Is this warping of PETG?  

RE: Is this warping of PETG?

Sorry, the link came out wrong: HERE IT IS

RE: Is this warping of PETG?

That curved underside is warping. If PETG is warping, you've definitely got adhesion issues. As you note, warping will cause problems further up as layers are compressed. This is a common problem that can be caused or aggravated by two factors that need to work together well for successful prints. Here's mama's tried and true copypasta recipe to get you going...

• A dirty PEI print surface. Even if you don't think this is the cause, it's always a good idea to make sure your PEI surface is clean before trying any other fixes. If it's a smooth PEI sheet, take it to the kitchen sink and give it a good dunk with Dawn (original formula, no vinegar or hand softener variants) dishwashing soap or your local equivalent (e.g. Fairy in UK). Use a clean paper towel to clean it off, and another to dry it. Avoid using any sponge or cloth that has been in contact with grease. Above all else, avoid touching the PEI print surface. Once it's good and clean, you should be able to use 91%+ isopropyl alcohol between prints, 100% acetone when that fails , and another dunk when acetone fails. Worst-case, use a 3M 7445 ScotchBrite pad or equivalent on smooth PEI to give it a very light buff, but only infrequently. If you've got a textured powder-coated PEI print surface, the official instructions are to use 91%+ isopropyl alcohol on it only. Rumors persist that some tribes deep in the jungle have had good luck getting started with these sheets by giving them a wipe with 100% acetone and a dunk with Dawn. Either way, there's no real warranty on these sheets. YMMV.
• If you have not already done so, try using Jeff Jordan's "Life Adjust" procedure for calibrating your Live-Z setting. It is much easier to use and understand than the on-board routine. It's much easier to make mid-print adjustments accurately with. In general, start high (less negative) and work lower (more negative) in large increments (e.g. 0.1mm) until the filament starts to stick on its own. When you've got your Live-Z setting adjusted properly, you should be able to gently rub the extruded lines on the PEI surface without dislodging them.  Then start lowering (more negative) the level until there are no gaps between layers.    

RE: Is this warping of PETG?

I had a very similar issue with PETG. The warping was small, but as the piece was getting taller it exacerbated the print artefacts to a point where I was getting what looked like layer shifting. The issue was adhesion, but also the nature of my part. I didn’t have enough surface area on the bed on a corner so it would eventually warp. My part was 205mm tall so there was a lot print time and probably the temperature of my room didn’t help.  I did a few things to overcome the issue so not sure if it was the combination or just one of the things:

1. Followed bobstro’s advice about cleaning the bed and also creating a rougher surface on the smooth PEI bed. I used steel wool to lightly scuff the surface.
2. Added “bunny ears” on the end that kept warping. Slicer allows you to add parts easily so you do not need to edit your model.
3. Kept the room at 23degrees

I managed to print one part with a brim, it still lifted, but it completed without any layer shifting although the x surface wasn’t as uniform. This print has come out almost flawless with smoother layers on axis, so there may have been some vibration issues too where my part wasn’t properly grounded. Lots of wasted filament learning this lesson, thanks posting the question and answer guys, it helped.