3D-Printed COVID Stuff That’s Not Face Shields Or Ventilators

The coolest stories from the hacker community this year are the rapid manufacturing efforts that have gone on in response to COVID-19. But [Mark Rehorst], frequently featured on these pages for his clever takes on 3D printing, shared a couple of really useful prints that are out of the ordinary for what we’ve been seeing: bias tape folders and ear savers.

Initial bias tape folding jig design by ongaroo

Tailors around the world have threaded the needle on grass-roots face mask production. One of the more labor intensive parts of sewing a face mask is the fastening mechanism. With elastic straps, the size of the loops needs to be just right, but when you run out of elastic you need to sew straps. Bias tape is a popular material for that, but it’s finicky to fold and hold it for sewing. [Mark] heard of the need and grabbed a bias tape folder design from Thingiverse. These work kind of like a zipper, pulling in the unfolded tape on one side and feeding it out the other, folded nicely for the needle and thread to take over. But of course he did one better, refining the original design to use less plastic to get more parts, faster, with less material use — win, win, win.

Speaking of those mask straps, it turns out the backs of your ears don’t like being rubbed raw for back-to-back-to-back 12-hour shifts at the hospital. We’ve seen health workers, themselves skilled hackers, recommend sewing buttons onto a headband to hold the mask straps.

But the 3D-printing world has an “earsaver” that provides a series of hooks on a plastic band that loops behind your head. Once again, [Mark] iterated on the standard design, finding ways to reduce material use while also fitting more units onto a single printer bed.

These functional prints are glamorous in their own ways. We love seeing hard-working 3D-printed items, but we love it even more when we see them getting better and better with each new version. The back story and the design files for the improved versions are available on his project writeup. Go [Mark]!

42 thoughts on “3D-Printed COVID Stuff That’s Not Face Shields Or Ventilators

      1. I confess that it is not an area where I claim any expertise (though I do own a sewing machine, and once made a wedding dress…). It seems that “snap on” is now a common type ( link to a YouTube video, but using bit.ly as I don’t like how embedding a YouTube link takes over the entire comment thread : https://bit.ly/34ZjSu9 )
        And I see snap-on adaptors for many types of sewing machines. It also looks like an easy interface to print. You just need to clean out some holes and push in a metal pin.

      2. actually if you look at what these are at a sewing store, these are made to feed the material strip through to make it easy to IRON the raw edges to the inside thus making it then easy to attach via sewing machine to the other piece of material (in this case a mask). The 3D printed object isn’t supposed to attach to a sewing machine foot. Used these for years back in the day making quilts… until I built my first 3D printer…then sewing machine gathered dust.

    1. Take a look at the two threaded holes that are undoubtedly in the bed of your home sewing machine (not sure about commercial machines) … eBay and other outlets have generic tape folders that mount to the bed with thumb screws. I have one for quilt binding that works great for tie-behind masks. It’s easy to use: thread your fabric strips into the device and hit the gas! Sew your strips together end-to-end and you only have to thread it once.

    2. My wife already had a bias tape folder. She asked me to print a bracket to hold it to the machine. We looked at the machine and the holder and came up with ideas using magnets, screws, etc.

      She ended up just taping the bias tape folder to the machine a few inches in front of the foot.

      1. Faster and cheaper to find a laser cuttable plastic that’s flexible enough to work. But of course there’s more waste VS 3D printing where for a simple flat shape like these nearly 100% of the material input becomes output product.

    1. Barrel of monkeys monkeys are being used some places, tried twice to post a link but post keeps getting eaten, not even saying it’s waiting for moderation. Odd, google it though.

    2. I actually think any old scrap of waste plastic could easily be used to make an earsaver simply by cutting it into a strip of the needed length and then cutting a couple slots to hold the ear loops. Milk jugs, 2 liter soda bottles, etc., could all be sources of plastic.

      I’ve had some feedback from nurses on the printed earsavers- it seems that get tangled in hair easily. I recommend that the unused ear loop hooks be cut off with scissors or a nail clipper.

      1. I suspect the plastic of milk or soda bottles would be too flexible. The mask does need to be quite firmly pulled onto the user’s face. You could probably layer some up and glue them though.

        Good idea on the hooks in 3D printed ear savers.

    3. As someone who has already printed a bunch of these, the multiple hook positions allow for adjustability on an individual basis. Snug fit, no stress on the back of the ear

      1. Sorry, but I just don’t see the utility here. It’s great you’re helping but there’s so many of these projects that are completely over engineered when there’s plenty of substitutes most people have laying around.

        We’ve been using paper clips here. Quite literally free in both time and materials as I don’t know anyone who doesn’t have a few at their desk. We bend them so there’s an opening (A bit of a hook) on one end and loop the other end of the strap to be held captive by the paper clip. Super quick and easy to remove. With about 20 people using these there’s no complaints over fitment or getting caught in people’s hair like with the printed ones.

        1. Hey Moke, it sounds like you see the utility just fine. You are mistaking efficiency for utility. If you have a solution that works for you and people are happy with that’s great! Having distributed several hundred of the ones recommended by the NIH I can tell you I’ve gotten lots of appreciation from everyone who’s requested them and received them and not a single complaint. But that’s all anecdotal, the important thing is helping and finding ways to hack what we’ve got to make something useful. I would encourage you taking a more positive approach towards the efforts people are contributing vs putting someone’s effort down. If someone helps even one person be them a nurse or doctor or other essential worker, that is enough.

          You find your best purpose. Encourage others to find theirs. Try not to critique unless that’s actually being requested. Good luck and I’m glad you found what works for you!

          1. You’re right, utility was the wrong word to use here.

            That said, I don’t understand the desire to excuse inefficiency because it’s a good cause. Why not (as many others have mentioned) laser cut these and 3D print things that lend themselves to the tech? Or, why not use a simple solution anyone can make in seconds and use the move advanced tools to make things not as easily accessible to the average person? When all you have is a hammer, everything is a nail. Perhaps the folks printing these things haven’t considered the other options?

            I’ve got plenty of purpose currently, but that is completely irrelevant to this discussion. Not really sure why you view criticism as something negative. I understand you mean well, but my critisims were neither rude nor unreasonable.

    1. The local newspaper had an article last week about people making masks and offering them on Etsy.
      The sellers were getting mixed results.

      I think they should have designs on the face masks like the “Heath Ledger Joker smile”, or Darth Vader or Clone Trooper partial mask.

  1. The earsaver looks neat, but tell me why a piece of wire that you can bend would not work as well and you could crank hundreds of them out in an hour? Again I think the bigger part of the idea is to come up with something thart wlll actually make a difference. These hi tech prototyping solutions all fail badly because they don’t scale well unless you use them just for prototyping and then jump to some other tech for the actual product, such as injection molding.

    1. I agree completely that FDM 3D printing is generally a terrible way to mass produce anything. OTOH, when you have thousands of people with 3D printers, sitting around at home looking for something useful to print, you can create a lot of product in very short order. The real problem is lack of coordination and transporting the finished parts to the end users.

      The original batch of 50 bias tape folders I ran took over 20 hours. The redesigned version print in batches of 77 parts at a time in about 13 hours. The first batch of earsavers I ran, before the redesign, took over 2 hours to print. The redesigned version takes about 40 minutes and are more flexible than the original design, and survive being removed from the print bed better.

      There are alternative ways to make the earsavers, but short of spending a fortune on molds, I don’t see a faster way to crank out the bias tape folders. Of course, you could just buy ready-made bias tape…

      1. Some things you are stuck with limited ways to make, but the idea is to think outside of the box. It is interesting that you mention tape because another thing I see a lot of is sewing masks. Why sew when tape is so much faster? It is kind of people to chip in, please don’t get me wrong there, but making 5 of something and having 1000 friends making 5 of something is still pissing in the ocean. Making 1000 and having friends make 1000 each could change the fate of a rural town. Assuming masks make any difference, and they are used correctly.

        When I used to do more sewing I cracked the SO up because I hated pins, I would tape the pieces together first. It worked really well.

  2. In the not a face shield or ventilator category I designed the ‘door doofer’ for unlocking keypad entry doors (entering the code with one action and then locking onto a door-knob attachment to unlatch the door) I think I mentioned it before, but have since completed the project.
    The STL’s (and design files) can be found here:

    I also made a web page that generates and then allows you to download STL files for your own custom code.

  3. The Earsaver that Mark redesigned was clinically reviewed by the National Institute of Health. Nice that he made a design that prints faster…but there are some solid reasons why the design is the way it is. The point of the rounded ends to prevent tangling in hair. While it might seem silly, the easiest way to ensure proper use of PPE is to make it comfortable.


    1. The hook is what catches the hair- it doesn’t matter if it’s round or not- if there’s a notch there, hair is going to get caught. One user only needs one set of hooks. Easy solution: clip or break off the unused hooks.

  4. This is not a recent discovery, in the Czech Republic we are using them for a while. The main reason is our government, they force(d) us to wear facemasks but didn’t provide us any of them, do we were forced to sewn our on our own.

  5. Absolutely must mention that ear-loop type surgical face masks are vastly inferior to strap type surgical face masks in terms of sealing against the face and properly filtering the .3 micron particles and virus-containing aerosols.

    The air leak in the ear-loop type on the sides of the mask means it’s basically useless for filtering virus-containing aerosols, because you end up inhaling air that isn’t filtered through the mask. The strap type doesn’t have this problem because it has a much tighter fit. You fix the ear-loop type by taping the edges of the face mask onto your face. Do a fit-check by inhaling while placing your hand over the mask, confirm that air is flowing through the face mask while you inhale.

    If you just want something that works, use an N95 respirator. BTW, this pandemic won’t go away until everyone in the world is wearing a face mask.

  6. It’s all about ensuring the pressure drop across the edge seals of the mask is much greater than the pressure drop through the mask, so that the majority of the air inhaled flows through the mask instead of the edges. It’s impossible to achieve an actual airtight seal between a paper mask and skin, but that isn’t necessary, only that the pressure drop is greater than through the mask.

    You can achieve the same amount of pressure drop even with a beard by increasing contact pressure, or having a wider seal interface. Or just use a hooded respirator. Maybe even some sort of gas mask or sealed helmet.

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