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FarmLoop Help Center

Toolhead front cover pops off during push

Specific to the Bambu P and X series (P1P, P1S, P2S, X1C). A1 printers don’t have this cover.

If you’re seeing the front magnetic cover on the toolhead detach during FarmLoop’s push sweep, or the printer goes into a “printing in mid-air” state with the bed dropped to the bottom, you’re in this cluster.

Symptoms

Section titled “Symptoms”
  • The toolhead’s magnetic front cover falls off during a push
  • The printer drops the bed to its lowest position and refuses to continue
  • On the next print attempt, the printer “prints in mid-air” with the bed way below the nozzle
  • The front cover keeps popping on subsequent loops even after you put it back
  • A visibly cracked or damaged cover after several loops

Why this happens

Section titled “Why this happens”

The magnetic cover on the P/X series toolhead is a safety feature: it pops off on impact to protect the print head. FarmLoop’s push sweep is not supposed to touch the cover at all, but it can when:

  1. The part didn’t fully release before the sweep started, and the cover hits the part
  2. The push height is too low (older app versions used 2 mm, which was tight)
  3. The pusher part on your kit is the V1 design, which presses against the cover’s front face instead of wrapping the toolhead

Once the cover detaches, the Bambu firmware interprets the missing cover as a fault and drops the bed to its lowest position. Recovery requires a power cycle plus a manual re-home.

Fix 1: release the part before the sweep starts

Section titled “Fix 1: release the part before the sweep starts”

The cover only pops when the sweep hits something. If the part is already off the plate, the sweep travels through empty air and the cover stays put.

Apply the adhesion fixes from parts won’t detach:

  • Z-offset at 0.00 to +0.04 mm
  • Cooldown threshold 4 to 6 °C below the temperature at which your part manually releases
  • A worn-in textured PEI plate, not Frostbite or SuperTack

Fix 2: print the updated toolhead cover (pusher V2)

Section titled “Fix 2: print the updated toolhead cover (pusher V2)”

The pusher V2 wraps around the toolhead rather than pressing against the front cover. The toolhead cover is included in the current FarmLoop Stage 2 MakerWorld bundle for your printer — download the latest version from FarmLoop Stage 2 for X1C / P1S / P1P on MakerWorld (or the P2S bundle) and reprint.

When installing the pusher:

  • The ring should seat fully on the toolhead and hold snugly
  • If the ring is loose, the pusher itself may have weak layer adhesion, reprint in PETG at higher temperature, slower speed, no supports (or PLA supports only)
  • Test fit without the plate attached before running a full loop

Fix 3: push height at 5 mm or higher

Section titled “Fix 3: push height at 5 mm or higher”

The app’s default push height is now 5 mm. If you’re on an older build, update first. If you can’t update, manually edit the modified G-code to raise the Z values in the push block by 3 mm.

Recovery after the bed dropped to the lowest position

Section titled “Recovery after the bed dropped to the lowest position”

Once the cover has popped and the printer went into “no cover” mode:

  1. Power cycle the printer (off, wait 10 seconds, on)
  2. Put the cover back on the toolhead, make sure the magnets click
  3. Home all axes from the Bambu screen (Device -> Axes -> Home All)
  4. Run a manual auto bed leveling before your next print
  5. Start with a single-loop test, not an overnight queue, to confirm the fix worked

When to contact support

Section titled “When to contact support”
  • Cover keeps popping with the V2 pusher installed correctly, adhesion fixes applied, push height at 5 mm: email contact@3d-farmers.com with a video of the push and your order number
  • Physical damage to the cover itself: free replacement if the damage happened during an authorized FarmLoop loop
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