The current spread of the Covid19 (Corona Virus) across the world and more particularly across South Africa has put our country on a standstill. This is more evident in the production and distribution of medical personal protective equipment (PPE). What are 3D printable masks and how is it used? This article will answer all the important questions about 3D printing face masks.
The Current Pandemic
The current Coronavirus disease (COVID-19) is an infectious disease caused by a newly discovered coronavirus strain.
What is Coronavirus Disease (COVID-19)?
The Coronaviruses are a large family of viruses that may cause respiratory infections to the host ranging from the common cold to more severe diseases. Some of these severe diseases include the Middle East Respiratory Syndrome (MERS) and Serve Acute Respiratory Syndrome (SARS). The most recent Coronavirus disease strain is COVID-19. This current virus has swept the globe and infected hundreds to thousands of people in various countries and has resulted in the death of many people.
How Big Are COVID-19 Particles?
The coronavirus virions (particles) are spherical particles with diameters of approximately 125 nm or 125 microns. The smallest particles are roughly 0.06 microns, while the largest is 0.14 microns. This means that the size of the coronavirus particles is smaller than bacteria particles or atmospheric particle matter, usually known as PM2.5 particles. The size of the coronavirus particles is, however, bigger than some dust particles and gases.
Importance of Knowing About the Pandemic
It is important that people are aware of this deathly virus and know all the correct information regarding it. The best source is the World Health Organisation. The button below is a link to their website. 3DWhip encourages our readers to visit their website if you want to learn more about COVID-19.
Personal Protective Equipment – Medical Face Masks
Medical face masks have been designed and developed to protect medical personnel against viruses.
What Size Particles Can Pollution/Medical Masks Filter?
Several medical tests have been done to determine the effectiveness of pollution and medical masks. The tests are done to see what size particles can be filtered. On average the medical-grade masks can filter particle sizes of up to 0.007 microns. This is roughly ten times smaller than the coronavirus particles.
| Mask | % Particles Blocked |
| Nothing | 0 |
| Cotton Handkerchief | 28 |
| Surgical Mask | 80 |
| Cycling Mask A | 82 |
| Cycling Mask B | 84.9 |
| Cycling Mask C | 55.1 |
| Cycling Mask D | 82.8 |
| Teflon Filter | 99.3 |
| 3M 8812 | 96.6 |
| Dust Respirator A | 98.5 |
| Dust Respirator B | 99.7 |
Filtration Medium for the Face Mask
With the current shortage of medical face masks experienced across the world, it is becoming even more crucial to find other material sources that may be used to make or create improvised face masks. If the general public, patients and medical personnel in South Africa find ourselves in a position were no masks are available, an improvised (homemade or DIY) one will undoubtedly be needed. Realistically, it would be far better to have an improvised mask as opposed to not having anything. As a last resort. This can only be a last resort.
Researchers at Cambridge University tested a range of household materials that people have access to. These materials were tested to see if improvised face masks could be used as a last resort. It also looked at the effectiveness of filtering out small particle sizes. The table summarises the results.
| Material | % Filtration Effectiveness Against 0.02-Micron Particles |
| Surgical Mask | 89 |
| Vacuum Cleaner Bag | 86 |
| Dish Towel | 73 |
| Cotton Blend | 70 |
| Antimicrobial Pillowcase | 68 |
| Linen | 62 |
| Pillowcase | 57 |
| Silk | 54 |
| 100 % cotton T-shirt | 51 |
| Scarf | 49 |
The final results based on particle capture and breathability, the researchers concluded that cotton t-shirts (100% cotton) and pillowcases (cotton) might be suitable choices for DIY masks.
Facial Shape and Sizes for the 3D Printed Face Mask
In order for the mask to be effective, it needs to create a suitable fit for the user and be airtight. In order to get the most effective design and allow for other designers, additive manufacturing operators, and the general public to print the designed mask out correctly, thankfully a database has been developed by the University of Southern California. It has a range of facial feature measurements for different age groups and genders. This height is measured from the ridge of the nose to the chin of the person’s face.
If you need facial measurements to ensure the printed mask may fit, the button below will take you to the database.
3D Printed Face Mask
A 3D printable face mask can be used as a last resort. It can help contain the spread of the virus from an infected person to uninfected people.
Mask Design
There are currently multiple versions and designs of 3D printable masks. Each one has a unique shape, structural design, print times, components and various other attachments and improvements. The mask presented in this report is an optimised version available online and initially created by Lafactoria3D.
Scaling the 3D Mask Model
If you are 3D printing the mask for yourself or for someone you are staying with, it would be easier to measure the person’s facial height (from the ridge of the nose to the bottom of the chin). This will be your scaling measurement. We recommend that you use Cura to scale the mask in the appropriate distance based on the measured facial height. Please ensure that the scaling is uniform so that the mask remains in its correct form.
3D Printer Settings for the Face Mask
The print setting for the mask is presented below. It has been determined to print the mask fast but still keep it robust, stable and strong.
Main Filtration Medium & Alternatives
The intend filter for the 3D printable face mask is the surgical earloop masks. These have been tested to be effective in filtering small particle sizes. The mask allows for a single surgical mask to be used between 4 to 6 times. This is done by cutting the mask into smaller pieces.
In a worst-case scenario or as a last resort alternative materials may be needed to be used for the filtration process. We have two alternatives but please key in mind that these are only as a last resort or when no medical-grade masks are available.
Alternative 1
Using 100% cotton materials as a filter medium. Up to 3 layers can be used but will be dependent on the breathability of the user.
Alternative 2
Non-woven kitchen cloths and kitchen paper towels. The filter is made by using two pieces of the kitchen cloths in cross directions with a kitchen paper towel piece in the center.
Assembling the 3D Printed Face Mask
After the mask is printed and fit checked, a seal is needed around the ends. This serves for two purposes. The first is to make it more comfortable for the wearer and second is to create an airtight seal. Foam padding is a good material to do this.
Adding the remaining parts.
Safety of the 3D Printed Face Mask
Safety is the number one priority of any medical personnel. It is important to know that face masks are usually a last resort measure, particularly, 3D printed versions. The information is provided to you the reader but please understand that this isn’t the only available source. There are currently a number of online social platforms that educate people of the virus, the use of these types of masks, the use of alternative filter materials and the safety and concerns regarding this.
If using these types of masks, ensure that you disinfect them correctly after every use and also make sure that the filtration medium is inserted correctly. 3DWhip does not take any responsibility for any misuse, misinformation or disregard of the safety.
NOTE: A version of this 3D printable face mask is currently been submitted and is being evaluated for suitability for clinical use. Please see the link below to find out more.
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This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
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