· Austin Prysock

Bambu Lab First Layer Calibration: The Complete Fix Guide

Fix first layer problems on any Bambu Lab printer — X1C, P1S, P2S, A1, A1 Mini. Step-by-step calibration guide covering adhesion, Z offset, bed leveling, and per-material settings.

bambu-lab3d-printingcalibrationfirst-layer

Good news: Bambu Lab printers have excellent auto-calibration systems. Most first layer problems are solved by running them correctly, then dialing in the small remaining adjustments manually.

Table of Contents

  1. What a Perfect First Layer Looks Like
  2. Run Auto-Calibration First (Always)
  3. Common First Layer Problems & Fixes
    • Not Sticking / Poor Adhesion
    • First Layer Too Low (Squished / Scraped)
    • First Layer Too High (Sparse / Gaps)
    • Uneven First Layer (Some Areas Good, Some Bad)
    • Rough / Blobby / Over-Extruded First Layer
    • Curling and Warping at the Edges
  4. Z Offset Fine-Tuning (Machine-by-Machine)
  5. Build Plate Selection & Maintenance
  6. Filament Moisture — The Hidden Killer
  7. First Layer Speed Settings
  8. How to Run a First Layer Test Print
  9. Machine-Specific Notes (X1C / P1S / P2S / A1 / A1 Mini)
  10. When Nothing Else Works: Advanced Manual Leveling

1. What a Perfect First Layer Looks Like

Before diagnosing problems, know what success looks like. A correct first layer will have:

  • Smooth, uniform lines that gently overlap without gaps
  • Lines fused together — no individual ridges visible
  • Flat surface with no raised edges or blobs
  • Consistent texture across the entire bed — no patches that look different
  • No curling at corners — all edges stay flat against the plate

If the lines are barely touching or look stringy, the nozzle is too high. If filament is squished with raised edges or the nozzle is dragging through material, the nozzle is too low.

2. Run Auto-Calibration First (Always)

Before doing anything else, run full auto-calibration. This step resolves 60–70% of first layer issues automatically.

X1C and X1E

  1. Go to Settings panel on the touchscreen
  2. Tap Print Calibration
  3. Tap Start
  4. Let it run completely (bed leveling + vibration compensation + motor noise + nozzle height)

P1S and P2S

  1. Go to Setting > Calibration > Print Calibration
  2. Run Auto Bed Leveling
  3. Also run High-temperature Bed Leveling if you print ABS, ASA, or PA

A1 and A1 Mini

  1. Navigate to the calibration menu on the touchscreen
  2. Run Full Calibration (includes bed leveling and flow calibration)

Enable Pre-Print Leveling (Every Print)

In Bambu Studio, when you send a print, enable “Auto Bed Leveling: On” in the print settings dialog. This runs a fast compensation pass before every print and catches thermal drift.

You can also enable it permanently on the printer screen: Advanced Options > Auto Bed Leveling.

Pro tip: If you’ve moved the printer, replaced the heatbed, or haven’t calibrated in 2+ weeks, run the full calibration again. Printers drift.

3. Common First Layer Problems & Fixes

Not Sticking / Poor Adhesion

Most common cause: Dirty build plate

This is the #1 fix that people skip. Oils from your hands are invisible but completely destroy adhesion. Even one touch to the build surface with bare fingers is enough to cause adhesion failures.

Fix:

  1. Wash the build plate with warm water and dish soap (Dawn works great)
  2. Rinse thoroughly
  3. Let it dry completely — or dry with a clean lint-free cloth
  4. Never touch the print surface with bare hands again

If you print daily, wash the plate every 5–10 prints. For PLA, a quick wipe with 99% isopropyl alcohol between prints is sufficient.

Secondary causes:

  • Filament is wet (see Section 6)
  • Bed temperature too low for the material
  • Wrong plate for the material (see Section 5)
  • First layer too high (Z offset issue — see below)

First Layer Too Low (Squished / Scraped)

Symptoms: Lines are compressed flat, no visible texture, filament squishes out to the sides, raised ridges between lines. In extreme cases, the nozzle scrapes audibly against the plate.

Risks: Nozzle and plate damage, print sticking so hard it tears the plate surface.

Fixes:

Step 1: Re-run Auto Bed Leveling — Often this alone resolves it.

Step 2: Check the nozzle wiper (P2S/A1/A1 Mini)

  • The hard steel sheet or silicone brush must be clean and properly positioned
  • A dirty nozzle during the leveling probe step causes incorrect height measurements
  • If the steel sheet is bent/concave in the middle, the nozzle won’t contact it properly

Step 3: Check nozzle installation

  • Wiggle the nozzle gently — it should not move
  • On A1/A1 Mini: ensure the nozzle fixing buckle is fully secured
  • On P2S: check the clips are fastened correctly

Step 4: Z Offset adjustment (see Section 4 below)

First Layer Too High (Sparse / Gaps)

Symptoms: Lines don’t connect to each other, you can see the plate between them, weak adhesion. Prints peel off mid-print or fail at the base.

Fixes:

Step 1: Re-run Auto Bed Leveling

Step 2: Check nozzle wiper for residue

  • Leftover filament on the nozzle before the leveling probe creates a false height reading
  • Manual wipe the nozzle tip clean before running calibration

Step 3: Z Offset adjustment (increase by 0.01–0.02mm — see Section 4)

Uneven First Layer (Some Areas Good, Some Bad)

Symptoms: Parts of the first layer look perfect; other areas are too high, too low, or have poor adhesion. The problem repeats in the same spots across multiple prints.

Most common cause: Contamination on the build plate

Finger oils, dust, or leftover adhesion spray (like glue stick) in specific areas cause localized adhesion failures while the clean areas print fine.

Fix:

  1. Thoroughly clean the plate (warm water + soap, full wash — not just IPA wipe)
  2. Re-run Auto Bed Leveling
  3. Print a first layer test (Section 8)

If the problem persists after cleaning:

  • This is a bed leveling issue — the physical bed surface is not level
  • Run Auto Bed Leveling again
  • If still uneven, proceed to Manual Bed Leveling (Section 10)

Rough / Blobby / Over-Extruded First Layer

Symptoms: Thick, inconsistent lines, blobs scattered across the first layer, filament piling up.

Common causes:

A1 / A1 Mini — Loose hotend screws: This is a documented hardware issue. The four screws on the hotend heating assembly can loosen over time, causing incorrect bed probe readings and apparent over-extrusion.

Fix:

  1. Loosen the 3 front screws of the ceramic base
  2. Flip the heater assembly over
  3. Retighten the 4 small screws on the back using an H1.5 hex key
  4. Reinstall the ceramic base
  5. Re-run calibration

All machines — Flow rate miscalibration: If the flow rate is set too high, every layer over-extrudes. Run the flow rate calibration in Bambu Studio (or OrcaSlicer for X1C/P1S) and dial it in per-filament.

Curling and Warping at the Edges

Symptoms: Corners and edges of the first layer lift off the plate. Gets worse as the print height increases.

Causes and fixes:

  1. Dirty plate — clean with warm water + soap (see above)
  2. Wrong plate for the material — ABS/ASA needs a smooth PEI plate with bed temperature 90–110°C, not a cool textured plate
  3. Draft / airflow — Bambu Lab printers are enclosed, but if the door is open or an A1/A1 Mini (open frame) is in a drafty area, warping increases. Close the door on enclosed models.
  4. Print cooling too aggressive on first layer — In Bambu Studio, set first layer fan speed to 0% for ABS/ASA. PLA can use 100% fans.
  5. First layer too thin / Z too low — Counter-intuitively, squishing the first layer too hard reduces the contact area and increases warping. Correct Z offset helps.
  6. Brim — For large flat prints or materials prone to warping, add a 5–8mm brim in Bambu Studio.

4. Z Offset Fine-Tuning

After running auto-calibration, there’s sometimes a small residual offset needed. Bambu Lab printers handle this through the start G-code, not a traditional Z offset menu.

Method: Modifying the Start G-code

In Bambu Studio, go to: Printer Settings > Machine start G-code

Find the line containing G29.1:

For textured PEI plate (default):

G29.1 Z{0.01}

For smooth/high-temp plate:

G29.1 Z{0.03}

The number is the nozzle lift height offset in millimeters.

Adjustment guide:

  • First layer too low (squished) → Increase the value (e.g., 0.01 → 0.03)
  • First layer too high (sparse/gaps) → Decrease the value (e.g., 0.01 → -0.01)

Recommended adjustment ranges:

  • Textured PEI plate: -0.01mm to +0.03mm
  • Smooth/high-temp plate: +0.01mm to +0.05mm

Start with ±0.01mm changes, run a test print after each adjustment, and iterate until the first layer is perfect.

P2S users: OrcaSlicer has a dedicated Z offset field in Printer Settings that’s much easier to use than editing G-code. If you’re on the P2S, OrcaSlicer is worth installing for this reason alone — though note that full OrcaSlicer support on P2S is partial; some features may not function as expected.

5. Build Plate Selection & Maintenance

Using the wrong plate for your material is a common cause of adhesion failures. Here’s the quick reference:

Bambu Lab Cool Plate (smooth blue):

  • Best for: PLA, PETG (with glue stick), TPU
  • Not for: ABS, ASA, PA (too low temp)

Bambu Lab Textured PEI Plate:

  • Best for: PLA, PETG, TPU, PLA-CF
  • Excellent release when cooled — parts pop off naturally
  • Not ideal for: ABS, ASA (can stick too aggressively or warp)

Bambu Lab High-Temp Plate (smooth black):

  • Required for: ABS, ASA, PA, PC
  • Needs glue stick for PETG to prevent over-adhesion
  • Bed temp: 90–110°C typical

Maintenance:

  • Textured PEI: Wash with warm water + soap every 10–15 prints. If adhesion drops on PLA, a thorough wash almost always restores it.
  • Smooth plates: Wipe with 99% IPA before each print.
  • Never use acetone on PEI-coated plates — it destroys the coating.

6. Filament Moisture — The Hidden Killer

Wet filament is the #2 cause of first layer problems (after dirty plates), and the least diagnosed. Moisture causes:

  • Uneven, bumpy first layers
  • Popping/crackling sounds during printing
  • Stringing everywhere
  • Inconsistent extrusion that looks like calibration problems

How to tell if filament is wet: Heat your nozzle, manually extrude ~100mm, and watch the output. Wet filament will crackle, pop, or produce bubbles. Dry filament extrudes smooth and silent.

Fix:

  • Dry filament before printing. Target temperatures:
    • PLA: 45–50°C for 4–6 hours
    • PETG: 65°C for 4–6 hours
    • ABS/ASA: 70–80°C for 4–6 hours
    • Nylon/PA: 80–90°C for 8–12 hours
  • Use a dedicated filament dryer (Sunlu FilaDryer S4 is the best value at ~$50; holds 4 spools)
  • If you have an AMS 2 Pro, enable AMS Drying in the Filament Settings tab — it maintains low humidity while printing

Storage: After drying, store filament in sealed bags or airtight containers with fresh desiccant packs.

7. First Layer Speed Settings

High print speeds cause first layer adhesion problems because the filament doesn’t have enough contact time with the heated bed surface to bond properly.

Recommended first layer speeds:

  • Outer walls: 30 mm/s (max)
  • Inner walls/infill: 60 mm/s (max)
  • First layer fan: 0% for ABS/ASA/PA; 30–50% for PLA; 0% for PETG

In Bambu Studio, these can be set in Process Settings > Speed. If you’re using a preset, look for the “Slow down first layer” option.

The X1C and P1S auto-calibration sets some of these optimally. On the A1/A1 Mini, where calibration is less comprehensive, manual speed adjustment matters more.

8. How to Run a First Layer Test Print

A standard first layer test is better than printing a full model and discovering problems on layer 1. Here’s the Bambu Studio method:

  1. Open Bambu Studio
  2. Right-click on the empty bed → Add Primitive → Cube
  3. Scale the cube to 200mm × 200mm × 0.2mm (or smaller for quick tests: 100×100×0.2mm)
  4. Slice with your normal profile
  5. Set layer height to 0.2mm (so the entire print is just the first layer)
  6. Print

Interpreting results:

  • Lines smooth and touching uniformly → ✅ Perfect
  • Lines separate with gaps → Z too high (increase offset)
  • Lines squished flat with raised ridges → Z too low (decrease offset)
  • Inconsistent by area → Dirty plate or uneven bed
  • Blobby / rough → Flow rate issue or loose hotend screws (A1)
  • Lines barely sticking or curling → Dirty plate + temperature issue

Adjust, re-print the test, iterate until consistent.

9. Machine-Specific Notes

X1C / X1E

  • The LiDAR sensor provides bed mesh leveling superior to the P-series
  • If you’re still having issues after full calibration, check that the LiDAR lens is clean (compressed air, not contact)
  • X1C has the most comprehensive auto-calibration of any Bambu printer

P1S

  • At $399 (current price as of Feb 2026 after the price drop), it’s the best value Bambu printer
  • Auto-calibration is solid but doesn’t include LiDAR mesh leveling
  • Z offset via G-code modification is the main tuning method

P2S

  • “Develop Mode” (accessed via Settings > Develop Mode) unlocks additional calibration options including manual flow calibration
  • OrcaSlicer has limited P2S support — some advanced features don’t function
  • P2S has documented first layer quality regressions compared to P1S — particularly with PETG. Run high-temperature bed leveling before PETG prints.
  • The nozzle wiper hard steel sheet deforms over time — inspect it if first layer height errors are inconsistent

A1 / A1 Mini

  • Most first layer issues on A1/A1 Mini trace back to the 4 loose hotend screws — check these first
  • Auto-calibration is less robust than X1C/P1S — manual speed dialing matters more here
  • No enclosure means temperature stability affects adhesion. Keep A1/A1 Mini away from AC vents or open windows.
  • The synthetic stone screw issue: check the screws holding the synthetic stone to the frame — loose screws cause inconsistent extrusion and apparent first layer problems

10. When Nothing Else Works: Advanced Manual Bed Leveling

If auto-calibration, Z offset adjustment, and plate cleaning haven’t resolved your issue, manual bed leveling is the last resort. This is an advanced procedure — don’t do it until you’ve exhausted all other options.

P2S Manual Leveling Procedure

  1. Home the printer (tap Home on screen)
  2. Preheat bed to 55°C, hold for 5 minutes (thermal stabilization)
  3. Loosen the 4 fixing screws of the heatbed in the order shown in Bambu’s wiki
  4. Re-tighten ensuring no contact between the metal heatbed and the Z-axis slide plastic
  5. Set bed temp to zero, re-run first layer test

For precise 3-point leveling (P2S):

  1. Locate the 3 leveling screws on top of the heatbed
  2. Fully tighten all 3 screws clockwise until they bottom out (baseline)
  3. Back them out to a mid-range position
  4. Download Bambu’s manual leveling G-code file from the P2S wiki
  5. Copy to USB, insert in printer, run the file
  6. At each corner probe point, insert A4 paper between nozzle and bed
  7. Adjust screw until paper slides with slight resistance
  8. Repeat for all 3 corners, 3 rounds

The G-code positions the nozzle and waits 30 seconds at each corner for your adjustment. Don’t rush.

Summary: The Calibration Order

When first layer problems hit, work through this sequence:

  1. ✅ Wash the build plate (warm water + soap)
  2. ✅ Run full Auto-Calibration (bed leveling + all options)
  3. ✅ Enable Auto Bed Leveling before every print
  4. ✅ Dry your filament if you haven’t recently
  5. ✅ Check nozzle cleanliness before calibration
  6. ✅ Check nozzle installation and hotend screws (especially A1)
  7. ✅ Run a first layer test print and read the result
  8. ✅ Adjust Z offset via G-code (±0.01mm at a time)
  9. ✅ Reduce first layer speeds if still having issues
  10. ✅ Manual bed leveling (last resort — P1S/P2S)

95% of Bambu Lab first layer problems are solved by steps 1–3.

Last updated: February 2026 | Covers: Bambu Lab X1C, X1E, P1S, P2S, A1, A1 Mini | Sources: Bambu Lab Wiki, r/BambuLab, Bambu Community Forum

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