So I decided to risk it and drink from my 3d printed espresso cup.
Added bonus, I’m still alive to tell the tale. #DontDoThisAtHome
Well, if you don’t drop dead instantly or of cancer in fifteen years we know the test was a success.
…I’m in the same boat as you, though. I used a few ice cubes made in my (printed) spherical ice mold, and in scotch no less, so if the ice picked up anything unpleasant I’m sure it also ended up in me.
ABS or PLA? Or something else?
@Stephen_Baird haha, that was my thought. I’m sure the guys that worked with radioactive materials thought it was totally fine too. Any how I’m sure the alcohol cleared up all the nasties 
@Aaron_Eiche it was printed in Bendlay. The worst I’ve seen is that coffee stains the cup.
There is probably a large difference between occasional use by hobbyists of things they create themselves (even of something such as a lead cup!) and wide-spread societal use of same. Remember that we see these things in the averages. It was not every member of Roman society that went insane from lead poisoning, nor every mercury-employing hatter that went mad.
But in the aggregate, trends can show up revealing shortened lifespans or increased risk of certain ailments over a long period for large numbers of people, and as a society, we have to decide between the balance of the increased harm versus the good we obtain.
One of the biggest dangers of using 3d printed objects for food purposes may be (I’m not a doctor) that the crevices and patterning of the surface provide a place for bacterial films to develop. These could cause much more severe and much quicker ailments than whatever might be leaching into a fluid or solid that is coming into contact with the plastic.
By the same token, however, your use of a hot liquid, @Yomi_Colledge , is probably more dangerous than @Stephen_Baird 's use, simply because the heat would allow more molecular activity, increasing the rate of outflow of gases or particulates. Alternately, his use might be worse for requiring more time in contact during the freezing (especially if he left it overnight). Hard to say without testing.
Primary thing I think is just to keep to personal use - don’t use 3d printed objects for catering, don’t sell items intended for use in food preparation or serving, etc.
3d printed plastic laminate objects, anyway - I doubt there is much risk from 3d printed pottery that is subsequently heat treated and glazed, or 3d laser-sintered objects, etc.
It is possible that objects that have been treated with surface smoothing techniques using acetone or similar vapor-bath techniques might be substantially safer due to the lesser surface area presented for contamination and resistant to cleaning.
However, my personal thought on this would be to look into something like food grade wax or a similar food-safe sealant. If the surface of the object is fully encased in a food-safe sealant, it ought to be safe to use, though you’d have to be sure to choose a sealant that could handle the treatment you intended to use - i.e. if using hot liquids, it needs to be able to handle that, etc.
On the rough surface providing crevices for bacterial development: I’m not super worried about that, personally. The same issue is true of ceramics with a crackle glaze (the cracks provide spaces for bacteria to develop that you can’t reach in cleaning, even thorough cleaning). There, the cautious recommendation is to heat sterilize the ceramic by microwaving it, empty, for a minute or so every month or two.
…I have never once done that with my crackle glazed ceramics and I have yet to make myself or anyone else sick with them. And even if you do manage to get sick from a bacterial colony it shouldn’t be anything worse than bad diarrhea for a day or two (assuming your immune system isn’t compromised). So, an unpleasant lesson at worst.
The potential for chemical leeching is what actually concerns me. In the amounts you’d be exposed to in a single use it shouldn’t (statistically speaking) be a big problem. But if you print all your drinkingware and use it continously… Who knows.
My ice mold was printed in Taulman Nylon, so I’m less worried about it, but it did go through a brass nozzle of uncertain chemical makeup, so there’s the possibility that it picked up something unsavory along the way. If I had money to burn, or I was more interested in making food safe prints, I’d probably send a sample off for analysis so I could say (for sure) what was and wasn’t in the printed filament.
But for me, for now, the level of risk presented by printed nylon in contact with my food is acceptable.
@Stephen_Baird same here. I wouldn’t advise others to do it not would I have a coffee party with the cups I’ve made.
It’s plastic… I’ve chewed and eaten so many pen caps and prob a GI Joe leg or seven as a kid as well… I understand about the bacteria in the creases, but a good scrub with a brush should clear that stuff out enough right? Wouldn’t the fumes while printing present more danger than eating/drinking out of a finished piece?
We’re doomed anyway, enjoy your coffee anyway you want to 
http://serc.carleton.edu/NAGTWorkshops/health/case_studies/plastics.html
Should be ok as long as the chinese filament manufacturers are more ethical than chinese toy manufacturers.