Lifting at one corner

Bambu Lab H2 Series
1

Hi, my PLA print is perfect however there is lifting at one corner.

IMG_2361
IMG_23611920×1768 311 KB

My brim-object gap setting was 0.1 and I’ve read that I should change
it to 0.
And my Max fan speed threshold Layer time was set to 4 I’ve read
changing it to 8 might help.
Should I change these settings and is there anything else I can do to avoid
lifting?

1 Like
2

Best way to avoid lifting is always to modify the design. Sharp corner with thick parts are always gonna generate a ton of lifting force.

Brim gap 0 doesn’t necessarily connect your part with the brim. It gets affected by the elephant foot compensation (which is VERY STUPID AND ANNOYING, and Prusa, Bambu, Orca all refuse to do a thing about it). So when you have elephant foot compensation (which is on by default) the brim can still have a gap.

Even if you do have the brim connected, with enough misfortune it can lift the brim as well.

Max fan speed layer time has nothing to do with this print.

Ultimately, no matter how experienced you are, eventually you would get onboard of the glue ship, because it’s just easier.

3
  • Bed prep is important. Hot water and dish soap with a really good scrub
  • How many walls do you have? High wall count can increase warping.
  • Increasing your bed temperature 5-10 degrees can help
  • The brim in your picture isn’t really doing anything as it is separate from the part. 0 object-brim gap can help.
4 Likes
4

Looks like mild warping:
Basics:

  • Dry Filament (yes, especially new filament)
  • Clean Plate
  • Warm chamber (while avoiding heat creep), I use 35°C on my X1 for PLA

For trickier prints:

  • Enable brim, brim distance may be lowered
  • Increase 1st layer temps by 5°
  • Reduce layer height and/or print speeds

:crossed_fingers: & :four_leaf_clover:

5

5 walls
Bed temperature was 55 for both initial and other layers.

6

Bed temp was 55 for both I’ll try raising initial layer to 60 thank you.

7

Btw does it matter how much infill you use? Would it change anything if I
lowered the infill from 30 to 15?

8

Lowering infill can indeed help. But it does not address the root cause of warping (fresh, hot layers cooling and hence shrinking on top of cooler layers).
That is why I usually follow up the basics (dry fila, clean plate, warm chamber) with a reduction of thermal input input per layer/time as less heat in = less heat out => more even cool down => greatly reduced warping and curling.

But I rarely need more than 25% infill and am happy to take longer for a good print. So take it with a pinch of salt for your use case.

:four_leaf_clover: & :crossed_fingers:

9

I dried the filament before the print and my plate was clean.
However is there a way to warm the chamber before starting the print?
Also could you please explain “with a reduction of thermal input input per layer/time as less heat in = less heat out => more even cool down”
Thank you.

1 Like
10

My X1 reads out the chamber temp on the display, Handy and Studio. So it is just a matter of propping open the lid depending on the temp. Usually, it reaches 35°C before finishing the 1st layer so I do not pre-heat for PLA.
When I do need to pre-heat, for example for PA6, I just set the bed temp and wait until I feel the chamber temp is good enough.

Regarding counter-warping measures, I take an energy approach. A given volume of material at a given temp contains a given amount of energy that dissipates during cool down.
If I now say halve the volume of material by either halving the layer height or speed, the volume and hence energy contained decreases by a factor of 8. So that very much evens out the thermal input and hence also the output/cool down. One of the cases where nonlinearity/volumetric effects work in our favour.
It works quite effectively against curling and warping with PLA, PETG and PA6, but I do not print ABS, ASA, HIPS and have not yet had to try it on PC or PPS.

:four_leaf_clover: & :crossed_fingers:

2 Likes
11

Lol sorry mine does too it’s 35°C.

2 Likes
12

Let me guess … back right corner?

1 Like
13

Yeah right in front of the fan.
My fan settings are 100-100
Aux: 70 and Exhaust: 0
But the new print is going good so far so fingers crossed.

14

Thats is what I was going to recommend. I turn down the exhaust fan 10% or completely off if it is cold in the printer room (AC is on). AUX I set at 50% for all my PLA profiles, and turn it off manually after the print starts for most items that are medium or large. I only keep it on for smaller items.

2 Likes
15

Does turning off the Aux fan affect your print quality negatively in some way?

1 Like
16

AUX fan is only there to provide additional cooling for objects that dont have enough time to cool between layers. Its only really needed for very small thin objects, I turn mine off on 80% of my PLA prints. I do turn in on for steep overhangs, and place the object facing the fan when needed.

3 Likes
17

So the chamber temp went up to 45°C so I turned on the Exhaust fan to 20%.
It’s 40°C now. Are these chamber temps bad for PLA? (It is down to 36°C now)

18

It can be problematic for PLA and may lead to clogs.
Regarding warping, there are many potential causes. An overheated bed is a common one—though likely not at 55 °C. On my CFX plate, 70 °C works well; at 80 °C the corners lift immediately. If I go cooler, the first layer suffers. You’ll need to dial in the sweet spot for your setup.

19

If it got clogged during printing (it is still printing now and went back to 36°C)
I would know by now right? :slight_smile: I mean it wouldn’t keep printing without any problem?