A method for calibrating and process checking of a copper strip hot rolling strip on-line thickness

Abstract

This invention relates to the field of online thickness measurement technology for hot-rolled non-ferrous metal strip, specifically a roller calibration and process verification method for online thickness measurement of hot-rolled copper strip. The method includes the following steps: device installation and initial geometric calibration; online dynamic reference calibration and thermal deformation compensation based on the transport roller; strip width-direction zone measurement; validity determination of thickness calculation for each zone and its correlation with process parameters; engineering-level classification and handling of abnormal measurement values; reconstruction of the full-width thickness distribution and calculation of quality indicators; measurement result feedback and mill process adjustment. This invention utilizes the transport roller as a natural reference body, automatically completing calibration during strip gap periods, solving the problems of traditional calibration requiring machine shutdown and low calibration frequency; combined with physical compensation for the thermal expansion of the mounting frame, it effectively suppresses reference drift caused by thermal deformation.

Description

Technical Field

[0001] This invention relates to the field of online thickness measurement technology for hot-rolled non-ferrous metal strip, specifically a roller calibration and process verification method for online thickness measurement of hot-rolled copper strip. Background Technology

[0002] After copper ingots undergo multiple passes in a hot rolling mill, the thickness of the strip needs to be measured before it is coiled. Current methods typically involve manual measurement by an operator using a micrometer after the three-roll coiler has stopped operating, or online measurement using a dual-laser rangefinder system. However, existing methods have several significant problems: First, benchmark calibration relies on machine shutdown. Traditional calibration requires placing a standard calibration plate on the roller conveyor and performing the calibration while the machine is stopped, which fails to reflect the true benchmark during hot operation and results in low calibration frequency and poor efficiency. Second, thermal deformation of the mounting frame causes benchmark drift. The high ambient temperature at the hot rolling site and the thermal expansion of the mounting frame after prolonged heating alter the distance between the upper and lower laser rangefinders, rendering the statically calibrated benchmark values ​​inapplicable and causing systematic measurement deviations. Therefore, this paper proposes a roller conveyor calibration and process verification method for online thickness measurement of hot-rolled copper strip. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the existing defects and provide a roller calibration and process verification method for online thickness measurement of hot-rolled copper strip. The method uses the transport roller as a natural reference body and automatically completes the calibration during the strip gap period, which solves the problems of traditional calibration requiring machine stoppage and low calibration frequency. Combined with the physical compensation of thermal expansion of the mounting frame, the reference drift caused by thermal deformation is effectively suppressed, which can effectively solve the problems in the background technology.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for online thickness measurement of hot-rolled copper strip using roller calibration and process verification, comprising the following steps:

[0005] S1 device installation and initial geometric calibration: Arrange the up-and-down through-beam laser rangefinder on the conveyor rollers between the shearer and the three-roller coiler. Use standard gauge blocks to perform initial calibration at room temperature, calculate the initial reference distance and record the ambient temperature.

[0006] S2 Online dynamic reference calibration and thermal deformation compensation based on conveyor rollers: During the strip conveying gap period, the upper surface of the conveyor rollers is used as a dynamic reference for online calibration. Based on the difference between the real-time temperature and the initial temperature of the mounting frame, the reference spacing is compensated based on the material thermal expansion coefficient to obtain the real-time dynamic reference spacing.

[0007] S3 Strip width direction zone measurement: The width of the strip is divided into multiple measurement zones, and the thickness of each zone is measured synchronously by setting multiple sets of laser rangefinders;

[0008] S4 Validity determination of the correlation between the thickness calculation of each zone and the process parameters: Calculate the preliminary thickness of each zone based on the dynamic reference spacing, and at the same time obtain the rolling force, roll gap set value, and rolling mill stiffness process parameters from the rolling mill control system. Calculate the theoretical thickness based on the rolling mill bounce equation, compare the measured thickness with the theoretical thickness, and determine whether the measured values ​​of each zone are valid.

[0009] S5 abnormal measurement value engineering hierarchical handling: For measurement values ​​determined to be abnormal, three levels of handling are performed in sequence: remeasurement, linear interpolation replacement of adjacent effective zones, and replacement with theoretical value and alarm.

[0010] The S6 full-width thickness distribution reconstruction and quality index calculation arranges the effective values ​​of each zone according to the width position, obtains the full-width thickness distribution curve through piecewise linear interpolation, and calculates the average thickness, convexity, and wedge quality index.

[0011] S7 Measurement Result Feedback and Mill Process Adjustment: The average thickness is compared with the target thickness to generate a deviation signal, which is fed back to the mill AGC system or prompts for adjustment of roll gap and bending roll force.

[0012] Optionally, the thermal deformation compensation formula in step S2 is:

[0013]

[0014] Where α is the coefficient of thermal expansion of the mounting bracket material, and L base0 T is the initial reference spacing. s0 The initial calibration time is the mounting bracket temperature, T. s ′ represents the mounting bracket temperature during online calibration, L u ′、L d ′ represents the readings of the upper and lower laser rangefinders on the roller conveyor surface during online calibration.

[0015] Optionally, the mill bounce equation in step S4 is:

[0016]

[0017] Where S is the roll gap setting value, F is the rolling force, F0 is the preload force, and M is the mill stiffness.

[0018] Optionally, the three-level handling method in step S5 is as follows: the first level is to re-measure and re-determine the abnormal partition; the second level is to use the linear interpolation of the measurement values ​​of the adjacent valid partitions as the replacement value for the partitions that are still abnormal after re-measurement; the third level is to use the theoretical thickness value as the replacement value and issue an alarm for abnormal measurement system when the adjacent partitions are also abnormal.

[0019] Optionally, the quality indicators in step S6 include: average thickness, maximum thickness, minimum thickness, thickness range, convexity, and wedge shape, wherein convexity is the difference between the average thickness of the central section and the average thickness of the two side sections, and wedge shape is the absolute difference between the thickness of the two side sections.

[0020] Optionally, the mounting frame includes a U-shaped fixed frame and an upper and lower crossbeam fixedly disposed between two vertical rods of the fixed frame. The upper and lower crossbeams are respectively disposed on the upper and lower sides of the conveyor roller conveyor, and at least three sets of laser rangefinders with corresponding positions are disposed on the lower surface of the upper crossbeam and the upper surface of the lower crossbeam.

[0021] Optionally, temperature sensors for detecting the temperature of the mounting bracket are provided on the lower surface of the upper crossbeam and the upper surface of the lower crossbeam.

[0022] Optionally, an encoder is mounted on the roller shaft end of the conveyor roller via a coupling. When the encoder detects that the head of the strip has arrived or the tail has left the thickness measurement area, it sends a signal to the computing terminal, triggering the online calibration program S2. At the same time, it can also determine whether the strip is in a stable operating state based on the strip running speed fed back by the encoder, and execute the validity determination of S4 only when the speed is stable (e.g., speed fluctuation < ±5%).

[0023] Optionally, a chassis is installed on the outside of the vertical rod of the mounting bracket, and a computing terminal is installed inside the chassis. The computing terminal can be an industrial control computer, such as Advantech IPC-610L, Advantech IPC-810E, or Siemens SIMATIC IPC547J, or a commonly used PLC controller. The computing terminal is electrically connected to the laser rangefinder, temperature sensor, and encoder via shielded signal cables, and is also connected to the rolling mill control system in the external control room via shielded signal cables or wireless transmission.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. By using the conveyor roller as a natural reference body, calibration is automatically completed during the strip gap period, which solves the problems of traditional calibration requiring machine stoppage and low calibration frequency; combined with the physical compensation of thermal expansion of the mounting frame, the reference drift caused by thermal deformation is effectively suppressed.

[0026] 2. By using the theoretical thickness calculated by the mill bounce equation as the reference standard for the measured value, abnormal measured values ​​can be quickly identified without complex algorithms, thus improving the reliability of the measurement results.

[0027] 3. A graded handling process of "retesting → interpolation substitution → theoretical value substitution + alarm" was established, which not only ensures data continuity, but also provides timely warnings when sensor failures occur, avoiding the misleading of production decisions by a single outlier.

[0028] 4. By using a zoned measurement method, the online acquisition of the full width thickness distribution of the strip is achieved without adding a complex scanning mechanism. It can simultaneously output multi-dimensional quality indicators such as thickness, convexity, and wedge shape, providing data support for strip shape control. It is low in cost and easy to use. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the present invention;

[0030] Figure 2 This is a side view of the structure of the present invention.

[0031] In the diagram: 1. Transport roller conveyor, 2. Belt material, 3. Mounting frame, 4. Upper crossbeam, 5. Lower crossbeam, 6. Laser rangefinder, 7. Encoder, 8. Chassis, 9. Temperature sensor. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Please see Figure 1-2 This invention provides a technical solution: a method for online thickness measurement of hot-rolled copper strip using roller calibration and process verification, comprising the following steps:

[0034] S1 device installation and initial geometric calibration:

[0035] On the conveyor roller 1 between the scissors and the three-roller winding machine, an up-and-down through-beam laser rangefinder 6 is arranged, with the center lines of the two sensors coinciding and perpendicular to the plane containing the top surface of the conveyor roller 6; after installation, initial calibration is performed under normal temperature conditions:

[0036] Given a standard thickness of H std The standard gauge block or calibration plate is placed horizontally on the upper surface of roller 1 of the conveyor roller, and the reading L of the laser rangefinder is recorded. u0 And the laser rangefinder reading L d0 Calculate the initial reference spacing:

[0037]

[0038] Simultaneously, the ambient temperature T0 is recorded by an external temperature monitoring device, and the surface temperature T of the mounting bracket 3 is detected by temperature sensor 9. s0 , will L base0 T0 and T s0 Store in the benchmark parameter library.

[0039] S2 is based on online dynamic reference calibration and thermal deformation compensation of transport rollers:

[0040] During the gap between when the head of strip 2 has not yet reached the thickness measurement area or when the tail of strip 2 has left the thickness measurement area, the online calibration program is automatically triggered:

[0041] S2.1: Control the upper and lower laser rangefinders to measure the upper surface of the conveyor rollers respectively, and obtain the upper reference reading L. u ′ and lower reference reading L d ′;

[0042] S2.2: Read the current mounting bracket surface temperature T s ′;

[0043] S2.3: Based on the coefficient of thermal expansion α of the mounting bracket 3 material, thermal deformation compensation is performed on the reference spacing to calculate the real-time dynamic reference spacing:

[0044]

[0045] S2.4: L base (t) serves as the dynamic reference value for this strip thickness measurement; a reference update cycle is set, and step S2 is repeated after each roll change or after each set number of passes to achieve reference tracking without stopping the machine.

[0046] S3 Strip width direction zone measurement:

[0047] The strip width W is divided into n measurement zones (n≥3, including the center zone, the drive side zone, and the operating side zone) along the transverse direction. Zone measurement is achieved in the following way:

[0048] If a single laser rangefinder is used, during the period of low-speed stable operation or short pause of the strip, the thickness measuring unit is moved to the center line position of each zone in turn by the lateral moving mechanism to measure point by point.

[0049] If multiple sets of laser rangefinders are used, each set of sensors is fixed and aligned with the center line of different zones, and multi-zone measurements are completed synchronously.

[0050] Record the laser rangefinder readings L on each zone. u,i And the laser rangefinder reading L d,i , where i = 1, 2, ..., n.

[0051] Determination of the validity of the correlation between the thickness calculation of each zone in S4 and the process parameters:

[0052] S4.1: Based on the real-time dynamic reference spacing L base (t), calculate the initial thickness value for each zone:

[0053]

[0054] S4.2: Obtain the rolling process parameters for the current pass from the mill control system, including: rolling force F, roll gap setpoint S, mill stiffness M, and preload force F0; calculate the theoretical value of the strip exit thickness based on the mill bounce equation.

[0055]

[0056] S4.3: Measure the thickness H of each zone. i With theoretical thickness H theory Compare and perform validity determination:

[0057] If |H i -H theory |≤ΔH max (ΔH) max If the maximum permissible deviation is preset according to the product tolerance, then the measurement value of that zone is determined to be valid.

[0058] If |H i -H theory |>ΔH max If the measurement value of that partition is found to be abnormal, it will be marked as pending processing.

[0059] Engineering-based hierarchical handling of S5 abnormal measurement values:

[0060] For the measurement values ​​determined to be abnormal in step S4.3, they shall be handled in a graded manner according to the following priority:

[0061] Level 1 – Retesting: If the zone meets the conditions for retesting (the strip is still in the measurement area and the operation is stable), then the thickness of the zone is remeasured, and the validity determination is performed again.

[0062] Level Two – Interpolation Substitution: If the partition is still determined to be abnormal after retesting, or if the partition does not meet the conditions for retesting, then the linear interpolation of the measurement values ​​of adjacent valid partitions in the same measurement is used as the substitution value; Suppose the k-th partition is abnormal, and its adjacent valid partitions are the (k-1)-th and (k+1)-th partitions, then:

[0063]

[0064] Level 3 – Theoretical Value Substitution and Alarm: If the measured values ​​of adjacent zones are also abnormal, the rolling theoretical value H is adopted. theory As a replacement value for this partition, it also sends a measurement system malfunction alarm to the control system, prompting the system to check the laser rangefinder's optical path or clean the sensor window.

[0065] S6 Full Width Thickness Distribution Reconstruction and Quality Index Calculation:

[0066] The effective measured values ​​and alternative values ​​of each zone are arranged according to the width position, and the transverse thickness distribution curve H(x) of the strip is obtained by piecewise linear interpolation;

[0067] Calculate the following quality indicators:

[0068] Average thickness:

[0069] Maximum thickness:

[0070] Minimum thickness:

[0071] Thickness variation:

[0072] Convexity:

[0073] wedge shape:

[0074] Where H center H represents the thickness of the central partition. left and H right The thicknesses of the two side sections are respectively.

[0075] S7 Measurement Results Feedback and Mill Process Adjustment

[0076] Average thickness H avg With target thickness H target Comparison, generating thickness deviation ΔH dev =H avg -H target ;

[0077] If |ΔH dev | If the rolling tolerance is exceeded, the deviation signal will be fed back to the mill AGC system or the operator will be prompted to adjust the roll gap setting.

[0078] Compare the crown C and wedge shape W with the process standard. If they are out of tolerance, it will prompt you to adjust the original crown of the roll or the bending force.

[0079] The laser rangefinder 6, encoder 7, temperature sensor 9, and computing terminal used in this application are all commonly used electronic components in the prior art. Their specific structures, working principles, control methods, and circuit connections are all well-known technologies and will not be described in detail here.

[0080] The specific connection methods mentioned in this application, such as fixed connections or settings, include but are not limited to conventional connection methods such as integral molding, welding, bolt connection, riveting, and adhesive bonding.

[0081] All parts not disclosed in this invention are prior art, and their specific structures, materials, and working principles will not be described in detail. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for online thickness measurement of hot-rolled copper strip using roller table calibration and process verification, characterized in that, Includes the following steps: S1 device installation and initial geometric calibration: A laser rangefinder (6) with up-and-down beams is arranged on the conveyor roller (1) between the shearing machine and the three-roller winding machine. The initial calibration is performed at room temperature using standard gauge blocks. The initial reference distance is calculated and the ambient temperature is recorded. S2 Online dynamic reference calibration and thermal deformation compensation based on transport rollers: During the strip transport gap period, the upper surface of the rollers of the transport roller (1) is used as a dynamic reference for online calibration. Based on the difference between the real-time temperature and the initial temperature of the mounting frame (3), the reference spacing is compensated based on the thermal expansion coefficient of the material to obtain the real-time dynamic reference spacing. S3 Strip width direction partition measurement: The width of the strip (2) is divided into multiple measurement partitions, and the thickness of each partition is measured synchronously by setting multiple sets of laser rangefinders (6); S4 Validity determination of the correlation between the thickness calculation of each zone and the process parameters: Calculate the preliminary thickness of each zone based on the dynamic reference spacing, and at the same time obtain the rolling force, roll gap set value, and rolling mill stiffness process parameters from the rolling mill control system. Calculate the theoretical thickness based on the rolling mill bounce equation, compare the measured thickness with the theoretical thickness, and determine whether the measured values ​​of each zone are valid. S5 abnormal measurement value engineering hierarchical handling: For measurement values ​​determined to be abnormal, three levels of handling are performed in sequence: remeasurement, linear interpolation replacement of adjacent effective zones, and replacement with theoretical value and alarm. The S6 full-width thickness distribution reconstruction and quality index calculation arranges the effective values ​​of each zone according to the width position, obtains the full-width thickness distribution curve through piecewise linear interpolation, and calculates the average thickness, convexity, and wedge quality index. S7 Measurement Result Feedback and Mill Process Adjustment: The average thickness is compared with the target thickness to generate a deviation signal, which is fed back to the mill AGC system or prompts for adjustment of roll gap and bending roll force.

2. The method for online thickness measurement of hot-rolled copper strip using roller calibration and process verification according to claim 1, characterized in that: The thermal deformation compensation formula in step S2 is: Where α is the coefficient of thermal expansion of the mounting bracket material, L base0 T is the initial reference spacing. s0 The initial calibration time is the mounting bracket temperature, T. s ′ represents the mounting bracket temperature during online calibration, L u ′、L d ′ represents the readings of the upper and lower laser rangefinders on the roller conveyor surface during online calibration.

3. The method for online thickness measurement of hot-rolled copper strip according to claim 1, characterized in that: The mill bounce equation in step S4 is: Where S is the roll gap setting value, F is the rolling force, F0 is the preload force, and M is the mill stiffness.

4. The method for online thickness measurement of hot-rolled copper strip according to claim 1, characterized in that: The three-level handling method in step S5 is as follows: the first level is to re-measure and re-determine the abnormal partition; the second level is to use the linear interpolation of the measurement values ​​of the adjacent valid partitions as the replacement value for the partitions that are still abnormal after re-measurement; the third level is to use the theoretical thickness value as the replacement value and issue an alarm for abnormal measurement system when the adjacent partitions are also abnormal.

5. The method for online thickness measurement of hot-rolled copper strip according to claim 1, characterized in that: The quality indicators in step S6 include: average thickness, maximum thickness, minimum thickness, thickness range, convexity, and wedge shape, where convexity is the difference between the average thickness of the central section and the average thickness of the two side sections, and wedge shape is the absolute difference between the thickness of the two side sections.

6. The method for online thickness measurement of hot-rolled copper strip according to claim 1, characterized in that: The mounting frame (3) includes a U-shaped fixed frame and an upper crossbeam (4) and a lower crossbeam (5) fixedly arranged between two vertical rods of the fixed frame. The upper crossbeam (4) and the lower crossbeam (5) are respectively arranged on the upper and lower sides of the conveyor roller (1), and at least three sets of laser rangefinders (6) are arranged on the lower surface of the upper crossbeam (4) and the upper surface of the lower crossbeam (5).

7. The method for online thickness measurement of hot-rolled copper strip roller calibration and process verification according to claim 6, characterized in that: Temperature sensors (9) for detecting the temperature of the mounting bracket (3) are provided on the lower surface of the upper crossbeam (4) and the upper surface of the lower crossbeam (5).

8. The method for online thickness measurement of hot-rolled copper strip according to claim 6, characterized in that: The roller shaft ends of the conveyor roller (1) are equipped with encoders (7) via couplings.

9. The method for online thickness measurement of hot-rolled copper strip according to claim 8, characterized in that: The mounting bracket (3) has a housing (8) on the outside of the vertical rod. The housing (8) contains a computing terminal. The computing terminal is electrically connected to the laser rangefinder (6), temperature sensor (9), and encoder (7) via shielded signal cables. The computing terminal is also connected to the rolling mill control system in the external control room via shielded signal cables or wireless transmission.

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