How to Calculate Shrinkage and Scaling Percentages in OrcaSlicer for Technical Parts

Why Shrinkage Compensation Matters for Technical Prints

Engineering filaments contract as they cool. The effect is global and scales with part size. A 200 mm ASA part that measures 199 mm after cooling needs a 0.5 % correction. Without compensation, assemblies that rely on precise hole-to-pin fits or stack-up tolerances become unreliable. OrcaSlicer isolates this correction at the filament profile level so the same scaling applies across every process that uses that material.

OrcaSlicer Shrinkage Parameters and Version Context

Current stable release v2.4.2 exposes two dedicated fields under Filament settings:

• Shrinkage (XY) – percentage applied to all X and Y dimensions
• Shrinkage (Z) – percentage applied to Z height

Both are clamped between 90 % and 110 %. These values operate on the entire model geometry before slicing. Separate process-level controls (xy_hole_compensation, xy_contour_compensation) handle local wall and hole adjustments afterward.

Recommended Calibration Workflow

Follow this sequence for repeatable results:

1. Print a 100 mm or 200 mm square test coupon in the target filament using default cooling.
2. Allow the part to cool completely on the bed before removal.
3. Measure the cooled X and Y lengths with calibrated calipers at multiple locations.
4. Calculate the required percentage:
   Shrinkage % = (measured / nominal) × 100
   Example: 199.0 mm measured on a 200 mm target yields 99.5 %.
5. Enter the value in the filament profile’s Shrinkage (XY) field.
6. Re-print and verify. Apply xy_hole_compensation or xy_contour_compensation only for residual local errors.

flowchart TD
    A[Print test coupon<br/>100 mm or 200 mm] --> B[Full cool on bed]
    B --> C[Measure X/Y at multiple points]
    C --> D{Calculate<br/>Shrinkage %}
    D --> E[Enter value in<br/>Filament → Shrinkage (XY)]
    E --> F[Re-print & check]
    F --> G{Local errors<br/>remain?}
    G -->|Yes| H[Add xy_hole_compensation<br/>or xy_contour_compensation]
    G -->|No| I[Profile complete]

Typical shrinkage values reported across Bambu Lab and Reddit threads

• ABS: 0.7–1.6 % (most common 0.8 %)
• ASA: 0.4–0.7 %

Users consistently reach sub-0.2 mm error on 100–200 mm parts after applying the measured percentage and a single skew calibration pass.

Comparison with Alternative Slicers

OrcaSlicer remains the only widely used fork that places percentage-based compensation directly in the filament preset without requiring external scripts.

Practical Takeaways for Functional Parts

• Always measure after full cooling; hot measurements understate shrinkage.
• Limit compensation to the 90–110 % window to avoid unintended geometry distortion.
• Combine global shrinkage with process-level hole and contour compensation for tight-tolerance assemblies.
• Store calibrated values per filament brand and color; different pigment loads can shift shrinkage by 0.2–0.3 %.

“After shrinkage compensation plus skew calibration, dimensional error dropped below 0.1 mm on calibration parts.” — CNC Kitchen, 2024

Conclusion

OrcaSlicer’s filament shrinkage fields provide a clean, measurable path to sub-0.2 mm accuracy on technical ABS and ASA parts. Print a simple coupon, record the cooled dimensions, calculate the percentage, and apply it once per filament profile. The remaining local corrections are handled by the existing XY hole and contour tools. This workflow eliminates the need for per-model scaling and delivers consistent results across Bambu and generic CoreXY machines.