Air-blowing micro-cable sheath forming control system and control method

Abstract

The application discloses a blowing micro-cable sheath forming control system, which comprises an extruding machine, a feeder, a cooling water tank, a diameter measuring instrument, a traction machine, an ultrasonic measuring probe and a granular material quantitative supply controller. The ultrasonic measuring probe is used for real-time detection of the wall thickness of the sheath, and the diameter measuring instrument is used for real-time detection of the diameter of the outer circle of the sheath. The concentricity of the sheath is obtained through the detected wall thickness and the outer diameter information, and the feeding speed of the feeder, the traction speed of the traction machine and / or the rotating speed of the extruding machine are controlled in real time through the granular material quantitative supply controller, so that the concentricity, the wall thickness and the outer diameter of the sheath are within the set threshold range. The ultrasonic measuring probe is placed in the water tank at the outlet of the machine head, the wall thickness condition of the sheath is fed back in real time, the feeding speed of the feeder and the rotating speed of the extruding machine can be adjusted in real time through the granular material quantitative supply controller, the wall thickness and the diameter are ensured to be stable, and the raw material use is saved through reducing the diameter fluctuation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of processing and manufacturing of air-blow micro-cable, more particularly, relates to an air-blow micro-cable sheath forming control system and a method for controlling the outer diameter of the air-blow micro-cable using the same. BACKGROUND

[0002] With the large-scale use of air-blow micro-cable, the production line speed is getting higher and higher, and the control requirements for the outer diameter and wall thickness of the optical cable are getting more and more stringent. The diameter of the air-blow micro-cable is generally φ4.6-13.4mm, and the wall thickness range is 0.35-0.55mm. The positive and negative error range is ±0.2. However, due to the continuous improvement of the production line speed, the deterioration of the wear of the extruder, the pressure of the material cost and other factors, the fluctuation of the quality of the optical cable sheath may deviate from the error range. Since the wall thickness of the air-blow micro-cable is very thin, if it is below the lower limit of the size error, there is a risk of exposed cable core; the positive size error is large, which will also be a defective product due to the unfavorable air-blow pipeline construction. Therefore, precise control of the overall uniformity of the air-blow micro-cable sheath is not only conducive to the stable control of the product diameter, but also can improve the production efficiency, reduce the risk of defective products, and reduce the material utilization rate.

[0003] At present, the method for controlling the quality of the sheath adopted by the industry is generally to control the diameter of the finished optical cable, mainly in two ways:

[0004] 1) By setting the pulling speed and cable diameter parameters, the matching extruder speed is obtained through PLC calculation. The linkage is operated, and the cable type change can be observed online, and the corresponding extruder speed is adjusted to meet the required diameter process requirements; this is only a monitoring of the cable diameter, and if the performance of the extruder deteriorates, it is impossible to automatically compensate in real time to adjust the diameter of the air-blow micro-cable.

[0005] 2) A diameter gauge is used at the outlet end of the extruder and the end of the cooling water tank. The change of the comparison value is fed back to the extruder to adjust the speed to compensate and control the diameter. Since the outlet section of the extruder, the optical cable has not been fully cooled, the detected diameter is not accurate, and only an empirical value is given with a certain correction value, and then compared with the diameter gauge at the end of the cooling water tank. Although this method is more accurate than the first method, the empirical value itself is not an official measurement value, and there is a large subjective factor. In addition, when producing different structures of optical cables, the empirical correction value needs to be adjusted. For the scenario of frequent production change, it is obviously not suitable.

[0006] In fact, the stability of the outer diameter of the optical cable cannot accurately and directly represent the quality of the optical cable sheath. Although the stability of the outer diameter of the cable can be maintained, when the concentricity of the optical cable sheath and the cable core deviates greatly, it may cause the sheath on one side of the optical cable to be too thin, with the risk of exposing the cable core, while the other side is relatively thick, and the optical cable as a whole appears uneven in the circumferential direction, affecting the bending and air blowing performance. Chinese patent document CN113625285A provides an ultrasonic probe and an eccentricity monitoring structure for the sheath of an optical cable, which can monitor the thickness of the sheath of the optical cable from multiple directions, thereby monitoring the eccentricity of the optical cable. However, due to the poor accuracy of the single ultrasonic head of the ultrasonic probe in air, it is necessary to use a multi-point average method to monitor the wall thickness to improve the accuracy, which is relatively high in cost. SUMMARY

[0007] In view of the above defects or improvement needs of the prior art, the present application provides a gas blowing micro-cable sheath forming control system and a method for controlling the outer diameter of the gas blowing micro-cable by using the same, which can adjust the rotating speed of the extruder in real time through the granular material quantitative feeding controller. The wall thickness and diameter are stable, and the use of raw materials is saved by reducing the diameter fluctuation.

[0008] To achieve the above-mentioned purpose, according to one aspect of the present application, a gas blowing micro-cable sheath forming control system is provided, comprising an extruder, a feeder, a cooling water tank, a diameter measuring instrument, a traction machine, an ultrasonic probe and a granular material quantitative feeding controller, the extruder, the cooling water tank, the diameter measuring instrument and the traction machine are arranged in sequence along the advancing direction of the gas blowing micro-cable, the feeder is installed on the extruder for adding sheath material into the extruder, characterized in that,

[0009] The ultrasonic probe is used for real-time detection of the wall thickness of the sheath, the ultrasonic probe has at least two and is arranged in the cooling water tank, including a first ultrasonic probe and a second ultrasonic probe, which can detect different detection points on the same cross section of the sheath;

[0010] The diameter measuring instrument is used for real-time detection of the diameter of the outer circle of the sheath, the number of the diameter measuring instrument is at least two, including a first diameter measuring instrument and a second diameter measuring instrument, the diameter detected by the first diameter measuring instrument passes through the detection point of the first ultrasonic probe on the sheath, and the diameter detected by the second diameter measuring instrument passes through the detection point of the second ultrasonic probe on the sheath;

[0011] The concentricity of the sheath is obtained through the detected wall thickness and outer diameter information, and it is judged whether the concentricity is within the set threshold range, if not, stop and check; if yes, it is further judged whether the wall thickness and the outer diameter are within the set threshold range, and the feeding speed of the feeder, the traction speed of the traction machine and / or the rotating speed of the extruder are controlled in real time through the granular material quantitative feeding controller, so that the concentricity, the wall thickness and the outer diameter of the sheath are within the set threshold range.

[0012] Preferably, the first and second ultrasonic probes are orthogonal.

[0013] Preferably, the cooling water tank is open at the top end, and each end of the length direction of the cooling water tank is provided with a guide wheel, so that the air-blowing micro-cable enters the cooling water tank and is wound on the two guide wheels before exiting the cooling water tank, and the first and second ultrasonic probes are arranged on the side wall and the lower bottom outside the optical cable in the water tank exit section of the cooling water tank, respectively.

[0014] Preferably, the ultrasonic outlet of the first ultrasonic probe is vertically upward, and the ultrasonic outlet of the second ultrasonic probe is horizontally toward the air-blowing micro-cable, so as to detect the wall thickness of the part closest to the side wall and the part closest to the bottom plate on the cross section of the sheath, respectively.

[0015] Preferably, the diameter measuring instrument measures the outer diameter of the optical cable in the same cross section and the same direction as the ultrasonic probe.

[0016] Preferably, the diameter measuring instrument is a non-contact measuring instrument, such as a laser diameter measuring instrument and a CCD diameter measuring instrument.

[0017] Preferably, a surface defect detector is further included to detect bulges and pits on the surface of the sheath.

[0018] Preferably, a speed sensor for detecting the pulling speed of the sheath is further included.

[0019] According to another aspect of the present application, a method for controlling the outer diameter of the sheath of the air-blowing micro-cable by the control system is also provided, characterized in that it comprises the following steps:

[0020] 1) After the sheath is extruded from the extruder, the sheath is sequentially cooled by the cooling water tank and measured by the diameter measuring instrument under the traction of the traction machine;

[0021] 2) The wall thickness of the diameter detected by the first diameter measuring instrument is obtained by the first ultrasonic probe and the first diameter measuring instrument, and the wall thickness of the diameter detected by the second diameter measuring instrument is obtained by the second ultrasonic probe and the second diameter measuring instrument;

[0022] 3) The concentricity of the sheath is obtained by the obtained wall thickness and diameter information, and it is judged whether the concentricity is within the set threshold range, if not, the machine is stopped for inspection, and if yes, step 4) is entered;

[0023] 4) The amount of sheath material used per unit time is compared with the set value, if the error is greater than 5‰, step 6) is entered, if the error is greater than 1‰ but less than 5‰, step 7) is entered, and if the error is less than 1‰, step 8) is entered;

[0024] 5) The granular material quantitative supply controller controls the rotation speed of the extruder and the feeding speed of the feeder, so that the amount of the sheath material per unit time is consistent with the set value, so that the wall thickness and the outer diameter of the sheath meet the set threshold range respectively;

[0025] 6) According to the relationship between the traction speed and the outer diameter of the sheath, the granular material quantitative supply controller controls the rotation speed of the extruder, the traction speed of the traction machine and the feeding speed of the feeder, so that the amount of the sheath material per unit time is consistent with the set value, so that the wall thickness and the outer diameter of the sheath meet the set threshold range respectively;

[0026] 7) Keep the existing running state.

[0027] Preferably, the granular material quantitative supply controller adopts a PID closed-loop control system for granular material quantitative supply control.

[0028] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0029] 1) The present application places the ultrasonic probe in the cooling water tank at the outlet of the machine head, and real-time feedback of the sheath wall thickness is realized. The diameter of the air-blowing micro-cable in the cooling water tank is detected in real time by using a diameter detector. By ingeniously combining the determination of the wall thickness and the outer diameter of the optical cable, the feeding speed of the feeder, the traction speed of the traction machine and / or the rotation speed of the extruder can be adjusted in real time by the granular material quantitative supply controller, so as to ensure the stability of the concentricity, the wall thickness and the outer diameter, maintain the axial stability of the optical cable sheath, and save the use of raw materials by reducing the diameter fluctuation. The present application can reduce the waste rate and solve the waste problem of feeding deviation during starting and production.

[0030] 2) The present application can realize instant control during starting, online continuous batching, reduce the time-consuming of manual mixing, and improve the efficiency;

[0031] 3) The present application is suitable for sheath materials of different raw materials, and is not affected by the density, size and proportion change of the raw materials;

[0032] 4) The present application adopts PID closed-loop control, intelligence and automation with high precision. The present application introduces independent speed detection and diameter detection feedback signals, further corrects the diameter of the optical cable, and can achieve the effect of precise control.

[0033] 6) The present application can control the wall thickness deviation of the optical cable to be ±0.1mm, and the traditional process can only control it to be ±0.2mm. The material utilization rate can be improved by 1 percentage point when producing air-blowing micro-cable, which can greatly save the cost. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a schematic diagram of the production system of the present application;

[0035] Figure 2 is a schematic diagram of the PID closed-loop control system adopted by the granular material quantitative feeding controller;

[0036] Figure 3 is a schematic diagram of the cross section of the optical cable;

[0037] Figure 4 is a schematic diagram of the axial cross section of the sheath;

[0038] Figure 5 is a logic flow chart of the present application;

[0039] Figure 6 is a schematic diagram of two ultrasonic probes detecting different detection points on the same cross section of the sheath;

[0040] Figure 7 is a schematic diagram of the air-blowing micro-cable winding on two guide wheels in the cooling water tank. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0042] Referring to Figures 1-7 , the control system for forming the sheath of the air-blowing micro-cable 6 includes an extruder 1, a feeder, a cooling water tank 2, a diameter measuring instrument 3, a traction machine 4, an ultrasonic probe 5 and a granular material quantitative feeding controller. The extruder 1, the cooling water tank 2, the diameter measuring instrument 3 and the traction machine 4 are arranged in sequence along the advancing direction of the air-blowing micro-cable 6. The feeder is installed on the extruder 1 for adding sheath material into the extruder 1. The upper end of the cooling water tank 2 is open. Each end of the length direction of the cooling water tank 2 is provided with a guide wheel 7 respectively, so that the air-blowing micro-cable 6 enters the cooling water tank 2 and winds on the two guide wheels 7 before it comes out of the cooling water tank 2.

[0043] The ultrasonic measuring probe 5 is used for real-time detection of the wall thickness of the sheath, and the real-time detection refers to detection at a set time interval and sending to the granular material quantitative feeding controller. The ultrasonic measuring probe 5 is at least two and is arranged in the cooling water tank 2, at the outer side of the water outlet tank section optical cable, and is used for detecting the wall thickness of the sheath of the water outlet tank section optical cable. The ultrasonic measuring probe 5 includes a first ultrasonic measuring probe 5 and a second ultrasonic measuring probe 5, and different detection points on the same cross section of the sheath can be detected. Each ultrasonic measuring probe 5 detects different parts of the sheath, the first ultrasonic measuring probe 5 detects the part, and the second ultrasonic measuring probe 5 does not detect the part, so that multiple parts in the circumferential direction can be detected. In the preferred embodiment, the directions of the first ultrasonic probe 5 and the second ultrasonic probe 5 are orthogonal. Specifically, the first ultrasonic probe 5 and the second ultrasonic probe 5 can be respectively arranged on the side wall of the water tank and the bottom of the water tank, so as to avoid interference of other sections of the optical cable without adding additional components.

[0044] The diameter of the outer circle of the sheath is detected in real time by the diameter measuring instrument 3. The diameter measuring instrument 3 is at least two, including a first diameter measuring instrument 3 and a second diameter measuring instrument 3. The diameter detected by the first diameter measuring instrument 3 passes through the detection point of the first ultrasonic measuring probe 5 on the sheath, and the diameter detected by the second diameter measuring instrument 3 passes through the detection point of the second ultrasonic measuring probe 5 on the sheath. The diameter measuring instrument 3 adopts a non-contact measurement, and existing laser diameter measurement and CCD diameter measurement can be used. The diameters detected by the first diameter measuring instrument 3 and the second diameter measuring instrument 3 are different.

[0045] Unlike the prior art, the precision of ultrasonic thickness measurement is improved by changing the ultrasonic coupling medium, placing the ultrasonic probe in the water tank, and improving the precision of ultrasonic thickness measurement. However, at least two problems are caused by the installation of the ultrasonic probe in the water tank, which leads to the fact that the ultrasonic probe cannot be uniformly arranged in the circumferential direction and the concentricity cannot be directly obtained.

[0046] First, as shown in FIG. 1, the positions suitable for arranging the ultrasonic probe in the water tank are limited, and it is not convenient to arrange multiple points in the circumferential direction. Figure 6 Second, as shown in FIG. 2, there are several turns of optical cables in the water tank, and the ultrasonic probe arranged in the circumferential direction will cause crosstalk.

[0047] Figure 7 Therefore, the positions suitable for arranging the ultrasonic probe are the side wall of the water outlet tank section and the bottom under the water outlet tank section optical cable, as shown in FIG. 3. However, the wall thickness of the sheath of the optical cable cannot directly measure the concentricity.

[0048] Figure 6

[0049] ​​​In order to solve the problem of measuring the concentricity of the cable sheath, the existing caliper for testing the outer diameter of the cable and the ultrasonic probe are creatively combined to measure the outer diameter and the wall thickness of one side in the same direction, which actually represents the sheath thickness of both sides in the direction; by maintaining the stability of the outer diameter and the wall thickness in different directions, the concentricity of the cable and the axial uniformity of the cable are maintained.

[0050] The concentricity of the sheath is obtained by detecting the wall thickness and the outer diameter information, and it is determined whether the concentricity is within the set threshold range; if not, the machine is stopped for inspection; if yes, it is further determined whether the wall thickness and the outer diameter are within the set threshold range, and the feeding speed of the feeder, the traction speed of the traction machine 4 and / or the rotating speed of the extruder 1 are controlled in real time by the granular material quantitative feeding controller, so that the concentricity, the wall thickness and the outer diameter of the sheath are within the set threshold range.

[0051] After the air-blowing micro-cable 6 comes out of the extruder 1, the cooling water tank 2 adopts a winding and circulating cooling strategy for the air-blowing micro-cable 6, the air-blowing micro-cable 6 is wound in parallel on two guide wheels, and two ultrasonic probes 5 can be used to detect the wall thickness at multiple positions. If the wall thickness is detected to control the concentricity, the caliper 3 after the cooling water tank 2 is used, there is a stable cable diameter, and the wall thickness of at least two or more positions is tested, which can represent the concentricity, so the ultrasonic detection is designed to be carried out in the cooling water near the outlet. Then the concentricity is adjusted by PID online negative feedback.

[0052] Further, since the cooling water tank 2 is open at the upper end, the first ultrasonic probe 5 and the second ultrasonic probe 5 are arranged on the side wall and the bottom plate of the cooling water tank 2 respectively, the ultrasonic outlet of the first ultrasonic probe 5 is vertically upward, and the ultrasonic outlet of the second ultrasonic probe 5 is horizontally toward the air-blowing micro-cable 6 to detect the wall thickness of the positions closest to the side wall and the bottom plate on the cross section of the sheath respectively.

[0053] Further, the control system further comprises a surface defect detector for detecting the bulges and pits on the surface of the sheath. The control system further comprises a speed sensor for detecting the traction speed of the sheath, so as to control the traction speed of the traction machine 4.

[0054] According to another aspect of the present application, the control system for controlling the outer diameter of the sheath of the air-blowing micro-cable 6 is also provided, which comprises the following steps:

[0055] 1) After the sheath is extruded from the extruder 1, the sheath is cooled in the cooling water tank 2 and the caliper 3 in turn under the traction of the traction machine 4;

[0056] 2) The wall thickness of both ends of the diameter detected by the first caliper 3 is obtained by the first ultrasonic probe 5 and the first caliper 3; the wall thickness of both ends of the diameter detected by the second caliper 3 is obtained by the second ultrasonic probe 5 and the second caliper 3;

[0057] 3) through the obtained wall thickness and diameter information, the concentricity of the sheath is obtained, and it is judged whether the concentricity is within the set threshold range, if not, stop checking, if yes, enter step 4);

[0058] 4) the amount of sheath material per unit time is compared with the set value, if the error is greater than 5‰, step 6) is entered; if the error is greater than 1‰ and less than 5‰, step 7) is entered; if the error is less than 1‰, step 8) is entered;

[0059] 5) the granular material quantitative feeding controller controls the rotating speed of the extruder 1 and the feeding speed of the feeder, so that the amount of sheath material per unit time is consistent with the set value, so that the wall thickness and the outer diameter of the sheath meet the set threshold range respectively;

[0060] 6) according to the relationship between the pulling speed and the outer diameter of the sheath, the granular material quantitative feeding controller controls the rotating speed of the extruder 1, the pulling speed of the traction machine 4 and the feeding speed of the feeder, so that the amount of sheath material per unit time is consistent with the set value, so that the wall thickness and the outer diameter of the sheath meet the set threshold range respectively; the granular material quantitative feeding controller adopts a PID closed loop control system for granular material quantitative feeding control;

[0061] 7) keep the existing running state, and no adjustment is needed for each parameter.

[0062] Further, the application also includes a speed sensor for detecting the sheath pulling speed, and the pulling speed of the traction machine 4 can be adjusted through the detected speed.

[0063] Referring to Figure 2 , after the production line is started, the rotating speed of the extruder 1, the pulling speed of the traction machine 4 and the feeding amount of the feeder are automatically controlled in real time, so that they are consistent with the set weight precision of the granular material consumed per unit time, so that the volume of the sheath extruded per unit time is constant, and the control precision is within 5‰. The granular material quantitative feeding control is a PID (proportional integral) closed loop control system, which feeds back the product wall thickness in real time through the ultrasonic wall thickness tester, automatically controls the cable extrusion production line at any time without interruption, and keeps the stability of the product wall thickness quality

[0064] Referring to Figure 3 , the mass M of the sheath material per unit time is calculated as follows

[0065] M = ρV

[0066] V = SL = [π (D1 / 2) 2 - π (D2 / 2) 2 ]

[0067] D1 and D2 are the outer diameter and the inner diameter of the sheath respectively, S is the cross-sectional area of the sheath, ρ is the density of the sheath material, and L is the length of the sheath extruded per unit time.

[0068] By setting D1, D2 and p, real-time detection of the pulling speed v, the mass M of the sheath material needed at each moment is calculated, and by adjusting the rotational speed of the extruder 1 and the feeding speed of the feeder, the output of M can be accurately controlled.

[0069] Referring to Figure 4 , the middle rectangular cross-section part 300 is the ideal sheath shape, the rectangular cross-section 300 plus the outer first curve 100 is the ordinary production line state, and the rectangular cross-section 300 plus the inner second curve 200 is the sheath shape after the granular material quantitative supply controller of the present application is installed, which reduces the fluctuation of the cable diameter and saves materials.

[0070] For example, if the cable core diameter is 8 mm and the cable wall thickness is at least 0.35 mm, the minimum required diameter is 8.7 mm, and the process deviation is ±0.2 mm. In order to meet the wall thickness, the average diameter of the actual production cable is 8.9 mm.

[0071] After using the granular material quantitative supply control system, the deviation is reduced to ±0.1 mm, and the average diameter of the actual production cable is 8.8 mm.

[0072] S = 3.14 * (4.452 - 4.42)

[0073] = 1.38945 mm 2

[0074] V = S * L

[0075] = 1.38945 mm 2 * 100 km (according to L = 100 km of cable produced per day per line)

[0076] = 0.138945 m 3

[0077] According to the current market price, 1 m 3 The material price is about 20,000 yuan.

[0078] Each line can save about 2779 yuan per day.

[0079] According to 300 working days per year, each line can save 830,000 yuan in material costs.

[0080] Those skilled in the art will readily understand that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An air-blown microcable sheath molding control system, comprising an extruder, a feeder, a cooling water tank, a diameter gauge, a traction machine, an ultrasonic measuring probe, and a granule controller, wherein the extruder, cooling water tank, diameter gauge, and traction machine are arranged sequentially along the forward direction of the air-blown microcable, and the feeder is mounted on the extruder for adding sheath material into the extruder, characterized in that, The ultrasonic probe is used to detect the wall thickness of the sheath in real time. There are at least two ultrasonic probes, both of which are set in the cooling water tank. The probes include a first ultrasonic probe and a second ultrasonic probe, which can detect different detection points on the same cross-section of the sheath. The diameter measuring instrument is used to detect the diameter of the outer circle of the sheath in real time. There are at least two diameter measuring instruments, including a first diameter measuring instrument and a second diameter measuring instrument. The diameter detected by the first diameter measuring instrument passes through the detection point of the first ultrasonic probe on the sheath, and the diameter detected by the second diameter measuring instrument passes through the detection point of the second ultrasonic probe on the sheath. The concentricity of the sheath is obtained by detecting the wall thickness and outer diameter information, and it is determined whether the concentricity is within the set threshold range. If not, the machine is stopped for inspection; if so, it is determined whether the wall thickness and outer diameter are within the set threshold range. The feeding speed of the feeder, the traction speed of the traction machine and / or the rotation speed of the extruder are controlled in real time by the pellet feed metering controller to ensure that the concentricity, wall thickness and outer diameter of the sheath are within the set threshold range.

2. The air-blown micro-cable sheath forming control system according to claim 1, characterized in that, The first ultrasonic probe and the second ultrasonic probe are orthogonal.

3. The air-blown microcable sheath forming control system according to claim 1 or 2, characterized in that, The upper end of the cooling water tank is open, and each end of the cooling water tank along its length is provided with a guide wheel to allow the air-blown micro-cable to enter the cooling water tank, wind around the two guide wheels, and then exit the cooling water tank. The first ultrasonic probe and the second ultrasonic probe are respectively located on the side wall outside the optical cable of the cooling water tank outlet section and the bottom below.

4. The air-blown microcable sheath forming control system according to claim 3, characterized in that, The ultrasonic outlet of the first ultrasonic probe is vertically upward, and the ultrasonic outlet of the second ultrasonic probe is horizontally oriented towards the air-blown microcable to detect the wall thickness of the part closest to the sidewall and the part closest to the bottom plate on the cross-section of the sheath, respectively.

5. The air-blown microcable sheath forming control system according to any one of claims 1 to 4, characterized in that, The diameter measuring instrument measures the outer diameter of the optical cable with the same cross section and direction as the ultrasonic probe.

6. The air-blown microcable sheath forming control system according to claim 5, characterized in that, The diameter gauge is a non-contact measuring instrument.

7. The air-blown micro-cable sheath forming control system according to claim 1, characterized in that, It also includes a surface defect detector to detect bulges and pits on the sheath surface.

8. The air-blown microcable sheath forming control system according to claim 1, characterized in that, It also includes a speed sensor for detecting the traction speed of the sheath.

9. The method for controlling the outer diameter of the air-blown microcable sheath according to any one of claims 1 to 8, characterized in that, Includes the following steps: 1) After the sheath is extruded from the extruder, it passes through the cooling water tank and the diameter measuring instrument in sequence under the traction of the traction machine; 2) The wall thickness at both ends of the diameter detected by the first diameter gauge is obtained through the first ultrasonic probe and the first diameter gauge; the wall thickness at both ends of the diameter detected by the second diameter gauge is obtained through the second ultrasonic probe and the second diameter gauge. 3) Obtain the concentricity of the sheath using the wall thickness and diameter information, and determine whether the concentricity is within the set threshold range. If not, stop the machine for inspection; if yes, proceed to step 4). 4) Compare the amount of sheathing material used per unit time with the set value. If the error is greater than 5‰, proceed to step 5); if the error is greater than 1‰ but less than 5‰, proceed to step 6); if the error is less than 1‰, proceed to step 7). 5) The pellet feed metering controller controls the speed of the extruder and the feeding speed of the feeder to keep the amount of sheath material used per unit time consistent with the set value, so that the wall thickness and outer diameter of the sheath meet the set threshold range respectively. 6) Based on the relationship between the traction speed and the outer diameter of the sheath, the pellet feed metering controller controls the speed of the extruder, the traction speed of the traction machine and the feeding speed of the feeder, so that the amount of sheath material used per unit time is consistent with the set value, so that the wall thickness and outer diameter of the sheath meet the set threshold range respectively. 7) Maintain the existing operating status.

10. The method according to claim 9, characterized in that, The pellet feed metering controller uses a PID closed-loop control system to control the pellet feed metering.

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