Comparison of small-batch face shield designs

3D verkstan

Link to original design

Manufacturing process

  1. 3D print plastic frame
  2. Punch holes
  3. Insert sheet onto frame
  4. Done!

Required hardware

  1. 3D printer
  2. Hole punch

BOM and suppliers

  1. 1x A4 transparencies - can be crowd-sourced from local residents/businesses. 
  2. 2m of 1.75 mm dia. PETG filament - we have some stock in the lab (for ~100 items). Can be sourced from the usual suppliers - Amazon etc. Unlikely to run out. 

Time to manufacture

  1. 11m to print on Ultimaker 2 with 1mm nozzle. Can easily be parallelised with multiple printers. 1m/piece if we had 10 printers.
  2. 10s to cut holes . Will go down with experience. Can be done in bulk. I'd say 1s.
  3. 10s to put on. Cannot be automated.

Total: Around 1.5 min. Units/person/day: ~250

Comfort

  • It feels reasonably stable on your head, I'll ask someone with a smaller head if it's OK for them as well. However, after a few minutes you can start feeling it biting into your forehead. It's not something I'd like to wear all day long. It also sits quite close to your face, basically resting on the respirator. I did not have issues with fogging, but my respirator had an exhaust valve.

  • Sharp corners of the A4 sheet are awkward as well, they sometimes catch on things.

  • Started biting into my forehead after 15 minutes. OK for short duration, but would not wear it all day.


Foam 1 - Peter's design

Link to original design

Manufacturing process

  1. Cut foam strips (11.2 sec)
  2. Cut foam squares (21.0 sec)
  3. Cut strips to length (4.8 sec)
  4. Punch holes in acetate (3.4 sec)
  5. Stick foam strip onto acetate (73.2 sec)
  6. Punch foam holes (38.0 sec)
  7. Cut/fit elastic (80.8 sec)
  8. Hot glue elastic (18.0 sec)
  9. Glue squares on (30.8 sec)

Required hardware

  1. A4 Hole punch
  2. Guillotine (or scissors)
  3. Leather punch (or skewer)
  4. Hot glue gun
  5. Ruler
  6. Pencil

BOM and suppliers

  1. A4 Acetate sheet (eBay, Amazon, stationers)
  2. 10mm EVA foam 126 sq cm (I used 5mm) (eBay, Amazon, camping store)
  3. Elastic (eBay, Amazon, haberdashery)
  4. Double sided tape (eBay, Amazon, stationers)
  5. Hot glue (eBay, Amazon, hardware store)

Time to manufacture

Total: 4 min 41 sec Units/person/day: ~90-100

Presumably will reduce with practice, jigs, templates, etc.

Comfort

  • Very comfortable. I've worn it all day.
  • Tough enough to survive me bumping into things when I forget it's on.
  • Vent reduces fogging.

Foam 2 - Hospital copy

Design based on commerical faceshield supplied to NHS

Design files for the laser

Manufacturing process

  1. Cut elastic band to size. Optionally cauterise.

  2. Cut transparent sheet to size and shape.

  3. (optional) Cut ridges in foam.

  4. Stick foam and strap to shield.

  5. (optional) Apply covering tape at front for cosmetics

Required hardware

  1. Laser cutter/punch/guillotine
  2. (optional) Hot wire foam cutter
  3. Scissors
  4. (optional) Hot surface to cauterise band
  5. (maybe) Stapler

BOM and suppliers

  1. Transparent sheet (300x190mm) - can be ordered or crowd-sourced from A4 transparencies.
  2. Foam pad (220x40x25mm). Currently using upholstery foam.
  3. Elastic band (450x25mm).
  4. Adhesive - can be contact adhesive or (if we staple the elastic) double-sided tape.

Time to manufacture (time in brackets for production solution)

  1. Cutting elastic band - 10s. (10s)
  2. Laser cutting - 50s incl. handling. Can be reduced by laser cutting multiple sheets at once or completely eliminated by using a die. (5-20s)
  3. Cutting ridges in foam - 50s. This is an optional step. Can be completely eliminated. I tested a design without ridges. Worked just the same. (0-10s)
  4. Gluing things - 20s to arrange, 20s to spray, 30s to dry, 30s to glue, 1 min to dry. Can be done in batches, so around 1min10s of actual operator time. Can be reduced greatly (and made much easier/more repeatable) by using double sided tape and stapling the bonds to the side (40s)
  5. Applying cover tape - 40s (optional). Could be replaced with a silkscreen for much faster operation. (10s)

Total:  5 min to make the prototype.            Fully operationalised solution (1min - 1min35s) Units/person/day: 100-250

Comfort

  • I would not mind wearing it all day. It doesn't touch your face mask. Looks quite good.
  • This is the design that the hospital already uses. It can easily be productionalised, I think we could drive manufacturing times down to 1min/piece if we keep improving our process/equipment. With the foam, I don't think it's reusable. .

Foam 3 - Hospital copy, productionalised

Design is revised form of above

Design files for the laser

Manufacturing process

  1. Cut elastic band to size. Cauterise.

  2. Cut transparent sheet to size and shape. Can be cut in bulk (5-10 sheets at a time!)

  3. Stick double sided tape to foam. 

4. Glue foam to transparent sheet.        5. Insert elastic through mask, staple it down.

:::

5. That's it!

Required hardware

  1. Laser cutter/punch for cutting sheet
  2. Scissors
  3. Hot surface to cauterise elastic band
  4. Stapler

BOM and suppliers

  1. Transparent sheet (300x190mm) - can be ordered or crowd-sourced from A4 transparencies.
  2. Foam pad (220x40x25mm). Currently using upholstery foam. Foam Centre Edinburgh can provide large quantities.
  3. Elastic band (5000x25mm). Can be bought from Edinburgh Fabrics. They said they can provide as much as we'll need.
  4. Adhesive, e.g. double-sided tape.

Time to manufacture (time in brackets for production solution)

  1. Cutting elastic band - 10s. (10s)
  2. Laser cutting - 50s incl. handling. Can be reduced by laser cutting multiple sheets at once or completely eliminated by using a die. (5-20s)
  3. Stick tape to foam and foam to transparent sheet (30s)
  4. Install & staple down elastic (20s)

Total:  5 min to make the prototype.            Fully operationalised solution **(1min5s  - 1min20s)

Units/person/day: ~300

Comfort

I would not mind wearing it all day. It doesn't touch your face mask. Looks quite good.

Glia model

Link to original design

Manufacturing process

  1. 3D print headband
  2. Cut elastic to size
  3. Cut sheet to size if required, insert into groove at front of headband 
  4. Thread elastic through buckle
  5. Thread elastic through headband and back through buckle to complete

Required hardware

  1. 3D printer

  2. Scissors

  3. Hot surface to cauterise elastic

BOM and suppliers

  1. A4  transparency

  2. 900mm x 10mm elastic strap

Time to manufacture

  1. 1hr8min print time per headband, could potentially be optimised but design features mean we can't blast them out on the ultimaker
  2. Fitting the elastic is quite fiddly, the elastic needs to be cauterised to fit through the slots easily, timed at 2.5mins including cauterising and stapling
  3. 45s to fit transparency, no hole punching required 

Total: 10 min (assuming we have 10 printers) Units/person/day: ~40

Comfort

  • Pretty comfortable, would be happy wearing all day, elastic running around front of headgear is the main reason for this.
  • Zero chance of fogging with massive vents at top (ingress risk?).
  • Fits well over large 3M half mask respirator

Prusa design

Link to original design

Manufacturing process

  1. 3d print frame
  2. Hole punch screen
  3. Cut holes in elastic (or better acquire a suitable punch)
  4. I'd probably deliver it as a kit like that but it could be put together.

Required hardware

  1. 3D printer
  2. PETG preferrable for flexibility but I don't think it really matters as it doesn't need to bend.

BOM and suppliers

  1. PETG, amazon
  2. elastic
  3. transparent sheet

Time to manufacture

  1. Printing I don't think I can do in less than 1 hour. 1.5 hour at default settings on the prusa. Prints on the Ultimaker were all bad, even slowly. Need non-terrible PETG for it, which has been ordered.
  2. Hole punching and elastic cutting from a minute without tools to seconds with suitable jig.

Total: 1h.

Comfort

  • Not great. Pressure on the forehead. Would be better padded.
  • It isquite stable though and feels secure.
  • Didn't have fogging problem, fits over FFP3 mask.
  • Much better compared to 3D verkstan which keeps feeling like it's going to fall off, and is too close to face so fogs up.