Frame Materials
Metal Frame Materials
What are the differences and advantages of different metal materials? We've put together some useful information to help educate you on choosing the best metal frame for what you need.
Titanium is a silver-gray metal that's lightweight, durable, strong and corrosion-resistant. It has been used for everything from the Gemini and Apollo space capsules to medical implants such as heart valves. Titanium eyewear can be produced in a variety of colors for a clean, modern look with a hint of color.Not all titanium frames are 100 percent titanium. Some are made from an alloy that is a combination of titanium and other metals, such as nickel or copper. In general, titanium alloy frames cost less than 100 percent titanium frames.
•Beryllium, a steel-gray metal, is experiencing increased popularity as a lower-cost alternative to titanium eyewear. It resists corrosion and tarnish, making it an excellent choice for wearers who have high skin acidity or spend a good amount of time in or around salt water. It's also lightweight, very strong, very flexible (making it easy for an optician to adjust your glasses) and available in a wide range of colors.
•Flexon is a titanium-based alloy. This unique and popular material, which is proprietary to the eyeglass manufacturer Marchon, is called a "memory metal" because it can go back to its original shape if damaged. Frames made of Flexon come back into shape even after twisting, bending and crushing. Flexon frames are lightweight, hypoallergenic and corrosion-resistant.
•Frames made from aluminum are lightweight and highly corrosion-resistant. Aluminum is used primarily by high-end eyewear designers because of the unique look it creates. Aluminum is not only the world's most abundant, but also the most widely used, nonferrous material. Pure aluminum is actually soft and weak, but commercial aluminum with small amounts of silicon and iron is hard and strong.
Zyl (plastic) Frame Materials
What are the differences and advantages of different metal materials? We've put together some useful information to help educate you on choosing the best metal frame for what you need.
•If you want the colors of the rainbow, then zyl (zylonite, or cellulose acetate) is your material. Zyl is a very cost-effective and creative option for eyewear and is extremely lightweight. Particularly popular right now are laminated zyl frames that have layered colors.
•Some manufacturers are also using propionate — a nylon-based plastic that is hypoallergenic. It's lightweight and has a different look and feel than other plastics.
•Eyeglasses made of nylon were first introduced in the late 1940s. Because of brittleness and other problems, eyeglass manufacturers switched to blended nylon (polyamides, co-polyamides and gliamides). Today's blended nylon frames are both strong and lightweight.
•Nylon is also a premier material for sports and performance frames — typically made of gliamides, which are very resistant to hot and cold and are more flexible, yet also stiff. Nylon is also easily molded into today's popular wrap styles, as well as other shapes that are difficult to produce.
•Plastic frames do have some drawbacks. They are easier to break than metal frames, they will burn (but are not easily ignited), and aging and exposure to sunlight slightly decrease their strength but do not affect color.
Semi Rimless (grooved) Frame Materials
•Semi Rimless or GROOVED frames are a great way to reduce material and weight. The lenses are held in the frame by a nylon cord. A channel must be cut into the lens so the cord will hold the lens in place. CR-39 and glass lenses may chip more easily than other materials when this groove is cut into the lens making these two materials not the best lens options. The frames can be made of either metal or plastic.
Drill Mount (3 piece) Frame Materials
Drill mount frames are coming back in great demand. These are frames that are actually 3 piece designs. Two temple assemblies and a bridge assembly. The lenses are drilled with holes to assemble the pieces. There are two assembly processes to achieve this
1.Nut and Bolt
The lenses are assembled to the frame chassis by nuts and bolts. The drawback to this is that over time, the nuts and bolts tend to loosen and the assembly is no longer secure. Constant maintenance may be required. This can be solved by applying “locktight” on the assemblies.
2.Bushings
The lenses are assembled using compression fittings that “grab” posts on the chassis parts. This is a more secure assembly and will hold the frames together with the least amount of maintenance. The drawback with this design is that very thick lenses such as very high plus and minus Rx’s can loosen and come apart. This can be solved by choosing higher index lenses for thinner edges.