Important: Flow calibration is filament-specific. Different colors, brands, and even batches may need different flow values. Calibrate for each new spool.
Flow Rate Calibration
Dial in the perfect flow ratio for accurate prints and good surface quality.
Why Calibrate Flow?
Correct flow rate ensures:
- Accurate part dimensions
- Good layer adhesion
- Smooth top surfaces
- No gaps between perimeters
- No over-extruded bulging
Prerequisites
Before calibrating flow, ensure:
- E-steps are correct: Verify in firmware first
- Temperature is calibrated: Wrong temp affects flow
- Filament diameter is correct: Measure with calipers
Running the Test
- Go to Calibration > Flow Rate
- Choose "Pass 1" for coarse calibration
- Print the calibration pattern
- Examine each test patch
- Select the best-looking patch
- Run "Pass 2" with the refined range
- Apply the final flow ratio
Evaluating Results
| Appearance | Flow Status | Action |
|---|---|---|
| Gaps between lines, rough surface | Under-extrusion | Increase flow |
| Bulging, lines overlapping | Over-extrusion | Decrease flow |
| Smooth, even surface | Correct | Use this value |
Alternative: Manual Wall Test
- Create a simple cube (30x30x30mm)
- Set to single wall, no infill, no top/bottom layers
- Print with current settings
- Measure wall thickness with calipers
- Calculate: New Flow = (Target Width / Measured Width) × Current Flow
Example Calculation
Target line width: 0.42mm
Measured wall thickness: 0.46mm
Current flow: 1.0 (100%)
New Flow = (0.42 / 0.46) × 1.0 = 0.913 (91.3%)Typical Flow Values
| Material | Typical Range | Notes |
|---|---|---|
| PLA | 0.95-1.00 | Often needs slight reduction |
| PETG | 0.92-0.98 | Usually needs lower flow |
| ABS | 0.95-1.00 | Similar to PLA |
| TPU | 1.00-1.10 | May need increase |
Applying Results
- Note the optimal flow percentage
- Update your filament profile's "Flow ratio" setting
- Save the profile
- Re-test if you change temperatures significantly