An interesting study into dispersal mitigation by any face covering (Via Professor Erwin Loh/ Linkedin)
Effects of #mask-wearing on the inhalability and deposition of airborne SARS-CoV-2 #coronavirus #aerosols in human upper airway - With a 65% filtration efficiency (FE) typical for a three-layer #surgicalmask, wearing a mask reduces dosimetry for all micrometer particles except those of size 1 µm–3 µm. Wearing a mask reduces particle penetration into the lungs, regardless of the FE of the mask. #COVID19 (Physics of Fluids, 15 Dec 2020)
Well, so much has happened in the last 7 months! Thought this was particularly useful:
The video on this page pretty much sums it up, an amazing watch!
A useful page giving sterilisation information and techniques via PRUSA3d.com for PET and PLA as well as other material options. A key table copied below.
PLEASE do check back on the original article as information will change:
*higher Ethanol concentration significantly decreases its effectivity
Visor #STL files now on THINGIVERSE
DENSE BED FDM 3DPRINTING PPE VISOR FRAMES
Having seen the great work done regarding 3DPrinting of PPE visor frames and taking the popular 3DVERKSTAN design as a start point, I have remodelled it to allow 3 or 4 similar performing designs to be printed on each bed.
This hugely reduces down time in bed clearing, sorting and resetting:
3 new iterations, 2 with clip in arms (one design of those has clip reinforcement, but this is only an option and perhaps not entirely necessary). Add a spot of any glue before you squeeze the clip into place maybe a drop of superglue or Dichlorimethane/ "chlory" /solvent weld available HERE.
The 3rd design is something I have been thinking about for a few days and then came across this article in Business Insider showing some great designs replacing arms with elastic, again allowing more to be printed on any given bed size.
All are designed for acetate or similar sheet with 4 holes or 2 repeated from any UK/Europe hole punch at 80mm centres. No problem to double up the acetate or Sellotape sheets together at edges etc
NO ARM ELASTIC QUICK 3DPRINT:
I created a quick 3DPrint version with no arms and a useful spring clip, any looped elastic can be used such as:
Hair ties chained
All are designed for acetate or similar sheet with 4 holes or 2 repeated from any UK/Europe hole punch at 80mm centres. No problem to double up the acetate or Sellotape sheets together at edges etc, worth trimming the lower corners of acetate to prevent snagging in use.
STL DOWNLOAD 3 nested
STL DOWNLOAD 3 nested
CLIP ARMS 2nd variant (5mm with 8mm local clip reinforcement)
STL DOWNLOAD 3 nested
#STL files now on THINGIVERSE
Face Protection using POP bottle plastic
It's been an incredible 2 weeks since I started this blog/process; going back to the first post (at bottom) POP bottle plastic was listed as ideal to make quick useful face masks, since then the entire 3DPrinting industry seems to be churning out various frame designs for clear sheet protection.
Amazingly we had a great working design (from the rubbish bin) some time back, with build instructions and hand (laser and 3Dprinting) cutting templates as DXF and PDF as below (seems it took a while to catch on). Great effort Craig Lynch!
Do read the useful information contained in this blog below, WHO comments clarified, infographics and some great textile FILTER research
As per full instructions and PDFs below, and now updated with these supporting images created at the time; simple safe face mask and protection Hacks:
Have been looking at options to make these more visually appealing to younger kids/children and think this works great!
Based on the same principles as the original flat frame, full instructions can be found below:
The simplest and most reliable thing you can do is to wash your hands when going from public/outdoor to home/indoor environments, and wash your phone etc regularly; this useful info-graphic explains more:
STL created file for the 3dprinted version of the simple face mask frame, this can be resized as required in your Slicing software; please DOWNLOAD
The JPEG below can be downloaded and printed full page centred on A4 to give all the patterns needed for the following (please read this RESEARCH and scroll down to look at full instructions and images):
1/ BLACK lines: Basic pull frame, this can be hand/machine cut/made from 4mm to 6mm thick material:
Any rigid board, the DXF can be extruded for 3dprinting or used for laser cut path files.
Ideal for adding elastic to it and pulling your scarf (suggested by PINK lines) or any fabric closer to your face for better viral protection in both breathing directions.
Or you can bond your specific fabric to the inner face using the BLUE fabric pattern for cutting it to fit, full instructions further below.
2/ GREEN line: Full face cover (requires laser cutter and thin acrylic/Styrene/HIPS sheet):
Use the DXF to choose cutting paths and create a full face mask that can either have fabric bonded to it or simply pull your scarf closer to your face/under chin area once elastic affixed.
3/ RED line: Full face HOME MADE option (requires acetate sheet/pop bottle plastic etc):
Us the RED line to trim a face protector from any thin clear sheet. This can then be bonded to your mask OUTER frame surface (suggest superglue/non solvent UHU or double sided tape) as per overlap shown in image. Then use frame to pull in a scarf or add specific fabric as per full instructions below.
Please let me know how you get on and do send any suggestions or images showing finished pieces to: email@example.com
A new design that simply incorporates an eye shield, this can be cut from thin acrylic or thick acetate and we are looking into using large fizzy pop bottles to harvest otherwise waste plastic:
This filter/eye protection combination can be used along with a filter cut from a cotton/tea towel scrap (see research link below) and bonded as per photo below (use the Blue line pattern for cutting a fabric filter, fill instructions below), or simply used to trap a scarf or similar tighter to one's face.
It is ideal to remind someone not to touch their face and eyes with hands.
HUGE THANKS to Craig Lynch for making one of the original frames and proving its effectiveness and simplicity, our messages led directly to the new full face variant above!
Having shared some great research on homemade face mask filters ( I recommend using thicker tea towel cotton fabric or t-shirt cotton for breathe-ability). Do read the following as this research and my frame can be re-purposed for a riot mask with the addition of dampening the fabric used:
I have knocked up a quick DXF/PDF file that will allow anyone to either print out the plans and use them as a cutting guide or simple laser cut and make (acrylic/HIPs/Ply etc). Download Links below.
The DXF/PDF has a frame round it at exactly A4 size so easy to paper print for a pattern, you can of course hand cut the loop from a plastic sheet, thin ply etc.
✔Find any decent clean tea towel
✔Cut out tea towel fairly neatly round the Blue line to create your "filter".
✔Use the green lines (Shrek eared loop) as cutting guides or to create a #3dprint extrusion, laser cut or hand cutting to create the flat frame for your filter.
Material thickness suggested: 4 to 6mm. It wants some flex.
🌡Please ensure someone competent using sharp hand tools and/or the machines suggested is overseeing these procedures. Children should be overseen.
✔Bond edge of your tea towel filter all the way round one face side of the loop. IT will pucker a little but spread it evenly and ensure bonded all round.
I suggest using solvent free UHU, (superglue will be coarse on the skin if it bleeds through) or other rubber glue.
The simplest way to wear the mask is with the bonded fabric side skin side and the fabric poking through the Shrek loop,outwards.
I had designed this to bond the fabric on the outer of the frame when worn and wrap around the frame fully, but struggled to allow for tie-ing on the rubber over the Shrek ears etc) . However it is as simple as slitting the fabric to clear the Shrek lugs and making good with adhesive.
🌡Please ensure any adhesives are set and aired before placing mask near or on face.
✔The fabric should be baggy as the flat face mask extends under the chin to allow free speech and enable flat build simplicity. It should sit flat and from under the chin to the nose bridge
✔Find some elastic and use the Shrek ears to tie each end of your elastic to the frame, you can choose to do two elastic loops, one for each of your ears or one loop that goes over your ears and round the back of your head.
Links to DXF and PDF A4 for average large male version: (to adjust size for petite females/children, print A4 on paper and scissor cut out frame out and adjust print size percentage to suit smaller face user).
Please do share photos of mask in use and please get creative with fabric and colour combinations (also, with more work the design can be 2 part with friction fit to enable easy fabric changing etc)!
Hope it helps.