperson says the company has adjusted the design for mass production and anticipates making 100,000 a week by next week. Ford’s vehicle production is currently on hiatus and is only manufacturing activity is for Covid-19 supplies, such as the open source face shields, and working with 3M and GE to produce respirators and ventilators.
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Rodgers says Summit Medical, a medical device manufacturer based in Saint Paul, Minnesota, is also picking up the face shield's open source design. His site has received requests for more than 1 million masks, including from people claiming to represent the states of New York and Wisconsin.
The Madison team’s design requires just three pieces and is relatively straightforward to make. Transparent faceplates measuring 9 by 13 inches are cut from large sheets of polyethylene using a laser cutter or cutting die. A 13-inch elastic headband is then stapled to each faceplate—Midwest Prototyping has been using electric staplers Rodgers bought in bulk at an office supply store. A short length of self-adhesive polyurethane foam 1 inch thick is added to position the faceplate on the wearer’s forehead.
McMaster, the project’s original supplier, quickly ran out of the necessary materials, so the group turned to foam and plastic suppliers. So far, access to materials hasn't been a problem, according to Darley.
Results of other volunteer efforts to help with medical supply shortages have been mixed.
Surgical masks and N95 masks with advanced filtration, worn by medical staff under face shields, are also in short supply. After the Centers for Disease Control and Prevention said fabric masks could be used as a “last resort,” individuals and fashion houses began to sew face masks for hospitals. Some hospitals are accepting fabric masks, but others, such as University of Michigan, have announced they will not. University of Wisconsin Health said Tuesday that anyone planning to donate sewn masks should give money, blood, or food for medical staff instead.
Engineers from a manufacturer in Brescia, Italy, lit up headlines this month when they used 3D printing to make single-use ventilator valves needed to care for Covid-19 patients—potentially saving lives. But Cristian Fracassi, one of the engineers, later posted a video declining to release the specifications for others to print their own valves, saying the local hospital now had enough of the components and none others had requested help.
Designs for 3D-printed face shield components have also begun to circulate online, and some companies and individuals are producing them and sending them to hospitals. Darley says the Madison team chose not to use 3D printers because they are generally too slow, and too distributed, to create the surge of supplies needed. More conventional processes like die cutting and slicing lengths of foam are much faster and cheaper, he adds: “We need very high volumes.”
Engineers at the interactive science museum the Exploratorium in San Francisco came to a similar conclusion in their own face shield project that will supply Bay Area hospitals. A spokesperson for the museum said its team reviewed a 3D printed design that took three to six hours to make a face shield, then devised a process involving computer-controlled cutting tools that produces a completed shield in minutes. The museum expects to make 200 or more face shields a day for the next few days and will publish its designs for others to use.
Darley is considering a second protective equipment design, based on open source, for a PAPR hood, which offers extra protection by combining a faceplate with fabric covering the head and shoulders, supplied with filtered air by a respirator. One challenge is that it would need to interface with the specific connectors of such a device, which may be protected intellectual property.
Rodgers says UW Hospital hasn’t alerted him to other needs, but he’s ready to heed any calls: “Now we have this network of manufacturers and a supply chain, maybe we can pull it off for a second one.” Ford’s next pandemic product line may depend on it.
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