Calibration: Use OrcaSlicer's built-in flow calibration test to find the optimal value for each filament. Small adjustments (0.95-1.05) are typical.
Flow Ratio
Fine-tune the amount of filament extruded to achieve accurate dimensions and surface quality.
Flow Ratio
- Parameter
extrusion_multiplier- Unit
- Ratio (0.0 - 2.0)
- Default
- 1.0 (100%)
- Description
- Multiplier applied to all extrusion amounts. Values greater than 1 increase flow, values less than 1 decrease flow.
When to Adjust Flow Ratio
| Symptom | Cause | Adjustment |
|---|---|---|
| Over-extruded lines, bulging | Too much flow | Decrease (e.g., 0.95) |
| Gaps between lines, weak infill | Too little flow | Increase (e.g., 1.05) |
| Poor layer adhesion | Under-extrusion | Increase slightly |
| Rough top surfaces | Over-extrusion | Decrease slightly |
| Dimensional inaccuracy | Incorrect flow | Calibrate precisely |
First Layer Flow Ratio
- Parameter
first_layer_extrusion_width- Description
- Some users prefer slightly higher flow on the first layer for better bed adhesion. This is typically controlled via line width rather than flow ratio.
Flow Calibration Methods
1. OrcaSlicer Built-in Test
Access via: Calibration > Flow Rate
- Print the calibration pattern
- Examine the test patches
- Select the best-looking patch
- Apply the suggested flow ratio
2. Manual Wall Method
- Print a single-wall cube (no infill, no top layers)
- Measure wall thickness with calipers
- Calculate: New Flow = (Target Width / Measured Width) × Current Flow
- Example: If target is 0.4mm and measured is 0.44mm: 0.4/0.44 × 1.0 = 0.91
Typical Flow Ratio Values
| Material | Typical Range | Notes |
|---|---|---|
| PLA | 0.95 - 1.00 | Often needs slight reduction |
| PETG | 0.93 - 0.98 | Usually needs lower flow |
| ABS | 0.95 - 1.00 | Similar to PLA |
| TPU | 1.00 - 1.10 | May need slight increase |
| Nylon | 0.95 - 1.00 | Calibrate carefully |
Important: Before adjusting flow ratio, ensure your E-steps are correctly calibrated in firmware. Flow ratio compensates for material-specific variations, not extruder mechanical issues.