Uneven surface at one single spot

Bambu Lab H2 Series Troubleshooting
1

Please advise, what could be the problem?

I hope you can help me. I have printed this angel (approx. 8 cm tall) several times now—so far without any problems. Now I suddenly have the following print image. The problem was also reproducible, meaning that three print attempts showed the same problem on the angel’s face. Everything about the angel is perfect, except for this problem on the head. Since it always appears in the same place with slight variations, I would rule out a defect or something similar, right? I’m a little at a loss right now.

The head is quite small. Could it be that it is too small and there are problems with the load-bearing capacity of the overhang because the printer is too fast aka layer speed? Could it also be the temperature in the room?

I am not sure but it might be that I’ve never printed one single angel but always > 1 what obviously would increase the layer speed. But that’s just a thought.

Printer H2S

Bambu PLA Milk Coffee Matt

0.12 layer height High quality

Support for all overhangs, only on the plate

Otherwise standard

Object was positioned in the center of the plate via auto placement

image
image1920×2560 182 KB

image
image1920×1440 206 KB

2

This looks like a cooling problem.

Did you in the past print more of them at the same time?

You might have a look in your filament settings for minimum layer time in the cooling section, and increase it.

You might also look for slowdowns on overhang.

1 Like
3

Yes,that was what came into my mind while writing this post. As far as I remember I always printed more of those (>=2).

I use the standard profile for BambuLab Matte PLA. And as far as I know „Slow down for better layer cooling” box is checked there and minimum layer time defaults to 4 seconds. If I raise minimum layer time to let’s say 10 seconds will the printer pause then? I’ve read some post here this setting might be ignored under certain circumstances?

Overhang speed is already reduced to 10 or 20 mm/s.

The problem is on the wings of the figure I can not go too slow as these overhangs look sluggish then.

other alternative: is it possible to add gcode for pausing?

4

The speed will be reduced to accommodate the minimum layer time.

There is also a lower speed so when this threshold is reached the layer time can go under the given layer time.

5

I ended up reducing the speed and that helped. Indeed that spot had not enough time to cool down.