Roll forming control method for non-constant cross-section variable thickness members

Abstract

The application discloses a rolling forming control scheme of a non-equal-section variable-thickness piece, and comprises the following steps: S1, analyzing a variable-thickness part along a length direction of a variable-thickness plate, and measuring an actual thickness of the plate by using a thickness detection device before the variable-thickness plate passes through a rolling mill; S2, dividing a thin area, a thick area or a transition area of the variable-thickness plate by using the collected actual thickness; and S3, the whole rolling mill has 20-50 rolling mills, and the control of the position of each rolling mill is realized by using a servo electric cylinder. In the application, the adjustment of the position of the rolling mill is changed in real time according to the specific value of the detected thickness due to the existence of the thickness tolerance of the actual incoming plate, the gap between the inner and outer rolling mills is changed by changing the position of the rolling mill on one side, the thickness change of the part is adapted, the required position of the rolling mill is calculated in real time, and therefore the precise rolling forming of the non-equal-section variable-thickness piece can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of roll forming, in particular to a roll forming control method for a non-uniform cross-section and variable thickness workpiece. Background Art

[0002] The rolling process is often used to produce parts with uniform cross-sectional shapes. It is characterized by high efficiency, economy and good forming quality. However, for parts with non-uniform cross-sectional shapes, the production process needs to be improved.

[0003] There are two common types of non-uniform cross-section parts: one is that the wall thickness of the part is constant and the cross-section changes along the length; the other is that the neutral line of the cross-section remains unchanged along the length, but the wall thickness of the part changes.

[0004] In the prior art, parts with variable thickness in the longitudinal direction can be divided into three categories:

[0005] 1. The inner wall of the part becomes thicker and the outer wall is straight;

[0006] 2. The outer wall of the part becomes thicker and the inner wall is straight;

[0007] 3. The thickness of the inner and outer walls of the parts changes.

[0008] However, in existing technology, variable-thickness sheets have a certain tolerance range along their length. Assuming the theoretical length of the thin section is Amm, the actual sheet measurement result may show A±amm, where a is the measurement error. If the roller press is set to move at a fixed tactile interval of once per Amm, the accumulated errors after forming multiple parts will result in substandard quality of subsequent products. Summary of the Invention

[0009] The purpose of the present invention is to provide a roll forming control method for non-uniform cross-section and variable thickness parts, specifically a roll forming process for parts with variable thickness along the length direction, so as to solve the problem raised in the above background technology that due to the presence of a certain tolerance range in the length direction of the variable thickness plate, if the roller press is set to move at a fixed beat, the cumulative error after the forming of multiple parts will lead to unqualified quality of subsequent products.

[0010] To achieve the above-mentioned object, the present invention provides the following technical solution: a method for controlling roll forming of a non-uniform cross-section and variable thickness workpiece, comprising the following steps:

[0011] S1. Analyze the thickness of the variable thickness plate along the length direction, and use a thickness detection device to measure the actual thickness of the plate before the variable thickness plate passes through the roller press;

[0012] S2. Dividing the variable thickness plate into a thin area, a thick area, and a transition area according to the collected actual thickness;

[0013] S3. The entire roller press has 20-50 pairs of rollers, and the position of each roller is controlled by a servo electric cylinder;

[0014] S4, during rolling, based on the real-time plate thickness measured by the thickness detection device and the distance between the rolling center line of each roller segment and the thickness detection point, the required position of each roller segment is calculated in real time, and the position signal is transmitted to the servo electric cylinder control board to control the response of the servo electric cylinder;

[0015] S5. For variable thickness plates with large thickness deviations, increase the number of position sensors and use closed-loop control of the servo electric cylinder to accurately meet the required position, or increase the rigidity of the entire roller press. During the rolling process, the control level corrects the response of the servo electric cylinder based on the plate thickness gradient.

[0016] In step S1, when the actual thickness of the plate is measured using the thickness detection device, the plate thickness detection is performed when the plate is in a slightly stretched state;

[0017] In step S5, the plate thickness change gradient refers to the change speed of the plate thickness along the length direction.

[0018] Preferably, in step S1, the analysis of the situation of the variable thickness plate and the variable thickness part along the length direction includes the following three categories: the inner wall of the part changes in thickness and the outer wall is straight; the outer wall of the part changes in thickness and the inner wall is straight; the inner and outer walls of the part both change in thickness.

[0019] Preferably, in step S3, the position of the roller in each section is adjusted in real time according to the specific value of the detected thickness.

[0020] Preferably, in step S4, the real-time plate thickness measured by the thickness detection device has an actual thickness detection accuracy of 0.01 mm.

[0021] Preferably, when the inner wall of the part changes in thickness and the outer wall is straight, during the forming process, the position of the inner roller is set to change with the thickness change. The change in the position of the inner roller causes the gap between the inner and outer rollers to change to adapt to the thickness change of the part.

[0022] Preferably, the outer wall of the part has variable thickness and the inner wall is straight. During the forming process, the position of the outer roller is set to change with the thickness. The change in the position of the outer roller causes the gap between the inner and outer rollers to change to adapt to the thickness change of the part.

[0023] Preferably, when the thickness of the inner and outer walls of the part changes, the positions of the inner and outer rollers are changed according to the thickness change.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] In the present invention, due to the existence of actual incoming material thickness tolerance, the adjustment of the roller position must change in real time according to the specific value of the detected thickness. By changing the position of the roller on one side, the gap between the inner and outer rollers is changed to adapt to the thickness change of the part, and the position of each section of the roller is individually controlled by the servo electric cylinder of the section. It calculates the required position of the section of roller in real time based on the real-time plate thickness measured by the thickness detection device and the distance between the rolling center line of the section of roller and the thickness detection point. The position signal is transmitted to the servo electric cylinder control panel to control the response of the electric cylinder, thereby realizing accurate roll forming of non-uniform cross-section and variable thickness parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a flow chart of the roll forming control method for non-uniform cross-section and variable thickness parts of the present invention;

[0027] Figure 2 Schematic diagram of thin and thick area analysis of variable thickness plate in the present invention. DETAILED DESCRIPTION

[0028] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the implementation regulations described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0029] Reference Figure 1-2 As shown: A roll forming control method for a non-uniform cross-section and variable thickness workpiece includes the following steps:

[0030] Step 1: Analyze the situation of parts with variable thickness along the length direction of the variable thickness plate. Analyze the situation of parts with variable thickness along the length direction of the variable thickness plate, which includes the following three categories:

[0031] 1. The inner wall of the part becomes thicker and the outer wall is straight;

[0032] 2. The outer wall of the part becomes thicker and the inner wall is straight;

[0033] 3. The thickness of the inner and outer walls of the parts changes.

[0034] Furthermore, before the variable thickness plate passes through the rolling mill, a thickness gauge is used to measure the plate's actual thickness, as it has a certain tolerance range along its length. This thickness measurement should be performed while the plate is slightly stretched. If the plate is relaxed, the plate will shake, and the measurement position will be unstable, making it impossible to provide stable and reliable data for subsequent rolling. If the plate is overstretched, it may crack or alter its microstructure and mechanical properties, compromising product quality.

[0035] Step 2: Divide the variable thickness plate into thin area, thick area, and transition area according to the actual thickness collected; the thickness detection not only reflects the thickness change of the plate, that is, the current forming area is a thin area, a thick area, and a specific position in the transition area.

[0036] Step 3: The entire roller press has 20-50 pairs of rollers. The position of each roller is controlled by a servo electric cylinder. The position of each roller is adjusted in real time according to the specific value of the thickness detected.

[0037] Step 4. During rolling, the required position of each roller is calculated in real time based on the real-time plate thickness measured by the thickness detection device and the distance between the rolling center line of each roller and the thickness detection point; the real-time plate thickness measured by the thickness detection device and the required position of each roller are calculated in real time, and the position signal is transmitted to the servo electric cylinder control board to control the response of the servo electric cylinder. The actual thickness detection accuracy must reach 0.01mm.

[0038] Step 5. For variable thickness plates with large thickness deviation, increase the number of position sensors, close the loop to control the servo electric cylinder to accurately meet the required position, or increase the stiffness of the entire roller press. During the rolling process, the control level corrects the response of the servo electric cylinder based on the plate thickness change gradient, where the plate thickness change gradient refers to the speed of change of the plate thickness along the length direction.

[0039] Specifically, such as Figure 2 As shown in the figure, the thickness variation in the transition zone between thin and thick areas can take many forms, including linear gradient, nonlinear variation, and sudden thickness change. Due to the actual thickness tolerance of the incoming plate, the roller position must be adjusted in real time according to the specific value of the measured thickness.

[0040] This is a flexible control method that adjusts the roller position in real time according to the thickness of the incoming material to achieve roll forming of parts with variable thickness along the length direction.

[0041] The entire roller press has 20 to 50 sections of rollers. The control of the position of each section of rollers needs to ensure sufficient accuracy and response speed, so a servo electric cylinder is used to achieve this.

[0042] The position of each roll section is independently controlled by its corresponding servo electric cylinder. The required position of each roll section is calculated in real time based on the real-time plate thickness measured by the thickness detection device and the distance between the rolling centerline of the roll section and the thickness detection point. The position signal is transmitted to the servo electric cylinder control board, which controls the electric cylinder's response.

[0043] Rolling force is proportional to plate thickness, with the required rolling force in thicker areas significantly greater than that in thinner areas. Therefore, for plates with large thickness variations, the actual response position of the electric cylinder in the thicker areas will deviate from the required position.

[0044] There are two solutions:

[0045] 1. Add a position sensor and close the loop to control the servo electric cylinder to accurately meet the required position;

[0046] 2. Increase the rigidity of the entire equipment, and at the same time, correct the response of the servo electric cylinder according to the change in plate thickness at the control level.

[0047] Because variable-thickness plates exhibit significant mechanical anisotropy in the transition zone, the control system must modify the servo cylinder response during the rolling process based on the plate thickness gradient. The thickness gradient refers to the rate of change in plate thickness along its length. The thickness detection device, signal processing, and individual servo cylinder control of all roller sections in the entire rolling mill all require a certain response time. To ensure coordinated operation of the entire system, the rolling speed should be kept to a minimum. This prevents any delay in response at any stage from causing quality issues in the entire part.

[0048] There are two other cases for parts with varying thickness in the longitudinal direction:

[0049] 1. When the inner wall of the part changes in thickness and the outer wall is straight, during the forming process, the position of the inner roller is set to change with the thickness change. The change in the position of the inner roller causes the gap between the inner and outer rollers to change to adapt to the thickness change of the part.

[0050] 2. The outer wall of the part changes in thickness, and the inner wall is straight. During the forming process, the position of the outer roller is set to change with the thickness change. The change in the position of the outer roller causes the gap between the inner and outer rollers to change to adapt to the thickness change of the part.

[0051] 3. When the thickness of the inner and outer walls of the part changes, the positions of the inner and outer rollers are set to change with the thickness.

[0052] The usage and working principle of this device: During the forming process, due to the existence of actual incoming plate thickness tolerance, the adjustment of the roller position must change in real time according to the specific value of the detected thickness. By changing the position of the roller on one side, the gap between the inner and outer rollers changes to adapt to the thickness change of the part, and the position of each section of the roller is controlled separately by the servo electric cylinder of that section. It calculates the required position of the roller in real time based on the real-time plate thickness measured by the thickness detection device and the distance between the rolling center line of the roller in that section and the thickness detection point. The position signal is transmitted to the servo electric cylinder control panel to control the response of the electric cylinder, thereby realizing accurate roll forming of non-uniform cross-section and variable thickness parts.

[0053] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A roll forming control method for non-uniform cross-section and variable thickness parts, characterized in that: The following steps are involved: S1. Analyze the thickness of the variable thickness plate along the length direction, and use a thickness detection device to measure the actual thickness of the plate before the variable thickness plate passes through the roller press; S2. Dividing the variable thickness plate into a thin area, a thick area, and a transition area according to the collected actual thickness; S3. The entire roller press has 20-50 pairs of rollers, and the position of each pair of rollers is controlled by a servo electric cylinder; S4, during rolling, based on the real-time plate thickness measured by the thickness detection device and the distance between the rolling center line of each pair of rollers and the thickness detection point, the required position of each pair of rollers is calculated in real time, and the position signal is transmitted to the servo electric cylinder control board to control the response of the servo electric cylinder; S5. For variable thickness plates with large thickness deviations, increase the number of position sensors and use closed-loop control of the servo electric cylinder to accurately meet the required position, or increase the rigidity of the entire roller press. During the rolling process, the control level corrects the response of the servo electric cylinder based on the plate thickness gradient. In step S1, when the actual thickness of the plate is measured using the thickness detection device, the plate thickness detection is performed when the plate is in a slightly stretched state; In step S5, the plate thickness change gradient refers to the change speed of the plate thickness along the length direction.

2. The roll forming control method for non-uniform cross-section and variable thickness parts according to claim 1, characterized in that: In step S1, the analysis is performed on the condition that the thickness of the variable thickness plate varies along the length direction. It includes the following three categories: the inner wall of the part changes in thickness and the outer wall is straight; the outer wall of the part changes in thickness and the inner wall is straight; the inner and outer walls of the part both change in thickness.

3. The roll forming control method for a non-uniform cross-section and variable thickness workpiece according to claim 1, characterized in that: In step S3, the position of each pair of rollers is adjusted in real time according to the specific value of the detected thickness.

4. The roll forming control method for a non-uniform cross-section and variable thickness workpiece according to claim 1, characterized in that: In step S4, the thickness detection device measures the real-time plate thickness, and the actual thickness detection accuracy must reach 0.01 mm.

5. The roll forming control method for a non-uniform cross-section and variable thickness workpiece according to claim 2, characterized in that: When the inner wall of the part becomes thicker and the outer wall is straight, during the forming process, the position of the inner roller is set to change with the thickness change. The change in the position of the inner roller causes the gap between the inner and outer rollers to change to adapt to the thickness change of the part.

6. The roll forming control method for a non-uniform cross-section and variable thickness workpiece according to claim 2, characterized in that: The outer wall of the part has variable thickness and the inner wall is straight. During the forming process, the position of the outer roller is set to change with the thickness change. The change in the position of the outer roller causes the gap between the inner and outer rollers to change to adapt to the thickness change of the part.

7. The roll forming control method for a non-uniform cross-section and variable thickness workpiece according to claim 1, characterized in that: When the thickness of the inner and outer walls of the part changes, the positions of the inner and outer rollers are changed according to the thickness change.

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