Cantilever Snap-fit Calculator

Input parameters

Material

Material properties

Beam geometry

Cross-section shape

Design type

Rectangle + Equal cross-section: delta = 0.67 x epsilon x L^2 / H | Z = B x H^2 / 6

Length L (mm)

Root thickness H (mm)

Root width B (mm)

Required deflection (mm) -- undercut depth

Assembly parameters

Lead angle alpha (deg)

Retention angle beta (deg)

Usage type

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Results

Permissible deflection

-- mm

Enter beam geometry and material.

Deflection check

Required vs permissible deflection.

Root strain

-- %

Actual strain at beam root.

Section modulus Z

-- mm3

Based on cross-section shape.

Deflection force F

-- N

Force to deflect the beam.

Assembly force W

-- N

Total force to snap joint together.

Geometry check

L/H ratio and width check.

Snap-fit design checklist

L/H ratio is between 5 and 10 Root strain is within permissible limit for selected material Lead angle is between 25 and 35 degrees for easy assembly Root radius R = 0.5 to 0.6 x H to reduce stress concentration Beam width does not exceed 50% of beam length If cyclic use: strain reduced to 60% of single-assembly permissible value Retention angle: 35-45 deg (detachable) or 90 deg (permanent) No sharp corners at root -- use tapered transition

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