Large-size machine shell processing springback detection method and system and processing method

Abstract

The present application relates to the technical field of detection, and relates to a large-size machine shell processing springback detection method and system and a processing method, which comprises sequentially arranging a plurality of pressure measuring points along the extension direction of the bending area of the machine shell, acquiring a pressure data set of the bending pressure applied to the bending area by a pressure sensor arranged at the pressure measuring point, and analyzing the pressure data set; sequentially arranging a plurality of displacement measuring points along the extension direction of the bending line of the machine shell, and correspondingly arranging a displacement sensor at each displacement measuring point to form a displacement sensor array; acquiring a first displacement data set and a second displacement data set of the machine shell at the moment of release of the bending pressure and after the springback of the machine shell is stabilized by the displacement sensor array, determining the weight of the first displacement data set according to the analysis result of the pressure data set; and measuring the bending springback angle of the large-size machine shell according to the second displacement data set and the first displacement data set weighted by the weight. The method and system reduce the detection error of the bending springback angle.

Description

Technical Field

[0001] This invention relates to the field of testing technology, and in particular to a method, system and processing method for detecting springback during the machining of large-size machine casings. Background Technology

[0002] Air conditioner housings are typically formed using a bending process. Due to the elastic deformation characteristics of the sheet metal itself, springback occurs after bending. This means that the workpiece undergoes a certain degree of reverse deformation after the pressure is released, resulting in a deviation between the actual bending angle and the theoretical design angle. Accurate detection of this bending springback angle is of great significance for improving the forming precision of the housing, ensuring product assembly consistency, and facilitating the smooth progress of subsequent processes.

[0003] However, industrial air conditioner housings face unique challenges during processing due to their large size (length exceeding 1.5m): when the bending length exceeds 1.5 meters, micron-level elastic bending easily occurs in the middle of the housing, resulting in actual pressure at both ends being 15% to 30% higher than the theoretical value, forming a "saddle-shaped" pressure distribution. This poses a challenge to springback angle measurement, as conventional contact or non-contact measurement methods have large errors and poor reliability. Consequently, the actual bending angle at both ends of the housing deviates from expectations after bending, exceeding industry tolerances (e.g., ±0.5°), causing V-shaped gaps during housing assembly and compromising the IP54 protection rating. Summary of the Invention

[0004] Therefore, the purpose of this invention is to overcome the problems of large springback angle detection error and poor reliability caused by span elastic bending in the processing of large-size machine housings in the prior art. It provides a springback detection method and system for large-size machine housings, which combines multiple sets of displacement data at the moment of pressure release and after springback stabilization, and based on the weighted processing related to pressure and springback, to more accurately reflect the actual springback behavior and springback angle of the machine housing, improve the accuracy and reliability of springback angle detection, and significantly reduce springback angle detection error.

[0005] Firstly, to solve the aforementioned technical problems, this invention provides a method for detecting springback during the machining of large-size housings, including:

[0006] Multiple pressure measuring points are sequentially set along the extension direction of the bending area of ​​the housing. Pressure data sets of the bending machine acting on the bending area are obtained through pressure sensors configured at the pressure measuring points, and the pressure data sets are analyzed.

[0007] Multiple displacement measurement points are sequentially set along the bending line of the housing, and a displacement sensor is configured for each displacement measurement point to form a displacement sensor array; the displacement sensor measures the vertical distance from its spot in the bending area to the bending line.

[0008] acquiring a first displacement data set of the bending pressure release moment by the displacement sensor array, and deciding the weight of the first displacement data set according to the analysis result of the pressure data set;

[0009] acquiring a second displacement data set of the shell after rebound stabilization by the displacement sensor array, and measuring the bending rebound angle of the large-size shell according to the second displacement data set and the first displacement data set weighted by the weight.

[0010] In an embodiment of the present application, the weight of the first displacement data set is decided according to the analysis result of the pressure data set, which includes comparing the bending pressure of the pressure measuring point with a pressure threshold value; if the bending pressure of the pressure measuring point is greater than or equal to the pressure threshold value one and less than or equal to the pressure threshold value two, the first displacement data of the corresponding detection area of the pressure measuring point is assigned a weight of 1; the pressure threshold value one is less than the pressure threshold value two; if the bending pressure of the pressure measuring point is less than the pressure threshold value one or greater than the pressure threshold value two, the first displacement data of the corresponding detection area of the pressure measuring point is assigned a weight less than 1.

[0011] In an embodiment of the present application, the weight of the first displacement data set is decided according to the analysis result of the pressure data set, which includes calculating the pressure gradient of adjacent pressure measuring points, the pressure gradient being the ratio of the pressure difference of adjacent pressure measuring points to the spacing; the greater the pressure gradient, the smaller the weight of the first displacement data of the corresponding detection area of the adjacent pressure measuring points; the smaller the pressure gradient, the greater the weight of the first displacement data of the corresponding detection area of the adjacent pressure measuring points.

[0012] In an embodiment of the present application, the weight is determined according to the following manner,

[0013] ;

[0014] wherein, wi represents the weight of the ith detection area; k represents the material sensitivity coefficient; G i Gi represents the pressure gradient of the ith detection area; G0 represents the reference gradient, which is related to the yield strength and thickness of the shell material.

[0015] In an embodiment of the present application, the pressure measuring point is embedded in the V-shaped groove slope of the lower die of the bending machine.

[0016] In an embodiment of the present application, the distance between the center of the pressure measuring point and the bottom of the V-shaped groove is 1.2-1.5 times the thickness of the shell.

[0017] In an embodiment of the present application, the arrangement spacing of the displacement sensor is related to the length of the shell: when the shell length is >1.5 m, the arrangement spacing is ≤100 mm; when ≤1.5 m, the arrangement spacing is ≤200 mm.

[0018] In one embodiment of the present application, the bending springback angle of the large-size machine shell is measured according to the second displacement data set and the first displacement data set weighted by the weight, comprising,

[0019] For each displacement sensor, the first displacement is weighted using a weight to obtain a weighted first displacement D1; and the bending angle one is calculated according to the weighted first displacement D1 : ;

[0020] For each displacement sensor, the bending angle two is calculated according to the second displacement D2 : ;

[0021] For each displacement sensor, the springback angle is calculated according to the bending angle one and the bending angle two : : ;

[0022] The average value of the springback angles of all the displacement sensors is calculated to obtain the bending springback angle of the large-size machine shell.

[0023] Wherein, the first displacement represents the displacement measured by the displacement sensor at the moment of releasing the bending pressure; D2 represents the displacement measured by the displacement sensor after the machine shell springback stabilizes; and L represents the horizontal distance from the displacement sensor to the bending line.

[0024] In the second aspect, based on the same inventive concept, the present application further provides a large-size machine shell processing springback detection system, comprising,

[0025] A plurality of pressure sensors are sequentially arranged on a plurality of pressure measurement points in the extension direction of the bending area of the machine shell, and are used to obtain a pressure data set of the bending machine acting on the bending area;

[0026] A plurality of displacement sensors are sequentially arranged on a plurality of displacement measurement points along the extension direction of the bending line of the machine shell; and are used to obtain a first displacement data set at the moment of releasing the bending pressure, and to obtain a second displacement data set after the machine shell springback stabilizes; the displacement sensor is used to measure the vertical distance from the light spot in the bending area to the bending line;

[0027] A processor is used to analyze the pressure data set; and is used to make decision processing on the weight of the first displacement data set according to the analysis result of the pressure data set; and is used to calculate and obtain the bending springback angle of the large-size machine shell according to the second displacement data set and the first displacement data set weighted by the weight.

[0028] In a third aspect, based on the same inventive concept, the application further provides a large-size machine shell processing method, which detects a bending springback angle of a large-size machine shell based on the large-size machine shell processing springback detection method and compensates the bending angle according to the bending springback angle.

[0029] The above technical solution of the application has the following beneficial effects compared with the prior art:

[0030] The large-size machine shell processing springback detection method, system and processing method combine multiple sets of displacement data at the pressure release moment and after springback stabilization, and perform weighted processing according to the correlation between pressure and springback, more accurately reflect the actual springback behavior and springback angle of the machine shell, improve the springback angle detection precision and reliability, and significantly reduce the springback angle detection error.

[0031] In the forming process of the large-size machine shell, the uneven pressure distribution caused by span elastic bending leads to a large springback angle detection error. Multiple pressure measuring points and pressure sensors are arranged in the extension direction of the bending area to comprehensively obtain and analyze the bending pressure distribution, accurately perceive the actual stress state of each region, and perform weighted displacement of the bending pressure release moment according to the bending pressure distribution. The springback angles of different pressure regions are accurately fused, and the deviation between the final springback angle measurement value and the theoretical value can be reduced to within ±0.3°.

[0032] For the sudden change in pressure caused by local structures such as screw holes and reinforcing ribs on the machine shell, multiple-point synchronous monitoring and joint analysis of pressure and displacement can identify and adjust the displacement data weight of the sudden change region, suppress the measurement interference caused by local abnormal stress, improve the overall robustness and reliability of the springback angle detection, and reduce the fluctuation amplitude of the springback angle calculation result by more than 50%. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to make the content of the application more easily understood, the application will be further described in detail below according to specific embodiments of the application and in conjunction with the drawings.

[0034] Figure 1 The flowchart of the large-size machine shell processing springback detection method in the preferred embodiment of the application;

[0035] Figure 2 The structure diagram of the large-size machine shell after forming;

[0036] Figure 3 The configuration diagram of the displacement sensor in the preferred embodiment of the application;

[0037] Figure 4 The flowchart of determining the springback angle in the preferred embodiment of the application;

[0038] Figure 5The structure block diagram of the rebound detection system for processing a large-size machine shell in the preferred embodiment of the present application.

[0039] Description of the drawings: 10 - bending area; 20 - bending line; 30 - displacement sensor. DETAILED DESCRIPTION

[0040] The present application will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present application and implement it, but the embodiments are not as a limitation on the present application.

[0041] The reason for uneven pressure distribution caused by elastic bending across the area is that:

[0042] The typical uneven pressure distribution is that the pressure at both ends is large and the pressure in the middle is small, which is mainly determined by the contact mechanics characteristics of the plate and the mold and the dynamic process of the bending process. When the plate is pressed into the mold V-shaped groove, the plate at the bending line will be deformed; due to the flexibility of the plate (especially thin or long plates), the deformation is not completely rigid, but will show a "bending deflection" phenomenon: both ends first contact the mold, at the beginning of bending, both ends of the plate (especially the end close to the operating side or the fixed end of the clamp) will first contact the mold V-shaped groove, at this time the pressure of the mold at both ends is directly applied to the contact point, forming a higher local pressure. The middle region lags behind, due to the flexibility of the plate, the middle part may not be completely close to the mold V-shaped groove (there is a small gap) at the initial stage, and needs to be "pressed into" the mold gradually with the progress of the bending process, therefore, the pressure in the middle region is gradually increased with the bending of the plate, but is always lower than that at both ends (both ends have completely adhered to the mold, and the pressure is directly transmitted).

[0043] The fundamental reason for the rebound angle detection error caused by uneven pressure distribution is that the difference between the plastic deformation degree and the elastic recovery ability of each region of the plate during the bending process is not effectively distinguished, resulting in that when the rebound angle is calculated based on single or averaged displacement data, the local deformation state cannot be truly reflected.

[0044] The bending force is concentrated in the high-pressure area, the plastic deformation is more sufficient, the internal lattice structure of the plate occurs more significant dislocation and slip, and a large amount of permanent deformation is formed; although elastic recovery occurs after the release of external force, due to the high proportion of plastic deformation, residual plastic deformation dominates, and the final rebound angle is small.

[0045] In the low-pressure area, the plastic deformation is not sufficient, only a small amount of permanent deformation occurs in the plate, and more deformation exists in the form of elastic deformation, after the release of external force, the elastic deformation quickly recovers, resulting in a significant increase in the rebound angle.

[0046] The traditional method does not distinguish the difference in pressure distribution, which may cause the small rebound angle in the high pressure area to be overestimated, the large rebound angle in the low pressure area to be underestimated, and the final calculation result to deviate from the real rebound angle distribution, which may result in the overall rebound angle to be underestimated or overestimated, and cause detection error.

[0047] The embodiment of the present application aims to solve the problem of large rebound detection error and poor reliability caused by uneven pressure distribution due to elastic bending of the span of the large size cabinet (the cabinet of the industrial air conditioner with a length of more than 1.5 m).

[0048] Embodiment one: in order to solve the problem, referring to Figure 1 the present application provides a rebound detection method for large size cabinet processing, comprising,

[0049] S100, a plurality of pressure measuring points are arranged in sequence along the extension direction of the cabinet bending area, the pressure data set of the bending machine acting on the bending area is obtained through the pressure sensor configured by the pressure measuring point, and the pressure data set is analyzed;

[0050] S200, a plurality of displacement measuring points are arranged in sequence along the extension direction of the cabinet bending line, a displacement sensor is configured corresponding to each displacement measuring point, and a displacement sensor array is formed; the displacement sensor measures the vertical distance from the light spot in the bending area to the bending line;

[0051] S300, the first displacement data set at the moment of releasing the bending pressure is obtained through the displacement sensor array, and the weight of the first displacement data set is decided according to the analysis result of the pressure data set;

[0052] S400, the second displacement data set of the cabinet after rebounding stably is obtained through the displacement sensor array, and the bending rebound angle of the large size cabinet is measured according to the second displacement data set and the first displacement data set weighted by the weight.

[0053] In a specific application scenario, for the convenience of understanding, referring to Figure 2 the bending area 10 and the bending line 20 position of the large size cabinet are shown, a plurality of pressure measuring points are uniformly arranged at intervals along the extension direction of the large size cabinet bending area, the pressure measuring points cover the full length of the bending area, a pressure sensor is installed at each pressure measuring point, and the pressure data applied by the bending machine to the bending area during the bending process is collected in real time. A piezoresistive pressure sensor can be used, the response time is <1ms, and the range covers 1.2 times the maximum pressure of the bending machine; it can be embedded in the V-shaped groove slope of the lower die of the bending machine. The pressure sensor uploads data to the data acquisition module, the data of all pressure measuring points are statistically analyzed, and the pressure distribution curve of each area is obtained, including the peak pressure, the average pressure, the pressure gradient, the pressure fluctuation rate, etc.

[0054] A plurality of displacement measurement points are arranged in turn along the direction of the bending line of the machine shell, and each displacement measurement point is provided with a displacement sensor. Figure 3 As shown in FIG. 1, which shows a schematic diagram of the arrangement position of the displacement sensor, in the height direction, the axis of the displacement sensor is flush with the opening of the V-shaped groove of the lower die of the bending machine; in the horizontal direction, the horizontal distance between the center of the light spot of the displacement sensor and the bending line is L, and the horizontal distance L is pre-calibrated; the displacement sensor can be fixed on a rigid support beside the body of the bending machine, above or beside the machine shell.

[0055] When the bending machine reaches the set bending pressure, the feedback bending pressure release moment is fed back, the control system instructs all displacement sensors to synchronously collect the displacement data at the bending pressure release moment to obtain a first displacement data set; in combination with the pressure distribution obtained in step S100, different weights are given to the first displacement data of each displacement measurement point, so that the data in the area with large pressure or complex structure has less influence on the springback angle calculation, and the interference of the data in the abnormal or non-key area is weakened.

[0056] After the springback process of the machine shell is completed and the deformation is stable, the displacement sensor array synchronously collects a second displacement data set again, and the bending springback angle is calculated through the displacement change before and after springback and the first displacement data weighted by the weights, to obtain the final springback angle detection result of the machine shell.

[0057] It should be noted that: the springback stability refers to the final state in which the internal stress distribution and shape of the machine shell gradually tend to be stable after the bending force is released, which can be determined based on the time window method, that is, if the standard deviation of the displacement data is less than the standard deviation threshold value within a fixed time window after the bending force is released, it is determined that the springback is stable; the standard deviation threshold value can be set to 0.01-0.05 mm.

[0058] The large-size machine shell processing springback detection method disclosed in the present application aims to solve the problem that the springback angle detection error is large due to uneven pressure distribution caused by elastic bending of the large-size machine shell during the forming process. A plurality of pressure measurement points and pressure sensors are arranged in the extension direction of the bending area to comprehensively acquire and analyze the bending pressure distribution, accurately perceive the actual stress state of each area, and realize the accurate perception of the actual stress state of each area according to the bending pressure distribution. The springback angle of different pressure areas is accurately integrated, and the deviation between the final springback angle measurement value and the theoretical value can be reduced to within ±0.3°.

[0059] For the local existence of screw holes, stiffeners and other structures on the shell, through the multi-point synchronous monitoring and joint analysis of pressure and displacement, the displacement data weight of the mutation area can be identified and adjusted, the measurement interference caused by local abnormal stress can be suppressed, the overall robustness and reliability of the rebound angle detection can be improved, and the fluctuation amplitude of the rebound angle calculation result is reduced by more than 50%.

[0060] Specifically, referring to Figure 2 and 4 , the bending rebound angle of the large-size shell is measured according to the second displacement data set and the first displacement data set weighted with the weight, including

[0061] For each displacement sensor, the first displacement d1 is weighted using the weight to obtain the weighted first displacement D1; the bending angle one is calculated according to the weighted first displacement D1 ; for each displacement sensor, the bending angle two is calculated according to the second displacement D2 ; for each displacement sensor, the rebound angle is calculated according to the bending angle one and the bending angle two . ; the average value of the rebound angles of all displacement sensors is calculated to obtain the bending rebound angle of the large-size shell; wherein d1 represents the displacement measured by the displacement sensor at the moment of bending pressure release; D2 represents the displacement measured by the displacement sensor after the rebound of the shell stabilizes; L represents the horizontal distance from the displacement sensor to the bending line.

[0062] On the basis of the above embodiment, the weight of the first displacement data set is decided according to the analysis result of the pressure data set, including comparing the bending pressure of the pressure measuring point with the pressure threshold value; if the bending pressure of the pressure measuring point is greater than or equal to the pressure threshold value one and less than or equal to the pressure threshold value two, the first displacement data of the detection area corresponding to the pressure measuring point is assigned a weight of 1; the pressure threshold value one is less than the pressure threshold value two; if the bending pressure of the pressure measuring point is less than the pressure threshold value one or greater than the pressure threshold value two, the first displacement data of the detection area corresponding to the pressure measuring point is assigned a weight less than 1.

[0063] In a specific application scenario, the pressure threshold value one P1 and the pressure threshold value two P2 are preset, satisfying P1

[0064] For each pressure measuring point, compare the actual measured bending pressure P, if P1≤P≤P2, it is considered that the region is moderately stressed, the data is reliable, and the first displacement data corresponding to the detection area is assigned a weight of 1; if P<P1, or P>P2, it is considered that the region is insufficiently stressed or excessively stressed, the data is abnormal or representative, and the first displacement data corresponding to the detection area is assigned a weight less than 1.

[0065] By setting the pressure threshold, the moderately stressed detection points are effectively screened out, the data with a weight of 1 dominates the entire rebound detection, and the authenticity and representativeness of the data are guaranteed. For regions with excessive or insufficient stress, the weight of the corresponding displacement data is reduced, and the influence of the displacement data on the overall measurement result is reduced, thereby improving the robustness of the detection result.

[0066] There are usually screw holes or ribbed regions on the shell of an industrial air conditioner. The pressure distribution of the regions with screw holes or ribs is compared with the regions without these components, and the phenomenon of increased pressure gradient occurs, which is specifically manifested as local pressure concentration and increased pressure distribution non-uniformity. The presence of screw holes can significantly change the local mechanical properties of the shell, forming a stress concentration effect, which can be understood as follows: the edge of the screw hole is a typical discontinuous region. When the shell is bent under pressure, stress will accumulate at the hole edge, and the maximum stress at the hole edge can be 2-3 times the average stress. At the same time, when bending, the pressure applied by the mold to the periphery of the screw hole cannot be uniformly transmitted due to the presence of the hole, resulting in a significantly higher pressure at the hole edge than in the region away from the hole. The contrast between this local high-pressure area and the surrounding low-pressure area significantly increases the pressure gradient. Pressure concentration can cause excessive plastic deformation at the edge of the screw hole, and even cause cracking risk, and intensify the non-uniformity of rebound.

[0067] The rigidity of the rib is much higher than that of the surrounding flat plate region, and the pressure applied by the mold during bending will be concentrated on the rib with higher rigidity. Since the rib is not easy to deform, the pressure is difficult to diffuse to the adjacent flexible region, resulting in a significantly higher pressure in the rib region and a lower pressure away from the rib, and the pressure distribution presents a clear "high rib and low plate" feature, i.e. the pressure peak is concentrated along the rib, and the pressure decreases sharply perpendicular to the rib, forming a steep pressure gradient. The plastic deformation of the rib region is more concentrated, and the rebound angle is smaller; while the plastic deformation of the adjacent flexible region is insufficient, and the rebound angle is larger, resulting in uneven overall rebound.

[0068] The presence of screw holes and ribs can significantly intensify the non-uniformity of pressure distribution, forming a steep pressure gradient. This gradient can cause excessive concentration of local plastic deformation, and then affect the rebound behavior (smaller local rebound), which affects the rebound angle detection error from another angle.

[0069] In areas with large pressure gradients, displacement sensor measurements cannot accurately reflect the actual rebound situation because displacement sensors can only capture macroscopic surface displacement and cannot distinguish the local differences between plastic deformation and elastic recovery. If the elastic recovery in a high-stress area is minimal due to excessive plastic deformation, the displacement sensor may misjudge the displacement change due to increased local rigidity (high deformation resistance), causing the measured value to deviate from the actual rebound angle.

[0070] To address this issue, in another embodiment of the present invention, the weight of the first displacement dataset is determined based on the analysis results of the pressure dataset, including calculating the pressure gradient between adjacent pressure measurement points, wherein the pressure gradient is the ratio of the pressure difference to the distance between adjacent pressure measurement points; the larger the pressure gradient, the smaller the weight of the first displacement data in the detection area corresponding to the adjacent pressure measurement point; the smaller the pressure gradient, the larger the weight of the first displacement data in the detection area corresponding to the adjacent pressure measurement point.

[0071] In specific applications, the pressure gradient is the ratio of the pressure difference between adjacent pressure measurement points to the distance between those points, characterizing the rate of pressure change in space. A high pressure gradient indicates stress concentration in a local area, with the casing undergoing non-uniform plastic deformation due to abrupt changes in rigidity, resulting in significant spatial differences in elastic recovery. By reducing the weight, the interference of abnormal displacement data in this area on the overall rebound angle calculation is suppressed. A low pressure gradient indicates uniform pressure distribution, continuous plastic deformation of the casing, and small spatial differences in elastic recovery. By increasing the weight, stable displacement data is ensured to fully participate in the calculation.

[0072] Specifically, the weights are determined according to the following method:

[0073] ;

[0074] in, represents the weight of the i-th detection region; k represents the material sensitivity coefficient, with stainless steel taking 0.6~0.9 and aluminum alloy taking 0.3~0.5; G i G represents the pressure gradient of the i-th detection zone; G0 represents the reference gradient, which is related to the yield strength and thickness of the casing material, and has a value of 0.5~2MPa / mm.

[0075] It represents the ratio of the actual pressure gradient to the material's theoretical bending gradient, directly reflecting the degree of local deformation anomaly.

[0076] It should be noted that the bending zone is parallel to the extension direction of the bending line, the displacement sensor and the pressure sensor are staggered, the displacement sensor is placed between adjacent pressure measurement points, and the pressure sensor is placed between adjacent displacement measurement points; the area between two adjacent pressure measurement points is the detection zone, and the pressure gradient between two adjacent detection points affects the first displacement data weight of the displacement sensor located in its detection zone.

[0077] Specifically, the pressure measuring point is embedded in the V-shaped groove slope of the lower die of the bending machine. During the bending process, the contact area between the shell and the V-shaped groove slope of the lower die bears the maximum pressure (more than 70% of the overall pressure). Embedding the pressure measuring point at this position can directly monitor the real pressure of the effective deformation area and avoid interference from other areas.

[0078] On the basis of the above embodiment, the distance between the center of the pressure measuring point and the bottom of the V-shaped groove is 1.2-1.5 times the thickness of the shell. This area is the starting point of plastic deformation (finite element analysis shows that the strain gradient is maximum), and the pressure measuring point is arranged here to detect material yield as early as possible; if the distance is too close (<1.2 times), it is easy to be disturbed by stress concentration at the groove bottom, and if the distance is too far (>1.5 times), it loses the monitoring ability of the core deformation area.

[0079] On the basis of the above embodiment, the arrangement spacing of the displacement sensor is related to the length of the shell: when the shell length is >1.5 m, the arrangement spacing is ≤100 mm; when ≤1.5 m, the arrangement spacing is ≤200 mm. The larger the shell length, the more complex the deformation during the bending process due to its own weight and rigidity, etc., and more intensive displacement sensor arrangement is needed for accurate measurement; for relatively short shells, the deformation is relatively simple, and appropriately increasing the sensor spacing can reduce the number of sensors used, reduce costs and workload, while ensuring a certain measurement accuracy.

[0080] Embodiment two: the embodiment of the present application discloses a large-size shell processing springback detection system, referring to Figure 5 As shown, the detection system comprises,

[0081] A plurality of pressure sensors are arranged in sequence on a plurality of pressure measuring points in the extension direction of the bending area of the shell, for obtaining a pressure data set of the bending machine acting on the bending area;

[0082] A plurality of displacement sensors are arranged in sequence on a plurality of displacement measuring points along the extension direction of the bending line of the shell; for obtaining a first displacement data set at the moment of releasing the bending pressure; and obtaining a second displacement data set after the shell springback stabilizes; the displacement sensor is used to measure the vertical distance from the light spot in the bending area to the bending line;

[0083] A processor is used to analyze the pressure data set; and to make a decision on the weight of the first displacement data set according to the analysis result of the pressure data set; and to calculate the bending springback angle of the large-size shell according to the second displacement data set and the first displacement data set weighted by the weight.

[0084] Embodiment three: the embodiment of the application discloses a large-size machine shell processing method, the bending rebound angle of the large-size machine shell is detected based on the large-size machine shell processing rebound detection method, and the bending angle is compensated according to the bending rebound angle.

[0085] Embodiments two and three above are the same as embodiment one in terms of the same inventive concept and the same technical effect, and will not be repeated here.

[0086] In summary, the large-size machine shell processing rebound detection method, system and processing method of the application combine multiple sets of displacement data at the pressure release moment and after rebound stabilization, and perform weighted processing according to the correlation between pressure and rebound, more accurately reflect the actual rebound behavior and rebound angle of the machine shell, improve the rebound angle detection accuracy and reliability, and significantly reduce the rebound angle detection error.

[0087] Among them, for the problem of large rebound angle detection error caused by uneven pressure distribution due to span elastic bending in the large-size machine shell forming process, multiple pressure measuring points and pressure sensors are arranged in the extension direction of the bending area, the bending pressure distribution is comprehensively obtained and analyzed, the actual stress state of each region is accurately perceived, the displacement at the bending pressure release moment is weighted according to the bending pressure distribution, the rebound angles of different pressure areas are accurately fused, and the deviation between the final rebound angle measurement value and the theoretical value can be reduced to within ±0.3°.

[0088] For the pressure mutation caused by local screw holes, reinforcing ribs and other structures on the machine shell, through multi-point synchronous monitoring and joint analysis of pressure and displacement, the displacement data weight of the mutation area can be identified and adjusted, the measurement interference caused by local abnormal stress can be suppressed, the overall robustness and reliability of the rebound angle detection can be improved, and the fluctuation amplitude of the rebound angle calculation result is reduced by more than 50%.

[0089] Obviously, the above embodiments are only examples for clear illustration, and are not limitations on the embodiments. For ordinary skilled persons in the art, other different forms of changes or variations can be made on the basis of the above description. Here, all the embodiments need not and cannot be exhausted. The obvious changes or variations derived therefrom are still within the protection scope of the application.

Claims

1. A method for detecting springback in large-scale cabinet machining, characterized by: Comprising, a plurality of pressure measuring points are arranged along the extension direction of the bending area of the machine shell, and a pressure sensor arranged at each pressure measuring point is used to obtain a pressure data set of the bending pressure applied to the bending area by the bending machine, and the pressure data set is analyzed; a plurality of displacement measuring points are arranged along the extension direction of the bending line of the machine shell, and a displacement sensor is arranged at each displacement measuring point to form a displacement sensor array; the displacement sensor is used to measure the vertical distance from the light spot on the bending area to the bending line; a first displacement data set is obtained by the displacement sensor array at the moment when the bending pressure is released, and the weight of the first displacement data set is determined according to the analysis result of the pressure data set; a second displacement data set is obtained by the displacement sensor array after the rebound of the machine shell is stabilized, and the bending rebound angle of the large-size machine shell is measured according to the second displacement data set and the first displacement data set weighted by the weight. The weight is determined according to the following method, ； wherein, Gk represents the weight of the ith detection zone; k represents the material sensitivity coefficient; G i Gk represents the pressure gradient of the ith detection zone; G0 represents the reference gradient, which is related to the yield strength and thickness of the case material; According to the second displacement data set and the first displacement data set weighted by the weight, the bending resilience angle of the large-size machine shell is measured, including: for each displacement sensor, the first displacement is weighted by the weight to obtain a weighted first displacement D1; according to the weighted first displacement D1, a bending angle one : ; for each displacement sensor, the bending angle two : is calculated according to the second displacement D2; for each displacement sensor, the resilience angle is calculated according to the bending angle one and the bending angle two : ; the average value of the resilience angles of all the displacement sensors is calculated to obtain the bending resilience angle of the large-size machine shell; wherein the first displacement represents the displacement measured by the displacement sensor at the moment of releasing the bending pressure; D2 represents the displacement measured by the displacement sensor after the resilience of the machine shell is stable; and L represents the horizontal distance from the displacement sensor to the bending line.

2. The method of claim 1, wherein: The pressure measuring point is embedded in the V-shaped groove slope of the lower die of the bending machine.

3. The method of claim 2, wherein: The distance between the center of the pressure measuring point and the bottom of the V-shaped groove is 1.2-1.5 times the thickness of the machine shell.

4. The method of claim 1, wherein: The arrangement interval of the displacement sensor is related to the length of the machine shell: when the length of the machine shell is greater than 1.5 m, the arrangement interval is less than or equal to 100 mm; when the length of the machine shell is less than or equal to 1.5 m, the arrangement interval is less than or equal to 200 mm.

5. A large-size cabinet machining springback detection system, which executes the large-size cabinet machining springback detection method according to any one of claims 1 to 4, characterized in that: Comprising, a plurality of pressure sensors are arranged at a plurality of pressure measuring points along the extension direction of the bending area of the machine shell, and are used to obtain a pressure data set of the bending pressure applied to the bending area by the bending machine; a plurality of displacement sensors are arranged at a plurality of displacement measuring points along the extension direction of the bending line of the machine shell; the displacement sensors are used to obtain a first displacement data set at the moment when the bending pressure is released, and to obtain a second displacement data set after the rebound of the machine shell is stabilized; the displacement sensors are used to measure the vertical distance from the light spot on the bending area to the bending line; a processor is used to analyze the pressure data set, and to determine the weight of the first displacement data set according to the analysis result of the pressure data set; and the bending rebound angle of the large-size machine shell is calculated according to the second displacement data set and the first displacement data set weighted by the weight.

6. A method of processing a large size cabinet, characterized by: The bending rebound angle of the large-size machine shell is obtained by the large-size machine shell processing rebound detection method according to any one of claims 1-4, and the bending angle is compensated according to the bending rebound angle.

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