These are troubling times, no doubt. The world is facing a crisis like none of us have experienced. It's up to us to band together and help out in whatever ways we can. I've started printing Face Shields to try and help just a little funded by donations from people in my local area I've made over 50 masks in 2 days.
Imagine what we could do for healthcare workers if everyone with a 3d printer did a few masks a day each. It would be amazing. So let's do this.
Since writing this post we've made a lot of progress. A good friend of mine Ed Ricker has made a YouTube video highlighting the work being done around the Triangle area in NC.
Bill of Materials
You will need:
- A 3d printer with a bed 185mm in size (Prusa Mini works just at 97.7% size)
- Lots of PETG filament preferred (PLA will also work)
- These STL files
- Overhead projector transparency acetate / clear binding sheets
- 3 hole holepunch
The Face Shield
The design I chose to print was this one.
Prusa also have an excellent Face Shield design but it requires elastic and takes more filament and time to print than this design. We're after getting PPE into the hands of people ASAP and so far what I've made has been warmly received.
With a little bit of care you can fit two bands at a time on the Prusa Mk3 bed (disable skirts to make it fit). And by reducing to 97.7% size I can fit one band on the bed of the Prusa Mini.
The exact STL I used is Visor_Frame_NORTH_AMERICA_letter_3-hole_v4.stl. Link here.
Each band takes around 40 minutes to complete on a 0.4mm nozzle, the design calls for 0.8mm (which I have on order) and should be printable in that configuration in around 20-25 minutes per unit.
Assembly takes seconds and can be done by anyone. Print the headband, punch 3 holes in the acetate sheets, slightly cut and round the corners of the sheets with some scissors (no fancy laser cutters required) and attach. That's it.
My wife cut 500 acetate sheets in a little under an hour.
Approximate cost to make
A completed headband weighs 12g. Spools of filament range from $20-40 a kg so let's use $30 per/kg as the average price. Assuming a perfect no waste scenario we should be able to make approximately 83 masks from 1kg of filament, let's call it 80 to allow for a couple of failures. This gives us about 38c per band in raw filament cost.
Electricity next. During a print the Prusa MK3 consumes about 100-200w so let's normalise that to 150 Watt hours per hour consumed. Electricity here in NC is 12.5c p/kWh. Therefore the electrical cost per machine per hour is about 2c.
Next we have the transparent overhead projector acetate sheets. Office Depot and places like that charge a lot for these relics but I found this ebay listing selling 200 sheets for $17.95 each. This works out to 9c per sheet based on that listing.
Therefore we have a total approximated cost per unit of 49c.
This obviously doesn't take into account wear and tear on machinery, people's time driving around delivering these things or their fuel or the fluctuations in raw materials cost but it should give you some idea of how the sausage is made. I've been suggesting to anyone who asks a $1 donation per unit and that seems to be well received. Any extra cash I have will be donated to charity at the end of this whole horrible saga.
Another option that seems very popular are the 'ear savers' for mask wearers. The STL in question is this one from Thingiverse user facfox3d.
These ear savers pictured above were printed at around 80% size so as to fill an entire bed with about 20 at a time. A bed load takes 3 hours so it is a good use of the 'overnight slot' of your printer.
Get the word out there. I used a mixture of Facebook, Nextdoor, Twitter and contacts through friends and family in the local healthcare networks in Raleigh. The demand is there. There is not enough PPE in the channels.
For example, NC Senator Jeff Jackson claims that they have only received 17% of the PPE ordered from the Feds.
Also look to join this group 'Masks for Docs'. It's been very helpful connecting me with those in need.
If you can print, please do. If you want to send them to me I can get them to where they need to go. I'm @IronicBadger on Twitter or @alexktz on Telegram. You can also donate if you don't have the means to print, reach out and I'll let you know more on this.
Stay safe people.