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3-D printing to the coronavirus rescue? Not so fast.

Hobbyists are scrambling to make substitute protective gear for health care workers, but some in the industry warn the products might not be up to standard.

Bennett Ahearn picked up one of the 3D-printed masks he made.Jessica Rinaldi/Globe Staff

Bennett Ahearn was teaching high school biology in North Andover until the virus came. Now, with school closed, Ahearn is busy in his home workshop, cranking out medical face masks on 3-D printers for health care workers on the front lines of the fight against COVID-19.

“I guess I’m putting myself on the line. I’ll keep cranking them out as long as I can,” said Ahearn, who’s made several dozen so far on four desktop printers. And he’s just ordered a fifth.

Ahearn is a soldier in a volunteer army of amateur and professional technologists firing up their 3-D printers and cranking out badly needed medical gear, such as nasal swabs for COVID-19 testing and personal protective equipment, as the availability of these items is in such short supply that it will take the medical supply industry weeks or months to catch up.


Bennett Ahearn is a Biology teacher at North Andover and has been churning out 3-D-printed masks to donate to Anna Jaques Hospital. Jessica Rinaldi/Globe Staff

“This is going to be a test for humanity,” said Greg Mark, founder of Markforged, a Watertown-based maker of 3-D printing machines developing a way to print swabs for COVID-19 testing. “This is going to be a time when the world comes together to fight a common threat.”

The big challenge for companies such as Markforged and the people who own 3-D printers is whether their machines, which are not designed for rapid mass production, can produce anywhere near enough of the millions of needed critical items. Moreover, should health care workers be betting their lives on safety equipment produced by a hobbyist in a home workshop without the precision and quality controls of a purpose-built factory?

“Many of the parts they make are not medical grade,” said Neil Gershenfeld, a professor at MIT and a pioneer of 3-D printing. In fact, the plastics used by many 3D printers would tend to trap virus particles, and increase the risk of exposure.


“You wouldn’t know that until you got sick,” said Gershenfeld. “This isn’t a place to do DIY epidemiology.“

Marc Succi, a radiologist at Massachusetts General Hospital, uses 3-D printing systems to make prototypes of new medical devices. But he said there’s no way anyone at his hospital would be allowed to care for patients while wearing a printed mask made by an amateur rather than the standard N95 medical mask.

“I can’t imagine that would be acceptable by anyone,” Succi said.

Yet last week, Mass General’s president, Dr. Peter Slavin, told NBC Boston that he’d welcome 3-D-printed supplies as a way to replenish his hospital’s depleted stocks.

“We have vast numbers of 3-D printers in this country,” Slavin said. “The formula for producing these masks is available online for free. I would hope companies across the country ... would start making masks later this afternoon.”

A 3D printer created a face shield at Markforged, a company based in Watertown that is dedicated to building industrial 3D printers. Erin Clark/Globe Staff

3-D printer users freely admit their masks don’t measure up to traditional standards. But they say their masks can be sterilized after each use, and contain removable filters that can be regularly replaced with clean material. Ahearn said he’s about to switch to a new kind of antimicrobial plastic embedded with copper particles that may render the COVID virus inactive.

Besides, they say that if the coronavirus epidemic worsens, and the supply of N95 masks dries up, their efforts might offer medical workers their best chance of safety.

Amy Wilson, marketing director of Lowell Makes, a nonprofit community workshop that provides 3-D printing resources, said that when her group posted the digital blueprints for a 3-D printed medical face mask on its website, they were inundated with requests from medical workers around the world.


“We’re hearing the desperation," Wilson said.

Lowell Makes has produced about 250 masks, though none have been officially accepted for hospital use. Mass. General tested one and rejected it, according to project leader Mike Rushton. Still, Lowell Makes has given two of the masks to nurses to try out. And the group plans to keep making them, to be ready for the day when local hospitals completely run out of FDA-approved masks.

Shuhan He, an emergency room doctor at Mass. General, is already desperate.

“This is really a scary time,” He said, “and we need to make sure we have the right protection.”

He helped launch GetUsPPE.org, a nonprofit group recruiting talented makers to 3-D print face shields — the clear plastic devices that protect workers from a patient’s bodily fluids.

He teamed up with a group of engineers on Facebook to design a face shield “that can easily be made and distributed across the country,” he said. He is testing the shield himself and if he finds it satisfactory, he said a national network of printer owners could begin making them by the hundreds every week.

And the Boston architectural firm CBT is using its 3-D printer to make the NanoHack Mask, which uses fabric snipped from a traditional N95 mask as a removable filter, so that one standard mask can be cut up and used by four or five workers. CBT is working with an undisclosed medical institution which will confirm the masks work properly before issuing them to health care workers.


Meanwhile, the state’s major 3-D printer manufacturers have joined the PPE arms race. Markforged is working on plastic nasal swabs needed to test patients for the virus. Prototypes of the design are being tested by a university on the West Coast, said Mark, the company’s founder. If they’re approved, the 20 printers he’s assigned to the task could produce up to 14,000 a day.

Sam McMahon looks at the 3D printer pattern for nasal swabs at Markforged.Erin Clark/Globe Staff

The company has also developed a prototype face shield and a printable face mask with removable filters that could be sanitized and reused over and over. The challenge, according to Mark, is finding the right kind of filter material.

“We call it the Apollo 13 program,” a reference to the ill-fated moon mission where astronauts had to redesign the space capsule’s air filter system in mid-flight.

Burlington-based Desktop Metal is also working on nasal swabs, in cooperation with the US Army. Chief executive Ric Fulop said that if the design pans out, the swabs could be mass-produced by dental laboratories, which already use 3-D printing systems to make dentures.

And Formlabs of Somerville hopes to have its factory in Ohio turning out 100,000 swabs per week, once the company’s prototypes win approval from researchers at local hospitals. Chief product officer David Lakotos thinks it’ll happen by week’s end.


In addition, Formlabs is working on a solution to the shortage of mechanical ventilators, which are essential in treating severe COVID-19 cases. Formlabs is testing printed parts called “splitters,” that could allow a single hospital respirator to be used by up to four patients at once. It’s also working on a printable air filtration device that would plug into a standard snorkel mask used by swimmers. The filter could be washed and reused.

Finished face guards awaited plastic shields at Markforged.Erin Clark/Globe Staff

Due to the severe shortages of equipment, the US Food and Drug Administration is allowing hospitals to relax their usual requirements and use protective gear that falls short of the normal standard.

But even if 3-D printers made world-class medical gear, they will never match the output of traditional factories.

In 2006, Gershenfeld launched the “Fab Lab” movement — a network of small manufacturing facilities with professional grade equipment. Today, there are about 350 Fab Labs in the United States and about 2,000 worldwide.

Gershenfeld said these labs are capable of building enough PPE gear to support their local hospitals, until the big medical suppliers can get up to speed.

“A lot of sites doing short runs adds up to the capacity of one factory,” he said. “We have thousands of these fab labs. "

Hiawatha Bray can be reached at hiawatha.bray@globe.com. Follow him on Twitter @GlobeTechLab.