Parts won't detach from the build plate

Rule this out first, bed-temperature mismatch

The app currently writes a bed temperature ~5 °C lower than what the UI shows. If you set the cooldown threshold to 25 °C, the G-code actually targets 20 °C. Workaround: add 5 °C to whatever you want, set 30 °C in the UI to target 25 °C. See Temperature mismatch for details. Engineering is fixing this.

If that’s not your issue, the bending routine is running but the part isn’t coming off, keep reading. Roughly 80 % of the time it’s a slice-setting problem, not a hardware one. Try the adjustments below in order.

Symptoms

You may see any of these:

• The bender pushes, the plate flexes, but the part stays attached
• The toolhead pushes the plate instead of the part, the part is so well-adhered that the plate moves with it
• Thin or flat parts (under ~2 mm) slip under the pusher and the pusher rides over the top
• The toolhead pops off its magnets during the push motion (Stage 1 only, Stage 2 has a reinforced head)

First things to try (in order)

1. Increase the Z-offset

Raise Z-offset to a higher value, try +0.02 mm first, up to +0.04 mm if needed. A higher Z-offset means the first layer sits slightly farther from the bed, which reduces adhesion. Lower Z-offsets (-0.02, -0.04) press the filament into the plate and make the problem worse.

Z-offset direction, in plain language

This catches people out: more positive = further from the bed = less sticky. More negative = closer to the bed = more sticky (and more likely to gouge). If you’re dropping z-offset to try to fix adhesion, you’re going the wrong way. Bambu’s default for textured plates is around -0.02 to -0.04 mm; the FarmLoop sweet spot is 0.00 to +0.04 mm. Step in 0.02 mm increments.

In Bambu Studio: Prepare → Process → Quality → Z-hop area, or use Device → Calibrate → Auto Z-offset, then nudge up.

2. Lower the cooldown temperature in the FarmLoop app

The app controls the cooldown temperature before the eject fires. Drop it to 20-25 °C for PLA, PETG, and ABS. Warmer plates hold parts better — the whole point of cooldown is that the PEI shrinks slightly faster than the filament, releasing adhesion. Too warm = adhesion never breaks.

3. Increase the number of bottom layers

More bottom layers = thicker, more rigid base = the bender has something solid to push against instead of flexing the part. Try 5 bottom layers instead of the default 3.

4. Place parts toward the front of the plate

The bender’s flex is strongest near the front edge. Parts placed at the back see less plate deformation and stick harder. When multi-printing, put the stickiest parts (wide flat bases) at the front.

5. Decrease the bed temperature during printing

Also in the FarmLoop app: lower the bed temperature used during the print itself, not just the cooldown threshold. A cooler print bed means the filament-to-plate bond forms weaker in the first place, which makes the eject much easier. Drop it in 5 °C steps from the Bambu default until the first layer still adheres cleanly but peels more easily once cool.

Edge cases

Thin or flat parts

Parts under ~2 mm tall may not be ideal for automation. The pusher can ride over them.

• Add a sacrificial block to one side of the part to give the pusher something to catch
• Or rely on plate bending alone, skip the push, let the flex do the work. This works well for very flat parts with broad bases.
• Parts 1 mm or less may need to be printed manually

Toolhead coming off during push (Stage 1)

This happens when adhesion is so strong that the push force exceeds the magnetic attachment. The fix is the same as above, reduce adhesion via Z-offset and bed temp. Stage 2 hardware uses stronger toolhead attachment and largely eliminates this.

Residue buildup on textured PEI

This is the single most overlooked cause of “my setup used to work and now it doesn’t”. Textured PEI gets stickier over time, not less sticky, as filament oils, handling marks, and print residue accumulate in the micro-texture. A plate that released cleanly in month one can become unreliable by month three purely through residue.

Try in this order:

• Swap in a new plate. If a new plate releases cleanly, the old plate is residue-contaminated and nothing in the slicer will fix it. Often the single biggest fix.
• Deep-clean the old plate. Hot water + dish soap + soft brush, then IPA, then dry fully. IPA alone doesn’t reach into the texture; the soap + agitation step is what actually strips oils.
• Rotate between two plates to extend useful life and give yourself a known-good reference to compare against.
• Avoid no-name AliExpress PEI sheets — several customers have reported they release fine for the first print, then fail unpredictably from print #2 onward. Stick with FarmLoop or Bambu OEM plates.

See choosing a build plate for the full explanation.

Height limit, Stage 1 on P/X series

Stage 1 can’t reach above ~200 mm on P1P / P1S / P2S / X1C. Tall prints (e.g. 237 mm) run through the eject routine without anything actually contacting the part, it stays on the plate. The pusher is a hardware reach limit, not an app setting. Stage 2 removes this restriction.

If your tallest model exceeds 200 mm and you’re on Stage 1: either split the model, print shorter parts in the loop, or upgrade to Stage 2.

The whole build plate gets pushed off during eject

Not the same as “part stays stuck”. Here the part holds onto the plate so strongly that the push sweep shears the entire plate off the printer’s magnets, and the plate ends up on the floor with the part still attached.

Happens most often with:

• Large flat parts (huge bond area, high leverage on the plate)
• High-adhesion or heavily residue-contaminated plates (see choosing a build plate)
• PETG at high bed temperature
• A-series bend torque popping the plate from its magnets on the very first bend

The root cause is adhesion. Apply everything above — lower Z-offset, drop cooldown threshold, swap to a fresh plate — before assuming it’s a mechanical retention problem.

When to contact support

If you’ve worked through the adjustments above and the part still won’t detach, send us:

1. The .3mf file you’re printing (attach directly, this has all slice settings)
2. A photo of the plate after the eject attempt
3. Your printer model and FarmLoop firmware version (from the Firmware page)

Email contact@3d-farmers.com.

Related

• Correct workflow reminder, make sure your slicing + queueing steps are right
• Printer compatibility, what each printer supports