Flexon Eyewear: NitroDur 3 Alloy and Living Hinge Technology

Flexon frames utilize a proprietary titanium-based alloy manufactured via the NitroDur 3 process, combined with a unique Living Hinge design.

NitroDur 3 Manufacturing Process

1. Vacuum melting: Base titanium alloy melted in vacuum to eliminate impurities and gas inclusions.
2. Nitrogen infusion: Nitrogen molecules interstitially diffuse into the alloy lattice under controlled pressure/temperature.
3. Thermomechanical processing: Controlled cooling, rolling, and aging to precipitate fine nitrides and optimize grain structure.
4. Resulting properties: ~25% higher tensile strength, ~35% greater flexibility (elastic strain limit) vs. conventional β-titanium alloys.

Living Hinge Design

• Integral flexible hinge region (not a separate mechanical hinge).
• Thin, tapered cross-section allows elastic bending without plastic deformation.
• Distributes stress over longer region → reduces peak stress, fatigue failure.
• No screws/barrels to loosen, corrode, or misalign.
• Weight distribution: Hinge flexibility conforms to temporal anatomy.

Combined Benefits

• Durability: Withstands repeated flexing (temple opening/closing, accidental sitting-on).
• Comfort: Low stiffness → reduced pressure points; "memory" returns to fit.
• Adjustability: Can be heated and bent for custom fit without fracture risk.
• Lightweight: Titanium density ~4.5 g/cm³ vs. 8–9 for stainless steel.
• Corrosion resistance: Titanium oxide passive layer; hypoallergenic.

Clinical/Consumer Relevance

Ideal for active lifestyles, children, safety eyewear, and patients with metal sensitivities. The technology represents a materials science advancement in eyewear engineering, not merely a marketing claim.