Prime Tower Knocked Off

Bambu Lab P Series Bambu Lab P2S
1

I am not sure why this keeps happening. It seems with tall models like this one, the prime tower is being knocked down. Anyone have any ideas on why this is happening? I washed my build plate the other day, so I would doubt it would be that.

It did finish the model, so I guess that is a plus.

20260119_084020
20260119_0840201920×3410 642 KB

20260119_084017
20260119_0840171920×3410 588 KB

2
  • Even if you have already washed the print plate, wash it again. Yes, it’s annoying, but this step accounts for 95% of the solution. As recommended, use additive-free soap; this is important. As a second step, you can use Isopropyl (IPA), but only in small quantities - don’t drown it. Also, don’t rub like crazy, as this will damage the surface; instead, wipe gently.
  • Use an infill that won’t constantly hammer against your 3D object. This will also indirectly affect your prime tower when clumps of filament form. So not a grid, but something sensible. Link at the end.
  • Another helpful tip is to use the right printing plate for the corresponding print. Use a plate with more adhesion. The textured plate you have is fine for standard printing, but not for more demanding jobs. You should consider using a different plate.
  • …and then, of course, the usual settings for the last 5% of success: Larger brim - also for the Prime Tower - it’s really tiny on yours. Optimize settings, etc.
3

Towers, and taller prints, get knocked over because filament blobs are being deposited on the top of the print. When the nozzle comes around on the next layer, it hits the blob and that knocks the print over.

You need to dry your filament and calibrate flow and PA better, so there’s no excess filament building up on the nozzle.

PETG is really hard to print because of this, it really likes to string and blob.

Oh yeah, don’t use Grid infill, since that causes the extruder to push through previous extrusions on the same layer - they’re still hot enough the nozzle can scrape them off.

1 Like
4

I am using 5% infill and Gyroid pattern, so I do not think that is the issue. I will wash my plate again, for good measure, but it seems that when I have tall projects like this it has issues.

EDIT: Could it also be a software issue? I know that this printer is newer, and hasn’t had many updates yet.

5

The reasons could be numerous , play about with the settings and its positioning in the slicer

image
image456×475 13.5 KB

your image looks to be a little to close when compared to the default placement on the top left of the plate

6

I can only urge you to use a decent printing plate for such prints. Here is a comparison of adhesion:

Screenshot 2026-01-09 011951
Screenshot 2026-01-09 0119512724×1649 205 KB

7

I am going to assume that higher is better in this case, that is good to know though.

8

Yes! I have linked the complete video on this topic. But please note: You must still follow the other advice that has already been given. :+1:

9

Yes, I understand. I came from an Ender 3, so I know quite a bit about slicers and the printer itself, just not used to the multi color quirks yet. Thank you for the replies, I will be trying these out.

1 Like
10

Wait, the placement is on the top left of the plate by the purge chute? I do not think I have ever seen it slice like that before.

11

Yes (A1) but it can be positioned in a user defined place

Prime tower | Bambu Lab Wiki

1 Like
12

image
image539×541 63.8 KB

Would this placement be alright, or should I move it to a different area?

13

Where does it place it by default , ?

14

image
image828×620 79 KB

Right here.

15

Then i (personally) would reorientate the model and position it in a more centralized position (beak facing the bottom of the plate) i didnt realize that was the p series default

which flush into setting do you use ?

16

I am currently using flush into supports.

17

Flush into infil maybe better , because supports end with the beak ?and that big peak on top of the prime tower could be being caused by a lack of support to flush into ? (thinking out loud)

18

I know I’m repeating myself, but… There are really only two reasons why something might get knocked over during printing.

  1. Parts with a tiny footprint can be pulled over by the drag of the extruding filament if the flow isn’t quite high enough. But usually, if it’s a taller part, the print surface just deflects a little and the remaining layers turn in to a swirly mess.

  2. Flow/PA/Temp not calibrated well enough causes excess filament to build up on the nozzle until a blob gets deposited on the print top layer, and the next time the nozzle gets there it hits the lump.

If flow parameters are properly tuned, there is very little force exerted on print during extrusion and stuff won’t get knocked over. Trying to get the print to stick to the build plate better will potentially help, but it’s really a band-aide and not the root-cause fix, which is tuning extrusion to make sure the nozzle won’t be able to exert any significant force on the print while it’s doing its thing…

The only time I typically use a brim is when I’m printing something I’m worried about warping. Not just to keep the print stuck down, with the one exception being PETG if I’m going to rely on the printer to calibrate the filament itself or I know the filament isn’t really as dry as it could be. PETG needs calibration to be really accurate, and it needs to be dry so it doesn’t ooze.

1 Like
19

What is the absolute best way of calibrating filaments on the P2S? Orca Slicer? Would I have to do it for every single color, or can it be just a brand flow calibration that would work (eg. using the Sunlu PLA 2.0 black calibration for Sunlu PLA 2.0 yellow)?

White is the main color of this print, which I have used Bambu filament and Sunlu PLA 2.0+. The tower that had been knocked over in the photo is the Sunlu, but the Bambu Filament did the same thing (in I am going to assume), the same/layer place in printing.

20

tower seems suffering in the last centimeters. For me it is over extrusion.