Tolerances & Fit for 3D Printing
Design parts that fit together correctly first time — without trial and error.
Tolerances define how accurately a 3D printed part matches its design dimensions. They determine whether parts fit together correctly — or fail completely.
Because 3D printing is not perfectly precise, every design needs intentional clearance to account for material behaviour and machine variation.
Typical Clearances
Types of Fit
Why Tolerances Matter
3D printers are not perfectly precise. Small variations in temperature, material, and calibration affect final dimensions. Proper tolerancing ensures parts still function correctly in real-world conditions.
Best Practices
• Always include clearance between mating parts
• Test tolerances for critical assemblies
• Account for material shrinkage
• Adjust based on printer accuracy
Key Takeaways
Use 0.2mm for tight fits
Use 0.3–0.5mm for standard assemblies
Increase clearance for moving parts
Always test critical fits