I was working on a teeny joint prototype today, using an equally teeny layer height and lamenting how I felt like .2mm layers turn out significantly better than layers around half that. So I decided to tweak things a bit--up the cooling to try to prevent the curled overhangs I was noticing and are often a result of plastic that hadn't cooled enough before the next layer goes on top[1]. This immediately had two effects:
- the overhangs were forming much more nicely
- the parts were popping off the plate shortly after the point where I could tell "yeah this is improving this overhang"
It actually took me a couple attempts to realize point two--I was starting the 10 min print then going off to do other things[2] so I didn't connect the dots (or, rather: all the dots I would have used to connect things up were in a smooshed blob of plastic stuck to the nozzle) till I started babysitting the print a bit more. I was a bit frustrated since bed adhesion is not normally a problem for PETG, but then I remembered my calibration of the teal-y cyan-y filament I got recently, and how I needed a hotter bed temp for it, and that clicked it all in place: the small part size plus the fan kicking on a little more aggressively was cooling the first few layers just enough to have them release from the bed once the print got about a third of the way through. Once I bumped the bed plate up to compensate for the cooling, I got my test done.
3D printing is a giant tangled mass of interconnected exchanges and balancing them all is wild.