Random poops left on bed during print?

Bambu Lab H2 Series
1

I’m printing a fairly large part using ABS (Bambu - normal settings). I just noticed a few random poops on the bed. The part looked fine and I didn’t notice any issues with the print. This was a first. How does this happen?

2

Why Bambu 3D Printing Can Drop Pieces on the Bed

On Bambu Lab printers, “random deposits” or pieces falling off the print bed are often caused by infill collision issues rather than a mechanical fault. Users have reported that when infill patterns like grid are used, the printer’s extruder can hit the bed during infill deposition, causing small pieces to be knocked off Reddit.

Common Causes

  • Grid infill collisions: The printer’s extruder moves in a way that can cause filament to collide with the bed during infill, especially with intersecting lines Reddit.

  • Fast infill retraction: If the slicer’s “reduce infill retraction” is enabled, the printer may retract too quickly, leading to filament clumping or dropping Reddit.

  • Overlapping or aggressive infill patterns: Complex or high-density infill can cause the printer to lose control during deposition.

Fixes and Workarounds

  1. Switch to a continuous, non-intersecting infill

    • Try gyroid, sculpted, or triangular infill instead of grid. These patterns reduce the chance of collisions Reddit.

  2. Disable or adjust infill retraction

    • Turn off “reduce infill retraction” in your slicer to prevent sudden retraction that can cause drops Reddit.

  3. Adjust infill speed and layer height

    • Slower infill speeds and slightly higher layer heights can reduce the risk of collisions.

  4. Check bed calibration and adhesion

    • Ensure the bed is level and the correct bed type is selected in the slicer. Poor adhesion can cause parts to shift or fall Bambu Lab Community Forum+1.

  5. Inspect and clean the nozzle and bed

    • Filament clumps or nozzle clogs can cause erratic extrusion and drops Reddit.

When to Check Further

If the problem persists after infill changes, it could indicate:

  • Mechanical issues (e.g., belt tension, nozzle misalignment)

  • Firmware or slicer settings that cause erratic movement

  • Bed adhesion problems that cause parts to shift mid-print

In such cases, running a full calibration and checking for firmware updates can help.

Tip: Many Bambu Lab users have found that switching to gyroid infill and disabling infill retraction completely eliminated the “random pieces on the bed” issue Reddit.

3

A picture of the filament piece you found would help narrow down the issue.

If it is infact a filament poop your AI response doesn’t address what is actually happening. If you have purge poop on the bed its because it didn’t drop down the poop shoot and was dragged out onto the print bed by the nozzle.

4

Check whether the chute is blocked and the swingy flap is swinging.

5

If you can’t be bothered to write it, we can’t be bothered to read it.

Also it’s most likely wrong.

Also I am probably talking to a bot, am I going insane?

6

These poops were dispersed around the bed area - randomly. There were not in or around the poop chute.

7

Last print was fine - no extra poops. If I see it again, I’ll take a picture.

8

if it gets stuck to the print head because the chute is blocked, it will end up anywhere the head has been, and will not necessarily be clustered around the chute.

i cant think of any other way that could happen as the nozzle does not eject filament like that when printing - unless your object falls over etc but then you will see noodles or spaghetti not a poop

9

From the AI agent I posted above - and I believe I searched for this issue - apparently using grid infill (which I am doing) causes collisions with print head while extruding.

Recommendations:

  • Use Gyroid infill and turn off infill retraction are solutions to this issue.

This just happened last print. If it happens again, I will take pics.

10

Just like in real life, a gas release tends to blow some to the side. But our printers don’t wear undies to catch them, and they wind up on the build plate.

At least, that’s my guess. :laughing: I’m more miffed about the amount of wasted filament in the first place perging the same filament from the last print. But hey, I just let it do its thing.

I use Brims a lot. I see it as cheap insurance against getting most of a print then having it detach, and wasting all that time, energy, and material. So Brims are my cheap insurance of reaching the finish line.

In a song it is said, “Don’t worry, be happy…”

11

Grid infill can cause you hear a knocking sound regularly, which can sometimes cause a piece to come loose from the build plate, or more likely, can cause a blob at the nozzle. A blob will not look like a printer poop, it is round, and not a knot of plastic string, and often leaves burn marks in it or the print.

For a task like these, these AIs aren’t worth the tokens they cost or the environmental damage they cause.