A non-contact linear velocity detection and closed-loop control wire drawing system and wire drawing process

Abstract

The application discloses a non-contact line speed detection and closed-loop control drawing system and a drawing process, the drawing system comprises a bushing, an oiling roller, a drawing machine, further comprises a first buncher and a second buncher below the oiling roller, a non-contact line speed detection device is arranged between the first buncher and the second buncher, and the non-contact line speed detection device detects the line speed of the glass fiber yarn bundle. The application mainly aims at the control design defects of the drawing machine, the line speed parameter is fed back to the drawing machine through actual detection of the line speed, the rotating speed of the drawing machine is controlled according to the difference between the set line speed, and then the constant line speed production is realized, so that the effects of stabilizing the tex of the yarn bundle and optimizing the product forming are achieved.

Description

Technical Field

[0001] This invention belongs to the field of glass fiber production technology, and in particular relates to a non-contact linear speed detection and closed-loop control drawing system and drawing process. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] The process of producing glass fiber using the tank furnace method involves molten glass flowing from a high-temperature baffle plate. After being cooled by spraying, the glass fiber is impregnated in a drawing sizing tank by an oiling roller, which applies a sizing agent to the surface of the glass fiber, giving it a certain degree of processing properties. Then, it is bundled into one or more strands by a bundler below the sizing tank, and finally wound into a bobbin shape on a drawing machine. The drawing machine relies on the rotation of the die head to pull the glass fiber flowing from the baffle plate, stretching a bundle of fibers to a specified linear density at a predetermined, constant linear speed and winding it into a regularly shaped tubular bobbin. The drawing machine generates a constant linear speed by controlling the rotation speed of the die head; the control program typically uses units of rpm (revolutions per minute) to specify the speed of the die head. To ensure the uniformity of the drawn fiber bundle, the winding unit of the die head needs to maintain a constant linear speed during the winding process. Its own rotation speed needs to decrease as the package diameter increases; therefore, the speed change pattern differs at different stages.

[0004] In actual production, due to the width of the yarn roll and deviations in theoretical calculations, the actual linear speed fluctuates, and there is a deviation between the actual linear speed and the theoretical linear speed. This results in the inability to maintain a constant linear speed to pull the yarn bundle, leading to instability in the yarn bundle tex.

[0005] In the prior art, as mentioned in patent application CN202511699645.3, the entire drawing process is controlled by an online laser diameter measuring instrument in a closed loop. This structure is similar to patent CN223272545U, which uses an adjustment component to facilitate the adjustment of the position of the detection wheel according to graphite rollers of different diameters, so that the detection wheel contacts and rotates with the rotating drawing graphite material. A high-precision linear velocity sensor captures this rotation speed and transmits the signal to the controller, displaying the measurement results in real time on the operation interface for the operator to view, thus ensuring the accuracy of the measurement results.

[0006] However, in this type of detection scheme, the linear speed of the glass fiber is determined by detecting the rotation of the wheel through the contact wheel encoder in the sensor. On the one hand, contact detection inevitably causes wear on the detection device, thus affecting accuracy and service life. On the other hand, slippage, vibration, wear and dirt at the contact point will all cause measurement errors, resulting in product loss and quality problems. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, this invention provides a non-contact linear velocity detection and closed-loop control wire drawing system and process. Based on a laser linear velocity measurement scheme, this invention achieves non-contact linear velocity detection. Furthermore, it utilizes the deviation between the measured and set values ​​to correct the wire drawing machine's rotational speed, thus overcoming the technical deficiency of existing wire drawing machines where large deviations in self-checked angular velocity and actual circumference variations lead to poor stability of the actual linear velocity.

[0008] To achieve the above objectives, the technical solution provided by the present invention is as follows: In a first aspect, the present invention provides a non-contact linear speed detection and closed-loop control fiber drawing system, including a spinneret, an oiling roller, a fiber drawing machine, and a first and a second bundler located below the oiling roller. A non-contact linear speed detection device is provided between the first and the second bundlers, the non-contact linear speed detection device being used to detect the linear speed of the glass fiber yarn bundle.

[0009] Preferably, the non-contact linear velocity detection device is a laser Doppler velocimeter, and in some embodiments of the present invention, it is specifically a laser meter.

[0010] In conventional structures, a bundler is placed below the oiling roller to gather the glass fibers into a single bundle for subsequent winding. However, in a single bundler structure, there is a relatively long (typically 2-4 meters) free-hanging section between the bundler outlet and the drawing machine head. This section of the bundle undergoes complex vibration and torsional motions, including vibration and torsional oscillations, under the influence of airflow disturbances, electrostatic effects, and tension fluctuations. In this case, vibration and torsion can severely interfere with laser reflection-based linear velocity detection. When the laser beam illuminates the surface of the moving bundle, a stable diffuse reflection signal is required for accurate calculation of the Doppler frequency shift. When the bundle surface tilts, rotates, or moves laterally rapidly, the reflected light may deviate from the field of view of the receiving optics, leading to signal interruption or a sharp drop in the signal-to-noise ratio.

[0011] This application sets up two clusters, which are used to create a smooth glass fiber interface between the first cluster and the second cluster, and to ensure that the glass fibers between them form a uniform strip, thereby ensuring that the laser meter accurately detects the linear velocity of the glass fibers.

[0012] Furthermore, the straight-line distance between the first and second bundlers is 200-500mm to ensure that the yarn bundles remain flat and stable, providing the necessary conditions for accurate detection by the laser meter counter.

[0013] Furthermore, the angle between the laser center line of the laser meter and the straight line between the first and second beam collectors is set to 90 degrees to avoid the influence of the tilt angle on the detection linear velocity results.

[0014] Furthermore, a spatial partition is provided between the first and second bundle collectors, with openings in the partition for the yarn bundle to pass through. The laser meter is positioned above the spatial partition, and the intersection of the laser center line of the laser meter and the straight line between the first and second bundle collectors is not lower than the height of the openings in the spatial partition. The spatial partition effectively separates the monitoring area from the yarn drawing area.

[0015] Preferably, the wire drawing machine includes a frequency conversion control system, wherein the frequency converter controls the rotational speed of the wire drawing machine head.

[0016] Preferably, it also includes a controller, which is signal-connected to the non-contact linear speed detection device and the frequency converter, respectively, receives the linear speed signal from the non-contact linear speed detection device, controls the frequency converter to regulate the speed of the wire drawing machine, and realizes constant speed traction of the wire drawing machine.

[0017] Preferably, the non-contact linear velocity detection device emits a laser beam into the glass fiber yarn bundle between the first and second bundlers to detect the linear velocity V of the glass fiber yarn bundle.

[0018] Preferably, the non-contact linear velocity detection device measures velocity by using the Doppler effect formula to calculate the velocity V of the object being measured.

[0019] Where V is the velocity of the object (m / s), and c is the speed of light (approximately 3 × 10⁻⁶ m / s in a vacuum). 8 (m / s), Δf is the frequency difference between the reflected light and the emitted light (Doppler shift, Hz), and f0 is the natural frequency of the emitted laser beam (Hz).

[0020] The present invention also provides a wire drawing process, comprising the following steps: Continuous glass fiber formation process: High-temperature viscous glass liquid flows out as droplets through the stencil and forms a continuous glass fiber bundle with stable fiber diameter under constant speed traction of the drawing machine. The fiber is coated with sizing agent by the oiling roller, and then guided by the first and second bundlers, passes through the space partition, and is wound into shape at the head of the drawing machine. During the continuous glass fiber formation process, laser velocimetry is performed: a non-contact linear velocity detection device installed between the first and second bundlers calculates the speed of the glass fiber bundle by emitting a laser beam and measuring the reflection time of the laser beam. The non-contact linear speed detection device detects the linear speed and feeds it back to the controller. The controller controls the frequency conversion control system of the drawing machine, and the frequency converter controls the speed of the drawing machine to achieve constant linear speed of glass fiber and realize closed-loop control of linear speed.

[0021] Furthermore, the wire drawing process also includes a risk control procedure: A permissible value for linear speed fluctuation is set for the non-contact linear speed detection device (e.g., permissible linear speed fluctuation ≤ 50 m / min), and the controller continuously monitors the deviation between the real-time linear speed and the set value. Once the speed fluctuation exceeds the permissible value, the system immediately performs an automatic control mode switch: the detection signal input of the non-contact speed measuring instrument is disconnected via a pneumatic valve, and the controller automatically switches to control via the motor encoder signal scheme of the wire drawing machine motor frequency converter. Simultaneously, an alarm system is triggered (alarm indicator light flashes, buzzer sounds, and alarm record is displayed on the host computer), reminding the operator to check the working status of the non-contact speed measuring device. After the fault is cleared, the system can manually or automatically return to the non-contact speed measurement closed-loop control mode.

[0022] The non-contact linear velocity detection and closed-loop control wire drawing system and wire drawing process provided by this invention have the following characteristics: 1. Non-contact linear velocity detection during wire drawing process: The entire process adopts laser Doppler technology to achieve non-contact linear velocity detection, which fundamentally eliminates contact wear and slippage problems, resulting in high detection accuracy and long service life.

[0023] 2. The entire process is automatically controlled. The theoretical value of the wire drawing machine is corrected by detection data. It is directly matched with the existing wire drawing machine without manual intervention, thus realizing refined management of the wire drawing process. 3. Applicable to all wire drawing machine models, without the need for large-scale modification of the original equipment or classification design; 4. A new method for controlling the speed of the wire drawing machine head was created, which uses direct linear velocity feedback control to replace the traditional indirect angular velocity control, thus greatly improving the accuracy of constant linear velocity control during the wire drawing process. 5. The non-contact detection device is fixed at a constant distance to ensure that it will not interfere with the normal operation of the filament bundle and will not affect the normal filament drawing operation.

[0024] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention provides a non-contact linear speed detection and closed-loop control yarn drawing system. This invention mainly addresses the design defects of yarn drawing machine control. By actually detecting the linear speed, the linear speed parameter is fed back to the yarn drawing machine. The difference between the actual linear speed and the set linear speed is used to control the speed of the yarn drawing machine, thereby achieving constant linear speed production, stabilizing the yarn bundle tex and optimizing product forming.

[0025] 2. Compared with the existing servo motor speed measurement method that directly measures angular velocity, the non-contact linear velocity detection device used in this invention measures linear velocity directly, thus making the speed measurement more accurate.

[0026] 3. The non-contact linear speed detection device feeds the measured speed back to the controller. The controller compares the measured speed with the set speed and corrects the speed deviation to achieve precise control and complete the constant speed production of the wire drawing machine.

[0027] 4. Based on the system and method provided by this invention, closed-loop control is achieved, thereby ensuring product quality. Attached Figure Description

[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0029] Figure 1 The graph shows the relationship between drawing speed and diameter during the yarn drawing process. The horizontal axis represents time (in minutes), the left vertical axis represents linear velocity (in m / min), and the right vertical axis represents yarn bobbin diameter (in mm). The curves indicate that to maintain a constant linear velocity, the machine head angular velocity must decrease inversely proportionally as the yarn bobbin diameter increases.

[0030] Figure 2 The figure shows the outer diameter and its growth curve during the winding process. It indicates that the outer diameter of the yarn bobbin increases parabolically over time, while the rate of increase gradually slows down.

[0031] Figure 3 This is a simulation diagram of the yarn bundle winding path; the horizontal axis represents the reciprocating time / position of the yarn (10-second cycle), and the vertical axis represents the rotation phase of the yarn bobbin (0~2π). The slope variation of the diamond-shaped line reflects the influence of the yarn width parameters on the actual winding position of the yarn bundle.

[0032] Figure 4 The present invention provides a schematic diagram of a non-contact linear velocity detection and closed-loop control wire drawing system.

[0033] Among them, 1. Spindle plate, 2. Glass fiber yarn bundle, 3. Oiling roller, 4. Non-contact linear velocity detection device, 5. Laser beam, 6. First bundler, 7. Fiber drawing machine, 8. Second bundler, 9. Space partition. Detailed Implementation

[0034] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0035] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0036] The fiber drawing and winding process involves setting the spinneret flow rate, yarn bundle tex, and yarn cake inner diameter to determine the initial angular velocity of the drawing machine. During the drawing process, the yarn cake diameter increases parabolically, while the angular velocity η changes inversely proportionally. The product of these two factors should be a constant value (e.g., ...). Figure 1 As shown), and as the silk cake increases in size, the rate of increase in outer diameter gradually slows down (as shown). Figure 2 (As shown).

[0037] However, in actual production, such as Figure 3 As shown, this figure is a diamond diagram of the winding phase of a glass fiber drawing machine. The horizontal axis is the time / position of the reciprocating motion of the yarn (10 seconds), and the vertical axis is the rotation phase of the yarn bobbin (0~2π). By observing the change in the slope of the diamond line, the change in the winding width can be intuitively judged. Due to the winding width and the deviation of theoretical calculation, the actual linear speed fluctuates. There is a deviation between the actual linear speed and the theoretical linear speed, which leads to the inability to maintain a constant linear speed to pull the yarn bundle, resulting in unstable yarn bundle tex.

[0038] In conventional wire drawing machines, speed measurement utilizes a servo motor encoder to measure the angular velocity of the machine head's rotation. The servo motor encoder, mounted on the servo motor, converts the motor's rotation angle and speed into digital signals, which are then fed back to the controller, enabling precise control of the motor's movement.

[0039] However, when using a contact speed measurement method, as the yarn bobbin width and weight increase, microscopic slippage may occur at the contact point between the yarn bundle and the encoder, causing the system to mistakenly believe that the speed is not fast enough and instead order acceleration, further exacerbating the problem.

[0040] To address the problem of actual linear velocity fluctuations and the drawbacks of conventional contact wheel structure linear velocity detection methods, this invention provides a non-contact linear velocity detection scheme, achieving closed-loop control to ensure product quality.

[0041] The technical solution of the present invention is described below with reference to specific embodiments. Experimental methods not specifically described in the embodiments are generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise specified, all equipment, reagents, etc., used are commercially available.

[0042] Example 1: A non-contact linear velocity detection and closed-loop control wire drawing system The system includes a stencil 1, an oiling roller 3 below the stencil 1, a first bundler 6, a second bundler 8, a drawing machine 7, and a non-contact linear velocity detection device 4. The first bundler 6 and the second bundler 8 are located below the oiling roller 3, and the straight-line distance between the first bundler 6 and the second bundler 8 is 200~500mm. The non-contact linear velocity detection device 4 is installed between the first bundler 6 and the second bundler 8. The non-contact linear velocity detection device 4 emits a laser beam 5 towards the glass fiber yarn bundle 2 between the first bundler 6 and the second bundler 8 to detect the linear velocity V of the glass fiber yarn bundle 2. The frequency conversion control system of the drawing machine 7 includes a machine head, the drawing machine head is connected to the output shaft of a motor, the motor is connected to a frequency converter, and the frequency converter controls the rotational speed of the drawing machine head.

[0043] A space partition 9 is provided between the first bundler 6 and the second bundler 8. The space partition 9 has openings for the yarn bundle to pass through.

[0044] It also includes a controller, which uses a Siemens S7-1200 series PLC, equipped with an analog input module (receiving a 4-20mA signal from the tachometer) and an analog output module (outputting a 0-10V control signal to the frequency converter). The controller is connected to the non-contact linear speed detection device 4 and the frequency converter respectively, receiving the linear speed signal from the non-contact linear speed detection device 4, controlling the frequency converter to regulate the speed of the wire drawing machine, and realizing constant speed traction of the wire drawing machine.

[0045] As a typical embodiment, the non-contact linear velocity detection device 4 is named a laser meter counter (model CTG01, Polytec GmbH, Germany) and the wire drawing machine 7 (model DS400). The angle between the laser center line of the laser meter counter and the straight line between the first and second beam collectors is 90 degrees.

[0046] The non-contact linear velocity detection device measures velocity by using the Doppler effect formula to calculate the velocity V of the object being measured.

[0047] Where V is the velocity of the object (m / s), and c is the speed of light (approximately 3 × 10⁻⁶ m / s in a vacuum). 8 (m / s), Δf is the frequency difference between the reflected light and the emitted light (Doppler shift, Hz), and f0 is the natural frequency of the emitted laser beam (Hz).

[0048] The non-contact linear velocity detection device feeds the measured velocity back to the controller, which compares it with the set rotation speed and corrects the velocity deviation to achieve precise control and complete the constant linear velocity production of glass fiber.

[0049] This invention can guide the optimization of on-site wire drawing control procedures to achieve constant linear speed production. It can also assist in calibrating on-site wire drawing processes, improving production stability and product quality. After implementation, speed detection achieves closed-loop control, improving process stability by 3% compared to the current open control method, and reducing product tex control accuracy to within 2% (current control accuracy is 5%-7%).

[0050] This invention can also assist in measuring and determining whether a product is abnormal, comparing it with previous data to analyze the causes of the abnormality, providing a basis for production adjustments, and achieving the effect of guiding production.

[0051] Example 2, wire drawing process The process includes the following: S1, Continuous glass fiber formation process: High-temperature viscous glass liquid flows out as droplets through the stencil 1 and forms a continuous glass fiber bundle 2 with stable fiber diameter under constant speed traction of the drawing machine 7. After the fiber is coated with sizing agent by the oiling roller 3, the disadvantage of glass brittleness is changed. Then, it is guided by the first bundler 6 and the second bundler 8 to be wound into shape at the head of the drawing machine 7.

[0052] S2, Laser velocity measurement process: The non-contact linear velocity detection device 4 installed between the first beam collector 6 and the second beam collector 8 calculates the velocity of the glass fiber yarn bundle 2 by emitting a laser beam 5 and measuring the reflection time of the laser beam. S3, Closed-loop control process: The detection value V of the non-contact linear speed detection device 4 is fed back to the controller. The controller controls the frequency conversion control system of the wire drawing machine, and the frequency converter controls the speed of the wire drawing machine 7 to achieve constant speed traction of the wire drawing machine.

[0053] S4, Risk Control Process: The non-contact speed measuring instrument is set with an allowable speed fluctuation value (e.g., allowable speed fluctuation value ≤ 50m / min). Once the speed fluctuation exceeds the allowable value, the control mode is immediately switched automatically (the pneumatic valve disconnects the non-contact speed measuring instrument's detection signal, and the machine head motor frequency converter automatically controls it for temporary monitoring), and the alarm system is triggered (alarm indicator light flashes) to ensure normal production operation.

[0054] Based on the system provided in Example 1, the specific installation parameters are as follows: The distance between the lower edge of the first bundle collector 6 and the lower edge of the oiling roller is 300mm; the distance between the upper edge of the second bundle collector 8 and the lower edge of the first bundle collector 6 is 250mm. The optical head of the non-contact linear velocity detection device is 150mm from the yarn surface, and the angle between the laser beam direction and the yarn movement direction is 90°. A space partition, with openings for the yarn to pass through, is installed on both sides of the yarn running path. It is made of anti-static PVC and is located 50mm below the intersection of the laser center line of the laser meter and the straight line between the first and second bundle collectors.

[0055] Operating parameters: Glass type: E-glass; Strainer temperature: 1230℃; Set the linear velocity V_set to 1500 m / min; Yarn bundle tex target value: 600 tex; Wetting agent: epoxy emulsion type; Sizing agent coating amount: 1.2% (as a percentage of fiber mass); Control parameters: Controller sampling period: 20ms; PID parameters: K_p = 1.2, Ki = 0.05, K_d = 0.15; Permissible speed fluctuation: ±50 m / min.

[0056] Execution result: Under the above conditions, the system operated continuously for 72 hours (completing the winding of approximately 96 spools). Each spool underwent tex testing and quality rating, and the statistical results are as follows: Table 1. Results of tex and quality rating tests on the precursor yarn spool in Example 1

[0057] As can be seen from the above results, based on the drawing system provided by Benfenming, the linear speed control accuracy reaches within ±15 m / min (within 1%), the yarn bundle tex variation coefficient is far lower than the industry standard (5%~7%), and the product quality stability and consistency are significantly improved.

[0058] Example 3 Adaptability verification under different process conditions To verify the adaptability and robustness of the system of the present invention under different process conditions, this embodiment, based on Example 1, changed the key process parameters and conducted multiple sets of comparative tests. The results are shown in Tables 2 and 3.

[0059] Table 2 Tests at different linear velocity settings

[0060] The results above show that, across all test speed ranges, the system of this invention maintains a linear velocity standard deviation ≤ 7.5 m / min and a tex CV% ≤ 1.7%, demonstrating excellent speed adaptability. As the speed increases, the fluctuation slightly increases, but remains within an acceptable range.

[0061] Table 3 Tests for different yarn bundle tex specifications

[0062] As can be seen from the above results, the system of the present invention can maintain excellent control accuracy under different tex specifications, indicating that the system has good versatility for different product specifications in glass fiber production.

[0063] Comparative Example To further verify the technical effectiveness of the dual-cluster structure and non-contact detection scheme in this invention, the following comparative experiments were conducted. All comparative experiments were carried out under the same process conditions (squeegee temperature 1230°C, set linear speed 1500 m / min, target tex 600) and equipment platform (except for the features being compared, the rest were the same as in Example 1).

[0064] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that a second bundler 8 is not provided; that is, only one bundler is provided below the oiling roller 3, and the non-contact linear speed detection device 4 is installed between the bundler and the drawing machine 7. The rest of the structure and process conditions are exactly the same as those in Example 1 and Example 2.

[0065] Experimental methods: Under continuous production conditions, the same laser Doppler velocimeter (CTG01) as in Example 1 was used to detect the yarn bundle linear speed. Data was recorded once per yarn bobbin winding cycle (approximately 45 minutes), and the process was carried out continuously for 72 hours (completing approximately 96 yarn bobbins). The results are shown in Table 4.

[0066] Table 4. Results of Tex testing and quality rating of the precursor yarn in Comparative Example 1

[0067] During the operation of Comparative Example 1, the following phenomena can be observed: Significant yarn bundle vibration: In the free section of about 3.5m between the single bundler outlet and the drawing machine, the yarn bundle exhibits obvious lateral oscillation with an amplitude of about ±8~15mm and a frequency of about 8~12Hz.

[0068] Frequent interruptions in the speed measurement signal: Controller records show that the speedometer output signal experiences a brief interruption every 20-50 seconds (lasting 20-200ms), with a total signal effectiveness of only 88.3%. Analysis suggests that the interruption is caused by the yarn bundle oscillation, resulting in reflected light deviating from the receiving field of view.

[0069] Severe speed fluctuations: When the yarn bundle swings with a large amplitude, the speed value output by the speed meter shows sharp fluctuations (momentary deviations of more than ±100 m / min). The controller mistakenly interprets this as a real speed change and makes drastic adjustments, which in turn exacerbates the tension fluctuations of the yarn bundle.

[0070] Decreased yarn quality: Some raw yarn bobbins showed appearance defects such as loose yarn layers, overlapping yarns, and yarn overflow. The Tex test results showed large dispersion, and the first-grade product rate decreased significantly.

[0071] Based on the results of Example 1 and Comparative Example 1, it is evident that under single-bundle conditions, the vibration and torsion of the free segment of the yarn bundle severely interfere with the normal operation of the laser Doppler velocimeter, resulting in low signal efficiency, high measurement noise, and large speed fluctuations, thereby affecting the quality of closed-loop control. The dual-bundle structure of this invention, by constraining the movement of the yarn bundle and stabilizing its spatial attitude, is a key innovative feature for achieving high-precision, continuous, and reliable speed measurement.

[0072] Comparative Example 2: The difference between this comparative example and Comparative Example 1 is that the non-contact linear velocity detection device is replaced with a contact encoder speed measuring wheel device. The structural parameters of this device are as follows: The speed measuring wheel is made of aluminum with a polyurethane rubber coating, 50mm in diameter and 10mm wide. The encoder is an incremental rotary encoder with 500 pulses / revolution. The speed measuring wheel is pressed onto the yarn bundle by a spring clamping mechanism (approximately 5N pressure) and rotates with the movement of the yarn bundle. The encoder pulse signal is converted into a 4-20mA signal by a frequency / voltage conversion module and sent to the controller.

[0073] The remaining structures (single bundler, wire drawing machine, etc.) and process conditions are the same as those in Comparative Example 1.

[0074] Experimental methods: Because the contact speed measuring wheel wears out quickly under high-speed operation, the continuous operating time of this comparative example was shortened to 24 hours (approximately 32 filament spools). The surface condition of the speed measuring wheel was checked every 2 hours, and the wheel diameter change was measured every 4 hours. The results are shown in Table 5.

[0075] Table 5. Results of tex and quality rating tests on the precursor yarn in Comparative Example 2.

[0076] result: Initial stage (0-4 hours): The contact speed measuring device works basically normally. The speed fluctuation is comparable to that of the laser scheme in Comparative Example 1 (18.6 vs 22.3 m / min). However, due to the absence of signal interruption, the speed continuity is better, and the tex CV% is slightly better.

[0077] Mid-stage (8-12 hours): Slight wear and dirt accumulation appear on the surface of the speed measuring wheel, and the measured speed values ​​begin to show a systematic underperformance (error approximately +2%). After detecting the underperformance, the controller issues an acceleration command, causing the actual speed of the yarn bundle to be slightly higher (over-adjustment), and the tex CV% rises to 5.23%.

[0078] In the later stage (20-24 hours): the wear of the speed measuring wheel intensified (the wheel diameter decreased by 0.15 mm, corresponding to approximately 0.6% speed measurement error), and at the same time, the coefficient of friction of the rubber surface decreased, resulting in intermittent slippage. During slippage, the encoder output frequency suddenly dropped, which the controller misinterpreted as a rapid speed drop and accelerated significantly, causing a momentary increase in yarn tension, leading to three yarn breakage incidents. The tex CV% deteriorated to 7.36%.

[0079] Final inspection analysis: After 24 hours of operation, the diameter of the speed measuring wheel decreased by a cumulative 0.15mm, and obvious wear marks and peeling were observed on the surface polyurethane layer, requiring replacement. Tex testing of the yarn bundles showed a significant decline in the quality of the raw yarn bobbins produced later, with nearly 50% of the products falling below the first-class standard.

[0080] In contrast, the non-contact laser velocimetry solution of Embodiment 1 of the present invention maintains stable performance throughout the 72-hour test, with no wear, no slippage, and no maintenance required, fully demonstrating the superiority of non-contact detection.

[0081] To more intuitively demonstrate the technical effects of the present invention, the key performance indicators of Example 1, Comparative Example 1, and Comparative Example 2 are summarized in Table 6: Table 6 Summary of performance indicators for Example 1 and Comparative Example

[0082] Based on the above comparison, it is evident that a dual-beam converter is an indispensable structural feature. Comparing Example 1 and Comparative Example 1, the dual-beam converter structure increases the signal efficiency of laser velocimetry from 88.3% to 99.97%, reduces the linear velocity standard deviation from 23.6 m / min to 4.8 m / min, and decreases the tex CV% from 4.72% to 1.37%. Without the dual-beam converter creating a stable detection window, the advantages of laser velocimetry cannot be fully realized. Comparative Example 1 and Comparative Example 2 show that although both use a single beam converter, the non-contact laser solution (Comparative Example 1) demonstrates superior long-term stability compared to the contact wheel solution (Comparative Example 2).

[0083] In summary, the dual-beam converter combined with laser velocimetry solution provided in Embodiment 1 of this invention combines the measurement stability brought by the dual-beam converter with the long-term drift-free advantage of laser non-contact detection, achieving optimal control accuracy and product quality stability.

[0084] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A non-contact linear velocity detection and closed-loop control wire drawing system, characterized in that, It includes a stencil, an oiling roller, a drawing machine, and a first and a second bundler located below the oiling roller. A non-contact linear velocity detection device is provided between the first and the second bundlers to detect the linear velocity of the glass fiber yarn bundle.

2. The non-contact linear velocity detection and closed-loop control wire drawing system according to claim 1, characterized in that, The non-contact linear velocity detection device is a laser Doppler velocimeter, or more specifically, a laser meter.

3. The non-contact linear velocity detection and closed-loop control wire drawing system according to claim 2, characterized in that, The straight-line distance between the first and second clusterers is 200~500mm.

4. The non-contact linear velocity detection and closed-loop control wire drawing system according to claim 3, characterized in that, The laser center line of the laser meter is set to form a 90-degree angle with the straight line between the first and second beam collectors; the non-contact linear velocity detection device emits a laser beam into the glass fiber yarn bundle between the first and second beam collectors to detect the linear velocity V of the glass fiber yarn bundle.

5. The non-contact linear velocity detection and closed-loop control wire drawing system according to claim 4, characterized in that, A space partition is provided between the first and second bundlers, and the space partition has openings for the yarn bundles to pass through.

6. The non-contact linear velocity detection and closed-loop control wire drawing system according to claim 5, characterized in that, The laser meter is positioned above the space partition, and the intersection point of the laser center line of the laser meter with the straight line between the first and second beam collectors is not lower than the opening height of the space partition.

7. The non-contact linear velocity detection and closed-loop control wire drawing system according to claim 1, characterized in that, The wire drawing machine includes a frequency conversion control system, in which the frequency converter controls the rotational speed of the wire drawing machine head.

8. The non-contact linear velocity detection and closed-loop control wire drawing system according to claim 1, characterized in that, It also includes a controller, which is connected to the non-contact linear speed detection device and the frequency converter respectively. The controller receives the linear speed signal from the non-contact linear speed detection device and controls the frequency converter to regulate the speed of the wire drawing machine, so as to realize constant speed traction of the wire drawing machine.

9. A wire drawing process, characterized in that, Based on the non-contact linear velocity detection and closed-loop control wire drawing system according to any one of claims 1 to 7, the wire drawing process includes the following steps: Continuous glass fiber formation process: High-temperature viscous glass liquid flows out as droplets through the stencil and forms a continuous glass fiber bundle with stable fiber diameter under constant speed traction of the drawing machine. The fiber is coated with sizing agent by the oiling roller, and then guided by the first and second bundlers, passes through the space partition, and is wound into shape at the head of the drawing machine. During the continuous glass fiber formation process, a non-contact linear velocity detection device installed between the first and second bundlers calculates the speed of the glass fiber bundle by emitting a laser beam and measuring the reflection time of the laser beam. The non-contact linear speed detection device detects the linear speed value and feeds it back to the controller. The controller controls the frequency conversion control system of the drawing machine, and the frequency converter controls the speed of the drawing machine to achieve a constant linear speed of glass fiber.

10. The wire drawing process according to claim 9, characterized in that, The wire drawing process also includes a risk control process: setting an allowable value for speed fluctuation for the non-contact linear speed detection device, and the controller continuously monitors the deviation between the real-time linear speed and the set value; When the linear speed fluctuation exceeds the allowable value, the system immediately performs an automatic control mode switching operation, disconnects the detection signal input of the non-contact speed measuring instrument, and the controller automatically switches to the wire drawing machine motor frequency converter to continue control based on the motor encoder signal, while triggering the alarm system.

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