[NEOPMask] - Respirator mask with removable filter

Description

WARNING: This is not meant to guarantee full protection against COVID-19 since the filter to be installed is up to the owner. Remember that effective filters are FFP3. The mask is aimed to stop the public from mass purchase of masks that shall be reserved to medical staff. Items required: Sealing strip (foam like - neoprene) / Suggested thickness 10 mm Chin piece L = 14cm Face piece L = 23.5cm I designed with a quite large space on the nose area and without a bottom layer in order to adapt to most of the faces. The one in the picture is printed in PLA (I would suggest to try TPU as well). I used thin silicone windows seals (5 x 5 mm) and already with this the sealing is perfect. If I close the front opening with hands it is basically impossible to breath. By using a thicker foam strip I believe that optimal sealing can be achieved on most of the faces. Print it and any suggestion is welcome. Remember: Print it for you, your friends and whoever and do stop buying professional masks. Medical staff seriously needs them. PS. I suggest to print is as in the picture since that orientation requires minimum supports. If you need the sliced file, text me. EDIT 23.03.2020 Filter cap added. Depending on the printer settings and precision, the cap the be just clicked in/out or (if it's loose) clockwise rotated for plug-in (end stroke present). I suggest a thick filter that will guarantee a better sealing and will make the click-in enough. EDIT 25.03.2020 Added inner neoprene sealing band 10mm x 10mm. The sealing level with the face is perfect and comfort increased. Working on some effective filters alternative at the moment. Will keep you posted. EDIT 26.03.2020 Created one-page website to ease distribution. https://3dsprint.wixsite.com/printable-respirator EDIT 27.03.2020 Chin area modified to better adapt to different faces. Already tested on male/female faces of different sizes. Print it, test it, leave a feedback on the website comment area! Thank you for contributing to the development. EDIT 29.03.2020 Added YouTube tutorial on website to guide people through correct assembly) EDIT 31.03.2020 Reduced thickness to 1.2mm (3 printing layers for optimal elasticity on the sides without compromising filling) - Print time reduced by 1h (with 0.4mm nozzle) Slightly increase of front intake area. EDIT 02.04.2020 Added Filter_Cap_Angle with inclined inflow channels. If you are using a HEPA filter or a piece of cotton, I suggest to use the file Filter_Cap_Angle. The slots for air intake are inclined in order to deviate the intake velocity of the flow. In this way air is forced to enter with an intake angle in the filtering media (rather than perpendicularly) crossing more useful filter volume and helping filtration by diffusion. It won't make it become a super effective filter and it's a free contribution. Other advantage is that the projected surface exposed to drops (if someone is in front of you) is virtually 0 (remember that ideally you want a DYI mask to be a shield more than a filter). Breathability is not affected since total intake area is similar to the other version. EDIT 06.04.2020 Filter_Cap_Angle (see above) optimized for better intake on filter area. Added Filter_Cap_Angle_SOS which is the same of the above one, with added SOS in morse code on the center area. If you want to customize your cap, contact me either here or through the linked website. EDIT 10.04.2020 Cheeks area slightly smoothed and bayonet lock correctly aligned. EDIT 20.04.2020 Since I have been asked to create a kid version, I am uploading 3D_Kid_Printable_RespiratorMask_FilterMod_v6 which is the same with a reduction of size of about 10% that makes it look less big on a small face. Filter area remains the same so you can keep using the same filter cap. For detailed dimensions, download the tech data from the website (currently only Italian but it's easily understandable from pictures). EDIT 29.04.2020 Added new version with reinforced area near string holes. This guarantees no damage even with extreme tensioning of strings. NOTE: Many DYI masks present a wide intake area in order to reduce the pressure drop and increase the filter efficacy. This makes sense for high level filters, such as FFP3/FFP2 which need to have a wide intake surface (the whole mask) since they capture the virus particles by different mechanics (such as interception and impaction) which are badly influenced by pressure drops. These 3D printed masks or dyi masks won't probably have that type of filter, but rather some cottons, fabrics or best case HEPA. Considering this last case (best solution), a standard one has a good filtration level with airflow up to 100 times the one of human breath. Moreover HEPA filters show a certain efficacy against viruses since they filter by diffusion which is a different mechanics, effective especially with low airflow (such as human breath). This is the reason why for 3D printed masks with homemade filters (to be used as last resort instead of pieces of clothes) I believe it is a better approach to keep the intake area as small as possible (always taking into account the ratio with the nose intake area). I see a 3D printed mask with homemade filters primarily as a shield and only secondarily as a low efficacy respiratory filter.

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