Calibrating Flow Rate and First Layer on a New Filament Spool

Every new spool — even same brand, same color — can vary slightly. Running a quick calibration takes 20 minutes and ensures consistent results.

Step 1 — Measure the Filament Diameter

Use digital calipers. Measure at 5 points along 50 cm of filament, rotate 90° at each point.

Average your measurements. Enter in Orca Slicer → Filament → Filament diameter.

Typical range: 1.70–1.75 mm. Cheap filament varies more.

Step 2 — Flow Rate Calibration (Orca Slicer)

1. Calibration → Flow Rate
2. Print the flow rate test (two passes: coarse then fine)
3. Coarse: look for the number where the top surface looks smoothest — no gaps, no ridges
4. Enter that value, run fine calibration
5. Fine: same evaluation — pick smoothest result
6. Save as Flow ratio in the filament profile

Step 3 — First Layer Calibration

The first layer needs to be squished slightly into the bed:

1. Print a single-layer 100×100 mm square
2. Watch live — adjust Z offset (baby step Z) in real time:
3. Gaps between lines = too high, go more negative
4. Lines merging together flatly = too low, go less negative
5. Slight squish, lines just touching = correct

Step 4 — Save and Note

In Orca Slicer filament notes, write down:

• Flow ratio found
• Best Z offset for this spool
• Date purchased
• Any observations (stringing level, color accuracy, etc.)

Quick Re-Check for Subsequent Spools

Same brand, different batch? Just measure diameter and run a quick flow rate check — skip full Z offset re-calibration unless something changed mechanically.