Vertical stretching fire bed of optical fiber preform

Abstract

The utility model provides a vertical stretching fire bed for an optical fiber preform, which comprises a base, a rotatable fixed chuck arranged at the lower end of the base, a rotatable movable chuck arranged on a chuck connecting seat capable of moving up and down arranged at the upper end of the base, a heating furnace capable of moving up and down arranged between the fixed chuck and the movable chuck on the base, and a core rod penetrating through the heating furnace, the tail rod parts are arranged at the two ends of the core rod, and the fixed chuck and the movable chuck respectively clamp the tail rod parts, so that the problem of diameter uniformity of the optical fiber preform rod is solved.

Description

Technical Field

[0001] This utility model relates to the field of optical fiber preform forming, and in particular to a vertical stretching firebed for optical fiber preforms. Background Technology

[0002] With the development of optical fiber preform technology, the manufacturing of optical fiber preforms now basically adopts a two-step method, that is, first manufacturing a core rod, and then depositing a cladding or sleeve on the outside of the core rod to obtain the optical fiber preform. The two-step method can not only improve the manufacturing efficiency of the preform, but also improve the qualification rate of the finished preform.

[0003] Generally speaking, known methods for manufacturing optical fiber preforms include chemical vapor deposition, external vapor deposition, and axial vapor deposition. These methods are used to manufacture optical fiber preform cores, followed by dehydration and sintering.

[0004] The aforementioned optical fiber preform mother rod is reheated and stretched to form the optical fiber preform core rod to prevent the optical fiber preform core rod from bending. However, due to the relationship between the temperature of the high-temperature furnace and the outgoing speed of the stretching and outgoing structure, the diameter of the optical fiber preform core rod may change. Furthermore, due to the airflow or foreign objects in the high-temperature furnace, it is difficult to achieve uniform heating, making it impossible to guarantee the uniformity of the core rod's diameter after stretching. Utility Model Content

[0005] This invention provides a vertical stretching firebed for optical fiber preforms, which solves the problem of uniformity in the diameter of optical fiber preforms.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: a vertical stretching fire bed for optical fiber preforms, including a base, a rotatable fixed chuck at the lower end of the base, a rotatable movable chuck on a chuck connecting seat at the upper end of the base, a heating furnace that can move up and down between the fixed chuck and the movable chuck on the base, a core rod passing through the heating furnace, and tail rods at both ends of the core rod, with the fixed chuck and the movable chuck clamping each tail rod respectively.

[0007] In a preferred embodiment, a first turntable motor is provided at the lower end of the base, a second turntable motor is provided on the chuck connecting seat, the first turntable motor and the second turntable motor are provided with rotatable flanges, the fixed chuck is connected to the flange of the first turntable motor, and the movable chuck is connected to the flange of the second turntable motor.

[0008] In a preferred embodiment, the base is provided with a vertical guide rail, the heating furnace is provided with a furnace mounting base, and the chuck connecting base and the furnace mounting base are provided with a slider device. The chuck connecting base and the furnace mounting base are slidably connected to the guide rail through the slider device.

[0009] In a preferred embodiment, a vertical rack is provided on the base, a furnace drive motor is provided at one end of the furnace mounting base, and a gear is provided at the shaft end of the furnace drive motor, which meshes with the rack.

[0010] In a preferred embodiment, a vertical first lead screw device is provided on the base, a tailstock drive motor is provided at one end of the first lead screw device, a first lead screw nut is provided on the chuck connecting seat, and the first lead screw nut is threadedly connected to the first lead screw device.

[0011] In a preferred embodiment, the heating furnace includes an insulation shell, a graphite guide sleeve in the center of the insulation shell, a heating tube cavity inside the graphite guide sleeve, openings at both ends of the heating tube cavity, an induction coil outside the heating tube cavity inside the insulation shell, and a high-temperature probe inside the insulation shell.

[0012] In the preferred embodiment, a temporary positioning fixture is provided at the openings at both ends of the heating tube cavity. The temporary positioning fixture includes two V-shaped clamping devices. Each V-shaped clamping device includes a positioning seat. One end of the positioning seat is provided with an arc-shaped positioning boss, which is located at the opening.

[0013] In a preferred embodiment, a guide rod is also provided. One end of the guide rod is threadedly connected to the V-block, and the other end of the guide rod is provided with a stop. The guide rod is slidably sleeved with the wall panel. A spring is sleeved on the guide rod, and the wall panel is provided with a recess. One end of the spring abuts against the bottom of the recess, and the other end abuts against the stop of the guide rod.

[0014] In a preferred embodiment, a vertical second lead screw device is provided on the base, a furnace drive motor is provided at one end of the second lead screw device, a second lead screw nut is provided on the furnace mounting base, and the second lead screw nut is threadedly connected to the second lead screw device.

[0015] The beneficial effects of this utility model are as follows: By heating and rotating simultaneously, the uniformity of circumferential shrinkage is ensured. At the same time, the upper chuck moves and stretches, uniformly stretching the thick mandrel into a thinner preform, ensuring that the diameter of the mandrel is uniform after stretching and improving the mandrel's pass rate. It can effectively prevent the mandrel from bending during the stretching process, ensuring the mandrel's yield rate. At the same time, the vertical layout can also reduce the footprint of the device and reduce the restrictions on the placement of the equipment. By adding a detachable temporary positioning fixture at the heating furnace end, the alignment accuracy between the chuck and the furnace axis is used to assist in the docking and positioning of the mandrel and the tail rod, preventing the problem of misalignment between the mandrel and the tail rod. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 This is a side view of the present invention.

[0018] Figure 2 This is a schematic diagram of the heating furnace of this utility model.

[0019] Figure 3 This is a structural diagram of the V-shaped clamp device of this utility model.

[0020] Figure 4 This is a cross-sectional view of the V-shaped clamping device of this utility model. Figure 1 .

[0021] Figure 5 This is a cross-sectional view of the V-shaped clamping device of this utility model. Figure 2 .

[0022] Figure 6 This is a diagram of the screw-driven structure of the furnace mounting base.

[0023] In the diagram: Base 1; Heating furnace 2; Insulation shell 201; Heating cavity 202; Induction coil 203; High temperature probe 204; Control board 205; Opening 206; Graphite guide sleeve 207; First turntable motor 3; Second turntable motor 4; Fixed chuck 5; Moving chuck 6; Chuck connecting seat 7; Slider device 8; Guide rail 801; First lead screw device 9; First lead screw nut 901; Furnace mounting base 10; Furnace drive motor 11; Tailstock drive motor; 12; Rack; 13; Gear; 1301; Mandrel; 14; Tailstock section; 15; Temporary positioning fixture; 16; V-clamp device; 17; Positioning seat; 1701; V-block; 1702; Wall panel; 1703; Push bolt; 1704; Guide rod; 1705; Spring; 1706; Arc-shaped positioning boss; 1707; Slot; 1708; Stop section; 1709; Second lead screw device; 18; Second lead screw nut; 1801. Detailed Implementation

[0024] Example 1:

[0025] like Figure 1-6 In a vertical stretching firebed for optical fiber preforms, there is a base 1, a rotatable fixed chuck 5 at the lower end of the base 1, a rotatable movable chuck 6 on a chuck connecting seat 7 that can move up and down at the upper end of the base 1, and a heating furnace 2 that can move up and down between the fixed chuck 5 and the movable chuck 6 on the base 1. A core rod 14 passes through the heating furnace 2, and tail rods 15 are provided at both ends of the core rod 14. The fixed chuck 5 and the movable chuck 6 respectively clamp each tail rod 15.

[0026] The fixed chuck 5 and the movable chuck 6 are three-jaw chucks. The two ends of the mandrel 14 are pre-welded with tail rods 15. The tail rods 15 are waste rods, mainly used for clamping. They can be cut off after the pre-formed rod is stretched and can be reused next time, saving resources.

[0027] In the preferred embodiment, a first turntable motor 3 is provided at the lower end of the base 1, a second turntable motor 4 is provided on the chuck connecting seat 7, the first turntable motor 3 and the second turntable motor 4 are provided with rotatable flanges, the fixed chuck 5 is connected to the flange of the first turntable motor 3, and the movable chuck 6 is connected to the flange of the second turntable motor 4.

[0028] In the preferred embodiment, the base 1 is provided with a vertical guide rail 801, the heating furnace 2 is provided with a furnace mounting base 10, and the chuck connecting base 7 and the furnace mounting base 10 are provided with a slider device 8. The chuck connecting base 7 and the furnace mounting base 10 are slidably connected to the guide rail 801 through the slider device 8.

[0029] In a preferred embodiment, a vertical rack 13 is provided on the base 1, a furnace drive motor 11 is provided at one end of the furnace mounting base 10, and a gear 1301 is provided at the shaft end of the furnace drive motor 11, which meshes with the rack 13.

[0030] Another driving method is that the furnace drive motor 11 drives the furnace mounting base 10 to move up and down through the second lead screw device 18.

[0031] In the preferred embodiment, the base 1 is provided with a vertical first lead screw device 9, one end of the first lead screw device 9 is provided with a tailstock drive motor 12, the chuck connecting seat 7 is provided with a first lead screw nut 901, and the first lead screw nut 901 is threadedly connected to the first lead screw device 9.

[0032] The furnace drive motor 11 and the tailstock drive motor 12 are geared servo motors, which can precisely and in real time adjust the height of the heating furnace 2 and the chuck connecting seat 7, respectively.

[0033] After the mandrel 14 is passed through the heating furnace 2, the tail rod 15 is clamped on the fixed chuck 5 and the movable chuck 6. The first turntable motor 3 and the second turntable motor 4 rotate, and the heating furnace 2 heats the mandrel 14 to melt it. At this time, the chuck connecting seat 7 moves up to stretch the mandrel 14, so that the mandrel 14 is stretched thinner and longer.

[0034] In a preferred embodiment, the heating furnace 2 includes an insulation shell 201, a graphite guide sleeve 207 is provided in the center of the insulation shell 201, a heating tube 202 is provided inside the graphite guide sleeve 207, and openings 206 are provided at both ends of the heating tube 202. An induction coil 203 is provided outside the heating tube 202 inside the insulation shell 201, and a high-temperature probe 204 is also provided inside the insulation shell 201.

[0035] The part of the mandrel 14 that needs to be heated is placed inside the heating chamber 202.

[0036] The heating furnace 2 also includes a control board 205, an induction coil 203 and a high-temperature probe 204 which are electrically connected to the control board 205. When the induction coil 203 is energized, the graphite guide sleeve 207 generates eddy currents and heats up, generating high temperature in the heating tube cavity 202. The high-temperature probe 204 detects the temperature of the induction coil 203, which facilitates feedback and real-time adjustment.

[0037] In a preferred embodiment, a temporary positioning fixture 16 is provided at the openings 206 at both ends of the heating tube cavity 202. The temporary positioning fixture 16 includes two V-shaped clamping devices 17. Each V-shaped clamping device 17 includes a positioning seat 1701. One end of the positioning seat 1701 is provided with an arc-shaped positioning boss 1707, which is located at the opening 206.

[0038] A magnet is installed at the end of the opening 206 to hold the insulation shell 201. The core rod 14 is pre-installed in the heating furnace 2. Each temporary positioning fixture 16 is installed at the opening 206. The push bolt 1704 is rotated to clamp the outer wall of the core rod 14. The advance of the V-block 1702 is adjusted to ensure that the core rod 14 is installed in the center. The waste rod material is clamped on the fixed chuck 5 and the movable chuck 6, aligned with the end of the core rod 14, and concentrically adjusted. It is then melted and welded using a spray gun. After cooling, the tail rod part 15 is formed.

[0039] In a preferred embodiment, a guide rod 1705 is also provided. One end of the guide rod 1705 is threadedly connected to the V-block 1702, and the other end of the guide rod 1705 is provided with a stop part 1709. The guide rod 1705 is slidably sleeved with the wall panel 1703. A spring 1706 is sleeved on the guide rod 1705. The wall panel 1703 is provided with a recess 1708. One end of the spring 1706 abuts against the bottom of the recess 1708, and the other end abuts against the stop part 1709 of the guide rod 1705.

[0040] After the core rod 14 is connected to the tail rod 15, the V-blocks 1702 can be loosened and the V-clamp device 17 can be removed.

[0041] Example 2:

[0042] A vertical stretching fire bed includes a vertical bed body, an upper chuck, a lower chuck, a high-temperature furnace, and a controller. The vertical bed body is made of cast iron. The upper chuck is located above the high-temperature furnace and can be controlled to move to the uppermost limit position of the entire stretching device. The upper chuck is mounted on the upper base, i.e., the tailstock, and uses a combination of screw and guide rail transmission. A servo motor, reducer, and synchronous pulley combination controls the up-and-down movement of the tailstock, allowing for both inching and automatic continuous up-and-down movement. The lower end of the upper chuck is equipped with a heat insulation plate for protection. The lower chuck is a fixed part located below the high-temperature furnace and cannot be moved. The upper chuck is also equipped with a heat insulation protection device. The high-temperature furnace is mounted and fixed on a lamp holder between the upper and lower chucks. The high-temperature furnace is protected by circulating cooling water, and inert gas is introduced into the furnace to protect the graphite heating element. The synchronous rotation and up-and-down movement of the upper and lower chucks, as well as the temperature control of the high-temperature furnace, are all controlled by the controller. The controller includes a PLC, servo driver, servo motor, and some detection units, using well-known electrical brands such as Siemens and Schneider Electric. The synchronous rotation of the upper and lower chucks adopts the synchronous motion module of Siemens motion control to ensure the synchronization accuracy of the upper and lower chucks. The vertical movement adopts absolute value control, and the movement accuracy is controlled within 0.1mm. The maximum stroke of the upper chuck during extension is 2.2m. The temperature control adopts improved PID control to ensure that the temperature is controlled within ±1 degree during the stretching stage.

[0043] The cross-sectional area of ​​the graphite conductor between the inlet and outlet of the high-temperature furnace body changes linearly. The temperature distribution of the furnace body follows the axial direction of the furnace body, with the temperature increasing linearly from the initial 1800℃ to 2100℃. There is a short heat preservation distance at the highest temperature, and then the temperature drops sharply after exiting the furnace.

[0044] The extended upper chuck is a vertically movable chuck with a maximum stroke of 2.2m.

[0045] The high-temperature furnace is a custom-made graphite resistance furnace with a heating range of room temperature to 2500℃. Temperature is measured using an infrared thermometer.

[0046] The fiber optic preform vertical stretching device and the method for stretching the core rod of this utility model include the following steps:

[0047] Step 1: Prepare the optical fiber preform and fix the upper shaft of the tail rod 1 of the optical fiber preform to the upper chuck.

[0048] Step 2: Move the lamp holder and heating furnace upwards so that the heating furnace heats the effective part of the fiber preform core rod. At the same time, move the tailstock downwards so that the lower end of the tail rod 2 moves to the lower chuck jaws. Heat the tail rod to the appropriate position with the hydrogen-oxygen hand lamp. After calibration, the tail rod 2 is clamped in the lower chuck jaws.

[0049] Step 3: Detect the diameter of the precast mandrel and the diameter after stretching to determine the upward movement speed of the heating furnace and tailstock, as well as the temperature of the heating furnace;

[0050] Step 4: Move the lamp holder and heating furnace to the starting point of the mandrel stretching, and at the same time start the synchronous rotation of the upper and lower chucks at a speed of 15 r / min;

[0051] Step 5: After completing the above preparations, start the heating furnace and start the stretching process when the temperature reaches the stretching temperature.

[0052] Step 6: During the stretching process, check the diameter of the mandrel, adjust the tailstock speed and lamp holder speed, and stretch the preform into the required mandrel in one go.

[0053] The above embodiments are merely preferred technical solutions of this utility model and should not be considered as limitations on this utility model. The protection scope of this utility model should be the technical solution described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the protection scope of this utility model.

Claims

1. A vertical stretching firebed for optical fiber preforms, characterized in that: Includes a base (1), a rotatable fixed chuck (5) at the lower end of the base (1), a rotatable movable chuck (6) on a chuck connecting seat (7) at the upper end of the base (1), a heating furnace (2) that can move up and down is provided between the fixed chuck (5) and the movable chuck (6) on the base (1), a core rod (14) passes through the heating furnace (2), and tail rods (15) are provided at both ends of the core rod (14), with the fixed chuck (5) and the movable chuck (6) clamping each tail rod (15) respectively.

2. The vertical stretching firebed for the optical fiber preform according to claim 1, characterized in that: The base (1) is equipped with a first turntable motor (3) at the lower end, and a second turntable motor (4) is equipped on the chuck connecting seat (7). The first turntable motor (3) and the second turntable motor (4) are equipped with rotatable flanges. The fixed chuck (5) is connected to the flange of the first turntable motor (3), and the movable chuck (6) is connected to the flange of the second turntable motor (4).

3. The vertical stretching firebed for the optical fiber preform according to claim 1, characterized in that: The base (1) is provided with a vertical guide rail (801), the heating furnace (2) is provided with a furnace mounting seat (10), the chuck connecting seat (7) and the furnace mounting seat (10) are provided with a slider device (8), and the chuck connecting seat (7) and the furnace mounting seat (10) are slidably connected to the guide rail (801) through the slider device (8).

4. The vertical stretching firebed for the optical fiber preform according to claim 3, characterized in that: The base (1) is provided with a vertical rack (13), and the furnace mounting base (10) is provided with a furnace drive motor (11) at one end. The shaft end of the furnace drive motor (11) is provided with a gear (1301), which meshes with the rack (13).

5. The vertical stretching firebed for the optical fiber preform according to claim 3, characterized in that: The base (1) is provided with a vertical first lead screw device (9), and one end of the first lead screw device (9) is provided with a tailstock drive motor (12). The chuck connecting seat (7) is provided with a first lead screw nut (901), and the first lead screw nut (901) is threadedly connected to the first lead screw device (9).

6. The vertical stretching firebed for the optical fiber preform according to claim 1, characterized in that: The heating furnace (2) includes an insulation shell (201), a graphite guide sleeve (207) in the center of the insulation shell (201), a heating tube cavity (202) inside the graphite guide sleeve (207), openings (206) at both ends of the heating tube cavity (202), an induction coil (203) outside the heating tube cavity (202) inside the insulation shell (201), and a high temperature probe (204) inside the insulation shell (201).

7. The vertical stretching firebed for the optical fiber preform according to claim 6, characterized in that: Temporary positioning fixtures (16) are provided at the openings (206) at both ends of the heating tube cavity (202). The temporary positioning fixtures (16) include two V-shaped clamping devices (17). Each V-shaped clamping device (17) includes a positioning seat (1701). One end of the positioning seat (1701) is provided with an arc-shaped positioning boss (1707), which is located at the opening (206).

8. The vertical stretching firebed for the optical fiber preform according to claim 7, characterized in that: A guide rod (1705) is also provided. One end of the guide rod (1705) is threadedly connected to the V-block (1702), and the other end of the guide rod (1705) is provided with a stop (1709). The guide rod (1705) is slidably sleeved with the wall panel (1703). A spring (1706) is sleeved on the guide rod (1705). The wall panel (1703) is provided with a recess (1708). One end of the spring (1706) abuts against the bottom of the recess (1708), and the other end abuts against the stop (1709) of the guide rod (1705).

9. The vertical stretching firebed for the optical fiber preform according to claim 3, characterized in that: The base (1) is provided with a vertical second lead screw device (18), one end of the second lead screw device (18) is provided with a furnace drive motor (11), and the furnace mounting base (10) is provided with a second lead screw nut (1801), which is threadedly connected to the second lead screw device (18).

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