Bed leveling system

Automated bed mesh leveling: a probe attached to the extruder maps the bed surface at multiple points to compensate for unevenness during the first layer.

Function

• Probes the bed at a grid of points
• Generates a height map (mesh) used during printing
• Compensates for bed warping, frame flex, and non-flat surfaces
• Combined with the Z offset, produces a perfect first layer

Components

Part	Purpose
Probe	A switch lowered by a small servo motor. The servo drops the switch during probing and lifts it again as soon as probing finishes. When down, the switch acts as both endstop and probe
Probe arm (E21)	The 3D-printed arm that carries the switch, mounted on a factory-calibrated metal arm. When replacing the printed arm, do not remove the metal arm it attaches to
Servo connector	A black 3-pin JST connector links the servo to the board behind the extruder — a frequent fault point (see Probe arm bending)
Probe cable	Signal to MCU; sensitive to bends and disconnects
Bed surface	Tempered glass (standard); some customers use a fibreglass plate — see Bed surface

Note

Probe-to-nozzle offset (Z offset). With the probe lowered, the offset between the probe tip and the nozzle is roughly 10 mm. It must be re-checked with correct Z offset (Klipper) whenever you change the nozzle, and occasionally needs corrections of a few tenths of a millimetre. Save Config afterwards. See Z offset.

Before homing or leveling — clean the nozzle

Danger

Always check the nozzle is clean before homing or leveling. If a blob of plastic is stuck under the nozzle, it hits the glass first and the Z axis does not stop — it keeps driving down. The Z axis and the gantry are deliberately decoupled (to prevent damage and avoid Z wobble), so a dirty nozzle can crash without the probe ever triggering.

Recovering after a crash / to raise the gantry: tap Home Z a few times. Each tap performs only the gantry raise that precedes homing, without actually running the Z home — this lifts the gantry away from the bed safely. Then clean the nozzle and re-run the bed calibration (follow the Ginger bed-leveling video).

How it works

1. Bed leveling macro starts
2. Printer homes XY
3. Probe descends at each grid point and records Z height
4. Mesh saved to firmware
5. During printing, the firmware adjusts Z per the mesh

Running a bed leveling

The correct path on the display is More → Bed Level (not just the Macros menu).

The More menu on the display contains: Bed Level, Bed Mesh, Z Calibrate, Limits, Fan, Leds, Macros, Console, Update, Input Shaper, Save Config, KlipperScreen, Network, Notifications, System, Fine Tuning.

1. From the printer display, open More → Bed Level
2. Wait for all points to be probed (1–3 min)

3. Confirm the mesh map on screen looks consistent
4. More → Save Config to store the result

Caution

Saving from the display vs. from the computer can mismatch. If the first layer is wrong despite a recent leveling, see Z offset and first layer for the fix.

Z screw adjustment (manual tram)

Before running the full bed mesh, the Z lead screws should be trammed so all four corners are at the same height. This uses the screw_adjustment macro:

1. Bed must be empty (no print, no objects)
2. From the display: Macros → screw_adjustment (also accessible via More → Z Calibrate)

3. The macro probes near each screw and reports a value in minutes (e.g., 0.36 minutes = about half a turn) 4. The front-left corner is the reference — it is fixed. Turn the other three couplers by the reported amount in the direction shown

5. The display shows a clockwise/counter-clockwise diagram to indicate which direction to turn each screw

6. Re-run the macro until all values are near zero
7. Then run a full Bed Leveling mesh and save

Note

Values like 0.36 = ~½ turn. 1.00 = 1 full turn. Turn clockwise to raise, counter-clockwise to lower — the direction is shown on the display for each screw.

Ginger Slicer vs Grasshopper — how each uses the mesh

The two print paths handle bed mesh differently:

• Ginger Slicer: performs bed leveling on every print, automatically, within the bounding box of the part being printed (adaptive meshing). You do not need to manage the mesh manually.
• Grasshopper: does not do adaptive meshing (no KAMP). Instead it loads the saved height map named GLOBAL, produced by the BED_LEVEL macro.

Caution

If you print from Grasshopper, remember to refresh the GLOBAL mesh periodically. Run BED_LEVEL from the display and Save Config so the GLOBAL map reflects the current bed — Grasshopper G-code always relies on that stored map, not on a fresh probe.

When to re-level

• After every nozzle change
• After moving the machine
• After replacing endstops / probe / cables
• Monthly during routine use
• If the first layer suddenly looks wrong

Known issues

• Z offset and first layer — the most common downstream problem
• Probe Z offset drifting after cable changes → re-tune live Z and save
• Mesh saved from display not loaded by slicer G-code → run from the correct source
• Bed leveling pushes nozzle hard into bed → probe Z offset diverged from nozzle

Probe arm bending / breaking

Causes — the probe fails to descend or trigger, so the printer keeps lowering Z and crashes the extruder into the bed:

1. Plastic stuck under the nozzle — the nozzle hits the glass before the probe can trigger (see Before homing or leveling)
2. The servo did not actuate — the switch never came down, so there is no probe signal
3. Bad 3-pin JST connector — the black 3-pin JST that connects the servo to the board behind the extruder may look fine but the internal metal pins are not making good contact. This is a very common cause and can also make the servo actuate during a print, dropping the probe so it hits the print or drags across the bed mid-job

How to identify:

• The extruder slams into the bed at the start of a leveling routine, or the probe suddenly drops during a print
• The probe arm is visibly bent after the event
• The probe/servo cable may have come loose

Fix:

1. Re-seat and inspect the black 3-pin JST servo connector behind the extruder — reseat it even if it looks OK, since the metal pins often lose contact. This is the most common cause
2. Confirm the servo actually lowers the switch during probing
3. Replace the bent printed probe arm (E21) if needed — contact Ginger support for the STL/spare. Do not remove the factory-calibrated metal arm that the printed part mounts to
4. After repair, re-run bed leveling carefully and verify the probe triggers before the nozzle reaches the bed
5. Set Z offset conservatively positive (nozzle higher) until you confirm the probe triggers reliably

Maintenance

• Keep the probe clean (no pellet dust on the sensor face)
• Check probe cable routing — no sharp bends
• Verify the bed surface is flat (no warps, no debris) before leveling

Bed orientation reference

The bed has a “FRONT / ginger.” label on the front crossbar — use this to orient the probe arm correctly during assembly and after any mechanical maintenance.

Related notes

• Z offset and first layer
• Bed surface
• Bed heater
• Initial calibration
• Nozzle set