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Introduction: The Easy Face Shield
When the COVID-19 pandemic shut down all schools in New Jersey, I had time to read the news and see what was going on around the world. It was clear that there was a huge shortage of Personal Protection Equipment (PPE) for our front-line workers, especially where I live (greater NYC area of Northern NJ). I was inspired by the movement taking place by thousands of DIY makers using their shops and equipment to craft respirators, splitter valves, masks, shields, and all kinds of PPE to support those who were supporting us. I wanted to help.
I teamed up with 10 Tech/Engineering teachers from local districts around me to bring home all of our 3D printers from our schools (45 in total) and setup shop to begin to produce PPE. There were tons of great models out there to pick from, we began producing and donating everything we could to support our local hospitals.
After a few weeks and a few thousand donations, I had found ways to improve some of the popular PPE models out there, specifically face shields. I found that the more popular and preferred ones were also models that were difficult to assemble or too large for the average classroom 3D printer's build plate. In this instructable, I outline the creation of the Easy Shield or E Shield, as well as included all models and assembly instructions. Models and change logs can also be seen on my the model's thingiverse page here or the public Onshape document here.
It is important for me to point out safety before proceeding. Manufacturing PPE via 3D printers in your home has many risks and specialized care and precautions should be taken to protect those you interact with. I urge all of you to read through the phenomenal guidelines created by Prusa 3D here.
Step 1: Inspiration From Existing Solutions
As previously stated, there were tons of great models out there to pull from. I want to highlight two specifically that provided inspiration for the E Shield:
The Prusa Shield - A pioneering product that was quick to release not only models, but guidelines for assembly and care. Pros: multiple sizes available, comfortable, easy to clean, stackable mass printing options Cons: slow to print, lots of material, difficult to assemble
The 3D Verkstan Visor - A quick to print and assembly model that was recommended by medical staff. Pros: Quick to print, quick to assemble, little material used, stackable mass printing options Cons: too large for many printers, uncomfortable, easy to lose rubber band
From printing, assembling, using, and receiving feedback from hundreds of medical professionals, I had a good idea of what changes I wanted to make in order to create the E Shield:
- Small enough to fit on average classroom printers (150mm x 150mm)
- Easy to assemble, use a 3-hole-punch pattern
- Quick to print, under an hour with little material usage
- Maintain comfort and ease of use
Step 2: Version 1
Version 1 was the pioneering proof of concept for the E Shield. Overall build size was about 150mm x 150mm x 11.5mm (LxWxH) so it could easily fit on our Lulzbot Mini printers, and we could print three at a time on our larger Lulzbot TAZ printers. It was also quick to print at about 50 minutes for one shield.
Most importantly, it was easy to assemble. Unlike the Prusa shield and some versions of the 3DVerkstan, a standard 8.5" x 11" three hole punch could be used to punch the sheets and assemble the shields quickly. See the assembly section of this instructable for more details.
For print settings, I use the following:
- Material - PETg
- Layer Height - 0.3
- Fill Density - 20%
- Supports - No
- Bed Adhesion - None
Step 3: Version 2
After printing, assembling, and providing version 1 to frontline workers, we gathered some feedback and ways to improve for version 2.
- Increase the amount of forehead room to accommodate for larger respirators or goggles
- Decrease the size of the "nubs" holding the plastic sheets to reduce the chance of ripping
- Add a hole rather than a hook so the rubber band could stay attached to the shield
The build volume and print settings remained the same as for version 1.
Step 4: Version 3
After printing and donating hundreds of version 2 shields, we felt pretty confident in the design and received excellent feedback on the comfort and ease of use. There was only one component missing that other existing solutions were able to do; stackable shields for mass printing
To achieve this goal, the following changes were made to the V2 design:
- "nubs" were lifted and centered on the shield frame
- support ribs were added under the nubs
- holes in the forehead rest were removed
For stacking, I found that separating the shields by 0.013" worked best in ease of separating, and maintaining print quality. We have successfully begun to produce stacks of five shields without issue on our Lulzbot printers.
For model slicing, I have only testing on Lulzbot printers and I am uncertain as to how other printers will react to the model. Overall slice settings remain the same as for V1 and V2 except with one change: You must enable retraction on layer changes. this reduced the "strings" left during head movement and allows the shields to separate easily.
Step 5: Version 4
In preparation for schools reopening, I began receiving a lot more face shield requests from tons of people for themselves, or even their kids. In response to this, I redesigned v2 to come in multiple sizes and to allow for a padded strip to be added for additional comfort. For all models, a three hole punch pattern can still be used in order to punch and attach the clear plastic for the shield.
The size used for versions 1 through 3 became v4 Medium, then two smaller and two larger sizes were added. The forehead rest remained the same size on all models to allow for a wide shield coverage, and for a common foam pad size to be used. Sizes XS through M will fit on smaller 150mm x 150mm build plates while sizes L and XL will require larger print beds.
The E Shield is still sort of a one size fits all, but now users can find the best possible fit and comfort. For added fit, use a hair dryer to gently warm the plastic to mold the frame into a better fit as demonstrated in the attached video.
Step 6: Assembly
Assembling any of the E Shield versions is quick and easy! Here's what you'll need:
Materials:
- 3D printed frame
- 8.5" x 11" clear plastic sheet (7mm - 12mm thickness recommended by most hospitals) I used these
- 7" or 8" non-latex rubberbands
Tools / Equipment:
- 3 hole punch
- PPE to wear during assembly if donating to others
Steps for assembling the E Shield:
- 3D print the shield frame
- Punch holes into clear plastic sheet
- Snap the sheet onto the frame by hooking one side of the "nub" into the hole, then pulling the sheet over the other side. Start from the center nub, then the outer side nubs
- If V2 or V3, slide the rubber band through the hole at the back of the frame, then insert the rubber band through itself to create a loop that can be pulled and locked over the ridge of the frame
- Remember to clean and care for your shield regularly during use!
Again if you haven't already, check out Prusa's guidelines for assembly, cleaning, and care of 3D printed PPE here.
Step 7: Next Steps
Hopefully the need for these shields will soon pass and we can stop making them. Until that happens, I plan to continue to produce and donate as many as we can and as many as are needed. I hope that this instructable helps you in the same way that Prusa, 3DVerkstan, and many other groups helped me.
What truly makes the E Shield unique is that it is comfortable and fits large respirators or goggles with ease while still being able to be manufactured on a 3D printer with a small build plate. As of now, I have no plans for a version 4, but that isn't to say there is no room for improvement. Version 2 is still probably the best model overall for easy of use and manufacturability, though the stacking capability of version 3 is vital when trying to produce a few thousand shields a week out of my living room.
Thanks for reading, stay safe!
***update July 2020, a version 4 has been added that includes additional sizes and redesigned for improved long-duration comfort.
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Source: https://www.instructables.com/The-Easy-Face-Shield/