EuroWire July 2020

Technical Article

The disadvantage is that the optical cable outer sheath is mostly made of polyethylene (PE). Polyethylene is composed of a simple carbon structure with regular molecular structure and high flexibility. The molecular chain of polyethylene is easy to fold and stack to reduce the surface energy and make the system more stable, which means higher crystallinity, but this often leads to poor adhesion with the ink. On the other hand, additives added in the production process of polyolefin polymer materials are usually small molecule materials, which are also easy to adhere to the surface, resulting in a layer of isolation film between the ink and the sheath, and reducing the adhesion of ink. It is easy to cause the printing to wear and even disappear, which has a great impact on later maintenance and traceability. At present, some manufacturers increase the bonding force between the sheath material and ink by means of low temperature plasma treatment of the optical cable sheath, so that the optical cable print shows high strength and wear resistance. 2.2 Hot embossing Another common method of optical cable printing is hot embossing. Its principle is that the meter device starts to rotate due to the friction on the surface of the cable along the direction of the cable production. The edge of the printing wheel is equipped with fixed-interval raised printing blocks. At the same time, the central part of the printing wheel has a heating device, which is used to heat the printing block. In the process of rotation, the printed strip is hot extruded to form a layer of polymer film on the surface of the printing block. After contacting with the sheath, the printed strip is imprinted on the outer sheath to form the final printing. A fixed guide wheel and base guide wheel can prevent the optical cable from shaking in the process of rotation, and the tension adjustment cylinder can adjust the tension of cable.

Device type

Passive UHF radio frequency identification transponder

Support agreement

EPC Global Class1 Gen2 ISO 18000-6C

Working frequency

Full spectrum of 860-960 MHz

Chip type

Higgs 3

Memory division

EPC 96 bits; TID 64 bits; User storage 512 bits

▲ ▲ Table 1 : Electrical performance of RF chips

3 Radio frequency

The advantages of hot embossing are that the impression mark is permanent, and the impression is concave, so is not susceptible to wear and tear. The disadvantage is that it is difficult to debug in the hot embossing process. The problems of uneven embossing depth, residual indentation on the surface and uneven coverage of the printing tape are easy to occur. At the same time, because hot embossing needs to customise special printing blocks according to the printing needs of customers, it will increase the cost and production cycle of optical cable, and affect the production efficiency of manufacturers. Common hot embossing devices and hot embossing blocks are shown in Figures 3 and 4 . 2.3 Other printing methods At present, there are some other printing methods, such as relief printing, laser printing and so on. Relief printing is relatively rare. Its working principle is to install a printing wheel between the sheath extruder head and the cooling water tank. The printing block on the printing wheel adopts a concave structure. When the sheath material is extruded from the extruder head and the forming mould, it will form protruding characters when the sheath material gets through the printing wheel. The water tank helps for further cooling and shaping. However, due to the difficulty in controlling the printing process, the principal printing method in the industry is still jet printing.

identifiable optical cable

Under the background of large-scale optical network construction, how to use optical cable resources more intelligently and efficiently has become a key issue for communication management. The traditional methods of recording information usually use plastic- encapsulated labels, which have problems such as environmental pollution and human error. In order to improve the maintenance efficiency of traditional optical cable lines, Hengtong Optic-Electric Co, Ltd investigated the technology of electronic information storage. Through demonstration, it finally chose the RFID chip for information storage and identification. In the production process of optical cable sheath, the chip is directly added to the optical cable sheath layer, which not only prevents the label chip from falling off, but also protects the chip and reduces the shadow in the outdoor environment. It can be scanned and recognised in buried, overhead, pipeline and even underwater scenarios. 3.1 Radio frequency identifiable technology (RFID) Radio frequency identifiable (RFID) technology refers to a fixed radio frequency chip (also known as an “electronic tag”) that stores information in the optical cable. When the radio frequency chip enters the magnetic field, it receives the radio frequency signal from the interpreter, and then transmits the product information stored in the chip by the energy obtained from the induced current. Another method is that the radio frequency chip actively sends a signal of a certain frequency, and the interpreter reads the information and decodes it, then sends it to the central information system for relevant data processing.

▼ ▼ Figure 3 : Hot embossing machine

▼ ▼ Figure 4 : Hot embossing printing block

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July 2020