Guide / Snap Fits

Snap-Fit & Living Hinge Design

Designing assembly features for plastic parts

Snap-Fit Types

TypeDeflectionRetention ForceAssembly/Disassembly
Cantilever2-5mmMedium-HighMultiple cycles
Annular0.5-1.5mmHighOne-time (permanent)
Torsion5-15 degMediumMultiple cycles
U-Shape3-8mmMediumMultiple cycles (low stress)

Living hinge: only PP and PE are suitable. Hinge thickness = 0.2-0.3mm. Expected cycles: 1-5 million (PP). Radius at hinge root = 0.25-0.5mm.