How to Fix Your 3D Printer's First Layer: The Complete Guide

## Why the First Layer Is Everything The first layer is the foundation. If it doesn't stick, bond correctly, or look smooth, everything above it fails. Most 3D printing problems trace back to a bad first layer. ## Step 1: Level Your Bed Manual levelling: use a sheet of A4 paper. The nozzle should have slight resistance when dragging the paper — not too tight, not floating. Auto bed levelling (ABL): run the probe sequence after every cold start or after bumping the printer. **Pro tip**: Re-level after the bed heats up — thermal expansion changes the Z-gap. ## Step 2: Dial In Z-Offset Z-offset is the fine adjustment of your nozzle height above the bed. - Too high: filament doesn't stick, strings appear, gaps between lines. - Too low: nozzle scrapes bed, filament squishes out sideways, clogs possible. Adjust in 0.05 mm increments while the first layer prints. The extruded line should be slightly squished — not a round bead. ## Step 3: Set First Layer Speed Reduce first layer speed to 25–40 mm/s regardless of your normal speed. This gives the filament time to bond with the bed surface. In Bambu Studio: First layer speed is under Quality → Speed. In PrusaSlicer: Print Settings → Speed → First layer speed. ## Step 4: Bed Temperature | Material | Bed Temp | |----------|----------| | PLA | 55–65°C | | PETG | 70–85°C | | ABS | 100–110°C | | TPU | 40–60°C | ## Step 5: Bed Adhesion - **PEI sheet**: excellent for PLA/PETG, no glue needed. Clean with IPA. - **Glue stick**: thin layer helps for ABS and PETG on glass. - **Hairspray**: light coat on glass for ABS/ASA. - **Brims**: add a 5–8 mm brim in your slicer for parts with small contact area. ## Step 6: Check Extrusion Calibration Under-extruded first layers gap. Calibrate your extruder E-steps and flow rate before blaming the bed. ## Quick Checklist - [ ] Bed levelled (hot) - [ ] Z-offset set - [ ] First layer speed ≤ 40 mm/s - [ ] Correct bed temperature - [ ] Clean bed surface (IPA wipe) - [ ] Flow rate calibrated