First Layer Adhesion Failure

What It Is

The part detaches from the build plate during printing. Leads to spaghetti if undetected.

How It Forms

The first layer is the foundation. For it to stick, three conditions must be met simultaneously:

1. Correct nozzle height — Close enough to squish filament into the bed texture, far enough not to scrape
2. Correct bed temperature — Warm enough to keep plastic slightly soft at the interface, creating a bond
3. Clean bed surface — Oils, dust, or residue prevent the plastic-to-surface bond

If any condition fails, adhesion is weak. As the print grows, forces increase: warp stress pulls corners up, nozzle can bump overhangs, vibration shakes the part. Eventually, the weakest point gives way.

Visual Signature

• Part slides across bed during printing
• First layer doesn’t stick at all (“skiing”)
• Partial detachment — one corner lifts, rest stays
• Full detachment → spaghetti
• First layer lines not squished flat (round cross-section = too far)

Root Causes

Cause	Calibration Variable	Direction
Nozzle too far from bed	Z-Offset	↑ (too far)
Bed temp too low	Bed Temperature	↓
Bed mesh stale/missing	Bed Mesh	outdated
Dirty bed surface	— (maintenance)	—
First layer speed too fast	Speed Profile (first layer)	↑
No first-layer flow boost	Flow Rate (first layer)	↓

How the Auto-Tuner Detects It

• Camera: First layer monitoring — are lines squished flat? Are they connecting? Any gaps?
• Anomaly detection: Part outline tracking — if outline shifts or disappears, adhesion failure detected
• Vibration sensor (future): Loose parts vibrate differently than bonded parts

How the Auto-Tuner Fixes It

• Calibration: Z-offset via contact sensing, bed mesh before every print, bed temp optimization
• Live tuning: First layer monitoring. If adhesion looks weak, pause and alert before it becomes spaghetti.