Re-Purposing Your Robot to make N95 Masks

I hear ya! :slight_smile:

I just don’t want to crush some FIRST student’s ideas when the purpose here is to mentor and inspire them. In a few years they’re going to be out in the world taking part in all these… fun times.

My point is that this could be a good learning experience.

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N95 masks are electrostatically filtered. You could not breathe through a 0.3 micron pore filter.

Edit: MERV 16 HVAC filters trap 95%+ of 0.3-1.0 micron particles at a very high flow rate. Investigate this.

N95 masks do not have batteries, so can’t be “electrostatically” filtered.

Can’t tell if you’re kidding, but air passing through a membrane can eletrostatically charge it.

Edit: More info:

In some fibrous filters constructed from charged fibers, an additional mechanism of electrostatic attraction also operates. This mechanism aids in the collection of both larger and smaller particle sizes. This latter mechanism is very important to filtering facepiece respirator filters that meet the stringent NIOSH filter efficiency and breathing resistance requirements because it enhances particle collection without increasing breathing resistance.

yet millions of people are doing it. Consider the total surface area and the cumulative 0.3 “holes”. …yeah there are leaks too which reduce your 95% rating.
HEPA and N95 masks are rated to filter 95% of things greater than 0.3 micron.

I also saw a CNN (I believe) piece on work being done at Markforged to use 3d printing to make nasal swabs and face shields. I don’t think they are quite to the point of having tested, usable designs suitable for “mass production” yet, but I believe they are close, and it might be worthwhile to follow their blog for more information. I know a number of teams and their sponsors have access to Markforged printers, some of which may still be accessible even with schools closed.

!=

Please do research before asserting such things in times like these.
I’m sure we can all think of recent examples of people speaking with authority harming people.

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OK, my mistake. To me, “electrostatically filtered” applies to cleanroom filters with high voltage between 2 plates.

These materials have a permanent dipole charge, so yes they do filter based on an electric field. I guess that counts as electrostatic, but certainly not the same as the “typical” use of that term (for instance: https://en.wikipedia.org/wiki/Electrostatic_generator)

Sorry. Just a dumb 'ol nurse here. Please explain what is wrong with my statements. To my knowledge, they are accurate based on previous research and experience.

I may be a complete layman here, but when I google “electostatic filter” 5/5 of the results I checked were for passive static-electricity filters. i.e.“Certain air filters actually use static electricity to catch particles as they pass through the filter media. These are known as electrostatic air filters.”

I’m certain that in your day-to-day you’re more familiar with devices that utilize high voltage, but it looks like your environment is not what a layperson would consider “typical”.

Two things come to mind reading this thread:

  1. Not sure if Gore-Tex is breathable enough to actually breathe through. Emphasis on Not Sure.
  2. Electrostatic: The term is not ambiguous but its usage here is.

Ok, the gracious professionalism rating of this conversation is starting to tank rapidly. :slight_smile:

If I could summarize… the main problem in ramping up N95 mask production is not the availability of automation or labour, it’s the availability of (1) a suitable filter material and (2) a certified design using the material. All the other problems are already solved: given the raw materials and a certified design, any number of idled companies can start putting masks together in a matter of days. Many already have.

If anyone else has suggestions for material not already thought of, feel free to post it. If someone wants to test breathing through raw gore-tex, that would be an interesting experiment. If you can come up with another source of melt-blown fabric that nobody’s thought of, please shout it from the rooftops. :slight_smile:

Thank you.

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I think you hit the nail on the head with the “certified design” aspect. That was sort of the focal point of this whole concept. To collaborate on a common design that would be made available to teams; after all necessary approval of course, which is NOT something that is going to happen over night.
And as mentioned before, yes, my company & myself recognize the shortage of the raw material and the time / financial constraints to make more - which is exactly why are we looking into other approved alternative materials which we would NOT ask teams to make in house.
My fault for not clarifying that up front with this post.
Furthermore, I figured since the tooling is basically die cut and thermoform, overall output could be increased by leveraging students & mentors who are likely respectively out of school and work now. I understand many of the automotive tier 1’s and OEMs are retooling for N95 production. There is no doubt in my mind they will burn through the current approved materials faster than a collaborative FRC effort. Plus with a ton of smaller “shops” for the lack of a better term, it helps promote the social distancing that full-scale plants will struggle with.
So this isn’t going to be an overnight project. There are many layers of red tape & developmental hurdles to overcome first.

I know many N95 masks are made from a layer of “melt blown” polypropylene sandwiched between to layers of “non-woven” polypropylene. Now I know the “melt blown” is near impossible to get without the machine that actually makes it. But what about 3 layers of simple non-woven polypropylene? That’s a lot easier to find. How much do you think it would filter? How do you think we could test to find out?

We have some people looking into the CDC and FDA’s functional objectives; filtration, moisture absorption, C02 retention, heat retention, etc. And of course cost and availability.
And you are 100% right about the almost non-existent availability of the material which is for sure going to only be available to large scale manufacturing such as 3M or any of the re-tool(ing) automotive plants.
Multi-layer non-woven >PP< is among the 100+ possible candidates depending on denier and compression.

Among the automotive industry I’m seeing more interest in making ventilators. The designs are proven, and the materials (injection molded plastics, fasteners, etc.) are a better fit for the automotive supply chain. At least one ventilator maker has partnered with GM and GM has their design. Tesla is also trying and claims they will have 1300 ready this week. I wonder about the electronics, but given the relatively small volumes I think the factories in China could make ventilator electronics boards in a hurry.

Masks are a concern but there are some very large forces being brought to bear on the problem. I’m a pessimist, but not when it comes to human ingenuity at solving problems. If you have a workable solution, by all means, continue.

The biggest thing right now is slowing the spread to buy our heroes in the health care and medical manufacturing industry some time. Definitely follow physical distancing rules. Do everything you can to educate others (calmly and patiently because people don’t like hearing things they don’t want to hear). Disinfect surfaces. Self-quarantine if you show symptoms. Governments are right to be reluctant to use draconian measures, but if people don’t follow quarantines voluntarily, the government is going to be pushed to enforce quarantines. Soldiers make terrible police officers. It’s better if everyone pulls together on this.

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This, this, this - especially the last one. We are education & outreach organizations first. Lean into that strength.

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Sorry if I came off a bit harsh… Cabin fever’s got me on edge .

It takes a remarkable amount of energy to push air through a filter. I’m not knowledgeable to explain it with physics, but try doubling up a soft t-shirt or a sheet and breathing through it. Not super easy. Now consider that a .82 mm of dense unwoven fiber is only 43.7% effective1. Conversely, an electrostatic melt blown filter uses comparatively sparse charged strands of plastic to attract and capture the particulate (think of a balloon sticking to the wall after being imbued with a charge). This ALSO means that electrostatic filters are effective at capturing particulate under their rated size (0.3μ). this last part is very important as SARS-CoV-2 itself is found to range from 0.05-0.2μ.

No worries. Cabin fever and events have most of world on edge.

I understand your analogy. A N95 mask is not hard to breath thru. Not easy either, but I can work hard in my yard and not experience respiratory difficulty. And that’s with a mask with LOTS of dust, dirt, pollen, etc. on it.

From another post I made:
…As explained to me by our infectious disease doc, the rationale behind using a bandana, cloth mask… any less than ideal protection, is to keep you from touching your face (mucous membrane areas) with “dirty” hands. Yes, you can still rub your eyes…

The cloth material will not physically stop something as small as a virus, or bacteria for that matter. Heck, it might not even stop smoke particles which you can see! Having said that, the virus is held in, and travels via the droplets of saliva/sputum when a patients cough/sneeze, etc. The cloth material will stop and trap the droplets.

Ideally, at this junction of rationing PPE, the bandana/cloth is a stop gap measure until production ramps up for proper PPE. You all know this. The bandana should be worn OVER the N95 to help preserve it’s life span.

So, with the above thoughts, perhaps an interim solution is to build cheapo face masks with material at hand and with skills that have a low entry threshold. That’s not to imply FRC are not capable, but my experience is that FRC teams are not really familiar with production runs. That is a skill set not yet developed (I have a hard enough time getting the students to use a mill/lathe stop when making multiple parts…). So make something that will minimize adverse events by starting simple rather than something as simple (yet complicated) as a N95 mask.

Our team is planning on manufacturing hydroxychloroquine instead. Thanks for the offer though.

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