During this difficult period, respirators are becoming quite an essential.

Even for the most common activities such as going to the supermarket, people are wearing high level ones without any specific need, consuming precious resources essential to healthcare workers.

This tutorial will guide you through the creation of a 3D printed respirator which will save you some money and mostly it will stop you from buying the ones that are required in hospitals.

Its advantages:

- It fits most of the faces (already tested on many different ones)

- It has a great level of sealing on the side (unlike the homemade sewed ones that are widely open)

- Filter can be customized and substituted

- It can be sterilized after each use

This respirator will not give you 100% protection from viruses when you are really close to an infected person, but in normal situation it will protect you from droplets and can be a valid help for daily activities.

You will find more details about it at: https://3dsprint.wixsite.com/printable-respirator

Supplies

- A 3D Printer

- 50 gr of PLA filament (color is up to you)

- Adhesive neoprene sealing band 10mm (thickness) x 10mm (width): https://www.amazon.com/Adhesive-Conditioner-Bracke...

- Filter materials such as make up cottons (https://www.amazon.com/Amazon-Brand-Solimo-Cotton-... or HEPA filter sheets (https://www.amazon.com/EnviroCare-Replacement-Supr...)

- 2mm string (https://www.amazon.com/656Feet-Cotton-Cooking-Kit... )or elastic bands if you prefer

Step 1: Slice and Print

Once you download the files from the link above (they are freely available) you have to slice them to get the printable code. In this case I have been using Ultimaker Cura for this step.

For an optimal print in terms of resistance/flexibility/printing time and material, I suggest to place the model as in the picture (45° inclination with respect to the initial loading position).

Suggested print setting are available on the website and are:

- Layer height: 0.28

- Wall thickness: 1.2 (same as the model thickness)

- Wall line count: 3 (will avoid to have gaps and holes left on the printed model)

- Supports: yes (suggested zig zag with 10% density)

- Supports overhang angle: 60°

Temperature, speed and other settings are up to the material you are using.

These settings will give you a minimum number of supports and the finished print will look like the one in the picture.

Filter cap and Ear clip don't require supports and should be just placed horizontally on your printing plate.

Once printing is complete, remove supports and clean every residual.

Step 2: Sealing Assembly

At this point you will need to cut two pieces of neoprene band:

- Chin piece = 14cm

- Face piece = 23.5cm

I suggest to start from the chin area and stick the horizontal small piece.

Once it's placed, you add the remaining one following it on the border with your hand.

Watch the video tutorial to see my way of doing it.

If you prefer to do it in other ways it's still ok.

The thickness and material of this band has been chosen in order to guarantee the right comfort and sealing on different types of faces.

Step 3: Filter Assembly

As mentioned before, filter material is up to you.

HEPA filters are showing great performances against viruses since they filter by diffusion mechanism. For this reason, filter cap has been optimized with inclined intake blades in order to deviate intake flow and ease this mechanism. At the same time front projected area is virtually close to 0 protecting you from frontal droplets.

Once you have cut your filter piece (diameter about 35mm), you can position it in the filter cap as shown in the picture.

At this point the filter cap can be clicked in the face piece on the dedicated slots.

After some usage, the cap will loosen. For this reason it has been added a bayonet similar locking system so after insertion the cap can be rotated clockwise and locked.