What are your experiences with PETG warping?  

What are your experiences with PETG warping?

Hi! I'm somewhat new to 3D printing, as I've only been doing it for a few months now. I tend to mostly print PETG, since I like making larger models and the colors are fun :). That being said though, one of the things I've heard from almost everyone when talking about PETG is that it's less prone to warping. Despite this, I've found warping to be a pretty big issue - which leads me to wonder if I'm doing something generally wrong with my prints. The big example I've got of warping at the moment is this glasses container I've been trying to print. Warping tends to happen with the Case 1 and Case 2 files. You can see it on one of the corners here:

As you might expect, the warping tends to affect the upper layer of the models later on, making it difficult for them to fit together. This being said, I've also seen this same warping very often with certain other models like Gridfinity bins (although everyone tells me those are notorious warpers). My current suspicion is air flow - the room I print in is an open room connected to our living room and the rest of the house with no doors. There's a fan running in here and an AC in the other room running intermittently, but I've already tried with at least the fan off in my office off (AC still running in the other room) and didn't see any significant changes.

Note that I'm using Prusament Ultramarine Blue Transparent PETG here, with the Prusament PETG preset in PrusaSlicer. So 240°C/85°C for the first layer, 250°C/90°C for subsequent layers, fan speed 30-50% running at half speed on layer 4, full speed on layer 5+. The humidity in this room is definitely not ideal (reading 39% at 26°C around the printer), but to counter that I print out of a dry box where I don't let the humidity inside go above 10-15%. I've made sure the sheets I'm using are totally clean (e.g. used dish soap and a sponge I specifically set aside for sheet cleaning, +IPA right before the print) and seen warping on both the Textured PEI sheet I have and the Satin Powder PEI sheet. The only thing I haven't tried is brim - but I started up a print of one of these parts with brim enabled about an hour ago so I should soon see the results. I set the distance of the brim from the model to 0.3mm, since this seems to be the magic number the internet tells me makes brim removal easier.

While I'll be a bit shocked if brim doesn't fix it, this brings me to ask - when people say PETG "is less prone to warping", how true is this really - particularly when it comes to warping off the print sheet? A substantial number of the resources I can find seem to suggest that PETG shouldn't be prone to warping, or that brims aren't needed - yet I've also found sources and some friends of mine who claim otherwise even with PETG. With all of this being said, I'm perfectly fine getting used to enabling brims if that really is the solution here - I just want to make sure that doing so isn't working around some potentially larger issue with my setup that might be causing the warping. So I figured the best way to figure this out was to just post on a forum and ask as many people as possible :).

Also of course, feel free to ask if you'd like any more information on the settings I'm using and my setup.