Marechan

You might not be better off with metal ustensils, loads of PFAS are used in the manufacturing process and end up in the finished product.

A professor once told me: "You cannot avoid contamination, you just have to diversify the sources."

FYI items labeled as microwavable are tested to assess what leaches in the food or liquids under normal use. The leachate has to be identified and approved by the FDA (doesn't mean safe but at least ok-ish)

PFAS are hydrophobic molecules so, not knowing what to do with it, your system will store them with the fat (also hydrophobic). Doesn't do much in itself (depends on the exact molecule though) but the issue is bioaccumulation and amplification: imagine the food chain as a large hopper, sprinkle a bit of none biodegradable shit on top and imagine the dose you get at the bottom of it. In larger quantities you start disrupting processes in the body often leading to cancers or a myriad of symptoms caused by endocrine disrupting.

Edit: commented before watching your link, there's slightly more to it but that's the gist yup

Horny Wan Kenobi

Despite your extensive testing I would strongly advice against using it, due to things you might not be able to detect. A main concern is what we call leachables, molecules that can, well, leach from the material to the product (such as plastifiers, melting agents, etc). Since you are spraying the substance straight to your lungs, the danger level is maximum in terms of contaminants (the regulation regarding extractables and leachable actually started with Metered Dose Inhalers) and I doubt that a plastic designed to melt easily is really fit for this kind of applications. In the industry you would have to track the components of the raw materials and conduct several tests on each part of the device, to insure that it is below accepting doses. And then you would have to account for the sterility aspect of 3D prints...

That being said, very nice design though!

Edit: it is quite similar to why you should use 'microwave OK' plastic only (but in your lungs and with another kind of plastic)

I had to go through the regulations regarding plastic packaging and delivery systems of drugs for work and, yeah, you would have to go through a lot of testing and certifications for it to FDA compliant, especially for a inhaler.

c/aneurysmprotesting

Looks a bit like a thermostatic radiator valve without the head on