JP4770819B2 - Optical cable manufacturing method - Google Patents

Description

The present invention accommodates a large number of optical fibers in the grooves of the grooved slot, about the periphery of the slot roughly coiled cord, the holding tape, and manufacturing how optical cable comprising applying sheath.

  As networking using optical cables progresses with the progress of information and communication, the amount of used optical cables is increasing. However, from the viewpoint of global environmental protection and effective use of resources, measures to recycle optical cables are required. Yes. In carrying out recycling of optical cables, various proposals have been made so far regarding optical cables considering recycling costs, quality of recycled products, and recycling.

  Some optical cables have a single core and more than 1000 cores. As shown in FIG. 4A, a typical optical cable 1 is constituted by a slot 2 (also referred to as a spacer) made of a plastic material in which a tension member 3 is embedded and integrated at the center and a plurality of grooves 2a are provided on the outer periphery. Is done. The groove 2a of the slot 2 is formed in a spiral shape or SZ shape, and a plurality of optical fiber core wires or tape-like optical fiber core wires 4 are collected and stored in the groove 2a.

  In order to prevent the optical fiber core 4 from dropping out of the groove 2a (particularly in the case of an SZ-shaped slot) immediately after the optical fiber core 4 is housed in the groove 2a during the manufacturing process of the optical cable 1, the coarse winding is performed. The string 5 is immediately spirally wound around the outer periphery of the slot 2 at a relatively coarse pitch. On the outer periphery of the slot 2 to which the coarsely wound string 5 is applied, a presser winding tape 6 (also referred to as an upper winding tape) for water insulation in the cable or thermal insulation at the time of forming the sheath is spirally wound or vertically attached. The optical cable 1 is formed by covering the outside with a sheath 7 (also referred to as a jacket). In order to prevent water running, the presser winding tape 6 is made of a material having water absorption.

  In general, a wide tape is used as the presser winding tape 6 and is wound spirally so that a part of the tape overlaps the outer peripheral surface of the slot 2. In general, this winding method is called horizontal winding. Then, the coarsely wound string 5 and the presser winding tape 6 are wound so as to cross each other as shown in FIG.

  When disassembling the optical cable 1 in FIG. 4A for recycling, first, the sheath 7 is cut, and this is peeled off and recovered by the recovery means. Next, as shown in FIG. 4 (B), the presser winding tape 6 exposed by removing the sheath 7 is cut by applying a cutter 8a to cut the presser winding tape 6 and the coarse winding string 5. Disconnect. The cut pieces of the presser wound tape 6 and the coarsely wound string 5 are collected and discarded by dropping them forcibly by dropping them naturally or by rubbing the surface of the slot with a die 10 of a dismantling device.

  However, when the presser winding tape 6 and the coarsely wound string 5 are cut by the cutter 8a, the presser winding tape 6 is a wide tape and has a certain amount of friction, so that cutting is easy, but FIG. ), The coarsely wound string (5a) may remain without being cut. The reason for this is that when the cutter 8a hits the coarsely wound string in the rib part of the slot 2, the rib part becomes a wall and the coarsely wound string does not escape, so it is relatively easy to cut, but straddles the groove part 2a of the slot 2. The rough winding string may not be cut because it escapes to the cutter 8a. Moreover, since the coarsely wound string 5 with one end cut is loosened in a state in which the tension is released, even if the push cutter 8a hits, it may escape in the longitudinal direction of the slot 2 without being cut.

  When a portion that cannot be cut occurs in the coarsely wound string 5, the string wound around the slot 2 is easily loosened, and the coarsely wound string 5 on the rib portion may not be cut. Therefore, cutting becomes insufficient, and it may be difficult to drop the rough winding string 5 and the presser winding tape 6 by dropping them naturally. Further, when the surface of the slot is removed by squeezing using a die 10 or the like, the coarsely wound string 5 is accumulated and entangled to become a hairball shape, preventing the presser winding tape 6 from being cut or blocking the through hole of the die 10. There was a problem that the failure of the movement of the slot 2 occurred and the cable could not be efficiently disassembled.

  As a method for improving the above problem, for example, as shown in FIG. 4 (C), after the presser winding tape 6 is exposed, the intermittent cutter 8b is pressed from above the presser winding tape 6 in the longitudinal direction of the optical cable 1. Then, intermittent cuts 9b are made and the coarsely wound string 5 is cut so as to have a short length. After this, the cutter 8a cuts 9a into the presser winding tape 6 and cuts it into short pieces for each turn, and the inside of the presser winding tape 6 drops the coarsely wound string 5 that has been previously cut short by the intermittent cutter 8b. Has been proposed (see, for example, Patent Document 1).

In addition, it has also been proposed to use a monofilament, a twisted fiber bundle, a narrow and flat band-like shape, etc., for the coarsely wound string 5 so that the coarsely wound string 5 is not fuzzy or entangled and hardened into a hairball shape. (For example, refer to Patent Document 2).
JP 2007-212522 A JP 2007-212523 A

  When using the disassembly method of FIG. 4 (C), it is necessary to separately install the intermittent cutter 8b, and it is necessary to set the cutting timing according to the winding pitch of the coarse winding string 5, and the configuration of the optical cable to be disassembled in advance It is necessary to know the information about, but there are cases where it is impossible to obtain information, and there is a problem that it takes time to prepare for work. Moreover, when using a special thing for the coarsely wound string 5 as disclosed in Patent Document 2, even if it can be expected to reduce the occurrence of fuzz and entanglement, it is not perfect, and a special string is used. Cost increases.

  As a method for improving the above points, as shown in FIG. 1 (A), the presser winding tape 6 is formed by open winding with a gap 6a so that a part of the coarse winding string 5 inside is exposed. However, an optical cable having a structure in which the sheath 7 applied thereon is fused to a part of the coarsely wound string 5 exposed from the gap 6a has been studied. This optical cable has an effect that when the sheath 7 is peeled off, the coarsely wound string 5 is cut at the fused portion, and at the same time as the sheath is removed, the coarsely wound string 5 is cut short. It is also useful for intermediate branching.

However, when the presser winding tape 6 is wound with a gap 6a therebetween, the heat of the sheath material (resin) heated at the time of forming the sheath is easily transmitted to the optical fiber core 4 housed in the slot, thereby increasing transmission loss. The problem arises. For this purpose, it is necessary to strictly control the temperature of the molten resin at the time of forming the sheath below a set value.
Accordingly, the present invention, the temperature of the molten resin optical cable sheath molding comprising wound with a gap the holding tape, controlled accurately, the purpose of providing the optical cable manufacturing how excellent in removability of the coating And

An optical cable manufacturing method according to the present invention is an optical cable manufacturing method in which a rough winding string, a presser winding tape, and a sheath are sequentially applied to the outer periphery of a slot that accommodates an optical fiber core. The temperature of the molten resin for the sheath that is wound with a gap so that part of it is exposed and extruded on the outside is maintained below the set value by controlling the screw rotation of the resin extruder, and the line drawing speed The sheath is applied while maintaining the cable outer diameter constant by controlling the above.
In addition, after the temperature of the molten resin is continued for a certain period of time below the set value, it is desirable to compare the measured value with the set value again to control the screw rotation and the line speed.

According to the manufacturing how the optical cable of the present invention, it is possible to control the temperature of the molten resin sheath molding at set values less precision, affecting the transmission loss of the optical fiber by the heat of the sheath Therefore, it is possible to provide an optical cable excellent in the removability of the coating. In addition, it is possible to suppress a reduction in the line drawing speed in connection with the control of the temperature of the molten resin for the sheath, and the reduction in manufacturing efficiency can be minimized.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1A is a diagram for explaining an example of an optical cable that is a subject of the present invention, and FIG. 1B is a diagram for explaining an outline of a sheath forming process of the optical cable. In the figure, 1 is an optical cable, 2 is a slot, 2a is a groove, 3 is a tension member, 4 is an optical fiber core wire, 5 is a rough winding string, 5a is an exposed portion, 6 is a presser winding tape, 6a is a gap, 7 is Sheath, 11 is a supply reel, 12 is a take-up reel, 13 is an extruder, 14 is a forming die, 15 is a cooling device, and 16 is a take-up capstan. 1A is the same as that used in the description of FIG.

  An optical cable targeted by the present invention, for example, as shown in FIG. 1A, a slot (spacer) made of a plastic material in which a tension member (also referred to as a tensile body) 3 is embedded and integrated in the center and a plurality of grooves 2a are provided. (Also referred to as 2). The groove 2a of the slot 2 is formed in a spiral shape or SZ shape, and a plurality of optical fiber core wires or tape-like optical fiber core wires 4 are accommodated in the groove 2a. In order to prevent the optical fiber core 4 from dropping out of the groove 2a (particularly in the case of the SZ slot) after the optical fiber core wire 4 is housed in the groove 2a during the optical cable manufacturing process, It is wrapped around.

  As the coarsely wound string 5, for example, a string-like one in which nylon fibers having a thickness of 1260 denier are bundled or a tape-like one is used. Further, in the case of an optical cable of about 100 cores and a slot outer diameter of about 9 mm, the coarsely wound string 5 is formed by winding two strings at a pitch of 20 mm (with a pitch of 10 mm). The coarsely wound string 5 can be made of various materials such as polyamide, such as thermoplastic nylon, polyester, acrylic, polyolefin, etc., but before applying the presser wound tape 6, the optical fiber core wire is used. It is only necessary to hold 4 to such an extent that it does not fall off from the groove 2a, and a material that is easy to handle and inexpensive is used.

  Thermal insulation is provided on the outer periphery of the slot 2 to which the coarsely wound string 5 is applied so that the molten resin material for the sheath heated during the molding of the sheath does not directly contact the optical fiber core wire. A presser winding tape 6 is applied. As the presser tape 6, various tapes made of polyester, polyethylene, polypropylene, or the like are used, and a tape width of, for example, about 10 mm to 30 mm is used.

  The presser winding tape 6 is spirally wound or vertically attached on the slot 2, and the outer side thereof is covered with a sheath 7 (also referred to as a jacket) to form the optical cable 1. Whichever winding method is employed, when the winding portion 5a is wound so that the exposed portion 5a emerges from the gap 6a for each turn of the coarsely wound string 5, and when the outer periphery is covered with the sheath 7, the sheath 7 is formed. The exposed portion 5a of the coarsely wound string 5 exposed from the gap 6a is fused or cut by the heat of the sheath 7 due to the temperature of the molten resin (hereinafter referred to as the molten resin temperature).

Thereby, when the sheath 7 is peeled off, the rough wound string 5 can be cut every turn, so that the rough wound string 5 can be easily removed.
However, when the temperature of the molten resin at the time of molding the sheath 7 is equal to or higher than the set temperature, the resin entering from the gap 6a is not directly contacted with the optical fiber core 4 accommodated in the groove 2a of the slot. There is a risk of deteriorating the transmission characteristics of the fiber.

  FIG. 1B is a diagram for explaining a process of forming the sheath 7 of the optical cable 1 described above. In the optical cable sheath forming step, first, the optical cable 1 ′ with the presser winding tape 6 before being covered with the sheath 7 is wound out from the supply reel 11, and then this optical cable is passed through the forming die 14. To be implemented. The molding die 14 is supplied with a resin material for a sheath heated and melted from a resin extruder 13 (hereinafter referred to as an extruder), and the resin extrusion amount of the extruder 13 and the line drawing speed (speed of moving an optical cable). ), The sheath 7 having a predetermined thickness is formed. Thereafter, the optical cable covered with the sheath 7 is passed through the cooling device 15 and cooled, and then wound around the take-up reel 12. The optical cables 1 and 1 ′ are transported while being controlled to a predetermined line speed by the take-up capstan 16.

2 and 3 are schematic diagrams for explaining the outline of the optical cable manufacturing method and the manufacturing apparatus therefor according to the present invention , and more specifically the optical cable sheath forming control method and the control apparatus therefor . 2A is a diagram for explaining the outline of the extruder, FIG. 2B is a control block diagram, and FIG. 3 is a control flow diagram. In the figure, 17 is a barrel, 18 is a screw, 19 is a hopper, 20 is a heater, 21 is a cooling fan, 22 is a main motor, 23 is a transmission, 24 is a control device, 25 is a temperature sensor, 26 is an outer diameter sensor, Reference numeral 27 denotes a capstan motor.

  In order to mold the sheath on the optical cable, the optical cable with the press-wound tape is inserted into the molding die 14 and the outer side thereof is covered with a molten resin supplied from the extruder 13 in a predetermined shape. As shown in FIG. 2A, the extruder 13 heats and melts a solid resin material supplied from a hopper 19 by a heater 20 in which a screw 18 is rotatably arranged in a cylindrical barrel 17. However, it is gradually transported and extruded in the direction of the forming die 14 by the rotation of the screw 18. The screw 18 is driven by the main motor 22, and the rotational speed is adjusted to be reduced by the transmission 23. A temperature sensor 25 is provided in the vicinity of the extrusion outlet of the extruder 13, and the molten resin temperature is detected and controlled to be a predetermined temperature.

  The molten resin temperature at the extrusion outlet of the extruder 13 generally varies depending on various factors such as the line speed, the molten state of the resin material, the outside air temperature, and the like, but various methods are available for controlling to a predetermined molten resin temperature. is there. For example, various methods such as on / off control of the heater 20 and the cooling fan 21 and PID control, a method of flowing a cooling fluid into the extruder screw 18, and control using self-heating of the resin by the rotation of the screw 18 can be considered. .

  In the present invention, the optical fiber in the cable is prevented from being affected through the gap of the presser winding tape by appropriately controlling the molten resin temperature at the time of forming the sheath of the optical cable. For this reason, it is necessary to control the molten resin temperature for the sheath (for example, 150 ° C. to 200 ° C.) extruded from the extruder 13 to the molding die 14 with an accuracy of ± 5 ° C.

  The temperature control by the on / off control of the heater 20 and the cooling fan 21 is slow in responsiveness, and highly accurate temperature control is difficult. Therefore, in the present invention, by using a temperature control method by screw rotation capable of fine control with good responsiveness, temperature control within ± 5 ° C. is performed, and the molten resin temperature for the sheath is controlled to a set value or less, The influence on the optical fiber core wire is reduced. Further, when the screw rotation speed is changed, the extrusion amount of the resin for the sheath changes, so that the line speed of the sheath molding changes. However, it is necessary to consider that the line speed does not decrease from the viewpoint of productivity.

  Specifically, in the temperature control of the molten resin according to the present invention, a temperature sensor 25 is disposed in the vicinity of the extrusion outlet of the extruder 13, and the molten resin temperature at the outlet portion of the extruder 13 is constantly measured. As the temperature sensor 25, a contact type such as a thermocouple or a non-contact type such as a radiation thermometer can be used, and the measurement result is input to the control device 24. Further, the cable outer diameter (sheath outer diameter) of the optical cable 1 is measured by the outer diameter sensor 26, and the measurement result is similarly input to the control device 24.

  In the control device 24, as shown in FIG. 2B, the measured molten resin temperature for the sheath is compared with a preset set temperature, and the deviation is calculated. If the measured temperature is higher than the set value, a control process for lowering the rotational speed of the main motor 22 is performed by performing a calculation process for lowering the screw rotational speed of the extruder so that the molten resin temperature is lowered. Further, when the molten resin temperature is equal to or lower than the set value, a calculation process for increasing the screw rotation speed of the extruder is performed, and control for increasing the rotation speed of the main motor 22 is performed.

  Further, when the screw rotation speed of the extruder is changed, the resin extrusion amount is changed. For example, the extrusion amount of the resin decreases when the screw rotation speed decreases, and the sheath outer diameter (cable outer diameter) decreases when the line drawing speed is constant. Therefore, in order to maintain the sheath outer diameter at a predetermined value, when the screw rotation speed decreases, the line drawing speed is calculated, and the capstan motor 27 is controlled to decrease the cable take-up speed. On the other hand, when the screw speed increases, the line speed is calculated and the capstan motor 27 is controlled to increase the cable take-up speed.

  Further, the cable outer diameter of the optical cable 1 is constantly measured by the outer diameter sensor 26 and is compared with a preset set value. If it is larger than the set value, an arithmetic operation is performed to increase the line speed, and the capstan The motor 27 is controlled to increase the cable take-up speed. Further, when the cable outer diameter is smaller than the set value, the cable wire speed is reduced to control the capstan motor 27 to reduce the cable take-up speed.

  Next, an outline of the above-described optical cable sheath forming control method will be described with reference to the control flowchart of FIG. First, in FIG. 2A, a solid resin material for the sheath is put into the extruder 13 from the hopper 19 and heated by the heater 20 while being transported by the rotation of the screw 18 in the barrel 17 and sequentially fluidized. Then, it can be extruded to the forming die 14. In this initial stage, the molten resin temperature is heated and melted to a temperature set in advance by the heater 20 and the cooling fine 21 to enter a sheath molding standby state.

  With the extruder 13 ready, the optical cable is inserted into the forming die 14, the optical cable line travel is started by driving the capstan motor 27, and sheath molding is started. When a stable state is reached after a certain amount of travel, control of sheath forming is started.

  First, in step S1, a molten resin temperature, a cable outer diameter, and the like are measured, and it is determined whether these are within preset manufacturing conditions. As a result of the measurement, if the set condition is not satisfied (S1 No), in step S3, control is performed to increase or decrease the rotation of the screw of the extruder. Further, in response to the change in the screw rotation of the extruder, in step S4, control is performed to increase or decrease the line linear velocity so as to correspond to the increase / decrease in the amount of extruded resin and to make the sheath outer diameter constant. Next, returning to the start, it is determined again in step S1, and this is repeated until the set condition is satisfied.

  As a result of the measurement, when the set condition is satisfied (S1 Yes), sheath molding is executed under the manufacturing condition, and the measurement of the molten resin temperature and the cable outer diameter is continuously monitored. Next, when it is detected in step S2 that the molten resin temperature has reached the upper limit of the set value, in step S5, the screw is immediately turned down to control to lower the molten resin temperature. Further, in response to the screw rotation of the extruder being lowered, in step S6, the line linear speed is also lowered to cope with a decrease in the amount of extruded resin.

  Next, in step S7, it is determined whether or not the molten resin temperature is lower than the set value. If not lower than the set value (S7 No), the process returns to step S5 to further reduce the screw rotation of the extruder, and then the line Control to reduce the line speed. Hereinafter, the flow of steps S5 to S7 is repeated until the molten resin temperature becomes equal to or lower than the set value.

  If the molten resin temperature is equal to or lower than the set value in step S7 (S7 Yes), the process proceeds to step S8. If the molten resin temperature is stable below the set value and this state continues for a certain time (S8 Yes). ), The process returns to step S1. This is a process for reviewing this state because the production efficiency is somewhat lowered because the screw rotation is lowered to lower the molten resin temperature and the line linear velocity is lowered. As a result, it is possible to increase the line rotation speed by increasing the screw rotation of the extruder and improve the production efficiency.

If the duration of the molten resin temperature is less than the set value is less than the predetermined time (No in S8), the production is continued in step S9, the process returns to step S1 after the predetermined time has elapsed, the line speed is increased, and the production efficiency is improved. It becomes possible to make it.
The cable outer diameter is also measured, but this is measured as a parameter separate from the molten resin temperature, and the control of the line drawing speed is calculated and processed together with the screw rotation of the extruder. The

It is a figure explaining the outline of the optical cable made into object by this invention, and a manufacture example. It is a figure explaining the outline of the manufacturing method and manufacturing apparatus of the optical cable of this invention. It is a figure explaining the outline of the control flow of the molten resin temperature in this invention. It is a figure explaining a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical cable, 2 ... Slot, 2a ... Groove, 3 ... Tension member, 4 ... Optical fiber core wire, 5 ... Coarse winding string, 5a ... Exposed part, 6 ... Pressing winding tape, 6a ... Gap, 7 ... Sheath, 8a 8b ... Cutter, 9a, 9b ... Incision, 10 ... Dies, 11 ... Supply reel, 12 ... Take-up reel, 13 ... Extruder, 14 ... Molding die, 15 ... Cooling device, 16 ... Take capstan, 17 ... Barrel, 18 ... screw, 19 ... hopper, 20 ... heater, 21 ... cooling fan, 22 ... main motor, 23 ... transmission, 24 ... control device, 25 ... temperature sensor, 26 ... outer diameter sensor, 27 ... capstan motor .

Claims (2)

A method of manufacturing an optical cable in which a rough winding string, a presser winding tape, and a sheath are sequentially applied to the outer periphery of a slot that stores an optical fiber core wire,
The temperature of the molten resin for the sheath, which is wound around the presser winding tape with a gap so that a part of the rough winding string is exposed and is extruded to the outside, is set by controlling the screw rotation of the resin extruder A method of manufacturing an optical cable, wherein the sheath is applied while maintaining the cable outer diameter constant by controlling the line drawing speed while maintaining the value below the value.   2. The optical cable according to claim 1, wherein after the temperature of the molten resin is continued for a certain time at a temperature equal to or lower than a set value, the measured value and the set value are compared again to control the screw rotation and the line drawing speed. Manufacturing method.

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