A method of calibrating a coiler mandrel

Abstract

The present application relates to a kind of methods for calibrating coiler mandrel, belong to the technical field of rolling mill equipment maintenance method.The technical scheme of the present application is: using a pull rope type encoder, after its rope head is wound around mandrel one circle, fixed at the surface of mandrel three o'clock position, pull rope type encoder is installed below the coincident point of rope head, according to certain step, expand mandrel, calculate mandrel expansion diameter by the length of pull rope increase measured by pull rope type encoder each time, write mandrel expansion diameter and the data obtained by mandrel hydraulic cylinder sensor into mandrel expansion diameter calibration table, after completing the whole mandrel expansion stroke, the calibration of mandrel can be completed.The beneficial effects of the present application are: by increasing the detection of mandrel circumference by pull rope type encoder, the accuracy of mandrel expansion control is improved, the ability of inner ring expansion of strip steel entering coiler is improved;The calibration process is safe and fast, the difficulty of mandrel calibration, downtime cost, time arrangement difficulty is greatly reduced.

Description

Technical Field

[0001] This invention relates to a method for calibrating the mandrel of a coiler, belonging to the technical field of rolling mill equipment maintenance methods. Background Technology

[0002] The coiler is a critical quality control device in a hot-rolled strip production line, significantly impacting the successful establishment of tension and coil shape control. It is expensive, requires frequent replacements, and is a key maintenance item in the hot-rolling production line. In hot continuous rolling, successfully establishing tension after the strip enters the coiler is a crucial technology, determining whether the strip signal can be successfully established from finishing to coiling, achieving a stable rolling-coiling transition. The mandrel plays a vital role in this process, with strict requirements on its expansion. When the strip head enters the coiler, it forms an initial loop around the mandrel. After three loops, the mandrel begins to expand. This process requires extremely high speed and sufficient expansion to tightly grip the small loop formed by the strip head onto the mandrel. Generally, after the mandrel expands, sufficient and stable tension is established on the strip, ensuring that the strip head does not loosen after the auxiliary coiling rolls open, thus allowing the coiling process to proceed to the next stage. As can be seen, mandrel expansion is a crucial step in the tension-building stage of the coiler. Sufficient expansion plays a key role in successfully establishing tension and achieving successful coiling. Inaccurate expansion often results in the mandrel failing to tighten the inner coil after expansion, leading to loose coiling and steel piling.

[0003] To ensure accurate mandrel expansion, the mandrel's expansion diameter must be accurately calibrated. Mandrel calibration involves rewriting the mandrel expansion diameter at each point with the corresponding length of the hydraulic cylinder used for expansion into the mandrel expansion diameter calibration table within the program. This table stores the correspondence between mandrel expansion diameters and hydraulic cylinder lengths, recording 20 sets of data ranging from 727 to 765 mm, forming a curve from smallest to largest. When the system performs mandrel expansion, it drives the hydraulic system according to the corresponding values ​​on this curve. Currently, online calibration of the mandrel expansion diameter is done manually due to space constraints and the inability to use bulky outside micrometers; instead, a simple, homemade steel tape measure is used, often resulting in excessive measurement errors. The mandrel diameter range was measured from 727 mm to 762 mm, totaling 35 sets of data, which, after verification, amounted to 70 sets of data. Because the measurement work must be performed inside the winding machine cavity, the space is extremely confined, making it impossible for personnel to stand. They must bend over and operate by stepping on the swing arm of the auxiliary winding roller, with a deep trench below. Furthermore, the large amount of data to be measured and the process taking over three hours make the calibration process highly dangerous and result in significant data errors. These problems restrict the accuracy of mandrel expansion diameter control and affect the improvement of winding success rate. Summary of the Invention

[0004] The purpose of this invention is to provide a method for calibrating the mandrel of a coiler. By adding a drawstring encoder to detect the mandrel circumference, the accuracy of mandrel calibration can reach the sub-millimeter level, which is an order of magnitude higher than manual measurement. This improves the precision of mandrel expansion control and enhances the ability of the strip to tighten its inner ring when entering the coiler. The calibration process is safe and fast, eliminating the need for personnel to operate inside the coiler for extended periods. It significantly reduces the difficulty of mandrel calibration, downtime costs, and scheduling challenges, encouraging on-site personnel to increase the timeliness and frequency of calibration. This results in a substantial improvement in the accuracy retention rate of mandrel expansion diameter, effectively solving the aforementioned problems in the background technology.

[0005] The technical solution of the present invention is: a method for calibrating a winding machine mandrel, comprising the following steps:

[0006] (1) Install the pull-cord encoder on the tangent downward direction at the three o'clock position of the spindle, and wrap the pull-cord head around the spindle once and fix it at the three o'clock position of the spindle. After backing up the original calibration data, shrink the spindle to its minimum size.

[0007] (2) Clear the length value of the pull-cord encoder to zero, and the corresponding spindle expansion feedback value is the diameter of the contraction position;

[0008] (3) Write the current spindle expansion diameter feedback value and hydraulic cylinder length into the calibration table;

[0009] (4) Add π to the target encoder length value;

[0010] (5) Check if the target encoder length value is >35π. If not, expand the mandrel until the feedback value of the pull-cord encoder reaches the target encoder length, and then return to step (3) to repeat the process. If yes, it means that the calibration is complete and the calibration process ends.

[0011] In step (1), the pull rope of the pull rope encoder is installed in the middle section of the spindle. After the end of the pull rope wraps around the circumference of the spindle, it coincides with the starting point, that is, the three o'clock position on the circumference of the spindle. A plastic guide groove is fixed at this point with strong adhesive, and the end of the rope is fixed on it. A guide groove is also installed at the nine o'clock position to fix the position of the pull rope, so that the pull rope can only slide in the groove and prevent it from shifting to the side and affecting the calibration accuracy. In the PLC program, the original spindle expansion diameter calibration data table in the program is backed up and copied to the backup storage area for rollback. By giving a certain amount of hydraulic valve opening in the contraction direction, about 20%, the spindle is contracted to the minimum position. At this time, the spindle will contract to the mechanical minimum position, and the corresponding spindle expansion diameter is 727 mm.

[0012] In step (2), the length value variable of the pull-cord encoder is cleared to zero in the program, and the spindle expansion feedback value is modified to 727 mm.

[0013] In step (3), the spindle expansion diameter is calculated by the length value of the pull-cord encoder. The calculation formula is: spindle expansion diameter = length value of pull-cord encoder / π + 727. The calculated spindle expansion diameter and the length of the spindle hydraulic cylinder are written into the spindle expansion diameter calibration table.

[0014] In step (4), the target encoder length is increased by π. When the mandrel circumference reaches this value, the mandrel diameter is increased by 1 mm.

[0015] In step (5), the main process of calibration is to expand the mandrel according to the increased target encoder length, and then return to step (3) to perform the cycle until it is repeated 35 times. When the target encoder length is >35π, that is, the mandrel expansion diameter reaches 762 mm, the calibration process ends.

[0016] The pull rope encoder is equipped with a rollback structure.

[0017] The beneficial effects of this invention are as follows: by adding a pull-cord encoder to detect the mandrel circumference, the accuracy of mandrel calibration can reach the sub-millimeter level, which is an order of magnitude higher than manual measurement. This improves the precision of mandrel expansion control and enhances the ability of the strip to tighten its inner ring when it enters the coiler. The calibration process is safe and fast, eliminating the need for personnel to operate inside the coiler for extended periods. This significantly reduces the difficulty of mandrel calibration, downtime costs, and scheduling challenges, encouraging on-site personnel to increase the timeliness and frequency of calibration, thereby greatly improving the accuracy retention rate of mandrel expansion diameter. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the system installation of the present invention;

[0019] Figure 2 This is a flowchart of the process of this invention;

[0020] In the diagram: 1. Winder spindle; 2. Cable encoder; 3. Network control template; 4. Analog input template; 5. CPU template; 6. Electromagnetic induction sensor; 7. Spindle hydraulic cylinder induction plate; 8. Spindle hydraulic cylinder extension length. Detailed Implementation

[0021] To make the purpose, technical solutions, and advantages of the invention's embodiments clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only a small part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0022] A method for calibrating a winding machine mandrel includes the following steps:

[0023] (1) Install the pull-cord encoder on the tangent downward direction at the three o'clock position of the spindle, and wrap the pull-cord head around the spindle once and fix it at the three o'clock position of the spindle. After backing up the original calibration data, shrink the spindle to its minimum size.

[0024] (2) Clear the length value of the pull-cord encoder to zero, and the corresponding spindle expansion feedback value is the diameter of the contraction position;

[0025] (3) Write the current spindle expansion diameter feedback value and hydraulic cylinder length into the calibration table;

[0026] (4) Add π to the target encoder length value;

[0027] (5) Check if the target encoder length value is >35π. If not, expand the mandrel until the feedback value of the pull-cord encoder reaches the target encoder length, and then return to step (3) to repeat the process. If yes, it means that the calibration is complete and the calibration process ends.

[0028] In step (1), the pull rope of the pull rope encoder is installed in the middle section of the spindle. After the end of the pull rope wraps around the circumference of the spindle, it coincides with the starting point, that is, the three o'clock position on the circumference of the spindle. A plastic guide groove is fixed at this point with strong adhesive, and the end of the rope is fixed on it. A guide groove is also installed at the nine o'clock position to fix the position of the pull rope, so that the pull rope can only slide in the groove and prevent it from shifting to the side and affecting the calibration accuracy. In the PLC program, the original spindle expansion diameter calibration data table in the program is backed up and copied to the backup storage area for rollback. By giving a certain amount of hydraulic valve opening in the contraction direction, about 20%, the spindle is contracted to the minimum position. At this time, the spindle will contract to the mechanical minimum position, and the corresponding spindle expansion diameter is 727 mm.

[0029] In step (2), the length value variable of the pull-cord encoder is cleared to zero in the program, and the spindle expansion feedback value is modified to 727 mm.

[0030] In step (3), the spindle expansion diameter is calculated by the length value of the pull-cord encoder. The calculation formula is: spindle expansion diameter = length value of pull-cord encoder / π + 727. The calculated spindle expansion diameter and the length of the spindle hydraulic cylinder are written into the spindle expansion diameter calibration table.

[0031] In step (4), the target encoder length is increased by π. When the mandrel circumference reaches this value, the mandrel diameter is increased by 1 mm.

[0032] In step (5), the main process of calibration is to expand the mandrel according to the increased target encoder length, and then return to step (3) to perform the cycle until it is repeated 35 times. When the target encoder length is >35π, that is, the mandrel expansion diameter reaches 762 mm, the calibration process ends.

[0033] The pull rope encoder is equipped with a rollback structure.

[0034] In practical applications, utilizing the existing PLC, hydraulic drive equipment, and mandrel hydraulic cylinder position sensor in the system, a new draw-wire encoder is added to detect the mandrel circumference. Using the existing execution system, the mandrel is slowly expanded from the contracted position (727 mm diameter). For every 3.14 mm increase in mandrel circumference, the current mandrel diameter and the mandrel hydraulic cylinder position are recorded in the mandrel expansion diameter curve point table, enabling rapid calibration of the mandrel expansion diameter. This draw-wire encoder is installed perpendicular to the mandrel's tangent to ensure detection accuracy. A rollback function is also designed to restore the original data in case of errors during execution. Based on the characteristics of mandrel expansion, this method designs 35 points from the contracted position (727 mm diameter) to the fully expanded position (762 mm diameter). The accuracy of mandrel calibration reaches sub-millimeter level, an order of magnitude higher than manual measurement, improving the precision of mandrel expansion control and enhancing the ability to tighten the inner ring of the strip as it enters the coiler. The calibration process is safe and fast, requiring no personnel to operate inside the coiler for extended periods. The entire process can be completed within 30 minutes, significantly reducing the difficulty of mandrel calibration, downtime costs, and scheduling challenges. This encourages on-site personnel to enhance the timeliness of calibration and increase its frequency, resulting in a substantial improvement in the accuracy retention rate of mandrel expansion. It also greatly improves the control accuracy of the mandrel when the coiler feeds steel, leading to a significant increase in the coiling success rate.

Claims

1. A method for calibrating a winding machine mandrel, characterized in that... Includes the following steps: (1) Install the pull-cord encoder on the downward direction of the tangent at the three o'clock position of the spindle, and wrap the pull-cord head around the spindle once and fix it at the three o'clock position of the spindle. After backing up the original calibration data, shrink the spindle to its minimum size. (2) Clear the length value of the pull-cord encoder to zero, and the corresponding spindle expansion feedback value is the diameter of the contraction position; (3) Write the current mandrel expansion diameter feedback value and mandrel hydraulic cylinder length into the calibration table; (4) Add π to the target encoder length value. When the mandrel circumference reaches this value, the mandrel diameter increases by 1 mm. (5) Check if the target encoder length value is >35π. If not, expand the mandrel until the length value of the pull-cord encoder reaches the target encoder length, and then return to step (3) to repeat the process. If yes, it means that the calibration is complete and the calibration process ends.

2. The method for calibrating a winding machine mandrel according to claim 1, characterized in that: In step (1), the pull rope of the pull rope encoder is installed in the middle section of the spindle. After the end of the pull rope wraps around the circumference of the spindle, it coincides with the starting point, that is, the three o'clock position on the circumference of the spindle. A guide groove is fixed at this point with strong adhesive, and the end of the rope is fixed on the guide groove. A guide groove is also installed at the nine o'clock position to fix the position of the pull rope, so that the pull rope can only slide in the guide groove and prevent it from shifting to the side and affecting the calibration accuracy. In the PLC program, the original spindle expansion diameter calibration data table in the program is backed up and copied to the backup storage area for rollback. By giving a 20% opening of the hydraulic valve in the contraction direction, the spindle is contracted to the minimum position. At this time, the spindle will contract to the mechanical minimum position, and the corresponding spindle expansion diameter is 727 mm.

3. The method for calibrating a winding machine mandrel according to claim 1, characterized in that: In step (2), the length value of the pull-cord encoder is cleared to zero in the program, and the spindle expansion feedback value is modified to 727 mm.

4. The method for calibrating a winding machine mandrel according to claim 1, characterized in that: In step (3), the spindle expansion diameter is calculated by the length value of the pull-cord encoder. The calculation formula is: spindle expansion diameter = length value of pull-cord encoder / π + 727 mm. The calculated spindle expansion diameter and the length of the spindle hydraulic cylinder are written into the spindle expansion diameter calibration data table.

5. The method for calibrating a winding machine mandrel according to claim 1, characterized in that: In step (5), the main process of calibration is to expand the mandrel according to the increased target encoder length, and then return to step (3) to perform the cycle until it is repeated 35 times. When the target encoder length is >35π, that is, the mandrel expansion diameter reaches 762 mm, the calibration process ends.

6. The method for calibrating a winding machine mandrel according to claim 1, characterized in that: The pull-cord encoder is equipped with a rollback structure.

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