Summary Here is my latest hard shell mask design. This is designed to be printed without any supports using PLA or other similar filaments. I did not have any success printing it with TPU but I have only just started playing with flexible filaments so it may just be me.
There are 3 parts to the mask that can be printed in PLA. These consist of the main shell body, the filter cartridge and the cartridge cap. There is also a cartridge tool that you can print that makes assembling the cartridge a little easier.
Note: the nose pad and copper filter are not included in the parts. They are only for visual demonstration purposes.
I just used some of my wife's make-up remover pads as the filter material. The filter material gets inserted into the cartridge and the cartridge cap is screwed in to hold the material in place. The whole cartridge assembly is then screwed into the front of the mask. Use some TPU filament or other material as the straps to hold it on. The shell is only 1.2 mm thick so it can be softened and reformed a little if necessary.
It fits my face but the nose bridge is quite high so it may need some foam or other padding around the upper edges. There are different types of material such as self adhesive weather stripping or soft, flexible medical tape that could be used depending on the thickness needed. I am looking at ways to print a TPU upper seal and will update it if I come up with a simple solution.
Note: This is a dust mask and is not meant as a medical equipment replacement.
If you do succeed in printing it in TPU please let me know.