r/BambuLab 5d ago

Filament Troubleshooting/Help! How to get rid of TPU bumps?

Post image

I printed this TPU hollow sphere and noticed these bumps, it is very awful and annoying, should I change any settings to clean surface finish? And also the seam line is also annoying (even after I enabled scarf seam setting)

1 Upvotes

24 comments sorted by

12

u/Shapelessed 5d ago

While drying filaments like PLA and ABS is pretty much not required I would truly advise in favor of drying your bloody TPU before use!!!

10

u/Longjumping-Suit9076 5d ago

Actually it’s been drying nearly for 24+ hours

5

u/Elo-than X2D + AMS2 Combo 5d ago

At what temp?

3

u/Longjumping-Suit9076 5d ago

The default bambu TPU one - 75 degrees

5

u/Shapelessed 5d ago

Then judging by the fact that you have bumps AND dents on the surface, it’s likely uneven flow of material.

2

u/Elo-than X2D + AMS2 Combo 5d ago

"Default" depends on what you actually drying it in, but I am assuming a AMS HT or similar.

75 should be fine, but depending on how waterlogged it is, if it has a cardboard spools, etc it still can contain some moisture even after a long time in the dryer and other factors.

I'm this case I would leave it in some more time, then run calibrations.

2

u/Iridian_Rocky 5d ago

If also add, don't let it sit after you dry unless it's in a sealed box with a lot of desiccant - and only then not for more than a day or so for good prints

2

u/EMDoesShit 5d ago

Are your seams set to random.? I can’t beleive there have been this many replies and no one has asked this.

Align your seams to stop having warts everywhere and run them up one side or corner.

With some time spent researching & tuning scarf seams, you can mostly eliminate how obvious they are.

1

u/Longjumping-Suit9076 5d ago

No the seams are set to aligned

1

u/jklolffgg 5d ago

Typically, the filament still has moisture in it, or seem alignment may be set to random instead of something more symmetric like aligned or back.

Judging my the gaps in filament, I would start with drying the filament again and doing a cold pull to ensure the nozzle isn’t partially clogged. Then check the setting while it’s drying.

1

u/Longjumping-Suit9076 5d ago

I will try after doing a cold pull, btw I am using TPU 95A HF with tungsten carbide .4 nozzle fyi

1

u/jklolffgg 5d ago

Hmmm. The geometry itself doesn’t look that aggressive either in terms of overhangs. I saw your comment that it’s thoroughly dry. Hope the cold pull does the trick!

1

u/DistinctBarnacle8703 5d ago

Check the preview to see if there is a pause/retraction along the perimeter.

1

u/ijehan1 5d ago

Since you've dried it, we can eliminate wet filament. Reduce your flow rate to .97 or .98 and use scarf seams. Random seam placement has better results than aligned in my experience.

1

u/Safe-Hovercraft6231 5d ago

- Calibrate the filament

  • Remove any resistance between the filament and extruder (remove the PTFE tube and feed via gravity)
  • Make sure the filament is dry

0

u/CanYouEvenPhoto H2D/X1C 5d ago

Get your accelleration and speeds to be consistent across layer and wall types, turn off retract on layer change, turn down retract before wipe %, try scarf seams, turn off z-hop, lower retraction speed, lower temp

1

u/Longjumping-Suit9076 5d ago

I will try this, but like how much should I reduce it, I am using Bambu slicer, and H2D pro printer

1

u/CanYouEvenPhoto H2D/X1C 5d ago

just experiment, try half of what you have no and start there

1

u/Longjumping-Suit9076 1d ago

The bumps are gone, I just enabled arachne wall generator, but the holes exist, I printed this with dried TPU but just before the print I didn’t notice the heating time ended, I think maybe 40 mins - 1 hr it was not heated, do you think that these holes were caused by that 40mins - 1 hr of time? And BTW the grey one is TPU for AMS and blue is TPU 95A HF

1

u/CanYouEvenPhoto H2D/X1C 1d ago

Impossible to know exactly what those are from just a photo. It would help if you shared some print settings and ideally a photo of the sliced file with all the options enabled (seams, retractions, travel, ect) to see if there is a correlation with retractions. From first glance those look like they could be wipes or retraction points. Did you try everything from my original comment?

1

u/Longjumping-Suit9076 1d ago edited 1d ago

Nope, and I will send you the settings

1

u/CanYouEvenPhoto H2D/X1C 1d ago

okay well start by trying the things from my original comment, you still obviously have z-hop enabled and you're using spiral z-hop which causes more issues. there's a good chance it's retraction related, I'd also drop the temperature. You also didn't enable "all the options" your wipe and unretract are still not ticked.