Crazy time !
I was asked if it was feasible to print a facial mask to protect from virus, to be used by normal people or also for medical teams.
So I decided to run some tests and see first hand some feasibility and if these can somehow works.
I am kind of skeptical about the feasibility and functionality of such solution, then I did find some people pointing out to a project.
At this time I'm NOT endorsing in any way to use this mask as real solution since too many questions are unanswered and potential CO2 accumulation is possible !
First of all, here some links to this project .
Is quite important to state that currently, this and similar projects, need to be considered a way to prolong the life of common surgical masks.
These are NOT TO BE CONSIDERED equivalent to N95 type masks or respirators !!!
Let me be repeat that :
THIS AND SIMILAR PROJECTS ARE NOT DESIGNED TO BE EQUIVALENT TO N95 MASKS !!!!
G-code file preparation
Once downloaded the project from Thingiverse I did opened it with the slicer Cura 3.6.0 on LXDE Ubuntu 18.04.
The project is divided in three parts, so three different STL files are present.
Here the setting I used for all three STL files in the project:
- Material : Hatchbox white PLA
- Printer : Ender 3 Pro (stock but with yellow springs and glass bead)
- Shell :
- Wall thickness : 1 mm
- Wall Line count : 2
- Infill :
- 10
- Cubic
- Material :
- Printing temperature : 200 C
- Build plate temperature : 60 C
- Enable retraction
- Speed :
- Print speed : 60 mm/s
- Build Plate adhesion :
- Skirt
The file was then uploaded to OctoPrint for the print.
Instructions
The project "as is" is ready to print and I did print it without any adjustment.
Results
(the results will be updated as I will be able to run more tests)
- a mask cap
- a mask grid
- the mask itself
After leveling the printer I started to print the mask cap and it was not bad actually.
It took about 24 minutes.
The mask grid took about an hour and the mask about 4 hours.
The first impression is kind of positive.
The mask has a good adhesion and is not too uncomfortable but something should be done, maybe smoothing the border and/or/adding something to create a better adhesion.
I'm not sure how effectively to test the mask.
I did put two elastic bands and I did try to use the mask "without filter".
After few minutes I did start to experience some dizziness, probably not enough oxygen or too much CO2 trapped in the mask.
I wonder how bad can be putting also the filter in place, much less fresh air and CO2 accumulation could become a big problem if wearing the mask for long time.
My suspect about the building up of CO2 in this type of mask is more than founded, also a very famous maker, Naomi Wu, raised the alarm for this type of mask, as described in this article.
The risk of this types of mask so needs to be evaluated very carefully.
They are not designed to handle correctly the CO2 expulsion and a right intake of fresh air.
Basically a small hole is used to carry in the fresh air and out the CO2 and a filter is placed on it ... this can be quite dangerous.
It is possible to run some measurements using some CO2 sensors, however at the moment (March 2020) is impossible to order them since everything is shutting down.
I maybe will resume the tests adding a sensor in the future.
The two pieces to hold the filter in place seems be able to help to have a decent sealing capability and easy to change the filter.
There are some important questions to answer in this particular application.
Probably I can say that is better than nothing but there is no guarantee it can prevent the virus to enter or exit the mask and I'm not sure if practically somebody can breath via this mask for long time without any discomfort and even danger from CO2.
Again, if the choice is between this and nothing, then of course go ahead.
The cost is low enough but it takes anyway about more than 5 hours to print one plus some extra time to prepare the mask and anyway filters are needed, so if you don't have surgical masks then this mask is totally useless.
The first impression is kind of positive.
The mask has a good adhesion and is not too uncomfortable but something should be done, maybe smoothing the border and/or/adding something to create a better adhesion.
I'm not sure how effectively to test the mask.
I did put two elastic bands and I did try to use the mask "without filter".
After few minutes I did start to experience some dizziness, probably not enough oxygen or too much CO2 trapped in the mask.
I wonder how bad can be putting also the filter in place, much less fresh air and CO2 accumulation could become a big problem if wearing the mask for long time.
My suspect about the building up of CO2 in this type of mask is more than founded, also a very famous maker, Naomi Wu, raised the alarm for this type of mask, as described in this article.
The risk of this types of mask so needs to be evaluated very carefully.
They are not designed to handle correctly the CO2 expulsion and a right intake of fresh air.
Basically a small hole is used to carry in the fresh air and out the CO2 and a filter is placed on it ... this can be quite dangerous.
It is possible to run some measurements using some CO2 sensors, however at the moment (March 2020) is impossible to order them since everything is shutting down.
I maybe will resume the tests adding a sensor in the future.
Comments
I like the design of this mask aesthetically and for keeping the filter in place.The two pieces to hold the filter in place seems be able to help to have a decent sealing capability and easy to change the filter.
There are some important questions to answer in this particular application.
- Is PLA suitable for the application ?
Specifically : - is it safe to breath through it ?
- Is it possible to disinfect it ?
- Is it sturdy enough ?
- It guarantee enough fresh air intake ?
- What is the best design ?
- How long can be used ?
PLA (PolyLactic Acid) is generally non toxic (see Everything You Need To KNow About PLA) so in theory should be OK to have it in contact with the skin and breath through it.
The PLA is considered to be a porous material and thus this could be a problem.
Dirt and thus viruses could enter easily in a pore and be difficult to clean.
However it depends about how to clean it.
Dirt and thus viruses could enter easily in a pore and be difficult to clean.
However it depends about how to clean it.
Somebody suggest to use a solution of Sodium Hypochlorite (bleach) and water.
It seems a very effective solution against the corona virus (system used by the Italian Red Cross to clean up the ambulances after transporting infect people).
Maybe nebulized or immerse the mask in it and leave for at least an hour.
It seems a very effective solution against the corona virus (system used by the Italian Red Cross to clean up the ambulances after transporting infect people).
Maybe nebulized or immerse the mask in it and leave for at least an hour.
If the solution is not damaging the mask (melting) and if after it can be cleaned with distilled water (really not good to breath vapors of Sodium Hypochlorite) then the mask should be probably used.
Alternatively to sanitize the mask is probably possible to place it in a small environment filled up with Ozone for few hours.
Another point to be explored is how good the filter operate and thus how to attach the filter to the mask.
Mechanically speaking the mask is sturdy and should last safely for few months at least.
Conclusion
At this time I can not say this masks can be a viable solution, still too many unanswered questions about the safety of the material and the sealing capability and the air intake and filtration.Probably I can say that is better than nothing but there is no guarantee it can prevent the virus to enter or exit the mask and I'm not sure if practically somebody can breath via this mask for long time without any discomfort and even danger from CO2.
Again, if the choice is between this and nothing, then of course go ahead.
The cost is low enough but it takes anyway about more than 5 hours to print one plus some extra time to prepare the mask and anyway filters are needed, so if you don't have surgical masks then this mask is totally useless.
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