Building Face Shields
In these strange times, it is important that we do all we can to help our medical staff on the front lines. After months of political blunders, we suddenly find ourselves in a country completely unprepared for the Covid-19 situation at hand.
My wife is an Emergency Room physician, so I am constantly thinking that at some point she will come home and either be sick or I will get sick. To watch as our government fumbles to provide adequate support to people on the front lines, the burden is just too great and like a slow and painful train-wreck. I find myself unable to just sit in self-quarantine for whatever amount of time without making some impact.
My wife is an Emergency Room physician, so I am constantly thinking that at some point she will come home and either be sick or I will get sick. To watch as our government fumbles to provide adequate support to people on the front lines, the burden is just too great and like a slow and painful train-wreck. I find myself unable to just sit in self-quarantine for whatever amount of time without making some impact.
However, if you own a 3D printer and some material.. I believe you can make a difference.
The Design
There are various 3D face shield designs out there in the wild now. To start, there are various NIH approved designs: budmen, DtM, arista, etc.. However, the quickest design to implement is anything which uses a standard 3-hole punch for the visor to clear film interface. We do not recommend using adhesive for ease of sterilization.
We prefer the Josef Prusa face shield design overall (see google). The design is easy to print and stack-print, it also offers enough support for people who will be wearing these for 8 to 12 hours, and it does not seem to fog as much (which my wife prefers). Staff should be wearing face masks as well.. and this should be thought of as not the only layer of protection for staff.
We prefer the Josef Prusa face shield design overall (see google). The design is easy to print and stack-print, it also offers enough support for people who will be wearing these for 8 to 12 hours, and it does not seem to fog as much (which my wife prefers). Staff should be wearing face masks as well.. and this should be thought of as not the only layer of protection for staff.
Print material considerations:
Shield considerations:
Clear PETG, Polyester and others are in super short supply worldwide. After calling several vendors and getting in touch with larger shop manufacturing shield designs, the universal bottleneck seems to be in procuring 5mil to 20mil clear plastic. It is just not available.
However, there is a simple workaround to this problem. In most office supply stores you can easily find back stock of overhead projector clear acetate. This is our choice as it is sterilizable with alcohol, comes in 5mil thickness, and is still quite accessible.
Harness considerations:
Most people are trying to source elastic bands which are also very hard to procure at the moment due to the massive increase in demand. However, a simple workaround to the shortage in supply chain is to switch to rubber bands.
Caution: Most hospitals are non-latex zones and we do not wish anyone to go into anaphylactic shock over several headbands in the room. Although this risk it quiet low, the higher risk is with the care provider with a latex allergy.
Caution: Most hospitals are non-latex zones and we do not wish anyone to go into anaphylactic shock over several headbands in the room. Although this risk it quiet low, the higher risk is with the care provider with a latex allergy.
Again, office supply is ahead of you in this department. One material for considerations is EPDM (ethylene propylene diene monomer) rubber, which happens to be both UV safe and non-latex.
Waste considerations:
In most cases, care providers will likely choose to toss the rubber bands after shift rather than sterilize. However, for the foreseeable future we need reduce waste of PPE. Already most hospitals are recycling equipment by sterilizing with alcohol before and after use, and then placing the devices in paper bags for 5-7 days before they are reused. This protocol is not exactly what should be done, but it is what we are doing while there are no additional solutions.
For this reason, we did not choose to add foam for comfort to the design. The headband will likely end up being submersed in a chlorine-water solution or alcohol after shift. And if the face plastic is detachable, it can be cleaned properly with alcohol. Foam simply adds a layer where potential contaminates may live, in addition to comfort. If you are using foam in the design, we recommend single side adhesive so that it may be disposed after use, rather than glue.
For this reason, we did not choose to add foam for comfort to the design. The headband will likely end up being submersed in a chlorine-water solution or alcohol after shift. And if the face plastic is detachable, it can be cleaned properly with alcohol. Foam simply adds a layer where potential contaminates may live, in addition to comfort. If you are using foam in the design, we recommend single side adhesive so that it may be disposed after use, rather than glue.
Our Design Choice:
Construction:
- Headband: Prusa 3-hole 14mm design -thinner that original 20mm design
- Shield: 5mil 8.5x11" acetate -for overhead projectors via any office supply
- Harness: the best recommendation for this is non-latex 1/8" rubber bands
- #33 EPDM (3.5" x 1/8") -double bound so that 7" is achieved
- #117B EPDM (7" x 1/8")
Cost:
We estimate the cost at about $1.75 per shield.
- 1 kg roll of PLA can make about 33 headbands.. which is about $1.30 in plastic.
- 50 packet of acetate is about $10-12.. which is about 20-25 cents a sheet.
- EPDM rubber bands are about 5-10 cents in small bulk.
The Build
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| 3-hole 14mm Prusa remix |
After printing the 3D headbands, we used a standard hole punch. Many of the first designs had 4-6 holes. We recommend buying an adjustable 2-7 hole paper punch. This will allow the most flexibility in punching holes in acetate stock.
There is a recommended process which involves wearing rubber gloves, sterilizing the print bed, and also using a respiration mask while packaging and removing printed parts. These should be followed. What is most important is to sterilize the part with alcohol (as this does nothing to PLA), pretend you have Covid-19 and store the part for at least 3-days in separate containers to reduce transmission risks. The hospital we are working with does this before use and after use during recycling PPE as part of their protocol.
Additionally we have outsourced the hole punching to the hospitals, which is why we recommend a 3-hole design for attaching the clear film to the headband. This allows hospital staff to sterilize before use as well as follow appropriate protocol in a clean environment. For this reason we do not recommend 4-6 hole designs unless you also intend to calibrate the spacing of the hole punches and provide hole punches separately to the hospitals in need.
There is a recommended process which involves wearing rubber gloves, sterilizing the print bed, and also using a respiration mask while packaging and removing printed parts. These should be followed. What is most important is to sterilize the part with alcohol (as this does nothing to PLA), pretend you have Covid-19 and store the part for at least 3-days in separate containers to reduce transmission risks. The hospital we are working with does this before use and after use during recycling PPE as part of their protocol.
Additionally we have outsourced the hole punching to the hospitals, which is why we recommend a 3-hole design for attaching the clear film to the headband. This allows hospital staff to sterilize before use as well as follow appropriate protocol in a clean environment. For this reason we do not recommend 4-6 hole designs unless you also intend to calibrate the spacing of the hole punches and provide hole punches separately to the hospitals in need.
The Results
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While our impact is limited. We are helping and recruiting others with 3D printers.
Today, our first shipment of 60 units was delivered to Contra Costa Regional Medical Center (CCRMC) in Martinez, California! This county hospital has a very large catchment zone from Richmond to Antioch. There are also 500+ employees in need of proper shielding, not just the ER staff.
Additionally, staff are expected to grow as Gavin Newsom's creation of California Health Corps will pull retirees and medical students into the workforce to combat Covid-19. CCRMC has had a standing purchase order for over a month to buy 5000 shields. This order has not been filled, and we do not expect that it will be filled.
The members of IDEO GoFundMe group have donated 100 face shields to CCRMC after I reached out to them, and they are promising an additional 200+ more. Meanwhile, Mayfair Plastics in Michigan has created a single cavity injection mold based roughly on the Prusa design and they have promised us 1000 units soon. Also we have a verbal promise of 500 units from The Port Workspaces in Oakland who are building an NYU open-face shield design using clear PETG and laser cutters. And another 140 are coming from MakerNexus. In addition, we are also working on procuring and additional 1000 from Fictiv in SF.
Currently our main focus is on supplying CCRMC, however, we have also reached out to GetUsPPE.org who is coordinating efforts nationally for supplying PPE to facilities in need.
Currently our main focus is on supplying CCRMC, however, we have also reached out to GetUsPPE.org who is coordinating efforts nationally for supplying PPE to facilities in need.
