Living Hinge Calculator
A living hinge is a thin portion of polymeric material that bridges two heavy walls, providing the ability for the part to open and close or flex without the use of a mechanical hinge. This calculator analyzes your hinge design and classifies it based on stress and strain characteristics.
Enter your material and hinge dimensions to determine if the design will operate in elastic, plastic, or failure mode. Results include specific recommendations for design improvements.
Design Guidelines
- Material: Polypropylene (PP) is strongly recommended - it can survive over 1 million flex cycles
- Thickness: Typical range 0.25-1.0 mm; thinner = more flexible but less durable
- Length: Typical range 2.0-6.5 mm; affects stiffness and stress distribution
- Tolerance: Maintain ±0.05mm thickness tolerance to prevent preferential bending points
- Transitions: Use smooth land zones (1.0-1.5mm) between thick walls and thin hinge
💡 Pro Tip: Living hinges should be molded with the hinge "closed" or partially closed. The first opening causes controlled plastic deformation that actually strengthens the hinge for subsequent cycles.
Note: This calculator provides engineering estimates for preliminary design evaluation. Always validate living hinge performance through prototype testing before committing to production tooling.