The differences between metal and plastic hinges in sunglasses

1. Strength and durability: Metal hinges are generally stronger and more durable than plastic hinges. Metals such as titanium or stainless steel have high strength and wear resistance, which can effectively resist daily wear and tear. On the other hand, plastic hinges may be relatively fragile and prone to wear or breakage after repeated folding and friction.
2. Weight: Metal hinges are usually heavier than plastic ones. As metals have a much higher density than plastics, a metal hinge of the same volume will be heavier than a plastic one. For those who prefer lightweight sunglasses, plastic hinges may be a better choice.
3. Appearance and luster: Metal hinges can have a unique metallic luster, which adds a unique touch to sunglasses. In addition, metal hinges can come in multiple colors and surface finishes, such as polished or brushed, providing greater customization options. On the other hand, plastic hinges are usually semi-transparent or solid in color, with a more limited aesthetic variety.
4. Allergic reactions: Some people may have metal allergies, especially to nickel or other alloys. For these individuals, using non-metal hinges on sunglasses is a better choice to avoid possible skin contact allergies.
5. Price: Metal hinges typically have a higher manufacturing cost than plastic ones, resulting in a higher final product price. However, this may lead to greater durability and strength of metal hinges.

In summary, metal and plastic hinges each have their own advantages and disadvantages, and the specific choice depends on personal needs and preferences.