Production and equipment introduction of the hotte

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Brief analysis of the production and equipment introduction of data cable

at present, foreign automobile brands in the world have widely used plastic composites and high-performance engineering plastics. They are stepping into the information society. The construction of information superhighway is developing rapidly in some industrialized countries, with a view to realizing this epoch-making grand plan in the early 21st century. Local area is the basic unit of high-speed information, so the demand for data cables for local area is also growing rapidly. So far, there are two kinds of data cables: one is the 100 Ω cable promoted in America, mainly for unshielded cables; The other is 150 Ω cable promoted in Europe, mainly for shielded cables

up to now, the relevant international standards for data cables are generally divided into three categories, four categories (cancelled), five categories, enhanced five categories and six categories. Their corresponding transmission bandwidths are 16mhz, 20MHz, 100MHz, 100MHz (supporting full duplex transmission) and 250MHz respectively. At present, there is no formal definition of category 7 and even Category 3 to 8 in the international standards, but the hype of various wiring manufacturers; Corresponding to different data cable levels, iso/iec has corresponding channel levels symmetrical with it. At present, it is generally divided into classA, ClassB, ClassC, ClassD and classe levels. Of course, classf level is also being promoted now. In fact, the cables with different impedance requirements in two different regions are produced based on their different structures. The 100 Ω cable promoted in America is mainly because the shielding structure is not promoted in America so far. This is because if there is a shielding structure, the proximity effect between the conductor and the shielding layer will be formed, and the low-frequency parameters such as the capacitance and resistance of the conductor will be changed. In addition, there will be high-frequency vortex current on the shielding layer. However, without the shielding structure, the cable has no ability to resist external interference and poor confidentiality. Moreover, it is difficult to achieve transmission above 300MHz, so Europe has implemented the shielding structure. How to eliminate the problems caused by the shielding layer, we have to increase the impedance. Therefore, Europe is generally promoting 150 Ω cable. Whether the two structures are good or bad depends on different application environments, so the international wiring is generally about the combination of the two wiring methods

but at present, unshielded structure is still widely used. Due to the development of information technology and the follow-up of transmission bandwidth requirements, five categories and incremental five categories of unshielded data cables are more popular at present. Here is an introduction to this point:

1. Production process flow chart (taking the most popular two-step production method as an example):

2. Production process and equipment characteristics:

at first glance, The structure of a 4-Pair data cable is similar to that of an ordinary local telephone cable, but it is relatively difficult to fully meet the specification of the data cable. Generally, the local telephone cable is only used in the audio range, that is, the pulse code is used to modulate the call system. The test frequency of the cable is only about 1MHz, while the test frequency of the data cable is 100 MHz, 250 MHz and even 500 MHz. Therefore, the symmetry and precision of cable structure are highly required

the current production process of data cables can be summarized as follows (currently applied in China):

note: Taiwan funded enterprises now have jackets and loops together

the main difference between these three schemes lies in the two processes of twisted pair and cabling, whether they are separated or combined. In the past, many people believed that group stranding must be used to produce high-quality data cables. The biggest advantage of group stranding is that the two processes of pair stranding and cable forming are combined into one, which saves the winding after pair stranding and the release during cable forming, and reduces the repeated bending of pair stranding, thus improving the quality of cable. However, its disadvantages are low production efficiency and large investment. Through years of practice in various countries, it has been proved that there are advantages and disadvantages in twisted pair, cable separation or combination, and the final result can produce high-quality data cables. In the scheme of separate twining and cabling, the setting out of the twining machine is outside the rotating body of the machine. The characteristics of active setting out and precision tension control thermoplastic are that it is much easier to expand after heating than group stranding, and it is also convenient to add shielding. For cables of more than five categories and above, untwisting or partial untwisting and paying off have been adopted on the pair stranding machine and cable forming machine to improve the quality level of pair stranding and cable forming, but now the untwisting on the pair is widely used. This is easier to do in the separate process, but it is much more difficult in the group winch. To sum up, the biggest advantage of the group stranding scheme may be that it saves labor and occupies a small area, reduces core bending, and is easy to ensure performance. The biggest disadvantage is that the setting out is not easy to reverse, the pitch difference between the lines is long, the production speed is limited by the minimum pitch pair, the uniformity of the force on the line is less than that of the single process, and the investment is large. Therefore, at present, the two-step method is mainly used

the following is some analysis of the equipment of various processes:

A. wire drawing insulation tandem production line (hereinafter referred to as series line)

this is the most critical process for the production of data cables. In addition to the production of stranded wire cores of data cables, in order to ensure that the insulated wire cores achieve a highly refined geometric size and the best quality, series lines are used without exception. Related to cable series line, the production requirements and quality control indicators of data cable series line are much stricter

at present, there are few domestic manufacturers of high-speed serial lines that can meet the above requirements. Shanghai Jindong and Guangdong yongxiong have better cups, and the price can be about 1.5 million yuan, but the stability is still poor, and it is still a little difficult to produce high-level data cables, such as Category 6 cables. The linear speed is low, about 1000m/min, and physical foaming is not allowed. Therefore, imported series lines are generally used now, such as Rosenthal, Nike Sloan, Kobe Steel of Japan and Davis of the United States. Among these manufacturers, Rosenthal and Nike Sloan are the most widely promoted. Their speed is between 1800m/min and 2200m/min, which can be used for leather foam insulation (or some fluoroplastic insulation), laying the foundation for the future small core category 6 cables and higher-level data cables. However, the price is relatively expensive, and now the price is reduced. If a line is fully equipped, it is also more than 10 million yuan

at present, the recognized single line color separation in the market mostly adopts the American color code, with four pairs of lines: white basket, white orange, white green and white brown. In order to facilitate the separation, the color ring or color bar is printed on the white core in the cable factory now. When the color ring is used, the core passes through the high-speed color ring machine after the extruder head comes out. Although the imported color ring machine claims to be up to 1200m/min-2000m/min, the high-speed ink needs to be imported. Even if the high-speed ink is used, the color ring is sprayed when the line speed is 1200m/min on the polyethylene insulation. It is not easy to dry and the cost is high, so it is not used in some high-speed series lines. In the imported high-speed tandem line, the color bar is pushed. As long as a small extruder is added to the extruder head, the production cost is low, and the production speed is not affected

b. twisted pair machine

the twisted pair machine of data cable is not much different from the cable twisted pair machine in principle. Only the stranding pitch is very small, generally within the range of 10-25mm, but the stability of the pitch and tension control requirements are very high

the following is the comparison table of quality control requirements of the two kinds of stranding machines:

in order to meet the above requirements, the paying off device of the stranding machine should be active and have sensitive tension feedback, and keep the paying off tension of the two wires uniform and the same length. At the same time, all steering guide wheels on the machine should be increased as much as possible to prevent the adhesion between the copper wire and the insulation from being affected. Due to the short stranding pitch of data cable, it is necessary to improve the pantograph rotation speed as much as possible to improve the output

at present, Shanghai Jindong and Hefei Shenma are not bad among the mainland's stranding machine manufacturers, and Taiwan also has some ideal stranding machines. At present, what is really used and recognized by customers is imported, such as French Gordon, French Botia, and Japanese Qinling. They have good performance but high price

c. cable formers

data cable formers can be divided into two types: double twist and single twist. The double twist type has fast speed and relatively low accuracy, and is widely used in the production of category 5 and super category 5 cables of data cables. For category VI cables and requirements, it is required to conduct the test in tec-qte laboratory in Noordwijk, the Netherlands μ The high shielded cable in the VCM center is generally twisted into a cable machine with high precision in the world

the following is the performance comparison of single twist and double twist cable formers:

the manufacturers of cable formers at home and abroad are basically the same as that of twisted pair machines. French Botia adopts group stranding (pairing and cabling are combined into one). In addition, the cabling of large number of data cables also adopts the modified cable cabling machine, or the corresponding modified equipment of each equipment manufacturer

d. sheath machine

the data is that the cable sheath production line is characterized by a thin sheath thickness, which is generally only about 0.5mm. PVC or other polyolefin compounds are usually used. In the extrusion process, to keep the geometric position of the cable core structure unchanged, the centering extruder head and semi extrusion die are usually used. The identification shall be printed on the surface of the sheath. Because the cable shape is not necessarily smooth, it is usually printed by computer. Sheath production is the simplest control link in the whole data cable production process, so domestic sheath production line can generally meet the requirements. According to the extrusion outer diameter, type 65 extruder is generally used

e. ring packaging

because the packing length of data cable is generally 1000 feet (304.8 meters). In order to make the construction and setting out convenient, and to keep the cable from being twisted during setting out, so as not to affect the performance, there are two common methods: box type torsion free setting out packaging and winding paper box setting out packaging. The latter needs to wrap the cable on the cardboard tray, then put it into the carton, hold it with the mandrel, and pull the cable out of the slot when in use. This packaging method has high cost, and the cable tray needs to rotate. At present, this method is mainly used for the packaging of six types of cables. At present, the most popular in the world is the box type torsion free paying off. The cable adopts special cross winding when it is in a circle, so that the cable will not be twisted during paying off. There are many manufacturers of this kind of looping machine. The most advanced and effective one in the world is Wendeng in the United States, and the price is also very expensive

f. finished product testing

the requirements for finished product testing of data cables are much higher than those of cables. The cable test is up to 1 MHz, while the data cable is now subject to the international standard of 250 MHz. Both American eia/tia (Electronic Industry Association/Telecommunications Industry Association) standards and iso/iec (International Organization for Standardization/International Electrotechnical Conference) standards strictly stipulate the ex factory standards of cables. At present, there are hardcover and portable testers on the market. There are Swiss AESA, American DCM, Taiwan Huiying, German mea, etc. among these manufacturers, Swiss AESA and American DCM are the most widely used, and the price is also expensive. Portable ones include fluke, ideal, etc., which are generally used for engineering inspection, and cannot be used as factory inspection. Selecting advanced testing system is not only very important for controlling production quality and determining product grade. It is also of great help to improve the process and product quality according to the test statistical analysis results. (end)

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