Strange Warping on my Prints  

3 vs 2 perimeters shouldn't change anything. Most of my default profiles use 3 perimeters (and lower infill). I'd try a print outside of the enclosure, or at least leave the door open. I print PLA and PETG in Lack enclosures only with the door opened.

but how?

Thanks for your answer.

But if the enclosure at max 29°C is the problem. How people print PETG and PLA in summer days? or even on hot locations?

Posted by: @fuchsr

3 vs 2 perimeters shouldn't change anything. Most of my default profiles use 3 perimeters (and lower infill). I'd try a print outside of the enclosure, or at least leave the door open. I print PLA and PETG in Lack enclosures only with the door opened.

Could be that there is something wrong with the thermistor and I'm printing too hot?

Your print temperature seems to be ok (if there would be something wrong with thermistor, then you'd probably see some weird temperature values on display).
As @fuchsr mentioned, PLA and PETG are meant to be printed at average room temperature, where few degrees up or down doesn't matter that much. More important is, there's no draft!
Example: you print some object with thick walls (many parameters + high infill). When printing, high temperature is accumulated in filament and so, that wall will stay very warm during printing (especially because heat is coming from the bed). Now if you open a window, the draft will rapidly cool down the wall -however only outer perimeter(s). And because inside the wall filament is still warm, the print will warp (because of temperature difference). Conclusion: massive (thick) print objects should cool down slow enough.

thanks @BogdanH , your answer makes perfect sense.

I tried a print with the enclosure open, and the problem persists. Here is a picture revealing a similar distortion on both sides on the x axis.

It's strange the the y axis is intact and the problem appears only on the x axis. The doors of my enclosure are on the right side of the printer (on of the touch screen) and perhaps temperature changes should affect more the x axis, but the weird thing is that there is no wrap on the other axis of the prints.

Posted by: @bogdanh

Your print temperature seems to be ok (if there would be something wrong with thermistor, then you'd probably see some weird temperature values on display).
As @fuchsr mentioned, PLA and PETG are meant to be printed at average room temperature, where few degrees up or down doesn't matter that much. More important is, there's no draft!
Example: you print some object with thick walls (many parameters + high infill). When printing, high temperature is accumulated in filament and so, that wall will stay very warm during printing (especially because heat is coming from the bed). Now if you open a window, the draft will rapidly cool down the wall -however only outer perimeter(s). And because inside the wall filament is still warm, the print will warp (because of temperature difference). Conclusion: massive (thick) print objects should cool down slow enough.

I don't own a mini, and I'm probably wrong, but that looks like some kind of layer shifting to me, all be it very gradual, and I would be checking grub screws and making sure things on my printer were tensioned properly.

Good Luck

Swiss_Cheese

I agree with Swiss_Cheeses. Now I can see, that the warp (shift actually) is very symmetric on both sides. And if that only happens on X-axis, you should concentrate there  (belt tension & smooth movement). But as can be seen on photo, after certain height, print corrects itself again.. so I would also check Z-axis if everything is tight there.

I just finished a couple of successful prints, after tightening some screws, especially the x-axis grub screws in front of the motor. I have to note, this is a one month old preassembled mini+

I'll report back after some prints if the problem persists or it was just a loose grub screws issue.

😎

@denoise

I have to note, this is a one month old preassembled mini+

That really doesn't mean anything, while we might not expect to have these issues that soon after receiving a new machine, these are normal points of maintenance, at any time any of us could have missed tightening a screw, I don't think we need to fault anyone for that.

I'm glad that's all it was and your able to carry on your good work.

Enjoy

Swiss_Cheese 

P.s. If you do see any other minor artifacts after checking the tensions of all things as you have, it's always a good idea to re-run your calibration.