Unintended concave walls
Dear fellow makers,
I have some issues with flanks becoming concave when they shouldn't.
I printed this face shield here with 2 perimeters and 30% infill at my standard (Generic-)PETG settings (Hotend 225°C, Heatbed 90°C). The filament used is DasFilament White and Orange PETG.
Because I had problems with warping parts (away from the bed) before I am printing in a tent now. Parts that used to heavily warp before now almost don't warp since I use the tent. The inner tent temperature is at about max. 30°C (if it gets hotter, I open a flap at the top).
Here is the result:
the front side is okay-ish though:
FaceShield-Supreme_0.15mm_PETG_MK3S_2h33m
Before (in April last year) I printed the face shield without any unwanted concave walls on my Anycubic i3 Mega-S. Of course the little features are now much better but even though I used the same material I can't reproduce the perfect walls (I had a hard time to get these after many tests because I otherwise got rough walls (but never curved ones)) I had back then with the Anycubic.
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Perhaps the same issue but printed without a tent a while ago:
I explained the last example to myself because the black part is filled and the white part is not. Never the less an unsatisfying result.
I would really appreciate any form of idea how to solve this issue.
RE: Unintended concave walls
Might be helpful to upload the 3MF file you’re using. You have to zip it before upload.
Did you try printing it with just one color, to exclude effects from mixing filaments that may require different settings?
RE: Unintended concave walls
PETG in a tent might be the problem. If I close my enclosure door on PETG prints, it's almost a guaranteed set of problems.
The solution for warping isn't heated chamber for PETG IMO.
RE: Unintended concave walls
It may depend on your enclosure. I have LACKs for my minis and Mk3Ss, and I always print with the enclosure closed. Never experienced any warping issue with PETG. Each has a thermometer, never observed temps above 35 Celcius even on extended prints (> 12 hours). So your mileage may vary.
RE: Unintended concave walls
@fuchsr: I only got the STL file for the face shield provided by thingiverse and can't find the issue there.
I try to find some time this weekend to reprint a part of the face shield in white PETG only. But the unwanted curving starts even before the other color starts. I was able to monitore this during the print of the face shield shown above. Do you see those bumps? The white one was there before I changed the filament.
I'm not quite sure though if this might have been caused by (perhaps partially) unsticking from the powder coated sheet.
@dan-rogers The black and white part below was printed without having an enclosed chamber (a tent or "Creality Fireproof and Dustproof 3D Printer Enclosure" in my case). The enclosure now reduces warping almost to zero (here printed with the identical GCODE, the green and orange without enclosure, the green and black with enclosure) https://www.thingiverse.com/thing:4268815
