It looks like the 3d printed masks (esp. the N95 grade) are regulated by FDA so don't think we would be able to do much to help the healthcare workers but could certainly make them for your own protection. However, for face shields there don't seem to be much regulation around it and thats why more and more hospitals are okay to use the 3d printed face shields but want to stay away from non-traditional sources for "N95-grade" printed/custom masks.
Yeah, regulation is pretty heavy on a lot of stuff like that, face shields seem to be the best option for helping out rn.
I did see this article/mask design; basically uses HEPA filter or similar in a 3D printed shell. Looks like some medical folks at the UW think it's a good design and are doing some testing with it.