Background introduction:
From the view of the optic industry, optical fibers are important in telecommunications; they offer a series of outstanding advantages of broad bandwidth, fine diameter, low loss, freedom from crosstalk, freedom from electromagnetic induction, and high efficiency in resource consumption. However, optical fibers are typically categorized as brittle, like glass; compared with the copper conductors that are used in conventional telecommunication cables, they are at a disadvantageous position in terms of their mechanical durability and strength. It is an indisputable fact that optical fibers are subjected to high tensile forces; And to ensure that they can work normally under a variety of tough environments, superior static stretching and dynamic fatigue are a must.
For the reasons above, optical fibers are required to be covered by a resin coating to significantly improve their mechanical strength.
The basic structures of optical fibers:
Optical fibers, or fiber optics, refer to the technology of transmitting data in the form of light pulses. An optical fiber is made from either plastic or glass. Its basic structure consists of three major parts: the buffer or coating, the cladding, and the core. The core section is a cylindrical rod made of transparent, dielectric material that can guide light by total internal reflection. As we all know, electrical charges do not flow through this type of material; this ensures that light will propagate along the fiber core. And the fiber core is generally described as having a certain radius and index of refraction.
And the core needs to be surrounded by a concentric cladding of different glass or plastic (a layer of material with a slightly lower refractive index). The cladding layer also does not conduct electricity. In addition to its function of enhancing reflection within the fiber core, its main functions also include: reducing the radiation loss into the surrounding air, adding mechanical strength, protecting the fiber from physical damage, and preventing the fiber from absorbing surface contaminants.
For extra protection, the cladding layer is enclosed in an extra layer called the buffer or coating. This layer of material provides further protection from physical damage – this layer of material is generally a type of plastic, and it is highly elastic and prevents abrasions. Furthermore, the buffer or coating layer also prevents scattering losses in optical fibers due to a microbend; and a microbend is a fiber imperfection; it occurs when an optical fiber is pressed against rough and distorted surfaces.
UV LED curing in the application of manufacturing optical fiber:
And from the angle of optical fiber manufacturers, they need to resort to the high-speed UV curing technology in a series of processes (e.g. fiber drawing, ribboning, coloring, final fabrication of optic fiber cable, wire marking, and cable marking). To meet this need, in some cases, the curing speed of a UV LED curing machine is required to reach more than 200 meters per minute; what is more, a UV LED curing technology has an excellent performance in maintaining the process consistency for curing inks and coatings rapidly.
Obviously, UV-curable coatings can provide flexibility, strength, and protection to the fiber when it is being drawn. And UV-curable inks not only color code the optical fibers but also protect the fibers against the thermal decomposition of cable gels, especially in the process of multiple-fiber cable production. And the UV-curable ribbon matrix material encapsulates multiple optical fibers into a ribbon cable.
Like other common types of cable and wire, finished fiber optic cables need to use UV-curable inks for labeling to mark identification on a jacket layer. Usually, the jacket layer is rubber-based or plastic-based，and it plays a role in protecting the cable and wire and facilitating installation. By the way, an automated, high-speed inline marking of the wire and cable is a good way to display the specifications, surely, it is also conducive to brand promotion.