A method, system and apparatus for wafer grinding compensation

Abstract

The application relates to the technical field of grinding processing, and discloses a wafer piece grinding compensation method, a wafer piece grinding compensation system and a wafer piece grinding compensation device. The method acquires first surface height data of a wafer piece in a non-clamping state and second surface height data of the wafer piece in a clamping state of a grinding clamp, determines surface height variation caused by clamping according to the position matching relationship of the two, and determines a rebound correction amount after release in combination with a preset rebound relationship. Then, a grinding feed compensation amount is generated according to the second surface height data, a preset target machining surface height and the rebound correction amount after release, and a grinding device is controlled to grind the wafer piece. Therefore, the influence of temporary deformation caused by clamping on a grinding compensation reference can be reduced, and the machining surface height consistency in a released state is improved.

Description

Technical Field

[0001] This application relates to the field of grinding technology, specifically to a method, system, and equipment for grinding compensation of thin sheet parts. Background Technology

[0002] Grinding thin sheet parts typically requires fixing the sheet part in a grinding fixture on a surface grinder, CNC grinder, or other grinding equipment. The grinding wheel, grinding head, or worktable then removes the material according to the set grinding feed and machining allowance. For workpieces with small thickness and low rigidity, such as cage-like thin sheets, gaskets, and thin-walled plate-like parts, grinding fixtures often use methods such as vacuum adsorption, pressure plate clamping, locating pin limiting, or support point support to ensure the positional stability of the thin sheet part during the grinding process.

[0003] Existing grinding compensation methods for thin sheet parts typically use the surface height measured under clamping conditions as the basis for compensation. For example, after the sheet part is attracted or pressed, the height data of the surface to be ground is collected, and then the grinding feed compensation amount is determined based on the difference between the height data and the target machining surface, controlling the grinding equipment to perform surface grinding or zone grinding. This method is more suitable for thick-walled workpieces or workpieces with high rigidity because the shape of the workpiece changes little before and after clamping, and the measurement results under clamping conditions can basically represent the actual shape after machining.

[0004] However, when thin sheet parts are vacuum-adsorbed, clamped by pressure plates, or supported by fulcrums in grinding fixtures, any existing local warping may be temporarily flattened, or uneven local stress may cause local lifting or bending. In other words, the grinding equipment sees the "surface shape pressed out by the fixture," not the actual surface shape of the thin sheet part after it is unclamped. For example, a thin sheet part may have a slightly upturned center when left free, but after clamping, the center is vacuum-adsorbed and pressed down. If the grinding control system only calculates the wheel feed based on the height data under clamping conditions, it may mistakenly assume that the center allowance is small and reduce the grinding amount. After grinding is completed and the fixture is unclamped, the center will rebound due to internal stress, ultimately resulting in flatness deviation, thickness difference deviation, or assembly surface height deviation.

[0005] Therefore, in the field of grinding, the existing method of directly determining the grinding feed compensation based on the surface height in the clamping state lacks effective consideration of the surface height changes of the thin sheet before and after clamping, as well as the impact of springback after unclamping. This easily causes the grinding compensation datum to deviate from the actual shape of the thin sheet after release. How to avoid using the temporary deformation caused by clamping as the final machining datum during the grinding compensation process of thin sheets is a technical problem that needs to be solved in the high-precision grinding of thin sheets. Summary of the Invention

[0006] The technical problem this application aims to solve can be described as follows: In the process of surface grinding, partition grinding, or other removal processes of thin sheet parts, existing grinding equipment typically determines the grinding feed, grinding wheel feed, or machining allowance directly based on the surface height of the thin sheet part in the clamped state after it is adsorbed, pressed, or supported by the grinding fixture. However, the surface morphology in the clamped state may include temporary deformations caused by vacuum adsorption, pressure plate clamping, locating pin limiting, or fixture support, which cannot accurately reflect the morphology of the thin sheet part in the released state after it is unclamped. This easily leads to the grinding feed compensation amount using the distorted clamped surface height as the compensation benchmark, causing the thin sheet part to still have flatness deviation, thickness difference deviation, or assembly surface height deviation after grinding and release. Therefore, the technical problem this application needs to solve is: how to generate a grinding feed compensation amount for the released state based on the surface height change of the thin sheet part before and after clamping and the springback effect after release in the grinding processing scenario, and control the grinding equipment to perform grinding accordingly.

[0007] To address the shortcomings of existing technologies, the purpose of this application is to provide a method, system, and device for grinding compensation of thin sheet parts. By acquiring the first surface height data of the thin sheet part in an unclamped state and the second surface height data in a clamped state of the grinding fixture, the surface height change caused by clamping is determined. Based on the surface height change caused by clamping and a preset springback relationship, the springback correction amount after release is determined. Then, the grinding feed compensation amount is generated by combining the second surface height data and the preset target machining surface height, so that the grinding equipment grinds the thin sheet part according to the grinding feed compensation amount corrected for the release state, thereby reducing the impact of temporary clamping deformation on the grinding compensation reference.

[0008] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, this application provides a method for grinding compensation of thin sheet parts, including: Obtain the first surface height data of the sheet component in its unclamped state; After the sheet is clamped in the grinding fixture, the second surface height data of the sheet in the clamping state is obtained; The change in surface height caused by clamping is determined based on the positional matching relationship between the first surface height data and the second surface height data; The springback correction amount after release is determined based on the surface height change caused by clamping and the preset springback relationship; The grinding feed compensation is generated based on the second surface height data, the preset target machining surface height, and the springback correction amount after release. The grinding equipment is controlled according to the grinding feed compensation to grind thin parts.

[0009] Preferably, the method for determining the location matching relationship includes: Obtain the first sampling position corresponding to the first surface height data and the second sampling position corresponding to the second surface height data; The first sampling position and the second sampling position are transformed to the same sheet coordinate system, and the first surface height data and the second surface height data are transformed to the same height reference. The first and second sampling positions, whose distance is not greater than a preset position threshold, are determined as a matching sampling position group; The set of matching sampling position groups is the position matching relationship.

[0010] Preferably, the method for determining the surface height change caused by clamping includes: For each matching sampling location group, read the first surface height value from the first surface height data and the second surface height value from the second surface height data under the same height reference; The signed difference obtained by subtracting the first surface height value from the second surface height value is determined as the surface height change caused by clamping corresponding to the matching sampling position group.

[0011] Preferably, the method for determining the rebound correction amount after release includes: The height change amplitude is determined based on the absolute value of the surface height change caused by clamping, and the height change range to which the height change amplitude belongs is found in the preset springback relationship. Multiply the springback correction coefficient corresponding to the height change range by the surface height change caused by clamping to obtain the springback correction amount after release. The springback correction amount after release represents the height change of the sheet part relative to the clamping state after it is released from clamping.

[0012] Preferably, the method for determining the rebound correction amount after release further includes: The sheet component is divided into multiple compensation areas; Determine the surface height change caused by clamping for each matching sampling position group within each compensation area; The preset rebound relationship includes the correspondence between the compensation area, the height change range, and the rebound correction coefficient; Based on the height change range to which the surface height change caused by clamping in each compensation area belongs, the rebound correction amount after release corresponding to each compensation area is generated.

[0013] Preferably, the method for determining the rebound correction amount after release further includes: The vacuum negative pressure value, the clamping force of the pressure plate, the position of the support point, the limiting status of the locating pin, the thickness of the sheet and the material batch are obtained after the sheet is clamped in the grinding fixture. The springback correction coefficient is determined based on at least one of the following: vacuum negative pressure value, pressure plate clamping force, support point position, positioning pin limit status, sheet thickness, and material batch, as well as the height variation range.

[0014] Preferably, it further includes: After the sheet is ground, it is unclamped and the height data of the third surface of the sheet in the released state is obtained. The expected surface height data for the clamping state after grinding is generated based on the second surface height data and the grinding feed compensation. The third surface height data and the expected surface height data after grinding and clamping are converted to the same sheet metal coordinate system and the same height datum. Based on the same sheet coordinate system and the same height reference, the springback correction amount after release is corrected by the difference between the third surface height data and the expected surface height data in the clamping state after grinding.

[0015] Preferably, it further includes: Based on the third surface height data, the expected surface height data after grinding and the surface height change caused by clamping, the preset springback relationship is updated to obtain the updated springback relationship. The updated springback relationship is used to determine the springback correction amount after the release of subsequent sheet parts.

[0016] Preferably, the method for generating the grinding feed compensation includes: For each matching sampling position group, the sum of the second surface height value in the second surface height data and the springback correction amount after release is subtracted from the preset target machining surface height to obtain the grinding feed compensation calculation value corresponding to the matching sampling position group, and the grinding feed compensation amount is determined based on the grinding feed compensation calculation value.

[0017] Preferably, the method for generating the grinding feed compensation further includes: When the coordinate distance between two matching sampling position groups in the same sheet coordinate system is not greater than the preset adjacent distance threshold, and the difference between the grinding feed compensation amounts corresponding to the two matching sampling position groups is greater than the preset compensation change threshold, the difference between the grinding feed compensation amounts corresponding to the two matching sampling position groups is limited to the preset compensation change threshold.

[0018] Preferably, the method for controlling the grinding equipment to grind thin sheet parts includes: Convert the grinding feed compensation into the grinding head feed, table height adjustment, or zone machining allowance. The grinding equipment is controlled according to the grinding head feed rate, the table height adjustment amount, or the machining allowance for each zone.

[0019] Preferably, the method for obtaining the height data of the first surface includes: When the sheet is supported but not clamped by the grinding fixture, the surface height of the sheet is collected to obtain the first surface height data.

[0020] Preferably, the method for obtaining the height data of the second surface includes: After the sheet is clamped in the grinding fixture, the grinding fixture exerts at least one clamping action on the sheet, including vacuum adsorption, pressure plate clamping, positioning pin limiting, and fixture support, and collects the surface height of the sheet to obtain second surface height data.

[0021] Preferably, it further includes: Based on the difference between the third surface height data and the preset target machining surface height, a release state residual deviation is generated; After re-clamping the sheet material into the grinding fixture, obtain the fourth surface height data of the sheet material in the second clamping state; The secondary clamping position corresponding to the residual deviation of the release state is determined based on the fourth surface height data, and the secondary grinding feed compensation amount is generated based on the residual deviation of the release state mapped to the secondary clamping position. The grinding equipment is controlled according to the secondary grinding feed compensation amount to perform secondary grinding on thin sheet parts.

[0022] Secondly, this application provides a grinding compensation system for thin sheet parts, comprising: The first acquisition module is used to acquire the first surface height data of the sheet in the non-clamping state; The second acquisition module is used to acquire the second surface height data of the sheet in the clamping state after the sheet is clamped in the grinding fixture. The change determination module is used to determine the surface height change caused by clamping based on the position matching relationship between the first surface height data and the second surface height data; The springback determination module is used to determine the springback correction amount after release based on the surface height change caused by clamping and the preset springback relationship; The compensation generation module is used to generate grinding feed compensation based on the second surface height data, the preset target machining surface height, and the springback correction amount after release. The grinding control module is used to control the grinding equipment to grind thin parts according to the grinding feed compensation amount.

[0023] Thirdly, this application provides a thin sheet grinding compensation device, including a data acquisition interface, a processor, a memory, and a grinding control interface. The data acquisition interface is used to acquire surface height data required to execute the thin sheet grinding compensation method as described in any one of the first aspects. The memory stores a computer program. When the processor executes the computer program, it implements the thin sheet grinding compensation method as described in any one of the first aspects. The grinding control interface is used to output control commands generated according to the grinding feed compensation amount to the grinding equipment.

[0024] Compared with the prior art, the beneficial effects achieved by this application are as follows: First, this application does not directly determine the grinding wheel feed or grinding feed compensation amount based solely on the second surface height data of the sheet material after it is clamped in the grinding fixture. Instead, it first obtains the first surface height data of the sheet material in its unclamped state, then obtains the second surface height data of the sheet material in its clamped state, and determines the surface height change caused by clamping based on the positional matching relationship between the first and second surface height data. Therefore, the grinding compensation process for the sheet material can identify temporary surface height changes caused by the grinding fixture during vacuum adsorption, pressure plate clamping, locating pin limiting, or fixture support, avoiding directly using the temporary morphology in the clamped state as the final machining reference in the released state, thereby reducing the risk of grinding compensation reference distortion.

[0025] Second, this application determines the springback correction amount after release based on the surface height change caused by clamping and the preset springback relationship. Then, it generates a grinding feed compensation amount based on the second surface height data, the preset target machining surface height, and the springback correction amount after release. This ensures that the grinding feed compensation amount simultaneously includes the surface height in the clamping state and the springback correction information after unclamping. This process transforms the "measurable surface height in the clamping state" into a "grinding feed compensation basis for the release state," enabling the grinding equipment to consider not only the machining allowance in the current clamping state but also the height change trend of the sheet after unclamping when performing surface grinding, zone grinding, or other removal processes. This improves the consistency between the grinding compensation amount and the target machining surface height in the release state.

[0026] Third, this application converts the first and second sampling positions to the same sheet metal coordinate system and the first and second surface height data to the same height datum before generating a matching sampling position group. This allows for comparison of surface height values ​​before and after clamping under the same position diameter and the same height diameter. This method reduces the impact of sampling position misalignment, inconsistent coordinate datums, or inconsistent height datums on the calculation process of surface height changes caused by clamping, and provides a clear data source for subsequent springback correction and grinding feed compensation.

[0027] Fourth, this application uses the signed difference between the second surface height value and the first surface height value to determine the surface height change caused by clamping, and determines the springback correction coefficient based on the height change range to which the height change amplitude belongs. This allows for the simultaneous preservation of both the magnitude and direction information of the clamping deformation. Therefore, the springback correction amount after release is no longer a single fixed correction value, but can be determined accordingly based on the surface height change caused by clamping, reducing the problems of incorrect compensation direction or mismatched compensation amount caused by relying solely on fixed compensation based on experience.

[0028] Fifth, this application can divide the sheet material into multiple compensation zones and generate the springback correction amount after release for each compensation zone based on the correspondence between the compensation zone, the height change range, and the springback correction coefficient. Since the deformation response of the sheet material's periphery, edge, support point adjacent area, or other local areas may differ during the clamping and release process of the grinding fixture, determining the springback correction amount after release by dividing the area allows the grinding feed compensation amount to better adapt to the local stiffness differences and local clamping force differences of the sheet material, providing a basis for zoned grinding and local machining allowance control.

[0029] In summary, this application focuses on the morphological changes of thin sheet parts during the clamping, grinding, and release processes of grinding fixtures. It constructs a continuous processing procedure encompassing non-clamping state acquisition, clamping state acquisition, position matching, clamping deformation determination, springback correction, grinding feed compensation, and grinding equipment control. This allows the grinding feed compensation amount to be generated based on clearly defined clamping deformation and release springback criteria. Through the combined effect of these technical means, this application can reduce the impact of temporary clamping deformation on the grinding compensation datum of thin sheet parts and improve the consistency between the surface height and the target machined surface height of the thin sheet part in the released state after grinding. Attached Figure Description

[0030] Figure 1 A schematic diagram illustrating an implementation environment for grinding compensation of a thin sheet part, provided for an embodiment of this application; Figure 2 A flowchart of a grinding compensation method for thin sheet parts provided in Embodiment 1 of this application; Figure 3 A flowchart illustrating the process of determining the position matching relationship and the surface height change caused by clamping, as provided in Embodiment 2 of this application; Figure 4 This is a flowchart of the process for determining the rebound correction amount after release, as provided in Embodiment 3 of this application; Figure 5 This is a flowchart of determining the rebound correction amount after release according to the compensation area, provided in Embodiment 4 of this application; Figure 6 This is a flowchart of Example 5 of this application for determining the springback correction coefficient based on clamping parameters and sheet material properties; Figure 7 This is a flowchart of the grinding feed compensation generation and adjacent position restriction process provided in Embodiment 6 of this application; Figure 8 This is a flowchart of controlling the grinding equipment according to the grinding feed compensation amount provided in Embodiment 7 of this application; Figure 9 A flowchart for correcting the rebound correction amount after release based on the third surface height data provided in Embodiment 8 of this application; Figure 10A flowchart illustrating the updated preset springback relationship provided in Embodiment 9 of this application; Figure 11 A flowchart of the secondary grinding compensation process provided in Embodiment 10 of this application; Figure 12 This is a schematic diagram of a thin sheet grinding compensation system provided in Embodiment 11 of this application; Figure 13 This is a schematic diagram of a thin sheet grinding compensation device provided in Embodiment 12 of this application. Detailed Implementation

[0031] The technical solution of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments and specific features in the embodiments are detailed descriptions of the technical solution of this application, rather than limitations thereof.

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0033] It is understood that the terms "first," "second," "third," and "fourth" used in this application are used to distinguish surface height data obtained under different acquisition states; for example, the first surface height data is the surface height data acquired when the sheet is not clamped; the second surface height data is the surface height data acquired when the sheet is clamped in the grinding fixture; the third surface height data is the surface height data acquired when the sheet is unclamped and in a released state after grinding; and the fourth surface height data is the surface height data acquired when the sheet is reclamped in the grinding fixture in a second clamping state. The aforementioned serial numbers are only used to distinguish acquisition states and data sources, and are not used to limit the amount, type, or number of acquisitions of data other than the processing sequence explicitly stated in this application.

[0034] The sheet part can be a metal sheet, a cage sheet, a gasket, or a thin-walled plate-like workpiece; the sheet part has a shape feature where the thickness is less than its length and width, and the sheet part can produce a measurable change in surface height during the process of support, clamping, and unclamping; the grinding fixture can fix the sheet part through at least one clamping action of vacuum adsorption, pressure plate clamping, locating pin limiting, and fixture support; the surface height data can be collected by a laser displacement sensor, a contact probe, a three-dimensional vision measurement device, or an online measurement device; the surface height data includes at least the sampling position and the surface height value corresponding to the sampling position.

[0035] It should be noted that the non-clamping state in the embodiments of this application does not mean that the sheet is completely unsupported, but rather that the sheet is not constrained by the grinding fixture. The sheet can be in a supporting, low-constraint supporting, or inspection table placement state. In the non-clamping state, the supporting, low-constraint supporting, or inspection table is only used to limit the placement position and measurement height reference of the sheet, and does not apply clamping constraints for grinding. The clamping state refers to the state in which the sheet is clamped in the grinding fixture and subjected to at least one clamping action, such as vacuum adsorption, pressure plate clamping, locating pin limiting, and fixture support. The release state refers to the state after the sheet has been ground and the clamping action of the grinding fixture has been released. Among them, low-constraint supporting refers to a support state that only supports the sheet and restricts the overall position of the sheet, without applying vacuum adsorption, pressure plate clamping, or locating pin over-constraint limiting to the sheet.

[0036] This application primarily addresses the problem that existing thin-sheet grinding compensation methods rely solely on second surface height data collected during clamping to generate the grinding feed compensation amount. This results in the grinding feed compensation amount using temporary surface height changes caused by clamping as the basis for the final surface morphology of the thin-sheet after release. When the thin-sheet experiences local flattening, local lifting, or local bending under vacuum adsorption, pressure plate clamping, locating pin limiting, or fixture support, the second surface height data cannot independently represent the surface height distribution of the thin-sheet after release. Directly generating the grinding feed compensation amount based on the second surface height data will cause flatness deviation, thickness difference deviation, or assembly surface height deviation in the released state of the ground thin-sheet.

[0037] This application embodiment acquires the first surface height data of the sheet in an unclamped state, and acquires the second surface height data of the sheet in a clamped state after the sheet is clamped in the grinding fixture; then, based on the positional matching relationship between the first and second surface height data, it determines the surface height change caused by clamping at the same sampling position before and after clamping; subsequently, it determines the springback correction amount after release based on the surface height change caused by clamping and a preset springback relationship; finally, it generates a grinding feed compensation amount based on the second surface height data, the preset target machining surface height, and the springback correction amount after release, and controls the grinding equipment to grind the sheet according to the grinding feed compensation amount.

[0038] Through the above processing, when generating the grinding feed compensation amount, the thin sheet grinding compensation equipment uses the second surface height data in the clamping state and the springback correction amount after release in the release state, so that the grinding feed compensation amount reflects the surface height change of the thin sheet after it is released from clamping. This can reduce the influence of the temporary surface height change caused by clamping on the grinding compensation reference, and reduce the flatness deviation, thickness difference deviation and assembly surface height deviation of the thin sheet in the release state after grinding.

[0039] Figure 1 This is a schematic diagram of an implementation environment for grinding compensation of a thin sheet provided in an embodiment of this application. See also... Figure 1 The implementation environment includes a surface height acquisition device, a grinding fixture, a grinding machine, and a sheet grinding compensation device. The surface height acquisition device is connected to the data acquisition interface of the sheet grinding compensation device to transmit surface height data to the sheet grinding compensation device. The grinding fixture is installed on the worktable or fixture mounting position of the grinding machine to fix the sheet before the grinding machine performs grinding. The sheet grinding compensation device is connected to the grinding machine through a grinding control interface to output control commands generated according to the grinding feed compensation amount to the grinding machine.

[0040] In this embodiment, the surface height acquisition device is disposed on one side of the surface to be ground of the sheet material, and its measurement direction is consistent with the height direction of the sheet material coordinate system; the grinding fixture is disposed on the worktable of the grinding equipment, and there is a pre-calibrated coordinate transformation relationship between the positioning reference of the grinding fixture and the processing coordinate system of the grinding equipment; the data acquisition interface of the sheet material grinding compensation device is connected to the output end of the surface height acquisition device, and the grinding control interface is connected to the CNC system or execution control end of the grinding equipment, so that the surface height data can be input into the processor, and the grinding control command generated by the processor can be output to the grinding equipment.

[0041] The surface height acquisition device is used to acquire first surface height data when the sheet is in an unclamped state, second surface height data when the sheet is in a clamped state, third surface height data when the sheet is in a released state, or fourth surface height data when the sheet is in a secondary clamped state. Each time the surface height acquisition device acquires surface height data, it includes the sampling position and the surface height value corresponding to the sampling position, and transmits the sampling position and surface height value to the data acquisition interface of the sheet grinding compensation device.

[0042] A grinding fixture is used to clamp a sheet material in a clamped state; the clamping action includes at least one of vacuum adsorption, pressure plate clamping, locating pin limiting, and fixture support; before grinding, the grinding fixture confines the sheet material within the machining coordinate range of the grinding equipment, enabling the grinding equipment to grind the sheet material according to the control commands output by the sheet material grinding compensation equipment; after the grinding fixture releases the clamping action, the sheet material enters the released state.

[0043] The sheet metal grinding compensation device is used to receive first surface height data, second surface height data, third surface height data, or fourth surface height data transmitted by the surface height acquisition device; the sheet metal grinding compensation device is also used to determine the surface height change caused by clamping based on the position matching relationship between the first surface height data and the second surface height data; the sheet metal grinding compensation device is also used to determine the springback correction amount after release based on the surface height change caused by clamping and the preset springback relationship, and to generate the grinding feed compensation amount based on the second surface height data, the preset target machining surface height, and the springback correction amount after release.

[0044] The grinding equipment is used to receive control commands output by the thin-piece grinding compensation equipment through the grinding control interface, and to grind the thin-piece according to the control commands. The control commands can carry the grinding head feed amount, the table height adjustment amount, or the zoned machining allowance. The grinding equipment controls the grinding head to move along the feed direction according to the grinding head feed amount, controls the table height change according to the table height adjustment amount, or performs corresponding grinding amounts on different processing areas of the thin-piece according to the zoned machining allowance.

[0045] Optionally, the sheet grinding compensation device can be an industrial computer, a CNC system, an edge controller, a grinding equipment control unit, or an independent compensation controller. When the sheet grinding compensation device is a grinding equipment control unit, the data acquisition interface and the grinding control interface can be located inside the grinding equipment. When the sheet grinding compensation device is an industrial computer, an edge controller, or an independent compensation controller, the data acquisition interface is connected to the surface height acquisition device, and the grinding control interface is connected to the control terminal of the grinding equipment.

[0046] It should be noted that the aforementioned implementation environment is merely an example. The surface height acquisition device can be integrated with the grinding equipment or set up independently. The sheet grinding compensation device can be integrated with the grinding equipment or output control commands to the grinding equipment through the grinding control interface. As long as the surface height data required to execute the sheet grinding compensation method can be obtained and the control commands generated according to the grinding feed compensation amount can be output to the grinding equipment, it can be used as the implementation environment in the embodiments of this application.

[0047] Example 1: Please see Figure 2 As shown, this embodiment provides a method for grinding compensation of thin sheet parts, which can be executed by a thin sheet part grinding compensation device. In other embodiments, the method can also be executed by a grinding equipment control system or a control device with data processing capabilities. When the thin sheet part grinding compensation method is executed by the grinding equipment control system, the grinding equipment control system receives surface height data transmitted by the surface height acquisition device and outputs control commands to the grinding equipment. The thin sheet part grinding compensation method includes the following steps: Step S101: Obtain the height data of the first surface of the sheet in the non-clamped state.

[0048] A sheet metal grinding compensation device acquires the first surface height data of a sheet metal in an unclamped state. In some embodiments, the sheet metal is in a supported but not clamped state; the support, low-constraint support, or inspection table supports the non-machined surface or edge area of ​​the sheet metal; the support, low-constraint support, or inspection table does not apply the vacuum adsorption, pressure plate clamping, locating pin limiting, or fixture support required for grinding to the sheet metal; the acquisition state corresponding to the sheet metal being in the aforementioned state is recorded as the unclamped state.

[0049] The surface height acquisition device acquires the surface height of the sheet material according to a preset sampling path or a preset sampling grid. The preset sampling path or preset sampling grid is pre-generated by the sheet material grinding compensation device based on the grinding surface range of the sheet material, the sampling resolution of the surface height acquisition device, and the processing path of the grinding device. The surface height acquisition device acquires the corresponding surface height value at each sampling position. The sampling position obtained in the non-clamping state is determined as the first sampling position, and the surface height value corresponding to the first sampling position is determined as the first surface height value.

[0050] The first surface height data includes at least a first sampling position and a first surface height value; the first sampling position is used to indicate the position of the surface height acquisition point of the sheet in the acquisition coordinate system when it is not clamped; the first surface height value is used to indicate the height of the first sampling position relative to the height reference; the sheet grinding compensation device stores the first sampling position and the first surface height value together, so that each first sampling position can read a corresponding first surface height value.

[0051] The sheet metal grinding compensation device associates and stores the first surface height data with at least one of the following: sheet metal identification, acquisition time, acquisition coordinate system, and height reference. The sheet metal identification is generated when the sheet metal enters the grinding compensation process or is issued by the upper-level production management equipment. The acquisition time is recorded by the sheet metal grinding compensation device when it receives the first surface height data. The acquisition coordinate system is determined by the installation position of the surface height acquisition device or the reference position of the detection table. The height reference is determined by the surface height acquisition device after completing the reference surface measurement before acquisition.

[0052] In step S101, the sheet grinding compensation device obtains first surface height data to represent the surface morphology of the sheet in the non-clamping state; the first surface height data serves as non-clamping state reference data for subsequent determination of surface height changes caused by clamping.

[0053] Step S102: After the sheet is clamped in the grinding fixture, the second surface height data of the sheet in the clamping state is obtained.

[0054] After the sheet is clamped in the grinding fixture, the sheet grinding compensation device acquires the second surface height data of the sheet in the clamped state. In some embodiments, the grinding fixture performs at least one clamping action on the sheet: vacuum adsorption, pressure plate clamping, locating pin limiting, and fixture support. The vacuum adsorption action is formed by a vacuum adsorption hole or vacuum adsorption cavity. The pressure plate clamping action is formed by the pressure plate applying a clamping force to the sheet. The locating pin limiting action is formed by the locating pin contacting the locating hole or locating edge of the sheet. The fixture support action is formed by the support surface or support point of the grinding fixture supporting the sheet.

[0055] The surface height acquisition device acquires the surface height of the sheet in the clamping state. When acquiring the surface height of the sheet in the clamping state, the sheet is held on the grinding fixture, and the grinding fixture maintains the clamping effect on the sheet. The surface height acquisition device acquires the surface height of the sheet according to a preset sampling path or preset sampling grid corresponding to the first surface height data, or according to a sampling path or sampling grid that can be converted to the same sheet coordinate system. The sheet grinding compensation device determines the sampling position obtained in the clamping state as the second sampling position, and determines the surface height value corresponding to the second sampling position as the second surface height value.

[0056] The second surface height data includes at least a second sampling position and a second surface height value; the second sampling position is used to indicate the position of the surface height acquisition point of the sheet in the clamping state in the acquisition coordinate system or the grinding fixture coordinate system; the second surface height value is used to indicate the height of the second sampling position relative to the height reference; the sheet grinding compensation device stores the second sampling position and the second surface height value together, so that each second sampling position can read a corresponding second surface height value.

[0057] The sheet metal grinding compensation device associates and stores the second surface height data with at least one of the following: clamping parameters, grinding fixture coordinate system, and height acquisition reference. The clamping parameters include at least one of the following: vacuum negative pressure value, pressure plate clamping force, support point position, and positioning pin limit status. The grinding fixture coordinate system is determined by the positioning reference of the grinding fixture, the worktable reference, or the processing coordinates of the grinding equipment. The height acquisition reference is determined by the surface height acquisition device after measuring the reference surface before acquisition in the clamping state.

[0058] In step S102, the sheet grinding compensation device obtains second surface height data to represent the surface morphology of the sheet under the clamping action of the grinding fixture; the second surface height data serves as the clamping state basis data for subsequently generating the grinding feed compensation amount.

[0059] Step S103: Determine the surface height change caused by clamping based on the positional matching relationship between the first surface height data and the second surface height data.

[0060] The sheet metal grinding compensation device determines the surface height change caused by clamping based on the position matching relationship between the first surface height data and the second surface height data. In some embodiments, the first sampling position in the first surface height data and the second sampling position in the second surface height data are read first; then the first sampling position and the second sampling position are converted to the same sheet metal coordinate system; then the first sampling position and the second sampling position that meet the position matching condition are determined as the matching sampling position group.

[0061] After determining the matching sampling position group, the thin sheet grinding compensation equipment reads the first surface height value and the second surface height value corresponding to the matching sampling position group; firstly, the first surface height value and the second surface height value are converted to the same height reference; then, the signed difference between the second surface height value and the first surface height value under the same height reference is calculated; the signed difference is used to retain the height change direction of the thin sheet after it enters the clamping state from the unclamped state.

[0062] Optionally, the surface height change caused by clamping is determined by the thin-piece grinding compensation equipment according to the following formula: ; Where i represents the number of the matching sampling position group, and the number of the matching sampling position group is assigned by the sheet grinding compensation device according to the generation order of the matching sampling position groups; This represents the change in surface height caused by clamping corresponding to the i-th matching sampling position group; This represents the first surface height value corresponding to the i-th matching sampling position group; This represents the second surface height value corresponding to the i-th matching sampling position group; and All are height values ​​converted to the same height reference.

[0063] The change in surface height caused by clamping is used to represent the local height change caused by the clamping action of the grinding fixture. When the change in surface height caused by clamping is positive, it means that the second surface height value of the corresponding position of the i-th matching sampling position group in the clamped state is higher than the first surface height value in the unclamped state. When the change in surface height caused by clamping is negative, it means that the second surface height value of the corresponding position of the i-th matching sampling position group in the clamped state is lower than the first surface height value in the unclamped state.

[0064] In step S103, the sheet grinding compensation device compares the surface morphology of the sheet in the unclamped state with the surface morphology of the sheet in the clamped state at the same position, and obtains the surface height change caused by the clamping action; the surface height change caused by clamping is used as input data for subsequently determining the springback correction amount after release.

[0065] Step S104: Determine the springback correction amount after release based on the surface height change caused by clamping and the preset springback relationship.

[0066] The thin sheet grinding compensation device determines the springback correction amount after release based on the surface height change caused by clamping and the preset springback relationship; in some embodiments, the height change amplitude is determined based on the absolute value of the surface height change caused by clamping; the height change amplitude is used to represent the numerical magnitude of the surface height change caused by clamping; the sign of the surface height change caused by clamping is used to represent the direction of the surface height change caused by clamping.

[0067] The thin-piece grinding compensation equipment searches for the height change range to which the height change amplitude belongs in the preset springback relationship. The preset springback relationship is stored in advance by the thin-piece grinding compensation equipment. The preset springback relationship includes the correspondence between the height change range and the springback correction coefficient. The height change range is formed based on the historical clamping and release data of thin-pieces of the same specification, thin-pieces of the same material batch, or thin-pieces of the same grinding fixture under the same working conditions. The springback correction coefficient is determined based on the correspondence between the surface height change caused by clamping and the surface height change after unclamping in the historical clamping and release data.

[0068] The thin-piece grinding compensation equipment reads the springback correction coefficient corresponding to the height change range and multiplies the springback correction coefficient by the surface height change caused by clamping to obtain the springback correction amount after release. The springback correction amount after release represents the height change of the thin-piece relative to the clamping state after being unclamped. The springback correction coefficient is a signed coefficient, so the direction of the springback correction amount after release is determined by the sign of the springback correction coefficient and the sign of the surface height change caused by clamping. When the surface height change caused by clamping is negative and the springback correction coefficient of the corresponding height change range is negative, the springback correction amount after release is positive, indicating that the height of the corresponding position of the thin-piece relative to the clamping state increases after being unclamped. When the surface height change caused by clamping is positive and the springback correction coefficient of the corresponding height change range is negative, the springback correction amount after release is negative, indicating that the height of the corresponding position of the thin-piece relative to the clamping state decreases after being unclamped.

[0069] Optionally, the thin-piece grinding compensation device determines the springback correction amount after release according to the following formula: ; ; in, This represents the height change magnitude corresponding to the i-th matching sampling position group; This represents the change in surface height caused by clamping corresponding to the i-th matching sampling position group; This represents the rebound correction amount after release corresponding to the i-th matching sampling position group; This represents the rebound correction coefficient corresponding to the i-th matching sampling position group; According to the thin sheet grinding compensation equipment The relevant height variation range can be found in the preset rebound relationship.

[0070] In step S104, the sheet grinding compensation device converts the surface height change caused by clamping into a springback correction amount after release; the springback correction amount after release is used as correction data for the subsequent generation of grinding feed compensation amount facing the release state.

[0071] Step S105: Generate grinding feed compensation amount based on the second surface height data, the preset target machining surface height, and the springback correction amount after release.

[0072] The thin-sheet grinding compensation device generates a grinding feed compensation amount based on the second surface height data, the preset target machining surface height, and the springback correction amount after release. In some embodiments, the second surface height value, the springback correction amount after release, and the preset target machining surface height corresponding to the same matching sampling position group are read, and the sum of the second surface height value and the springback correction amount after release is subtracted from the preset target machining surface height to obtain the grinding feed compensation calculation value. The grinding feed compensation calculation value is the sum of the second surface height value and the springback correction amount after release minus the preset target machining surface height. The difference in surface height is used as the source for calculating the grinding feed compensation amount. The calculated grinding feed compensation value is used to represent the height difference between the corresponding position of the matched sampling position group and the preset target machining surface height after the release correction. When the calculated grinding feed compensation value is greater than 0, the calculated grinding feed compensation value is determined as the grinding feed compensation amount. When the calculated grinding feed compensation value is not greater than 0, the grinding feed compensation amount is determined as 0, and the corresponding matched sampling position group is marked as a position where the removal machining is not performed. The grinding feed compensation amount after non-negative constraint is used to output to the grinding equipment.

[0073] Optionally, when the preset target machining surface height is a uniform height, the thin sheet grinding compensation device generates the grinding feed compensation amount according to the following formula: ; ; in, This represents the calculated grinding feed compensation value corresponding to the i-th matching sampling position group; This represents the grinding feed compensation amount corresponding to the i-th matching sampling position group; This represents the second surface height value corresponding to the i-th matching sampling position group; This represents the rebound correction amount after release corresponding to the i-th matching sampling position group; Indicates the preset target machining surface height; The sheet metal machining drawings, process documents, or grinding equipment machining programs are given in advance; Used to determine the grinding feed compensation amount as 0 when the calculated grinding feed compensation value is not greater than 0; This is the grinding feed compensation amount output to the grinding equipment.

[0074] Optionally, when the preset target machining surface height is configured according to position, the sheet metal grinding compensation device reads the target machining surface height configuration table; the target machining surface height configuration table includes at least the target position coordinates, the target area number, and the target machining surface height value; the target machining surface height configuration table is given by the sheet metal processing drawing, local step height requirements, zone thickness control requirements, or the grinding equipment processing program; according to the position coordinates of the matching sampling position group in the sheet metal coordinate system, the corresponding target machining surface height value is read.

[0075] When the preset target machining surface height is configured according to the position, the thin sheet grinding compensation equipment generates the grinding feed compensation amount according to the following formula: ; ; in, This represents the target processing surface height value corresponding to the i-th matching sampling position group; The position coordinates of the matching sampling position group in the sheet metal coordinate system are read from the target machining surface height configuration table; This represents the calculated grinding feed compensation value corresponding to the i-th matching sampling position group, and serves as the source for calculating the grinding feed compensation amount; This represents the grinding feed compensation amount corresponding to the i-th matching sampling position group, and is a non-negative value output to the grinding equipment; when the sheet has non-planar targets, local steps, or zoned thickness control requirements, the corresponding values ​​for different matching sampling position groups are... Different values ​​can be taken; when When not greater than 0, If the value is 0, the grinding equipment will not perform removal processing at the position corresponding to the i-th matching sampling position group.

[0076] In step S105, the sheet metal grinding compensation device first calculates the grinding feed compensation calculation value and uses it as the source for calculating the grinding feed compensation amount. Then, based on the constraint that the grinding equipment cannot perform negative removal, the grinding feed compensation calculation value is subject to a non-negative restriction to obtain the actual grinding feed compensation amount output to the grinding equipment. The grinding feed compensation amount is not only determined by the second surface height data in the clamping state, but also by using the second surface height data, the springback correction amount after release, and the preset target machining surface height. When the preset target machining surface height is configured according to the position, the corresponding target machining surface height value is read according to the position coordinates of the matching sampling position group, so that the grinding feed compensation amount can correspond to non-planar targets, local steps, or partition thickness control.

[0077] Step S106: Control the grinding equipment to grind the thin sheet according to the grinding feed compensation amount.

[0078] The thin-piece grinding compensation device controls the grinding of the thin-piece according to the grinding feed compensation amount; the grinding feed compensation amount is a value after non-negative constraint; in some embodiments, the grinding feed compensation amount is converted into the grinding head feed amount, the table height adjustment amount, or the zone machining allowance; the grinding head feed amount is used to control the feed displacement of the grinding head relative to the thin-piece; the table height adjustment amount is used to control the height position of the table relative to the grinding head; the zone machining allowance is used to control the grinding amount corresponding to different processing areas of the thin-piece; when the grinding feed compensation amount is 0, the grinding device does not perform removal processing at the corresponding matching sampling position group or the corresponding compensation area.

[0079] The thin-piece grinding compensation equipment generates grinding control commands based on the grinding head feed rate, table height adjustment amount, or zoned machining allowance; the grinding control commands include control quantities corresponding to the matching sampling position group or compensation area; the grinding control commands are output to the grinding equipment through the grinding control interface; after receiving the grinding control commands, the grinding equipment performs grinding on the thin-piece according to the grinding control commands.

[0080] In step S106, the sheet grinding compensation device converts the grinding feed compensation amount facing the release state into a control quantity that the grinding device can execute; the grinding device completes the grinding of the sheet according to the control quantity, so that the surface height of the sheet after grinding in the release state is close to the surface height distribution corresponding to the preset target machining surface height.

[0081] The thin sheet grinding compensation method provided in this embodiment does not directly generate the grinding feed compensation amount based solely on the second surface height data under clamping conditions. The thin sheet grinding compensation method first determines the surface height change caused by clamping through the position matching relationship between the first surface height data and the second surface height data, then determines the springback correction amount after release based on the surface height change caused by clamping and the preset springback relationship, and then generates the grinding feed compensation amount based on the second surface height data, the preset target machining surface height, and the springback correction amount after release.

[0082] Using the sheet grinding compensation method provided in this embodiment, the sheet grinding compensation equipment can identify the surface height change caused by the clamping action of the grinding fixture from the second surface height data, and include the springback correction amount after release when generating the grinding feed compensation amount; thereby reducing the flatness deviation, thickness difference deviation or assembly surface height deviation of the sheet after unclamping.

[0083] Example 2: Please see Figure 3 As shown, based on the above embodiments, this embodiment further illustrates the positional matching relationship between the first surface height data and the second surface height data, and the process of determining the surface height change caused by clamping based on the positional matching relationship. This embodiment may include the following steps: Step S201: Obtain the first sampling position and the second sampling position.

[0084] The thin sheet grinding compensation device acquires a first sampling position corresponding to the first surface height data and a second sampling position corresponding to the second surface height data. The first sampling position corresponds one-to-one with the first surface height value. The first sampling position is used to indicate the position of the surface height acquisition point of the thin sheet in the non-clamping state, and the first surface height value is used to indicate the surface height at the first sampling position. The second sampling position corresponds one-to-one with the second surface height value. The second sampling position is used to indicate the position of the surface height acquisition point of the thin sheet in the clamping state, and the second surface height value is used to indicate the surface height at the second sampling position.

[0085] Step S202: Convert the first sampling position and the second sampling position to the same sheet coordinate system, and convert the first surface height data and the second surface height data to the same height reference.

[0086] The thin-piece grinding compensation equipment establishes a coordinate system for the thin-piece. The coordinate system can be established based on the positioning holes, outer boundaries, reference edges, marking points, or the coordinate system of the grinding fixture. When the thin-piece has positioning holes, the center of the positioning holes is taken as the origin of the coordinate system, and the direction from the center of the positioning holes to the reference edges is taken as the transverse direction of the coordinate system. When the thin-piece does not have positioning holes, the origin and direction of the coordinate system are determined by the outer boundaries or marking points.

[0087] The sheet metal grinding compensation device converts the first sampling position and the second sampling position to the same sheet metal coordinate system. When the first sampling position originates from the sampling coordinate system of the surface height acquisition device, the conversion is completed based on the calibration relationship between the sampling coordinate system of the surface height acquisition device and the sheet metal coordinate system. When the second sampling position originates from the grinding fixture coordinate system, the conversion is completed based on the clamping and positioning relationship between the grinding fixture coordinate system and the sheet metal coordinate system. After the conversion is completed, the first sampling position and the second sampling position are located in the same sheet metal coordinate system.

[0088] The sheet metal grinding compensation equipment converts the first surface height data and the second surface height data to the same height reference. The height reference can be determined based on the reference plane, the support point height, the reference surface of the inspection table, or the reference surface of the grinding fixture. When the first surface height data and the second surface height data use different height references, the height difference between the different height references is read, and the height difference is added to or subtracted from the first surface height value or the second surface height value, so that the first surface height value and the second surface height value participate in subsequent calculations under the same height reference.

[0089] Step S203: The first sampling position and the second sampling position, whose distance is not greater than the preset position threshold, are determined as the matching sampling position group.

[0090] The thin sheet grinding compensation device reads a preset position threshold; the preset position threshold is set according to the adjacent sampling interval of the preset sampling path, the measurement resolution of the surface height acquisition device, and the coordinate transformation error; one feasible setting method is to set the preset position threshold as half of the adjacent sampling interval and the coordinate transformation error; the adjacent sampling interval is given by the preset sampling path or the preset sampling grid, and the coordinate transformation error is obtained when the surface height acquisition device completes coordinate calibration.

[0091] Optionally, the sheet metal grinding compensation device calculates the coordinate distance between the first sampling position and the second sampling position according to the following formula: ; Where 'a' represents the number of the first sampling position, which is assigned by the sheet metal grinding compensation device according to the sampling order of the first sampling position; and 'b' represents the number of the second sampling position, which is assigned by the sheet metal grinding compensation device according to the sampling order of the second sampling position. This represents the coordinate distance between the a-th first sampling position and the b-th second sampling position; and This represents the x and y coordinates of the a-th first sampling position in the sheet metal coordinate system; and This represents the x-coordinate and y-coordinate of the b-th second sampling position in the sheet metal coordinate system.

[0092] Thin sheet grinding compensation equipment will Compare with a preset position threshold; when If the value is not greater than the preset position threshold, the a-th first sampling position and the b-th second sampling position are determined as a matching sampling position group.

[0093] When there are multiple second sampling positions that meet the preset position threshold at a first sampling position, the sheet grinding compensation device selects the second sampling position with the smallest coordinate distance to form a matching sampling position group; when a second sampling position has been written into a matching sampling position group, the same second sampling position will not be written into another matching sampling position group.

[0094] The thin sheet grinding compensation equipment summarizes all the matching sampling position groups to obtain a set of matching sampling position groups; the set of matching sampling position groups is the position matching relationship between the first surface height data and the second surface height data; the position matching relationship is used to limit the first surface height value and the second surface height value that need to be read when calculating the surface height change caused by clamping in the subsequent calculation.

[0095] Step S204: Determine the surface height change caused by clamping corresponding to the matching sampling position group.

[0096] For each matched sampling position group, the thin sheet grinding compensation equipment reads the first surface height value from the first surface height data and the second surface height value from the second surface height data under the same height reference. The first surface height value comes from the first sampling position in the matched sampling position group; the second surface height value comes from the second sampling position in the same matched sampling position group; both the first surface height value and the second surface height value are used in the calculation after the height reference is converted.

[0097] The sheet metal grinding compensation device determines the signed difference between the second surface height value and the first surface height value as the surface height change caused by clamping corresponding to the matching sampling position group; optionally, the sheet metal grinding compensation device calculates the surface height change caused by clamping according to the following formula: ; Where i represents the number of the matching sampling position group, and the number of the matching sampling position group is assigned by the sheet grinding compensation device according to the generation order of the matching sampling position groups; This represents the change in surface height caused by clamping corresponding to the i-th matching sampling position group; This represents the first surface height value corresponding to the i-th matching sampling position group; This represents the second surface height value corresponding to the i-th matching sampling position group; and All are height values ​​based on the same height reference.

[0098] Signed differences are used to preserve the direction in which the clamping action causes the surface height to rise or fall; when When the value is positive, the height of the second surface in the clamped state is higher than the height of the first surface in the unclamped state at the position corresponding to the i-th matching sampling position group; when When the value is negative, the height of the second surface in the clamping state is lower than the height of the first surface in the non-clamping state at the position corresponding to the i-th matching sampling position group; the sheet grinding compensation device will It is associated with the i-th matching sampling position group and stored as input data for subsequently determining the rebound correction amount after release.

[0099] In this embodiment, the sheet metal grinding compensation device first converts the first sampling position and the second sampling position to the same sheet metal coordinate system, and converts the first surface height data and the second surface height data to the same height reference. Then, it forms a matching sampling position group according to a preset position threshold. As a result, the first surface height value and the second surface height value participate in the calculation under the same position aperture and the same height aperture, which can reduce the influence of different sampling coordinate systems and different height references on the surface height change calculation process caused by clamping.

[0100] Meanwhile, the thin sheet grinding compensation equipment uses the signed difference between the second surface height value and the first surface height value to determine the surface height change caused by clamping, so that the surface height change caused by clamping includes both the height change value and the height change direction; the height change direction serves as the directional basis for the springback correction amount after subsequent release, and the height change value serves as the numerical basis for subsequently finding the height change range.

[0101] Example 3: Please see Figure 4As shown, based on the above embodiments, this embodiment further illustrates the process of determining the springback correction amount after release based on the surface height change caused by clamping and the preset springback relationship. This embodiment may include the following steps: Step S301: Determine the height change amplitude based on the absolute value of the surface height change caused by clamping.

[0102] The thin sheet grinding compensation device reads the surface height change caused by clamping for each matching sampling position group; the surface height change caused by clamping is obtained by subtracting the first surface height value from the second surface height value under the same height reference; the surface height change caused by clamping is associated with the matching sampling position group so that each matching sampling position group has a corresponding surface height change caused by clamping.

[0103] The grinding compensation equipment for thin sheet parts takes the absolute value of the surface height change caused by clamping to obtain the height change amplitude; optionally, the grinding compensation equipment for thin sheet parts determines the height change amplitude according to the following formula: ; Where i represents the number of the matching sampling position group; This represents the change in surface height caused by clamping corresponding to the i-th matching sampling position group; This represents the height change amplitude corresponding to the i-th matching sampling position group; the height change amplitude is used to represent the value of the height change caused by the clamping action, and the sign of the surface height change caused by the clamping action is used to represent the direction of the height change caused by the clamping action.

[0104] Step S302: Find the height change range to which the height change amplitude belongs in the preset rebound relationship.

[0105] The preset springback relationship includes multiple height change intervals and a springback correction coefficient for each interval. Each height change interval includes a lower limit and an upper limit. Height change intervals are divided according to the range of height change amplitude. The springback correction coefficient is a signed coefficient used to represent the proportional relationship between the height change after release and the surface height change caused by clamping within the height change interval. The height change after release is the height change of the sheet metal relative to its clamping state after being released from clamping. When the height change after release in historical clamping and release data is opposite to the direction of the surface height change caused by clamping, the springback correction coefficient for the corresponding height change interval is negative. When the height change after release in historical clamping and release data is in the same direction as the surface height change caused by clamping, the springback correction coefficient for the corresponding height change interval is positive. When the height change after release in historical clamping and release data is 0, the springback correction coefficient for the corresponding height change interval is 0.

[0106] The height variation range is established based on the clamping and release data, first-piece trial grinding data, material batch data, or process calibration data of similar thin sheet parts in history. When establishing the height variation range, the thin sheet grinding compensation equipment reads the surface height change caused by clamping and the height change after unclamping corresponding to each sampling position in the historical data. Then, a set of height variation amplitudes is formed based on the absolute value of the surface height change caused by clamping. Subsequently, according to the preset number of intervals or the interval boundaries given in the process document, the set of height variation amplitudes is divided into multiple height variation ranges.

[0107] The springback correction coefficient is determined based on the surface height change caused by clamping and the height change after release within the height variation range. Optionally, the sheet metal grinding compensation equipment reads the surface height change caused by historical clamping and the height change after historical release corresponding to each historical sampling position within the same height variation range. The height change after historical release is the height change of the sheet metal relative to the historical clamping state after it is released from clamping. The ratio between the height change after historical release and the surface height change caused by historical clamping is calculated respectively, and the arithmetic mean of multiple ratios is used as the springback correction coefficient corresponding to the height variation range. When the surface height change caused by historical clamping is 0, the corresponding historical sampling position does not participate in the calculation of the springback correction coefficient. When there is no historical data for the height variation range, the signed springback correction coefficient given in the process document is used.

[0108] The thin-piece grinding compensation equipment searches for the height change range to which the height change amplitude belongs in a preset springback relationship; optionally, the thin-piece grinding compensation equipment determines the height change range to which the height change amplitude belongs according to the following formula: ; Where m represents the number of the height change interval; This represents the lower limit of the m-th height change interval; This represents the upper limit of the m-th height change interval; and Given by a preset springback relationship; when satisfy At that time, the height change amplitude corresponding to the i-th matching sampling position group belongs to the m-th height change interval.

[0109] Step S303: Multiply the springback correction coefficient corresponding to the height change range by the surface height change caused by clamping to obtain the springback correction amount after release.

[0110] The thin-piece grinding compensation device reads the springback correction coefficient corresponding to the height change interval; when the height change amplitude corresponding to the i-th matching sampling position group belongs to the m-th height change interval, the springback correction coefficient corresponding to the m-th height change interval is determined as the springback correction coefficient corresponding to the i-th matching sampling position group; optionally, the thin-piece grinding compensation device determines the springback correction coefficient corresponding to the i-th matching sampling position group according to the following formula: ; in, This represents the rebound correction coefficient corresponding to the i-th matching sampling position group; This represents the rebound correction coefficient corresponding to the m-th height change interval; It is given by the preset springback relationship.

[0111] The thin-piece grinding compensation equipment multiplies the springback correction coefficient by the marked surface height change caused by clamping to obtain the springback correction amount after release; optionally, the thin-piece grinding compensation equipment determines the springback correction amount after release according to the following formula: ; in, This represents the rebound correction amount after release corresponding to the i-th matching sampling position group; This represents the rebound correction coefficient corresponding to the i-th matching sampling position group. These are signed coefficients; This represents the change in surface height caused by clamping corresponding to the i-th matching sampling position group; when When the value is negative, it indicates that the change in height after release is in the opposite direction to the change in surface height caused by clamping; when When positive, it indicates that the change in height after release is in the same direction as the change in surface height caused by clamping; when... When the value is 0, it means that no rebound correction amount is generated within the corresponding height change range.

[0112] The springback correction amount after release represents the change in height of the sheet metal relative to its clamping state after it is released from the clamping position; when When the value is positive, the height of the position corresponding to the i-th matching sampling position group increases relative to the clamping state after unclamping; when... When the value is negative, the height of the position corresponding to the i-th matching sampling position group decreases relative to the clamping state after unclamping; the thin sheet grinding compensation device will Associated with and stored with the i-th matching sampling position group, and Used to generate subsequent grinding feed compensation.

[0113] In this embodiment, the sheet metal grinding compensation device determines the height change amplitude based on the absolute value of the surface height change caused by clamping, and finds the signed springback correction coefficient in the preset springback relationship based on the height change amplitude; then, it multiplies the signed springback correction coefficient by the signed surface height change caused by clamping to obtain the springback correction amount after release; thus, the value of the springback correction amount after release is determined by the height change amplitude and the springback correction coefficient, and the direction of the springback correction amount after release is determined by the sign of the springback correction coefficient and the sign of the surface height change caused by clamping.

[0114] By adopting the springback correction method provided in this embodiment, the sheet grinding compensation device can determine the height change of the sheet relative to the clamping state after it is unclamped, based on the height change value and height change direction caused by the clamping action. When generating the grinding feed compensation amount, the second surface height data and the springback correction amount after release can be used simultaneously, reducing the situation where the grinding feed compensation amount is generated only based on the temporary surface morphology under the clamping state.

[0115] Example 4: Please see Figure 5 As shown, based on the above embodiments, this embodiment further illustrates the process of dividing the sheet into multiple compensation regions and determining the springback correction amount after release according to the compensation regions. This embodiment may include the following steps: Step S401: Divide the sheet into multiple compensation regions.

[0116] The thin sheet grinding compensation equipment divides the thin sheet into multiple compensation zones. These zones can be defined based on the thin sheet structure, the grinding fixture's working area, the hole periphery zone, the edge zone, the rib zone, the thin film zone, or the zone adjacent to the support point. When the thin sheet has a hole structure, the area within or outside the hole structure boundary that satisfies the hole edge coordinate distance not exceeding the hole periphery width is designated as the hole periphery zone, based on the hole edge coordinate distance from the matching sampling position group to the hole structure boundary and the hole periphery width. When the thin sheet has an edge contour, the area extending inward from the edge contour and satisfying the edge coordinate distance not exceeding the edge width is designated as the edge zone, based on the edge coordinate distance from the matching sampling position group to the edge contour and the edge width. When the thin sheet has support points, the area satisfying the support point coordinate distance not exceeding the support point radius is designated as the support point adjacent zone, based on the support point coordinate distance from the matching sampling position group to the support point and the support point radius.

[0117] Each compensation zone has a corresponding zone boundary or zone coordinate range; the zone boundary or zone coordinate range is determined by the sheet metal machining drawings, grinding fixture design data, or manual calibration data under the sheet metal coordinate system; the sheet metal grinding compensation equipment writes the zone boundary or zone coordinate range into the compensation zone configuration table; the compensation zone configuration table includes at least the compensation zone number, compensation zone name, zone boundary, zone coordinate range, hole perimeter range width, edge range width, and support point range radius; the hole perimeter range width is determined by at least one of the hole structure size, hole structure edge chamfer size, sampling interval, and grinding head working width; the edge range width is determined by at least one of the sheet metal edge allowance, sampling interval, and grinding head working width; the support point range radius is determined by at least one of the support pad radius, support point spacing, sheet metal thickness, and grinding fixture design data.

[0118] The thin-piece grinding compensation equipment assigns the matching sampling position group to the corresponding compensation region based on the position coordinates of the matching sampling position group in the thin-piece coordinate system; optionally, the thin-piece grinding compensation equipment determines the compensation region to which the matching sampling position group belongs in the following manner: ; Where i represents the number of the matching sampling position group; q represents the compensation area number, which is assigned by the sheet grinding compensation equipment according to the order of compensation area generation; and This represents the position coordinates of the i-th matching sampling position group in the sheet metal coordinate system; This represents the boundary or coordinate range of the q-th compensation region; when lie in When the i-th matching sampling position group is assigned to the q-th compensation region, and the q-th compensation region is the area around the hole, the edge region, or the area near the support point, It is formed by comparing the distance between the hole edge coordinates, the distance between the edge coordinates, or the distance between the support point coordinates with the corresponding range parameters.

[0119] When the q-th compensation region is the periphery of a hole, the sheet metal grinding compensation device reads the set of hole structure boundary points; the set of hole structure boundary points is obtained by discretizing the hole structure contour in the sheet metal machining drawing, or by manually calibrated data in the sheet metal coordinate system; for the i-th matching sampling position group, the sheet metal grinding compensation device determines the hole edge coordinate distance according to the following formula: ; in, This represents the distance to the edge of the hole corresponding to the i-th matching sampling position group; This represents the set of boundary point numbers for the hole structure. and This represents the x and y coordinates of the o-th hole structure boundary point in the sheet metal coordinate system; when When the hole circumference is not greater than the hole circumference width, the thin sheet grinding compensation device will assign the i-th matching sampling position group to the hole circumference region; the hole circumference width is given by the compensation region configuration table.

[0120] When the q-th compensation region is an edge region, the sheet metal grinding compensation device reads the edge contour point set; the edge contour point set is obtained by discretizing the outer contour in the sheet metal processing drawing, or by manually calibrated data in the sheet metal coordinate system; for the i-th matching sampling position group, the sheet metal grinding compensation device determines the edge coordinate distance according to the following formula: ; in, This represents the edge coordinate distance corresponding to the i-th matching sampling position group; This represents the set of edge contour point numbers; and This represents the x and y coordinates of the e-th edge contour point in the sheet metal coordinate system; when the i-th matching sampling position group is located inside the edge contour of the sheet metal, and When the edge range width is not greater than the edge range width, the sheet grinding compensation device will classify the i-th matching sampling position group into the edge region; the edge range width is given by the compensation region configuration table.

[0121] When the q-th compensation region is adjacent to the support point, the sheet metal grinding compensation device reads the support point position. The support point position is given by the grinding fixture design data and converted to the sheet metal coordinate system through the transformation relationship between the grinding fixture coordinate system and the sheet metal coordinate system. For the ith matching sampling position group and the p-th support point, the sheet metal grinding compensation device determines the support point coordinate distance according to the following formula: ; in, This represents the coordinate distance between the i-th matching sampling position group and the p-th support point; and This represents the x and y coordinates of the p-th support point in the sheet metal coordinate system; when at least one support point satisfies When the radius of the support point is not greater than the radius of the support point range, the thin sheet grinding compensation device will classify the i-th matching sampling position group into the support point's adjacent area; the support point's radius of range is given by the compensation area configuration table.

[0122] Step S402: Determine the surface height change caused by clamping corresponding to the matching sampling position group in each compensation area.

[0123] The thin-piece grinding compensation equipment reads the matching sampling position groups within each compensation area; for the q-th compensation area, it reads the position coordinates from the set of matching sampling position groups. The matching sampling position group within the q-th compensation region is used to establish the correspondence between the q-th compensation region and the matching sampling position group; the matching sampling position group within the q-th compensation region is used to generate the rebound correction amount after release corresponding to the q-th compensation region.

[0124] The thin-sheet grinding compensation device retains the surface height change caused by clamping corresponding to the matching sampling position group in each compensation area point by point; for the i-th matching sampling position group in the q-th compensation area, it reads the surface height change caused by clamping corresponding to the i-th matching sampling position group. ;Will It is stored in association with the q-th compensation region and the i-th matching sampling location group.

[0125] The surface height changes caused by clamping in each compensation area corresponding to the matching sampling position group are used to find the springback correction coefficient for each compensation area. The thin sheet grinding compensation equipment does not merge the surface height changes caused by clamping in all compensation areas into a single springback correction coefficient. The preset springback relationship is read according to the compensation area so that the hole periphery area, edge area, rib area, film area or support point adjacent area can use the corresponding springback correction coefficient. The hole periphery area is determined by the hole edge coordinate distance and hole periphery range width. The edge area is determined by the edge coordinate distance and edge range width. The support point adjacent area is determined by the support point coordinate distance and support point range radius.

[0126] Step S403: Based on the correspondence between the compensation area, the height change range and the rebound correction coefficient, generate the rebound correction amount after release for each compensation area.

[0127] The preset springback relationship includes the correspondence between compensation areas, height change intervals, and springback correction coefficients. In the preset springback relationship, each compensation area has at least one height change interval, and each height change interval has a corresponding springback correction coefficient. The height change interval is divided according to the height change amplitude in the historical clamping and release data within the corresponding compensation area. The springback correction coefficient is determined based on the surface height change caused by clamping and the height change after unclamping in the historical clamping and release data within the corresponding compensation area.

[0128] The thin sheet grinding compensation equipment locates the height change interval to which the height change amplitude belongs within the corresponding compensation area; for the i-th matching sampling position group within the q-th compensation area, it first determines the height change range based on the following: Determine the amplitude of height change Then search within the height change interval corresponding to the qth compensation region. The height variation range to which the height variation amplitude belongs; optionally, the thin sheet grinding compensation equipment determines the height variation range to which the height variation amplitude belongs according to the following formula: ; Where m represents the number of the height change interval; This represents the lower limit of the m-th height change interval in the q-th compensation region; This represents the upper limit of the m-th height change interval in the q-th compensation region; when satisfy At that time, the height change amplitude corresponding to the i-th matching sampling position group in the q-th compensation region belongs to the m-th height change interval in the q-th compensation region.

[0129] The thin-piece grinding compensation equipment reads the springback correction coefficients under the corresponding compensation area and the corresponding height change interval; when the height change amplitude corresponding to the i-th matching sampling position group in the q-th compensation area belongs to the m-th height change interval in the q-th compensation area, the springback correction coefficient corresponding to the m-th height change interval in the q-th compensation area is determined as the springback correction coefficient corresponding to the i-th matching sampling position group; optionally, the thin-piece grinding compensation equipment determines the springback correction coefficient corresponding to the i-th matching sampling position group according to the following formula: ; in, This represents the rebound correction coefficient corresponding to the i-th matching sampling position group; This represents the rebound correction coefficient corresponding to the m-th height change interval in the q-th compensation region; It is given by the preset springback relationship.

[0130] The thin-sheet grinding compensation equipment generates the springback correction amount after release for each compensation area; for the i-th matching sampling position group within the q-th compensation area, and Multiply to obtain the rebound correction amount after release corresponding to the i-th matching sampling position group. Optionally, the thin-piece grinding compensation equipment determines the springback correction amount after release according to the following formula: ; in, This represents the rebound correction amount after release corresponding to the i-th matching sampling position group; This represents the rebound correction coefficient corresponding to the i-th matching sampling position group; This indicates the surface height change caused by the clamping corresponding to the i-th matching sampling position group; the sheet metal grinding compensation device will... It is stored in association with the q-th compensation region and the i-th matching sampling location group.

[0131] In this embodiment, the thin sheet grinding compensation device first divides the thin sheet into multiple compensation areas, and then assigns the matching sampling position group to the corresponding compensation area according to the position coordinates in the thin sheet coordinate system; subsequently, it searches for the height change range and springback correction coefficient according to the compensation area, and generates the springback correction amount after release corresponding to the matching sampling position group in each compensation area.

[0132] By using the method of determining the springback correction amount after release according to the compensation area provided in this embodiment, the sheet grinding compensation equipment can determine the springback correction amount after release for the hole periphery area, edge area, rib area, thin film area or support point adjacent area respectively; thus, the springback correction amount after release can correspond to the surface height change caused by clamping in each compensation area and the preset springback relationship, and provide regional correction data for the subsequent grinding feed compensation amount generation.

[0133] Example 5: Please see Figure 6 As shown, based on the above embodiments, this embodiment further illustrates the process of determining the springback correction coefficient based on at least one of the following: vacuum negative pressure value, pressure plate clamping force, support point position, locating pin limit state, sheet thickness, and material batch, as well as the height variation range. This embodiment may include the following steps: Step S501: Obtain clamping parameters and sheet metal properties.

[0134] The sheet metal grinding compensation equipment acquires at least one of the following: vacuum negative pressure value, pressure plate clamping force, support point position, locating pin limit status, sheet metal thickness, and material batch. The vacuum negative pressure value is acquired by a pressure sensor in the vacuum adsorption device or output by the grinding fixture controller. The pressure plate clamping force is acquired by a pressure plate force sensor or calculated from the control parameters of the pressure plate drive mechanism. The support point position is given by a grinding fixture structure parameter table, which includes at least the support point number, the support point's position coordinates in the grinding fixture coordinate system, and the transformation relationship between the grinding fixture coordinate system and the sheet metal coordinate system. The first support distance threshold and the second support distance threshold; the first support distance threshold is used to divide the position range corresponding to the contact area of ​​the support point; the second support distance threshold is used to divide the position range corresponding to the influence area of ​​the support point; the second support distance threshold is greater than the first support distance threshold; the positioning pin limit status is given by the grinding fixture controller or manual process record, and the positioning pin limit status is used to indicate whether the positioning pin forms a lateral limit, end limit or multi-point limit on the sheet part; the sheet part thickness is collected by the thickness measuring device or given by the process document; the material batch is given by the sheet part production record or incoming material record.

[0135] The thin sheet grinding compensation equipment associates and stores the clamping parameters and thin sheet attributes with the second surface height data or the current processing batch. When storing the data in association, the thin sheet identifier is used as the data index, and the second surface height data, vacuum negative pressure value, pressure plate clamping force, support point position, positioning pin limit status, thin sheet thickness and material batch are written into the same data record. When determining the springback correction coefficient later, the aforementioned data record is read based on the thin sheet identifier.

[0136] Step S502: Determine the springback correction coefficient based on the clamping parameters, sheet material properties, and height variation range.

[0137] The preset springback relationship further includes the correspondence between clamping parameter range, sheet thickness range, material batch identifier, support point position type, height variation range, and springback correction coefficient; the clamping parameter range includes at least one of vacuum negative pressure value range and pressure plate clamping force range; the sheet thickness range is formed according to the process grouping of sheet thickness; the material batch identifier is formed according to the production management system or incoming material record; the support point position type is formed according to the coordinate distance of the nearest support point between the matching sampling position group and the support point; the coordinate distance of the nearest support point is the minimum coordinate distance between the position coordinates of the matching sampling position group in the sheet coordinate system and the position coordinates of each support point in the sheet coordinate system; the support point position type is formed according to the positional relationship between the support point position and the matching sampling position group; the positioning pin limit status code is formed according to the positioning pin status output by the grinding fixture controller or manual process record, and the positioning pin limit status code includes 0, 1, 2, and 3, where 0 indicates no limit, 1 indicates lateral limit, 2 indicates end limit, and 3 indicates multi-point limit.

[0138] The thin-piece grinding compensation device transforms the support point position to the thin-piece coordinate system; for the i-th matching sampling position group, it reads the position coordinates of the i-th matching sampling position group in the thin-piece coordinate system. And read the position coordinates of the p-th support point in the sheet metal coordinate system. The thin sheet grinding compensation equipment calculates the support point coordinate distance between the i-th matching sampling position group and the p-th support point according to the following formula: ; in, This represents the coordinate distance between the i-th matching sampling position group and the p-th support point; and This represents the x and y coordinates of the i-th matching sampling position group in the sheet metal coordinate system; and This represents the x-coordinate and y-coordinate of the p-th support point in the sheet metal coordinate system; the position coordinates of the support point in the sheet metal coordinate system are determined by the support point position and coordinate transformation relationship in the grinding fixture structure parameter table.

[0139] The grinding compensation equipment for thin sheet parts determines the coordinate distance of the nearest support point corresponding to the i-th matching sampling position group according to the following formula: ; in, This represents the coordinate distance of the nearest support point corresponding to the i-th matching sampling position group; This represents the set of support point numbers for the current grinding fixture; This represents the coordinate distance between the i-th matching sampling position group and the p-th support point; the set of support point numbers is given by the grinding fixture structure parameter table.

[0140] The thin-piece grinding compensation equipment determines the support point position type based on the coordinate distance of the nearest support point; when When the distance is not greater than the first support distance threshold, the support point location type corresponding to the i-th matching sampling location group is determined as the first support point location type; when When the distance is greater than the first support distance threshold but not greater than the second support distance threshold, the support point location type corresponding to the i-th matching sampling location group is determined as the second support point location type; when When the distance is greater than the second support distance threshold, the support point position type corresponding to the i-th matching sampling position group is determined as the third support point position type; the first support distance threshold and the second support distance threshold are given by the grinding fixture structure parameter table, or by the process document corresponding to the support pad radius, support point spacing and sheet thickness.

[0141] The thin-piece grinding compensation equipment, based on the clamping parameters, thin-piece properties, and height variation range obtained this time, searches for the corresponding springback correction coefficient in the preset springback relationship; when the preset springback relationship includes the vacuum negative pressure value range, it first determines the vacuum negative pressure value range to which the vacuum negative pressure value belongs; when the preset springback relationship includes the pressure plate clamping force range, it determines the pressure plate clamping force range to which the pressure plate clamping force belongs; when the preset springback relationship includes the thin-piece thickness range, it determines the thin-piece thickness range to which the thin-piece thickness belongs; when the preset springback relationship includes the positioning pin limit status code, it reads the current positioning pin limit status code and searches for records with the same positioning pin limit status code in the preset springback relationship.

[0142] When multiple factors exist simultaneously, the sheet metal grinding compensation equipment determines the springback correction coefficient according to a preset lookup table order. The preset lookup table order is given in advance by the process document and written into the sheet metal grinding compensation equipment. One feasible preset lookup table order is as follows: first, look up by material batch; then, look up by sheet metal thickness range; then, look up by support point position type; then, look up by positioning pin limit status code; then, look up by vacuum negative pressure value range or pressure plate clamping force range; and finally, look up by height change range. The support point position type is determined by the comparison result between the coordinate distance of the nearest support point and the first support distance threshold and the second support distance threshold. When a certain factor is not obtained in the current processing batch, the corresponding lookup field is skipped, and the springback correction coefficient is found according to the already obtained factors and height change range.

[0143] Optionally, when the preset springback relationships are stored in tabular form, the sheet metal grinding compensation device searches for records in the preset springback relationships that meet the following conditions: ； ； ； ； ; Where V represents the vacuum negative pressure value. This represents the lower limit of the vacuum negative pressure value range. This indicates the upper limit of the vacuum negative pressure range; F represents the clamping force of the pressure plate. This indicates the lower limit of the clamping force range of the pressure plate. This indicates the upper limit of the clamping force range of the pressure plate; T represents the thickness of the sheet material. This indicates the lower limit of the thickness range for thin sheet components. Z represents the upper limit of the thickness range of the sheet component; Z represents the current positioning pin limit status code. This indicates the positioning pin limit status code recorded in the preset springback relationship; This represents the height change magnitude corresponding to the i-th matching sampling position group. This represents the lower limit of the m-th height change interval. This represents the upper limit of the m-th height change interval; the vacuum negative pressure value interval, the pressure plate clamping force interval, the sheet thickness interval, the positioning pin limit status code, and the height change interval are all given by the preset springback relationship.

[0144] When the record corresponding to the above conditions exists, the sheet metal grinding compensation device reads the springback correction coefficient in the corresponding record and determines the springback correction coefficient in the corresponding record as the springback correction coefficient corresponding to the i-th matching sampling position group. When the preset springback relationship also includes material batch identifier, support point position type, or positioning pin limit status code, further read records with the same material batch identifier, the same support point position type, and the same positioning pin limit status code from the records that meet the above interval conditions; the support point position type is determined by the coordinate distance of the nearest support point corresponding to the i-th matching sampling position group; when there are no records with the same material batch identifier, the same support point position type, and the same positioning pin limit status code, read the springback correction coefficient according to the default record given in the process document.

[0145] Step S503: Generate the rebound correction amount after release based on the rebound correction coefficient.

[0146] The thin-sheet grinding compensation equipment multiplies the springback correction coefficient by the surface height change caused by clamping; for the i-th matching sampling position group, it reads the surface height change caused by clamping corresponding to the i-th matching sampling position group. And read the rebound correction coefficient corresponding to the i-th matching sampling position group determined in step S502. Subsequently, according to and Calculate the rebound correction amount after release corresponding to the i-th matching sampling position group.

[0147] Optionally, the thin-piece grinding compensation device generates the springback correction amount after release according to the following formula: ; in, This represents the rebound correction amount after release corresponding to the i-th matching sampling position group; This represents the rebound correction coefficient corresponding to the i-th matching sampling position group; This indicates the surface height change caused by the clamping corresponding to the i-th matching sampling position group; the sheet metal grinding compensation device will... Associated with and stored with the i-th matching sampling position group, and Used to generate subsequent grinding feed compensation.

[0148] In this embodiment, the sheet metal grinding compensation device, based on the height variation range, further determines the springback correction coefficient by combining at least one of the following: vacuum negative pressure value, pressure plate clamping force, support point position, locating pin limit status, sheet metal thickness, and material batch. Specifically, the support point position is converted into a support point position type using the coordinate distance of the nearest support point, and this type is used to participate in a preset springback relationship lookup table. The locating pin limit status is used to participate in a preset springback relationship lookup table using the locating pin limit status code. When the current locating pin limit status code matches the locating pin limit status code in the preset springback relationship, the corresponding springback correction coefficient is read.

[0149] Using the springback correction coefficient determination method provided in this embodiment, the sheet metal grinding compensation equipment can find the springback correction coefficient based on the clamping parameters and sheet metal properties of the current processing batch, and generate the springback correction amount after release based on the springback correction coefficient; thus, the subsequent grinding feed compensation amount can use the springback correction amount after release corresponding to the clamping parameters and sheet metal properties of the current processing batch.

[0150] Example 6: Please see Figure 7 As shown, based on the above embodiments, this embodiment further illustrates the process of generating a grinding feed compensation amount based on the second surface height data, the preset target machining surface height, and the springback correction amount after release, and limiting the grinding feed compensation amount between adjacent matching sampling position groups. This embodiment may include the following steps: Step S601: Generate grinding feed compensation amount point by point.

[0151] For each matching sampling position group, the thin sheet grinding compensation device reads the second surface height value from the second surface height data; the second surface height value is the height value corresponding to the second sampling position in the matching sampling position group; the second surface height value has been converted to the same height reference as the first surface height value; the second surface height value is read in association with the number of the matching sampling position group.

[0152] The sheet metal grinding compensation device reads the springback correction amount after release corresponding to the matching sampling position group; the springback correction amount after release is determined by the surface height change caused by clamping and the preset springback relationship; it reads the preset target machining surface height; the preset target machining surface height is given by the sheet metal machining drawing, process document or grinding equipment machining program, and is stored in advance in the sheet metal grinding compensation device; when the preset target machining surface height is configured by position, the corresponding target machining surface height value is read from the target machining surface height configuration table according to the position coordinates of the matching sampling position group in the sheet metal coordinate system; the target machining surface height configuration table is used to record the position height requirements corresponding to non-planar targets, local steps or zone thickness control.

[0153] The sheet metal grinding compensation device subtracts the preset target machining surface height from the sum of the second surface height value and the springback correction amount after release to obtain the grinding feed compensation calculation value. The grinding feed compensation calculation value is the difference obtained by subtracting the preset target machining surface height from the sum of the second surface height value and the springback correction amount after release, and is used as the calculation source of the grinding feed compensation amount. When the grinding feed compensation calculation value is greater than 0, the grinding feed compensation calculation value is determined as the grinding feed compensation amount. When the grinding feed compensation calculation value is not greater than 0, the grinding feed compensation amount is determined as 0, and the corresponding matching sampling position group is marked as a position where no removal processing is performed. Optionally, the sheet metal grinding compensation device generates the grinding feed compensation amount according to the following formula: ; ; Where i represents the number of the matching sampling position group; This represents the calculated grinding feed compensation value corresponding to the i-th matching sampling position group; This represents the grinding feed compensation amount corresponding to the i-th matching sampling position group, and is a non-negative value output to the grinding equipment; This represents the second surface height value corresponding to the i-th matching sampling position group; This represents the rebound correction amount after release corresponding to the i-th matching sampling position group; Indicates the preset target machining surface height; This is used to determine the grinding feed compensation amount as 0 when the calculated grinding feed compensation value is not greater than 0.

[0154] When the preset target machining surface height is configured according to the position, the thin sheet grinding compensation equipment generates the grinding feed compensation amount according to the following formula: ; ; in, This represents the target processing surface height value corresponding to the i-th matching sampling position group; The position coordinates of the matching sampling position group in the sheet metal coordinate system are read from the target machining surface height configuration table; This represents the calculated grinding feed compensation value corresponding to the i-th matching sampling position group, and serves as the source for calculating the grinding feed compensation amount; This represents the grinding feed compensation amount corresponding to the i-th matching sampling position group, and is a non-negative value output to the grinding equipment; when Not greater than 0 If the value is 0, the grinding equipment will not perform removal processing at the position corresponding to the i-th matching sampling position group.

[0155] Step S602: Determine whether there is excessive compensation change between adjacent matching sampling position groups.

[0156] The sheet metal grinding compensation device reads the position coordinates of two matched sampling position groups in the same sheet metal coordinate system; for the i-th and j-th matched sampling position groups, it reads the position coordinates of the i-th matched sampling position group. And read the position coordinates of the j-th matching sampling position group. The position coordinates are all position coordinates in the same sheet metal coordinate system.

[0157] Optionally, the sheet metal grinding compensation device calculates the coordinate distance between two matching sampling position sets according to the following formula: ; in, This represents the coordinate distance between the i-th matching sampling position group and the j-th matching sampling position group; and This represents the x and y coordinates of the i-th matching sampling position group in the sheet metal coordinate system; and This represents the x and y coordinates of the j-th matching sampling position group in the sheet metal coordinate system.

[0158] The sheet metal grinding compensation device determines whether the coordinate distance is not greater than a preset adjacent distance threshold; the preset adjacent distance threshold is set according to the sampling interval, the working width of the grinding head, or the interpolation path interval, and is pre-stored in the sheet metal grinding compensation device; when If the distance is not greater than the preset adjacent distance threshold, the i-th matching sampling position group and the j-th matching sampling position group are determined as adjacent matching sampling position groups.

[0159] The thin-piece grinding compensation device determines whether the difference between the grinding feed compensation amounts corresponding to two matched sampling position groups is greater than a preset compensation change threshold; the grinding feed compensation amount is a value after non-negative constraint; the preset compensation change threshold is set according to the allowable feed change of the grinding device, the local stiffness of the thin-piece part, or the surface quality requirements, and is pre-stored in the thin-piece grinding compensation device; optionally, the thin-piece grinding compensation device determines the difference between the grinding feed compensation amounts according to the following formula: ; in, This represents the difference between the grinding feed compensation amount corresponding to the i-th matching sampling position group and the j-th matching sampling position group; and All are grinding feed compensation amounts after non-negative constraints; when When the difference exceeds the preset compensation change threshold, the grinding feed compensation amount between the i-th matching sampling position group and the j-th matching sampling position group determined by the sheet grinding compensation equipment needs to be limited.

[0160] Step S603: Limit the difference between the grinding feed compensation amounts corresponding to adjacent matching sampling position groups.

[0161] When the coordinate distance is not greater than the preset adjacent distance threshold and the difference between the grinding feed compensation amounts is greater than the preset compensation change threshold, the sheet grinding compensation device limits the difference between the grinding feed compensation amounts corresponding to the two matched sampling position groups to the preset compensation change threshold; optionally, the sheet grinding compensation device uses the grinding feed compensation amount corresponding to the i-th matched sampling position group as a reference amount to limit the grinding feed compensation amount corresponding to the j-th matched sampling position group.

[0162] Optionally, the thin-piece grinding compensation device generates the limited grinding feed compensation amount according to the following formula: ; in, This represents the restricted grinding feed compensation amount corresponding to the j-th matching sampling position group; This represents the grinding feed compensation amount corresponding to the i-th matching sampling position group; This represents the grinding feed compensation amount corresponding to the j-th matching sampling position group; This indicates the preset compensation change threshold. The preset compensation change threshold is given by the process document based on the allowable feed change of the grinding equipment, the local stiffness of the sheet part, or the surface quality requirements, and is stored in advance in the sheet part grinding compensation equipment.

[0163] Optionally, the preset compensation change threshold can be the minimum value among the allowable adjacent feed change of the grinding equipment, the allowable height change of the local stiffness of the thin part, and the allowable step height of the surface quality; the allowable adjacent feed change of the grinding equipment is given by the grinding equipment control parameter configuration file, the allowable height change of the local stiffness of the thin part is given by the process document corresponding to the thickness of the thin part and the material batch, and the allowable step height of the surface quality is given by the surface quality requirements in the machining drawings.

[0164] The thin sheet grinding compensation device writes the limited grinding feed compensation amount into the grinding feed compensation amount set; when a matching sampling position group and multiple adjacent matching sampling position groups all need to perform difference limitation, the difference limitation is performed according to the preset processing order; the preset processing order is determined by the preset sampling path or the grinding equipment processing path; adjacent matching sampling position groups are read according to the preset processing order, and the limited grinding feed compensation amount is generated one by one.

[0165] Optionally, after completing one difference limit according to the preset processing sequence, the sheet grinding compensation device performs iterative verification of adjacent smoothing limits on the grinding feed compensation amount set; rereads all adjacent matching sampling position groups and calculates the grinding feed compensation amount difference between each group of adjacent matching sampling position groups; when the grinding feed compensation amount difference between any adjacent matching sampling position group is greater than the preset compensation change threshold, the difference limit is executed again and the grinding feed compensation amount set is updated.

[0166] The sheet metal grinding compensation device repeatedly performs iterative verification of adjacent smoothing limits until the difference in grinding feed compensation between all adjacent matching sampling position groups is no greater than a preset compensation change threshold, or the number of iterations reaches a preset maximum iteration count. The sheet metal grinding compensation device sets a preset maximum iteration count based on the number of adjacent relationship records. The number of adjacent relationship records is the number of adjacent matching sampling position pairs whose coordinate distance is no greater than a preset adjacent distance threshold. When the number of adjacent relationship records is less than 2, the sheet metal grinding compensation device sets the preset maximum iteration count to 2. When the number of adjacent relationship records is not less than 2 and not greater than a preset maximum verification count, the sheet metal grinding compensation device sets the preset maximum iteration count to 2. The maximum number of iterations is set to the number of adjacent relationship records. When the number of adjacent relationship records exceeds the preset maximum number of verifications, the sheet metal grinding compensation device sets the preset maximum number of iterations to the preset maximum number of verifications. The preset maximum number of verifications is given by the process document based on the allowable time for single compensation calculation by the grinding equipment controller, the number of matching sampling position groups, and the number of grinding paths, and is pre-stored in the sheet metal grinding compensation device. When the number of iterations reaches the preset maximum number of iterations and there are still adjacent matching sampling position groups where the difference in grinding feed compensation is greater than the preset compensation change threshold, the sheet metal grinding compensation device outputs a manual review mark and retains the set of grinding feed compensation obtained after the last iteration.

[0167] Optionally, the thin-piece grinding compensation device is set with a preset upper limit for the number of iterations according to the following formula: ; in, This indicates the maximum number of preset iterations; Indicates the number of adjacent relationship records; This indicates the preset maximum number of verifications; the number of adjacent relationship records is calculated by the sheet grinding compensation device based on the preset adjacent distance threshold and the coordinates of the matching sampling position group; the preset maximum number of verifications is given by the process document based on the allowable time for single compensation calculation by the grinding equipment controller, the number of matching sampling position groups and the number of grinding paths, and is pre-stored in the sheet grinding compensation device.

[0168] In this embodiment, the sheet metal grinding compensation device can first calculate the grinding feed compensation value for each matched sampling position group, and use the calculated grinding feed compensation value as the source of the grinding feed compensation amount; then, based on the constraint that the grinding equipment cannot perform negative removal amount in the removal process, the grinding feed compensation value is subject to a non-negative restriction to obtain the actual grinding feed compensation amount output to the grinding equipment; when the preset target processing surface height is configured according to position, the grinding feed compensation amount can correspond to non-planar targets, local steps, or partition thickness control; at the same time, the sheet metal grinding compensation device can determine adjacent matched sampling position groups based on the coordinate distance in the same sheet metal coordinate system, and when the difference in grinding feed compensation amount between adjacent matched sampling position groups is greater than the preset compensation change threshold, the difference between the grinding feed compensation amounts after non-negative restriction is restricted; the sheet metal grinding compensation device can also check and handle the situation where the adjacent difference exceeds the limit after being restricted according to the preset processing order through iterative verification of adjacent smoothing restrictions.

[0169] By employing the grinding feed compensation generation and adjacent position smoothing restriction methods provided in this embodiment, the sheet metal grinding compensation device can simultaneously reflect the second surface height data and the springback correction amount after release, and can adapt to non-planar targets, local steps, or partition thickness control through the target machining surface height configuration table; at the same time, the sheet metal grinding compensation device can avoid the grinding equipment from performing negative removal processing through non-negative restrictions, and can ensure that the difference in grinding feed compensation between adjacent matching sampling position groups meets the allowable feed variation of the grinding equipment, the local stiffness of the sheet metal, or the surface quality requirements through iterative verification of adjacent smoothing restrictions.

[0170] Example 7: Please see Figure 8 As shown, based on the above embodiments, this embodiment further illustrates the process of grinding thin sheet parts by controlling the grinding equipment according to the grinding feed compensation amount. This embodiment may include the following steps: Step S701: Convert the grinding feed compensation amount into a control quantity that the grinding equipment can execute.

[0171] The sheet metal grinding compensation device converts the grinding feed compensation amount into the grinding head feed amount; the grinding feed compensation amount is a value after non-negative constraint; when the grinding device performs grinding by moving the grinding head relative to the sheet metal, it reads the grinding feed compensation amount corresponding to each matching sampling position group, and writes the grinding feed compensation amount into the grinding head feed amount according to the feed direction configuration saved in advance by the grinding device; when the grinding feed compensation amount is 0, the grinding head feed amount is 0, and the grinding device does not perform removal processing at the corresponding matching sampling position group.

[0172] Optionally, when the positive direction of the grinding head feed of the grinding equipment is the direction of increasing the amount of material removed, the thin-piece grinding compensation device determines the grinding head feed according to the following formula: ; Where i represents the number of the matching sampling position group; This represents the grinding head feed rate corresponding to the i-th matching sampling position group; This represents the grinding feed compensation amount corresponding to the i-th matching sampling position group. The value is after non-negative constraints; the positive direction of the grinding head feed is given by the control parameter configuration file of the grinding equipment and pre-stored in the sheet metal grinding compensation device; when When it is 0, It is 0.

[0173] Alternatively, the sheet metal grinding compensation device converts the grinding feed compensation amount into a table height adjustment amount. When the grinding device performs grinding by moving the table relative to the grinding head, it reads the grinding feed compensation amount corresponding to each matching sampling position group, and writes the grinding feed compensation amount into the table height adjustment amount according to the table height direction configuration saved in advance by the grinding device. The table height adjustment amount is used to control the height position of the table at the corresponding matching sampling position group.

[0174] Optionally, when the positive direction of the worktable height adjustment is the direction of increasing the amount of material removed, the sheet grinding compensation equipment determines the worktable height adjustment amount according to the following formula: ; in, This represents the workbench height adjustment amount corresponding to the i-th matching sampling position group; This represents the grinding feed compensation amount corresponding to the i-th matching sampling position group. The value is after non-negative constraints; the positive direction of the table height adjustment is given by the control parameter configuration file of the grinding equipment and pre-stored in the sheet metal grinding compensation device; when When it is 0, It is 0.

[0175] Alternatively, the sheet grinding compensation equipment converts the grinding feed compensation amount into a zoned machining allowance. When the grinding equipment performs grinding according to the compensation area, it reads the grinding feed compensation amount corresponding to each matching sampling position group in the same compensation area, and determines the zoned machining allowance based on the grinding feed compensation amount in the same compensation area. The zoned machining allowance is used to represent the machining allowance that needs to be performed by the grinding equipment in the corresponding compensation area.

[0176] Alternatively, the thin-piece grinding compensation equipment determines the machining allowance for each zone according to the following formula: ; Where q represents the compensation area number; This represents the processing allowance for the q-th compensation region. This represents the set of matching sampling location group numbers within the q-th compensation region; This represents the number of matching sampling position groups within the q-th compensation region; This represents the grinding feed compensation amount corresponding to the i-th matching sampling position group; and The assignment is determined by the thin-piece grinding compensation equipment based on the relationship between the compensation area and the matching sampling position group.

[0177] Step S702: Generate grinding control commands based on the control quantities.

[0178] The thin-piece grinding compensation equipment generates grinding control commands based on the grinding head feed rate, table height adjustment amount, or zone machining allowance. When the control quantity is the grinding head feed rate, the position coordinates of the matching sampling position group and the grinding head feed rate are written into the CNC machining command or grinding path data. When the control quantity is the table height adjustment amount, the position coordinates of the matching sampling position group and the table height adjustment amount are written into the CNC machining command or grinding path data. When the control quantity is the zone machining allowance, the compensation area number, compensation area boundary, and zone machining allowance are written into the zone machining parameters.

[0179] Grinding control commands are associated with the sheet coordinate system, grinding path, or machining area; the sheet coordinate system is used to represent the position of the matching sampling position group or compensation area on the sheet; the grinding path is given by the grinding equipment processing program, or generated by the sheet grinding compensation equipment based on the position coordinates of the matching sampling position group; the machining area is determined by the compensation area boundary or the area coordinate range; the grinding control commands, sheet coordinate system, grinding path, and machining area are written into the same control file or the same command data package.

[0180] Step S703: Control the grinding equipment according to the grinding control command.

[0181] The thin-piece grinding compensation device outputs grinding control commands to the grinding equipment through the grinding control interface. After receiving the grinding control commands, the grinding equipment reads the grinding head feed amount, the table height adjustment amount, or the zone machining allowance according to the grinding control commands. The grinding equipment controls the movement of the grinding head relative to the thin-piece according to the grinding head feed amount, or controls the movement of the table relative to the grinding head according to the table height adjustment amount, or controls the grinding amount corresponding to the compensation area according to the zone machining allowance.

[0182] During the grinding process, the grinding equipment can perform grinding feed compensation according to sampling points, interpolation paths, or compensation areas. When performing grinding feed compensation according to sampling points, the grinding equipment executes the corresponding control quantity at the position corresponding to the matching sampling position group. When performing grinding feed compensation according to interpolation paths, the grinding equipment generates the control quantity corresponding to the middle position of the path based on the positional relationship between adjacent matching sampling position groups. When performing grinding feed compensation according to compensation areas, the grinding equipment executes the corresponding partitioned machining allowance within the same compensation area.

[0183] In this embodiment, the sheet grinding compensation device can convert the grinding feed compensation amount into the grinding head feed amount, the table height adjustment amount, or the zone machining allowance; the grinding device can perform grinding on the sheet according to the grinding head feed amount, the table height adjustment amount, or the zone machining allowance; thus, the grinding feed compensation amount can be adapted to the control methods of different grinding devices.

[0184] Example 8: Please see Figure 9 As shown, based on the above embodiments, this embodiment further illustrates the process of releasing the clamp after grinding the sheet material and correcting the springback correction amount after release based on the third surface height data. This embodiment may include the following steps: Step S801: After grinding the sheet, release the clamp and obtain the height data of the third surface of the sheet in the released state.

[0185] After the sheet is ground once, the grinding equipment stops grinding the sheet; the grinding fixture releases at least one of the clamping effects of vacuum adsorption, pressure plate clamping, locating pin limiting, and fixture support on the sheet; the sheet enters a released state after the grinding fixture is released; the sheet in the released state is placed on a support, low-constraint support, or inspection table, and the support, low-constraint support, or inspection table does not apply any clamping effect for grinding to the sheet.

[0186] The surface height acquisition device acquires the third surface height data of the sheet in the released state; the surface height acquisition device acquires the surface height of the sheet according to a preset sampling path or preset sampling grid corresponding to the first surface height data, or according to a sampling path or sampling grid that can be converted to the same sheet coordinate system; the sheet grinding compensation device determines the sampling position obtained in the released state as the third sampling position, and determines the surface height value corresponding to the third sampling position as the third surface height value.

[0187] The third surface height data includes at least a third sampling position and a third surface height value; the third sampling position is used to indicate the position of the surface height acquisition point of the sheet in the acquisition coordinate system under the release state; the third surface height value is used to indicate the height of the third sampling position relative to the height reference; the sheet grinding compensation device stores the third sampling position and the third surface height value together, and stores the third surface height data together with at least one of the sheet identifier, acquisition time, acquisition coordinate system and height reference.

[0188] Step S802: Generate the expected surface height data of the clamping state after grinding based on the second surface height data and the grinding feed compensation amount.

[0189] The sheet metal grinding compensation device generates the expected surface height of the sheet metal after grinding and while it is still in the clamping state, based on the second surface height data of the sheet metal in the clamping state before grinding and the grinding feed compensation amount that has been executed. The second surface height data is used to represent the surface height of the sheet metal in the clamping state before grinding. The grinding feed compensation amount is used to represent the height compensation amount executed by the grinding device at the corresponding matching sampling position group. The expected surface height value of the clamping state after grinding is obtained by subtracting the grinding feed compensation amount from the second surface height value.

[0190] Optionally, the sheet metal grinding compensation device generates the expected surface height value in the clamping state after grinding according to the following formula: ; Where i represents the number of the matching sampling position group; This represents the expected surface height value of the clamping state after grinding corresponding to the i-th matching sampling position group; This represents the second surface height value corresponding to the i-th matching sampling position group; This represents the grinding feed compensation amount corresponding to the i-th matching sampling position group; and All use the same diameter in the height direction. When the grinding feed compensation is positive, it means that the grinding equipment is performing removal processing on the corresponding position.

[0191] The sheet metal grinding compensation device associates the expected surface height value of the clamped state after grinding with the position coordinates of the corresponding matching sampling position group to generate the expected surface height data of the clamped state after grinding. The expected surface height data of the clamped state after grinding includes at least the expected sampling position and the expected surface height value of the clamped state after grinding. The expected sampling position adopts the position coordinates of the corresponding matching sampling position group in the sheet metal coordinate system.

[0192] Step S803: Convert the third surface height data and the expected surface height data after grinding and clamping to the same sheet metal coordinate system and the same height reference.

[0193] The thin-piece grinding compensation device adopts the same or corresponding coordinate transformation method as in Example 2 to transform the third sampling position to the thin-piece coordinate system. When the third sampling position comes from the acquisition coordinate system of the surface height acquisition device, the transformation is completed according to the calibration relationship between the acquisition coordinate system of the surface height acquisition device and the thin-piece coordinate system. The expected sampling position in the expected surface height data of the clamping state after grinding has already adopted the position coordinates under the thin-piece coordinate system, and the expected sampling position is directly read.

[0194] The thin sheet grinding compensation device adopts the same or corresponding height reference conversion method as in Example 2 to convert the third surface height data and the expected surface height data after grinding clamping state to the same height reference. The height reference can be determined based on the reference plane, support point height, detection table reference surface or grinding fixture reference surface. When the third surface height data and the expected surface height data after grinding clamping state use different height references, the height difference between the different height references is read, and height reference conversion is performed on the third surface height value or the expected surface height value after grinding clamping state.

[0195] After conversion, the third surface height data and the expected surface height data in the clamping state after grinding can be compared at the same position; the sheet grinding compensation device determines the third sampling position and the expected sampling position with a distance not greater than the preset position threshold as the release retest matching position group; the release retest matching position group is used to limit the third surface height value and the expected surface height value in the clamping state after grinding that need to be read when calculating the difference in the subsequent calculation.

[0196] Step S804: Correct the springback correction amount after release based on the difference between the third surface height data and the expected surface height data after grinding and clamping.

[0197] The sheet metal grinding compensation device reads the third surface height value and the expected surface height value of the clamping state after grinding at the corresponding position under the same sheet metal coordinate system and the same height reference; for the release retest matching position group corresponding to the i-th matching sampling position group, the third surface height value is read. And read the expected surface height value after grinding and clamping. Third surface height value Expected surface height value after grinding and clamping All are height values ​​based on the same height reference.

[0198] The sheet metal grinding compensation equipment calculates the difference between the third surface height value and the expected surface height value in the post-grinding clamping state; optionally, the sheet metal grinding compensation equipment determines the actual springback release amount according to the following formula: ; in, This represents the actual rebound amount corresponding to the i-th matching sampling position group; This represents the height value of the third surface corresponding to the i-th matching sampling position group; The value represents the expected surface height of the clamped state after grinding corresponding to the i-th matching sampling position group; the actual release springback represents the height change of the sheet piece in the released state relative to the expected surface height of the clamped state after grinding.

[0199] The thin-piece grinding compensation equipment corrects the springback correction amount after release based on the actual springback amount. One feasible approach is to determine the actual springback amount as the corrected springback correction amount. Optionally, the thin-piece grinding compensation equipment determines the corrected springback correction amount according to the following formula: ; in, This represents the corrected rebound amount after release corresponding to the i-th matching sampling position group; This represents the actual release springback amount corresponding to the i-th matching sampling position group; the thin sheet grinding compensation device will... Associated with and stored with the i-th matching sampling position group, and Used for subsequent compensation of the current sheet component or subsequent sheet component compensation.

[0200] In this embodiment, the sheet metal grinding compensation device releases the grinding fixture after one grinding operation and collects the third surface height data of the sheet metal in the released state. Based on the second surface height data and the grinding feed compensation amount, it generates the expected surface height data of the clamped state after grinding. Then, it converts the third surface height data and the expected surface height data of the clamped state after grinding to the same sheet metal coordinate system and the same height reference, and corrects the springback correction amount after release based on the actual release springback amount.

[0201] Using the release retest correction method provided in this embodiment, the thin sheet grinding compensation device can use the third surface height data after the actual release of the thin sheet to correct the springback correction amount obtained according to the preset springback relationship; the corrected springback correction amount after release can be used for the current thin sheet subsequent compensation or subsequent thin sheet compensation, providing a preliminary data basis for updating the preset springback relationship and generating the secondary grinding feed compensation amount.

[0202] Example 9: Please see Figure 10 As shown, based on the above embodiments, this embodiment further illustrates the process of updating the preset springback relationship according to the third surface height data, the expected surface height data after grinding and clamping state, and the surface height change caused by clamping. This embodiment may include the following steps: Step S901: Obtain data for updating the preset bounce relationship.

[0203] The sheet grinding compensation device acquires the third surface height data; the third surface height data includes the third sampling position and the third surface height value; the third surface height data is acquired by the surface height acquisition device after the sheet grinding is completed and the grinding fixture is released and in a released state; the third surface height data is converted to the sheet coordinate system and height reference.

[0204] The sheet metal grinding compensation device acquires the expected surface height data of the clamped state after grinding; the expected surface height data of the clamped state after grinding is generated by the second surface height data and the grinding feed compensation amount; the expected surface height data of the clamped state after grinding includes the expected sampling position and the expected surface height value of the clamped state after grinding; the expected sampling position adopts the position coordinates in the sheet metal coordinate system; the expected surface height value of the clamped state after grinding adopts the same height reference as the third surface height value.

[0205] The sheet metal grinding compensation device acquires the surface height change caused by clamping; the surface height change caused by clamping is obtained by subtracting the first surface height value from the second surface height value under the same height reference; the sheet metal grinding compensation device also acquires the grinding feed compensation amount corresponding to the matching sampling position group during a grinding process; the grinding feed compensation amount is used to represent the amount of removal processing performed by the corresponding matching sampling position group in a grinding process; the third surface height data, the expected surface height data of the clamping state after grinding, the surface height change caused by clamping, and the grinding feed compensation amount are associated and stored according to at least one of the sheet metal identification, material batch, compensation area, and height change range.

[0206] Step S902: Determine the actual release rebound amount based on the actual difference after release.

[0207] The thin-sheet grinding compensation equipment calculates the actual springback release based on the difference between the third surface height data and the expected surface height data after grinding and clamping. For the i-th matching sampling position group, the third surface height value under the same thin-sheet coordinate system and the same height reference is read. Expected surface height value after grinding and clamping The actual rebound amount is determined according to the following formula: ; in, This represents the actual rebound amount corresponding to the i-th matching sampling position group; This represents the height value of the third surface corresponding to the i-th matching sampling position group; This represents the expected surface height value of the clamping state after grinding corresponding to the i-th matching sampling position group.

[0208] The thin-sheet grinding compensation equipment correlates the actual springback amount with the surface height change caused by clamping; for the i-th matching sampling position group, it reads the surface height change caused by clamping corresponding to the i-th matching sampling position group. And read the grinding feed compensation amount in one grinding process corresponding to the i-th matching sampling position group. ;when Not equal to 0, and When the amount of material removed in a single pass is not greater than the preset threshold, the thin sheet grinding compensation equipment determines the actual springback ratio according to the following formula: ; in, This represents the actual rebound ratio corresponding to the i-th matching sampling position group; This represents the actual rebound amount corresponding to the i-th matching sampling position group; This represents the change in surface height caused by clamping corresponding to the i-th matching sampling position group; This represents the grinding feed compensation amount in one grinding process corresponding to the i-th matching sampling position group; the preset single-pass removal threshold is given by the process document based on at least one of the following: sheet thickness, material batch, allowable single-pass removal amount, and target machining surface height tolerance; when equal to 0, or When the amount removed in a single pass exceeds the preset threshold, the thin sheet grinding compensation device does not use the i-th matching sampling position group to update the preset springback relationship.

[0209] Step S903: Update the preset springback relationship to obtain the updated springback relationship.

[0210] The sheet metal grinding compensation equipment updates the correspondence between the height change range and the springback correction coefficient based on at least one of the following: surface height change caused by clamping, actual springback release, grinding feed compensation in one grinding process, compensation area, clamping parameters, and sheet metal attributes. First, it determines the height change amplitude based on the absolute value of the surface height change caused by clamping, and then finds the height change range based on the height change amplitude. The sheet metal grinding compensation equipment only uses matching sampling position groups where the grinding feed compensation is not greater than a preset single-time removal threshold as update samples. When the preset springback relationship includes a compensation area, clamping parameter range, sheet metal thickness range, or material batch identifier, the springback correction coefficient is updated under the corresponding compensation area, corresponding clamping parameter range, corresponding sheet metal thickness range, or corresponding material batch identifier.

[0211] The update method can be replacement, weighted average, batch correction, or interval correction. When the replacement method is used, the thin sheet grinding compensation device will write the actual springback ratio selected through the update sample into the corresponding height change interval as the updated springback correction coefficient. When the weighted average method is used, the existing springback correction coefficient and historical sample quantity in the corresponding height change interval will be read, and the actual springback ratio selected through the update sample will be written into the corresponding height change interval before recalculating the springback correction coefficient. The actual springback ratio that does not pass the update sample selection will not be written into the preset springback relationship, and will be associated with the thin sheet identifier, material batch, compensation area, and grinding feed compensation amount and stored as a post-processing release retest record.

[0212] Optionally, when using a weighted average method, the thin-piece grinding compensation device updates the springback correction coefficient according to the following formula: ; Where m represents the number of the height change interval; This represents the updated rebound correction coefficient corresponding to the m-th height change interval; This represents the rebound correction coefficient before the update corresponding to the m-th height change interval; This represents the number of historical samples corresponding to the m-th height change interval before the update; This represents the set of matching sampling location group numbers used to update the m-th height change interval and filtered by the update samples; express The number of matching sampling position groups in the data; This represents the actual rebound ratio corresponding to the i-th matching sampling position group; and Given by the preset springback relationship, and The height is determined by the thin sheet grinding compensation equipment based on the height change range to which the height change amplitude belongs and the preset single removal amount threshold.

[0213] When the preset springback relationship includes the compensation area, the thin-piece grinding compensation device updates the springback correction coefficient within the corresponding compensation area; optionally, the thin-piece grinding compensation device updates the springback correction coefficient within the corresponding compensation area according to the following formula: ; Where q represents the compensation area number; This represents the updated rebound correction coefficient corresponding to the m-th height change interval in the q-th compensation region; This represents the rebound correction coefficient before the update corresponding to the m-th height change interval in the q-th compensation region; This represents the number of historical samples corresponding to the m-th height change interval in the q-th compensation region before the update; This represents the set of matching sampling location group numbers used to update the m-th height change interval in the q-th compensation region and filtered by the update samples; express The number of matching sampling position groups in the data; This represents the actual rebound ratio corresponding to the i-th matching sampling position group; and The thickness is determined by the thin sheet grinding compensation equipment based on the compensation area, the height change range to which the height change amplitude belongs, and the preset single removal amount threshold.

[0214] The thin-piece grinding compensation equipment writes the updated springback correction coefficient into the preset springback relationship and generates the updated springback relationship. The updated springback relationship retains the correspondence between the height change range and the springback correction coefficient. When the preset springback relationship includes a compensation area, clamping parameter range, thin-piece thickness range or material batch identifier, the updated springback relationship simultaneously retains the correspondence between the compensation area, clamping parameter range, thin-piece thickness range or material batch identifier and the springback correction coefficient.

[0215] Step S904: The updated springback relationship is used to determine the springback correction amount after the release of the subsequent sheet component.

[0216] When the subsequent sheet material enters the grinding compensation process, the sheet material grinding compensation equipment calls the updated springback relationship; the updated springback relationship is formed by the matching sampling position group filtered by the updated sample; the height change amplitude is determined according to the surface height change caused by the clamping of the subsequent sheet material, and the height change range to which the height change amplitude belongs is found in the updated springback relationship; then, the updated springback correction coefficient is read, and the springback correction amount after release of the subsequent sheet material is determined according to the updated springback correction coefficient and the surface height change caused by clamping.

[0217] Subsequent thin-plate parts can be thin-plate parts of the same specification, thin-plate parts of the same material batch, or thin-plate parts under the same fixture conditions; when the updated springback relationship includes the material batch identifier, the thin-plate part grinding compensation equipment will preferentially apply the updated springback relationship to thin-plate parts of the same material batch; when the updated springback relationship includes the clamping parameter range, the updated springback relationship will be applied to thin-plate parts whose clamping parameters fall within the same clamping parameter range; when the updated springback relationship includes the compensation area, the corresponding updated springback correction coefficient will be called according to the compensation area.

[0218] In this embodiment, the sheet metal grinding compensation device can obtain the actual springback release amount and the actual springback ratio based on the third surface height data, the expected surface height data after grinding and the surface height change caused by clamping. Then, it updates the sample screening of the actual springback ratio based on the grinding feed compensation amount in one grinding process, and uses the actual springback ratio screened through the updated sample to update the correspondence between the height change range and the springback correction coefficient, thus obtaining the updated springback relationship.

[0219] By using the updated preset springback relationship provided in this embodiment, the thin sheet grinding compensation device can write the first release retest data or historical processing data into the preset springback relationship; when the springback correction amount after release is determined for the thin sheet in the future, the updated springback relationship can be called, so that the grinding compensation amount of the thin sheet of the same specification, the same batch of materials, or the thin sheet under the same fixture working conditions can be determined based on the actual release retest results.

[0220] Example 10: Please see Figure 11 As shown, based on the above embodiments, this embodiment further illustrates the process of generating a secondary grinding feed compensation amount based on the residual deviation of the release state, and controlling the grinding equipment to perform secondary grinding on the thin sheet. This embodiment may include the following steps: Step S1001: Generate a release state residual deviation based on the difference between the third surface height data and the preset target processing surface height.

[0221] The thin sheet grinding compensation device reads the third surface height data of the thin sheet in the released state; the third surface height data includes the third sampling position and the third surface height value; the third surface height data is collected by the surface height acquisition device after the thin sheet completes one grinding and the grinding fixture is released; the third sampling position is converted to the thin sheet coordinate system, and the third surface height value is converted to the same height reference as the preset target machining surface height.

[0222] The thin-sheet grinding compensation device reads the preset target machining surface height; the preset target machining surface height is given by the thin-sheet machining drawing, process document or grinding equipment machining program, and is stored in the thin-sheet grinding compensation device in advance; the third surface height value is compared with the preset target machining surface height under the same height reference.

[0223] The sheet metal grinding compensation equipment calculates the difference between the height data of the third surface and the preset target machining surface height, and determines the difference as the residual deviation in the release state; optionally, the sheet metal grinding compensation equipment generates the residual deviation in the release state according to the following formula: ; Where i represents the number of the matching sampling position group; This represents the residual deviation of the release state corresponding to the i-th matching sampling position group; This represents the height value of the third surface corresponding to the i-th matching sampling position group; Indicates the preset target machining surface height; when When the value is positive, the position corresponding to the i-th matching sampling position group is higher than the preset target processing surface height in the released state; when When the value is negative, the position corresponding to the i-th matching sampling position group is lower than the preset target processing surface height in the release state.

[0224] Step S1002: After re-clamping the sheet piece in the grinding fixture, obtain the fourth surface height data of the sheet piece in the second clamping state.

[0225] The thin sheet grinding compensation equipment controls or prompts the thin sheet to be re-clamped in the grinding fixture; the grinding fixture re-establishes at least one of the following clamping effects on the thin sheet: vacuum adsorption, pressure plate clamping, locating pin limiting, and fixture support; the clamping parameters in the secondary clamping state are recorded, including at least one of the following clamping parameters: vacuum negative pressure value, pressure plate clamping force, support point position, and locating pin limiting state.

[0226] The surface height acquisition device acquires the fourth surface height data of the sheet in the secondary clamping state; the surface height acquisition device acquires the surface height of the sheet according to the preset sampling path or preset sampling grid corresponding to the third surface height data, or according to the sampling path or sampling grid that can be converted to the same sheet coordinate system; the sheet grinding compensation device determines the sampling position obtained in the secondary clamping state as the fourth sampling position, and determines the surface height value corresponding to the fourth sampling position as the fourth surface height value.

[0227] The fourth surface height data includes at least a fourth sampling position and a fourth surface height value; the fourth sampling position is used to indicate the position of the surface height acquisition point of the sheet metal in the acquisition coordinate system or the grinding fixture coordinate system under the secondary clamping state; the fourth surface height value is used to indicate the height of the fourth sampling position relative to the height reference; the sheet metal grinding compensation device stores the fourth sampling position and the fourth surface height value together, and stores the fourth surface height data together with at least one of the sheet metal identification, clamping parameters under the secondary clamping state, acquisition coordinate system and height reference.

[0228] Step S1003: Generate secondary grinding feed compensation amount based on the fourth surface height data, release state residual deviation and preset target machining surface height.

[0229] The thin sheet grinding compensation device maps the residual deviation of the release state to the corresponding position in the secondary clamping state; first, the third sampling position and the fourth sampling position are transformed to the same thin sheet coordinate system, and then the third sampling position and the fourth sampling position with a distance not greater than the preset position threshold are determined as the secondary compensation matching position group; the residual deviation of the release state corresponding to the third sampling position is written into the fourth sampling position in the same secondary compensation matching position group.

[0230] The sheet metal grinding compensation equipment determines the secondary grinding feed compensation amount based on the fourth surface height data, the residual deviation of the release state, and the preset target machining surface height; for the i-th secondary compensation matching position group, the fourth surface height value is read. Read the residual deviation of the release status And read the preset target machining surface height. Preset target machining surface height Used to generate release state residual deviation in step S1001 Fourth surface height value Used to determine the current clamping height corresponding to the secondary compensation matching position group in the secondary clamping state, and used to handle the residual deviation in the release state. Associated to the fourth sampling position; based on the residual deviation of the release state associated with the fourth sampling position. Generate secondary grinding feed compensation amount, without including the fourth surface height value Height of the preset target machining surface The difference between them is then added to the residual deviation in the release state. .

[0231] Optionally, the thin-piece grinding compensation device generates the secondary grinding feed compensation amount according to the following formula: ; in, This represents the secondary grinding feed compensation amount corresponding to the i-th secondary compensation matching position group; This represents the residual deviation of the release state corresponding to the i-th quadratic compensation matching position group; when When positive, the secondary grinding feed compensation equals the residual deviation in the release state and is used to enable the grinding equipment to perform secondary removal processing at the corresponding position; when... When the value is not greater than 0, the secondary grinding feed compensation is 0, and the grinding equipment does not perform negative removal processing at the corresponding position.

[0232] The fourth surface height data is used to map the residual deviation of the release state to the fourth sampling position in the secondary clamping state, and is used to generate the position coordinates and current clamping height in the secondary grinding control command; the preset target machining surface height is used to generate the residual deviation of the release state, which already represents the height difference between the third surface height value and the preset target machining surface height; therefore, the sheet metal grinding compensation device determines the corresponding position in the secondary clamping state based on the fourth surface height data, forms the residual deviation of the release state based on the preset target machining surface height, and generates the secondary grinding feed compensation amount based on the residual deviation of the release state mapped to the fourth sampling position; the sheet metal grinding compensation device follows... Generate the secondary grinding feed compensation amount corresponding to the i-th secondary compensation matching position group.

[0233] Step S1004: Control the grinding equipment to perform secondary grinding on the thin sheet according to the secondary grinding feed compensation amount.

[0234] The sheet metal grinding compensation equipment converts the secondary grinding feed compensation amount into the grinding head feed amount, the table height adjustment amount, or the zone machining allowance. When the grinding equipment performs secondary grinding by moving the grinding head relative to the sheet metal, the secondary grinding feed compensation amount is written into the grinding head feed amount. When the grinding equipment performs secondary grinding by moving the table relative to the grinding head, the secondary grinding feed compensation amount is written into the table height adjustment amount. When the grinding equipment performs secondary grinding according to the compensation area, the zone machining allowance is determined based on the secondary grinding feed compensation amount within the same compensation area.

[0235] The thin-piece grinding compensation device generates secondary grinding control commands according to the secondary grinding feed compensation amount, and outputs the secondary grinding control commands to the grinding equipment through the grinding control interface. After receiving the secondary grinding control commands, the grinding equipment performs secondary grinding on the thin-piece according to the grinding head feed amount, worktable height adjustment amount, or zone machining allowance in the secondary grinding control commands. After the secondary grinding is completed, the thin-piece grinding compensation device can control or prompt the release of the grinding fixture clamping function, and collect the surface height data of the thin-piece in the released state after the secondary grinding.

[0236] In this embodiment, when a thin sheet still has a residual deviation in the release state after a single grinding operation, the thin sheet grinding compensation device can generate a residual deviation in the release state based on the difference between the third surface height data and the preset target machining surface height. Subsequently, it acquires the fourth surface height data in the second clamping state, determines the fourth sampling position and the current clamping height in the second clamping state based on the fourth surface height data, determines the reference for the residual deviation in the release state based on the preset target machining surface height, and then generates a secondary grinding feed compensation amount based on the residual deviation in the release state mapped to the fourth sampling position.

[0237] Using the secondary grinding feed compensation method provided in this embodiment, the thin sheet grinding compensation equipment can continue to form secondary compensation processing after the first grinding release retest; the secondary grinding feed compensation amount is used to handle the residual deviation of the release state that is still retained after the first grinding release, which is suitable for the processing of thin sheet parts with small target machining surface height tolerance requirements or the first piece debugging process.

[0238] Example 11: See Figure 12 As shown, this embodiment provides a thin sheet grinding compensation system. The thin sheet grinding compensation system is used to execute the thin sheet grinding compensation method of any one of Embodiments 1 to 10; therefore, the thin sheet grinding compensation system can determine the surface height change caused by clamping based on the first surface height data of the thin sheet in the unclamped state and the second surface height data of the thin sheet in the clamped state, and generate a grinding feed compensation amount based on the springback correction amount after release.

[0239] The thin sheet grinding compensation system includes a first acquisition module, a second acquisition module, a change determination module, a springback determination module, a compensation generation module, and a grinding control module. The first acquisition module is connected to a surface height acquisition device and is used to acquire first surface height data of the thin sheet in an unclamped state. The first surface height data includes at least a first sampling position and a first surface height value. The first acquisition module is also used to associate and store the first surface height data with at least one of the following: thin sheet identification, acquisition time, acquisition coordinate system, and height reference.

[0240] The second acquisition module is connected to the surface height acquisition device and is used to acquire the second surface height data of the sheet in the clamping state after the sheet is clamped in the grinding fixture. The second surface height data includes at least the second sampling position and the second surface height value. The second acquisition module is also used to associate and store the second surface height data with at least one of the clamping parameters, the grinding fixture coordinate system and the acquisition height reference. The clamping parameters include at least one of the vacuum negative pressure value, the clamping force of the pressure plate, the position of the support point and the limiting state of the positioning pin.

[0241] The change determination module is connected to the first acquisition module and the second acquisition module, and is used to determine the surface height change caused by clamping based on the position matching relationship between the first surface height data and the second surface height data. The change determination module first determines the position matching relationship based on the first sampling position and the second sampling position, then reads the first surface height value and the second surface height value corresponding to the matching sampling position group in the position matching relationship, and then determines the signed difference obtained by subtracting the first surface height value from the second surface height value as the surface height change caused by clamping.

[0242] The springback determination module is connected to the change determination module and is used to determine the springback correction amount after release based on the surface height change caused by clamping and the preset springback relationship. The springback determination module determines the height change amplitude based on the absolute value of the surface height change caused by clamping and finds the height change range to which the height change amplitude belongs in the preset springback relationship. The springback determination module reads the springback correction coefficient corresponding to the height change range and multiplies the springback correction coefficient by the surface height change caused by clamping to obtain the springback correction amount after release.

[0243] The compensation generation module is connected to the second acquisition module and the springback determination module. It is used to generate a grinding feed compensation amount based on the second surface height data, the preset target machining surface height, and the springback correction amount after release. The compensation generation module reads the second surface height value, the springback correction amount after release, and the preset target machining surface height corresponding to the matching sampling position group. It then subtracts the preset target machining surface height from the sum of the second surface height value and the springback correction amount after release to obtain the grinding feed compensation calculation value corresponding to the matching sampling position group. The grinding feed compensation calculation value is used as the calculation source of the grinding feed compensation amount. When the grinding feed compensation calculation value is greater than 0, the compensation generation module determines the grinding feed compensation calculation value as the grinding feed compensation amount. When the grinding feed compensation calculation value is not greater than 0, the compensation generation module determines the grinding feed compensation amount as 0 and marks the corresponding matching sampling position group as a position where no removal machining is performed. The compensation generation module outputs the grinding feed compensation amount after non-negative constraint to the grinding control module.

[0244] The grinding control module is connected to the compensation generation module and the grinding equipment. It is used to control the grinding equipment to grind the thin sheet according to the grinding feed compensation amount. The grinding feed compensation amount is the value output by the compensation generation module after non-negative limiting. The grinding control module converts the grinding feed compensation amount into the grinding head feed amount, the table height adjustment amount, or the partition machining allowance, and generates grinding control commands based on the grinding head feed amount, the table height adjustment amount, or the partition machining allowance. When the grinding feed compensation amount is 0, the grinding control module generates a control command not to execute the removal machining, or sets the grinding head feed amount, the table height adjustment amount, or the partition machining allowance to 0 at the corresponding matching sampling position group. The grinding control module outputs grinding control commands to the grinding equipment through the grinding control interface.

[0245] In some embodiments, the change determination module includes a position matching relationship determination unit and a surface height change determination unit; the position matching relationship determination unit is used to obtain a first sampling position and a second sampling position, convert the first sampling position and the second sampling position to the same sheet coordinate system, and determine the first sampling position and the second sampling position with a distance not greater than a preset position threshold as a matching sampling position group; the surface height change determination unit is used to read the first surface height value and the second surface height value corresponding to the matching sampling position group, and determine the surface height change caused by clamping.

[0246] In some implementations, the springback determination module includes a height change amplitude determination unit, an interval search unit, and a springback correction amount generation unit; the height change amplitude determination unit is used to determine the height change amplitude based on the absolute value of the surface height change caused by clamping; the interval search unit is used to search for the height change interval to which the height change amplitude belongs in a preset springback relationship; the springback correction amount generation unit is used to read the springback correction coefficient corresponding to the height change interval, and generate the springback correction amount after release based on the springback correction coefficient and the surface height change caused by clamping.

[0247] In some implementations, the springback determination module further includes a compensation region division unit and a region springback correction unit; the compensation region division unit is used to divide the sheet into multiple compensation regions and assign the matching sampling position group to the corresponding compensation region according to the position coordinates in the sheet coordinate system; the region springback correction unit is used to determine the springback correction amount after release corresponding to the matching sampling position group in each compensation region according to the correspondence between the compensation region, the height change interval and the springback correction coefficient.

[0248] In some embodiments, the springback determination module further includes a clamping parameter acquisition unit and a springback correction coefficient determination unit; the clamping parameter acquisition unit is used to acquire at least one of the following: vacuum negative pressure value, pressure plate clamping force, support point position, locating pin limit state, sheet thickness, and material batch; the springback correction coefficient determination unit is used to determine the springback correction coefficient based on at least one of the following: vacuum negative pressure value, pressure plate clamping force, support point position, locating pin limit state, sheet thickness, and material batch, as well as the height variation range.

[0249] In some implementations, the compensation generation module includes a point-by-point compensation generation unit and an adjacent compensation limiting unit. The point-by-point compensation generation unit generates a grinding feed compensation amount for each matched sampling position group. The point-by-point compensation generation unit reads the second surface height value, the springback correction amount after release, and the preset target machining surface height corresponding to the matched sampling position group, and subtracts the preset target machining surface height from the sum of the second surface height value and the springback correction amount after release to obtain the grinding feed compensation calculation value. When the grinding feed compensation calculation value is greater than 0, the point-by-point compensation generation unit determines the grinding feed compensation calculation value as the grinding feed compensation amount. When the grinding feed compensation calculation value is not greater than 0, the point-by-point compensation generation unit determines the grinding feed compensation amount as 0. The adjacent compensation limiting unit is used to limit the difference between the grinding feed compensation amounts corresponding to the two matched sampling position groups to the preset compensation change threshold when the coordinate distance between the two matched sampling position groups in the same sheet coordinate system is not greater than a preset adjacent distance threshold, and the difference between the grinding feed compensation amounts corresponding to the two matched sampling position groups after non-negative limiting is greater than a preset compensation change threshold.

[0250] In some embodiments, the sheet grinding compensation system further includes a release retest correction module; the release retest correction module is used to release the sheet after grinding and obtain the third surface height data of the sheet in the released state; the release retest correction module is also used to generate the expected surface height data of the clamped state after grinding based on the second surface height data and the grinding feed compensation amount, and to correct the springback correction amount after release based on the difference between the third surface height data and the expected surface height data of the clamped state after grinding.

[0251] In some embodiments, the sheet metal grinding compensation system further includes a springback relationship update module; the springback relationship update module is used to update the preset springback relationship based on the third surface height data, the expected surface height data of the clamping state after grinding, and the surface height change caused by clamping, to obtain the updated springback relationship; the springback relationship update module is also used to provide the updated springback relationship to the springback determination module, so that the springback determination module can determine the springback correction amount after release based on the updated springback relationship in the subsequent sheet metal grinding compensation process.

[0252] In some embodiments, the sheet grinding compensation system further includes a secondary grinding compensation module; the secondary grinding compensation module is used to generate a release state residual deviation based on the difference between the third surface height data and the preset target machining surface height; the secondary grinding compensation module is also used to obtain the fourth surface height data of the sheet in the secondary clamping state after the sheet is re-clamped in the grinding fixture, and generate a secondary grinding feed compensation amount based on the fourth surface height data, the release state residual deviation and the preset target machining surface height.

[0253] It should be noted that the sheet metal grinding compensation system provided in this embodiment is only described in terms of the above-mentioned functional module division; in practical applications, the aforementioned functions can be allocated to different functional modules for execution according to the data acquisition interface, processor resources, grinding equipment control interface and production line control architecture, or the same processor can execute the processing of multiple functional modules; as long as it can complete the acquisition of the first surface height data, the acquisition of the second surface height data, the determination of the surface height change caused by clamping, the determination of the springback correction amount after release, the generation of grinding feed compensation amount and the control of grinding equipment, it belongs to the sheet metal grinding compensation system of this embodiment.

[0254] Example 12: Please see Figure 13 As shown, this embodiment provides a thin-sheet grinding compensation device. The thin-sheet grinding compensation device includes a data acquisition interface, a processor, a memory, and a grinding control interface; the data acquisition interface is connected to a surface height acquisition device; the processor is connected to the data acquisition interface, the memory, and the grinding control interface; the grinding control interface is connected to the grinding equipment; the thin-sheet grinding compensation device receives surface height data through the data acquisition interface, generates a grinding feed compensation amount through the processor, and outputs control commands to the grinding equipment through the grinding control interface.

[0255] The data acquisition interface is used to acquire the surface height data required to execute any of the sheet grinding compensation methods; the surface height data includes first surface height data, second surface height data, third surface height data, or fourth surface height data; the first surface height data is the data collected when the sheet is not clamped; the second surface height data is the data collected when the sheet is clamped; the third surface height data is the data collected when the sheet is released; and the fourth surface height data is the data collected when the sheet is clamped again.

[0256] The data acquisition interface is also used to acquire data associated with the surface height data; the data associated with the surface height data includes at least one of the following: sheet identification, acquisition time, acquisition coordinate system, height reference, vacuum negative pressure value, pressure plate clamping force, support point position, positioning pin limit status, sheet thickness, and material batch; the data acquisition interface transmits the acquired data to the processor, and the processor writes it into the memory.

[0257] The memory is used to store computer programs, first surface height data, second surface height data, third surface height data, fourth surface height data, preset springback relationships, preset target machining surface height, grinding feed compensation, secondary grinding feed compensation, or updated springback relationships; the preset springback relationships include the correspondence between height variation ranges and springback correction coefficients, or include the correspondence between compensation areas, height variation ranges, and springback correction coefficients; the preset target machining surface height is given by sheet metal machining drawings, process documents, or grinding equipment machining programs.

[0258] When the processor executes a computer program in memory, it implements any thin sheet grinding compensation method; the processor is used to determine the surface height change caused by clamping based on the position matching relationship between the first surface height data and the second surface height data; the processor is also used to determine the springback correction amount after release based on the surface height change caused by clamping and the preset springback relationship; the processor is also used to generate a grinding feed compensation amount based on the second surface height data, the preset target machining surface height and the springback correction amount after release.

[0259] The processor is also used to generate the expected surface height data of the clamping state after grinding based on the second surface height data and the grinding feed compensation amount after unclamping the sheet workpiece and obtaining the third surface height data. It is also used to correct the springback correction amount after release based on the difference between the third surface height data and the expected surface height data of the clamping state after grinding. The processor is also used to update the preset springback relationship based on the third surface height data, the expected surface height data of the clamping state after grinding, and the surface height change caused by clamping, so as to obtain the updated springback relationship.

[0260] The processor is also used to generate a release state residual deviation based on the difference between the third surface height data and the preset target machining surface height; the processor is also used to generate a secondary grinding feed compensation amount based on the fourth surface height data, the release state residual deviation and the preset target machining surface height after the sheet is re-clamped in the grinding fixture; the processor transmits the grinding feed compensation amount or the secondary grinding feed compensation amount to the grinding control interface.

[0261] The grinding control interface is used to output control commands to the grinding equipment based on the grinding feed compensation amount, or to output control commands based on the secondary grinding feed compensation amount. The control commands include the grinding head feed amount, the table height adjustment amount, or the zoned machining allowance. The grinding equipment controls the movement of the grinding head relative to the workpiece, or controls the movement of the table relative to the grinding head, or performs grinding on the compensation area of ​​the workpiece according to the zoned machining allowance.

[0262] Optionally, the sheet metal grinding compensation device can be a controller integrated with the grinding equipment, a stand-alone industrial computer, a CNC system, or an edge computing device. When the sheet metal grinding compensation device is a controller integrated with the grinding equipment, the data acquisition interface and the grinding control interface are located inside the grinding equipment. When the sheet metal grinding compensation device is a stand-alone industrial computer, a CNC system, or an edge computing device, the data acquisition interface is connected to the surface height acquisition device via wired communication or an industrial communication bus, and the grinding control interface is connected to the grinding equipment via wired communication or an industrial communication bus.

[0263] It should be noted that the specific structure of the thin sheet grinding compensation device is not limited to the aforementioned structure; as long as the thin sheet grinding compensation device includes a data acquisition interface capable of acquiring surface height data, a memory capable of storing computer programs and process data, a processor capable of executing the thin sheet grinding compensation method, and a grinding control interface capable of outputting control commands to the grinding equipment, the thin sheet grinding compensation device provided in this embodiment can be realized.

[0264] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by hardware related to program instructions; the program can be stored in a computer-readable storage medium; the computer-readable storage medium can be a read-only memory, random access memory, disk, optical disk, flash memory or other media capable of storing computer programs; when the processor reads and executes the computer program in the computer-readable storage medium, it can implement the sheet grinding compensation method in the above embodiments.

[0265] The above description is merely a preferred embodiment of this application, and the scope of protection of this application shall be determined by the scope defined in the claims. Any improvements and modifications made by those skilled in the art without departing from the essence of the technical solution of this application shall fall within the scope of protection of this application. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of this application shall also be considered within the scope of protection of this application.

Claims

1. A method for grinding compensation of thin sheet parts, characterized in that, include: Obtain the first surface height data of the sheet component in its unclamped state; After the sheet is clamped in the grinding fixture, the second surface height data of the sheet in the clamping state is obtained; The change in surface height caused by clamping is determined based on the positional matching relationship between the first surface height data and the second surface height data; The springback correction amount after release is determined based on the surface height change caused by clamping and the preset springback relationship; The grinding feed compensation is generated based on the second surface height data, the preset target machining surface height, and the springback correction amount after release. The grinding equipment is controlled according to the grinding feed compensation to grind thin parts.

2. The grinding compensation method for thin sheet parts according to claim 1, characterized in that, Methods for determining positional matching relationships include: Obtain the first sampling position corresponding to the first surface height data and the second sampling position corresponding to the second surface height data; The first sampling position and the second sampling position are transformed to the same sheet coordinate system, and the first surface height data and the second surface height data are transformed to the same height reference. The first and second sampling positions, whose distance is not greater than a preset position threshold, are determined as a matching sampling position group; The set of matching sampling position groups is the position matching relationship.

3. The grinding compensation method for thin sheet parts according to claim 2, characterized in that, Methods for determining the surface height change caused by clamping include: For each matching sampling location group, read the first surface height value from the first surface height data and the second surface height value from the second surface height data under the same height reference; The signed difference obtained by subtracting the first surface height value from the second surface height value is determined as the surface height change caused by clamping corresponding to the matching sampling position group.

4. The grinding compensation method for thin sheet parts according to claim 3, characterized in that, Methods for determining the rebound correction amount after release include: The height change amplitude is determined based on the absolute value of the surface height change caused by clamping, and the height change range to which the height change amplitude belongs is found in the preset springback relationship. Multiply the springback correction coefficient corresponding to the height change range by the surface height change caused by clamping to obtain the springback correction amount after release. The springback correction amount after release represents the height change of the sheet part relative to the clamping state after it is released from clamping.

5. The grinding compensation method for thin sheet parts according to claim 4, characterized in that, Methods for determining the rebound correction amount after release also include: The sheet component is divided into multiple compensation areas; Determine the surface height change caused by clamping for each matching sampling position group within each compensation area; The preset rebound relationship includes the correspondence between the compensation area, the height change range, and the rebound correction coefficient; Based on the height change range to which the surface height change caused by clamping in each compensation area belongs, the rebound correction amount after release corresponding to each compensation area is generated.

6. The grinding compensation method for thin sheet parts according to claim 4, characterized in that, Methods for determining the rebound correction amount after release also include: The vacuum negative pressure value, the clamping force of the pressure plate, the position of the support point, the limiting status of the locating pin, the thickness of the sheet and the material batch are obtained after the sheet is clamped in the grinding fixture. The springback correction coefficient is determined based on at least one of the following: vacuum negative pressure value, pressure plate clamping force, support point position, positioning pin limit status, sheet thickness, and material batch, as well as the height variation range.

7. The grinding compensation method for thin sheet parts according to claim 1, characterized in that, Also includes: After the sheet is ground, it is unclamped and the height data of the third surface of the sheet in the released state is obtained. The expected surface height data for the clamping state after grinding is generated based on the second surface height data and the grinding feed compensation. The third surface height data and the expected surface height data after grinding and clamping are converted to the same sheet metal coordinate system and the same height datum. Based on the same sheet coordinate system and the same height reference, the springback correction amount after release is corrected by the difference between the third surface height data and the expected surface height data in the clamping state after grinding.

8. The grinding compensation method for thin sheet parts according to claim 7, characterized in that, Also includes: Based on the third surface height data, the expected surface height data after grinding and the surface height change caused by clamping, the preset springback relationship is updated to obtain the updated springback relationship. The updated springback relationship is used to determine the springback correction amount after the release of subsequent sheet parts.

9. A method for grinding compensation of thin sheet parts according to claim 3, characterized in that, Methods for generating grinding feed compensation include: For each matching sampling position group, the sum of the second surface height value in the second surface height data and the springback correction amount after release is subtracted from the preset target machining surface height to obtain the grinding feed compensation calculation value corresponding to the matching sampling position group, and the grinding feed compensation amount is determined based on the grinding feed compensation calculation value.

10. A method for grinding compensation of thin sheet parts according to claim 9, characterized in that, Methods for generating grinding feed compensation also include: When the coordinate distance between two matching sampling position groups in the same sheet coordinate system is not greater than the preset adjacent distance threshold, and the difference between the grinding feed compensation amounts corresponding to the two matching sampling position groups is greater than the preset compensation change threshold, the difference between the grinding feed compensation amounts corresponding to the two matching sampling position groups is limited to the preset compensation change threshold.

11. The grinding compensation method for thin sheet parts according to claim 1, characterized in that, Methods for controlling grinding equipment to grind thin sheet parts include: Convert the grinding feed compensation into the grinding head feed, table height adjustment, or zone machining allowance. The grinding equipment is controlled according to the grinding head feed rate, the table height adjustment amount, or the machining allowance for each zone.

12. The grinding compensation method for thin sheet parts according to claim 1, characterized in that, Methods for obtaining the height data of the first surface include: When the sheet is supported but not clamped by the grinding fixture, the surface height of the sheet is collected to obtain the first surface height data.

13. The grinding compensation method for thin sheet parts according to claim 1, characterized in that, Methods for obtaining the height data of the second surface include: After the sheet is clamped in the grinding fixture, the grinding fixture exerts at least one clamping action on the sheet, including vacuum adsorption, pressure plate clamping, positioning pin limiting, and fixture support, and collects the surface height of the sheet to obtain second surface height data.

14. The grinding compensation method for thin sheet parts according to claim 7, characterized in that, Also includes: Based on the difference between the third surface height data and the preset target machining surface height, a release state residual deviation is generated; After re-clamping the sheet material into the grinding fixture, obtain the fourth surface height data of the sheet material in the second clamping state; The secondary clamping position corresponding to the residual deviation of the release state is determined based on the fourth surface height data, and the secondary grinding feed compensation amount is generated based on the residual deviation of the release state mapped to the secondary clamping position. The grinding equipment is controlled according to the secondary grinding feed compensation amount to perform secondary grinding on thin sheet parts.

15. A grinding compensation system for thin sheet parts, characterized in that, include: The first acquisition module is used to acquire the first surface height data of the sheet in the non-clamping state; The second acquisition module is used to acquire the second surface height data of the sheet in the clamping state after the sheet is clamped in the grinding fixture. The change determination module is used to determine the surface height change caused by clamping based on the position matching relationship between the first surface height data and the second surface height data; The springback determination module is used to determine the springback correction amount after release based on the surface height change caused by clamping and the preset springback relationship; The compensation generation module is used to generate grinding feed compensation based on the second surface height data, the preset target machining surface height, and the springback correction amount after release. The grinding control module is used to control the grinding equipment to grind thin parts according to the grinding feed compensation amount.

16. A grinding compensation device for thin sheet parts, characterized in that, It includes a data acquisition interface, a processor, a memory, and a grinding control interface. The data acquisition interface is used to acquire surface height data required to execute the thin sheet grinding compensation method according to any one of claims 1 to 14. The memory stores a computer program. When the processor executes the computer program, it implements the thin sheet grinding compensation method according to any one of claims 1 to 14. The grinding control interface is used to output control commands generated according to the grinding feed compensation amount to the grinding equipment.

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