I recently had two print failures on my Ender 3 Neo. In both, it looked like the part came free from the heated build plate after about an hour or so of printing. Both had good starts in the first 15 minutes or so. I had a successful print finish two days ago.
It has been hot and humid here today, and my printer is in a non-AC shed not connected to the house.
I’m wondering if I should wait to kick off the next print until this evening when it should be cooler. Do I need to clean the build plate? I’ve not done that at all, other than make sure these isn’t any filament left on the plate when it finishes.
UPDATE: It’s apparent the problem isn’t the heat, but the fact that I haven’t cleaned the build plate since… well, ever. Adjusting the title to reflect that.
To answer your question from title:
Too hot is when your stepper driver is overheating and skipping, or when stepper motor is too hot to touch. There are more, but if you can be in the same room its not likely. Tbf using AC can only ruin your prints with uneven cooling. You want stable room (enclosure) temp