Method for predicting deformation degree of plate after layer cutting
By testing residual stress and calculating deflection layer by layer in the thickness direction of the sheet material, the problem of unpredictable deformation after sheet material layer cutting in the prior art is solved, achieving accurate prediction and effective control of deformation, and improving processing accuracy and efficiency.
Patent Information
- Application Number
- CN202511005089.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-21
- Publication Date
- 2025-10-17
AI Technical Summary
Existing technologies are unable to quickly predict the degree of deformation of the plate after layer cutting, which makes it difficult to control the residual stress inside the plate, thereby affecting machining accuracy and product quality.
By testing the residual stress layer by layer in the thickness direction of the plate and substituting the data into the formula to calculate the deflection, the degree of deformation of the plate after layer cutting is predicted, and the residual stress is measured using the peeling method, the slit warping method, the crack flexibility method or the neutron diffraction method.
It significantly reduces processing errors, improves product consistency and quality, lowers costs, increases processing efficiency, and prevents deformation by adjusting processing parameters and stress compensation.
Smart Images
Figure CN120809016A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of machining, in particular to a method for predicting deformation degree of plate after layering. BACKGROUND
[0002] The plate is widely used in the industrial field, and with the development of high-end equipment and products, the size accuracy of the plate machining is required higher and higher. Due to the uneven temperature field and deformation in the preparation process of the plate, the residual stress in the material is difficult to avoid, the release of the residual stress in the machining process breaks the mechanical balance, and the plate is deformed, so the residual stress in the plate is the main reason for the deformation in the machining.
[0003] For the plate material, assuming that the residual stress of the aluminum alloy thick plate is uniformly distributed on the same thickness, and the residual stress only differs in the thickness, the residual stress distribution in the thickness can be obtained by using the material internal residual stress testing technologies such as layering method, slit warping method, crack flexibility method and neutron diffraction method. However, there is currently no method for quickly predicting the workpiece machining deformation according to the known residual stress distribution in the thickness, and it is difficult to propose the control range required by the internal residual stress of the plate. SUMMARY
[0004] The main purpose of the present application is to provide a method for predicting the deformation degree of the plate after layering, so as to solve the problem that the deformation degree of the plate after layering cannot be predicted according to the residual stress in the prior art.
[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a method for predicting the deformation degree of the plate after layering is provided, which comprises the following steps: step S1, taking the horizontal plane of the plate to be layered as the starting point, testing the residual stress at each layering position in the thickness direction, and recording it as σ j ; step S2, substituting σ j obtained in step S1 into the formula , to obtain the deflection h i of the plate after layering i times; the deflection h i is used to predict the deformation degree of the plate after layering, and the absolute value of the deflection h i is positively correlated with the deformation degree after layering; wherein i is the total number of layering of the plate, j is the intermediate number of layering of the plate, △x is the thickness of each layering of the plate, E is the elastic modulus of the plate, s is the total thickness of the plate, and l is the length of the plate, the length direction is along the layering direction.
[0006] Further, the above-mentioned residual stress measurement method is selected from any one of the layering method, the slit warping method, the crack flexibility method and the neutron diffraction method.
[0007] Further, when h iWhen the h is positive, the warping deformation of the two sides of the milling surface towards the direction of the milling cutter is positive deformation. i When the h is negative, the warping deformation of the middle of the milling surface towards the direction of the milling cutter is negative deformation.
[0008] Further, the i is 1-20 times; and / or, the Δx is 1-5 mm.
[0009] Further, the i is 1-12 times; and / or, the Δx is 3-4 mm.
[0010] Further, the l is 200-2000 mm; and / or, the ratio of the width of the plate to the l is 1:(2-8); and / or, the s is 50-200 mm.
[0011] Further, the l is 300-1000 mm; and / or, the ratio of the width of the plate to the l is 1:(4-6); and / or, the s is 80-100 mm.
[0012] Further, the E is 42-210 GPa.
[0013] Further, the plate is any one of an aluminum alloy plate, a steel plate, a titanium alloy plate and a magnesium alloy plate.
[0014] Further, when the plate is an aluminum alloy plate, the E is 68-72 GPa; when the plate is a steel plate, the E is 190-210 GPa; when the plate is a titanium alloy plate, the E is 110-115 GPa; and when the plate is a magnesium alloy plate, the E is 42-45 GPa.
[0015] By applying the technical solution of the present application, the present application can calculate the deflection of the plate after different layer cutting times by testing the residual stress layer by layer in the thickness direction of the plate and then substituting these data into the formula, which helps to estimate the deformation that the plate may occur before processing so as to take corresponding preventive measures. The deformation in the plate processing process is one of the main reasons for causing the size deviation and irregular shape of the final product. By predicting the deformation in advance, the operator or the automatic system can adjust the processing parameters such as the cutting depth, the speed and the feed rate, and increase the stress compensation link when necessary, so as to help to significantly reduce the processing error, and thus help to improve the consistency and quality of the product, and reduce the processing cost and improve the processing efficiency. BRIEF DESCRIPTION OF DRAWINGS
[0016] The drawings accompanying the specification of the present application form a part thereof, serve to provide further understanding of the present application, and together with the specification explain the present application, and do not constitute an improper limitation on the present application. In the drawings:
[0017] Figure 1A front view of the layer-reduced plate according to the present application is shown in the figure.
[0018] Figure 2 A cross-sectional view of the layer-reduced plate according to the present application is shown in the figure.
[0019] Figure 3 A comparison chart of the predicted deflection and the actual deflection with the layer-reduced depth in Example 1 of the present application is shown in the figure.
[0020] Figure 4 A distribution chart of the plate sampling points according to the present application is shown in the figure.
[0021] Figure 5 A cloud chart of the overall warping deformation of the plate when the layer-reduced depth reaches 1 / 2 of the thickness of the plate in Example 1 of the present application is shown in the figure.
[0022] In the above figures, the following reference signs are used:
[0023] 1. Neutral plane. DETAILED DESCRIPTION
[0024] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.
[0025] Explanation of terms: The layer reduction in the present application refers to a process of cutting horizontally along the thickness direction of the plate to reduce the thickness of the plate; the deflection in the present application refers to the height in the vertical direction between the center position of the plate and the raised edge position of the plate.
[0026] As analyzed in the background art of the present application, the prior art cannot predict the deformation degree of the plate after layer reduction according to the residual stress. In order to solve the above problem, the present application provides a method for predicting the deformation degree of the plate after layer reduction.
[0027] In a typical embodiment of the present application, a method for predicting the deformation degree of the plate after layer reduction is provided, which comprises: step S1, taking the horizontal plane where the plate needs to be layer-reduced as the starting point, testing the residual stress at each position where layer reduction is needed along the thickness direction, and recording as σ j ; step S2, substituting σ j tested in step S1 into the formula to obtain the deflection h i of the plate after layer reduction i times; and predicting the deformation degree of the plate after layer reduction through the deflection h i , wherein h iThe absolute value of the sum of the product of i, j, △x, E, s, and l is positively correlated with the degree of deformation after layer cutting; i is the total number of layer cutting of the plate, j is the intermediate number of layer cutting of the plate, △x is the thickness of each layer cutting of the plate, E is the elastic modulus of the plate, s is the total thickness of the plate, and l is the length of the plate in the direction along the layer cutting.
[0028] The present application can calculate the deflection of the plate after different layer cutting times by layer-by-layer testing of the residual stress in the thickness direction of the plate and then substituting the data into the formula, which helps to estimate the deformation that may occur in the plate before processing so as to take corresponding preventive measures. The deformation in the plate processing process is one of the main reasons for causing the size deviation and irregular shape of the final product. The present application can make the operator or the automatic system adjust the processing parameters such as the cutting depth, speed, and feed rate, and increase the stress compensation link when necessary, so as to help significantly reduce the processing error, thereby helping to improve the consistency and quality of the product, and reduce the processing cost and improve the processing efficiency.
[0029] In an embodiment of the present application, i is 1-20 times; and / or, △x is 1-5 mm.
[0030] Controlling i and △x in the above range helps to improve the accuracy of the prediction.
[0031] In order to further improve the accuracy of the prediction, in an embodiment of the present application, i is 1-12 times; and / or, △x is 3-4 mm.
[0032] In an embodiment of the present application, l is 200-2000 mm; and / or, the ratio of the width of the plate to l is 1:(2-8); and / or, s is 50-200 mm.
[0033] Controlling l and s in the above range helps to make the prediction model based on the residual stress distribution more specific and accurate.
[0034] In order to further improve the accuracy of the prediction, in an embodiment of the present application, l is 300-1000 mm; and / or, the ratio of the width of the plate to l is 1:(4-6); and / or, s is 80-100 mm.
[0035] In an embodiment of the present application, E is 42-210 GPa.
[0036] For the same kind of plate, the range of E is smaller, and for different kinds of plates, the difference of E is more obvious.
[0037] In an embodiment of the present application, the plate is any one of an aluminum alloy plate, a steel plate, a titanium alloy plate, and a magnesium alloy plate.
[0038] The prediction method of the present application is universal and can be used to predict plates of different materials, especially the plates of the above-mentioned types.
[0039] In an embodiment of the present application, when the plate is an aluminum alloy plate, E is 68-72 GPa; when the plate is a steel plate, E is 190-210 GPa.
[0040] Aluminum alloy plates and steel plates generally have the elastic modulus in the above-mentioned range.
[0041] In an embodiment of the present application, when the plate is a titanium alloy plate, E is 110-115 GPa; when the plate is a magnesium alloy plate, E is 42-45 GPa.
[0042] Titanium alloy plates and magnesium alloy plates generally have the elastic modulus in the above-mentioned range.
[0043] In an embodiment of the present application, the measurement method of the residual stress is selected from any one of a layer peeling method, a slit warping method, a crack compliance method and a neutron diffraction method.
[0044] The residual stress of the plate in the thickness direction can be measured by using the above-mentioned measurement methods.
[0045] The layer peeling method is specifically as follows: a cutting tool is used to continuously layer cut along the surface of the plate, after each layer is peeled off, the geometric size change of the peeled area is immediately measured, mainly the springback deformation of the peeled area is measured, the deformation amount of the sample before and after each peeling is recorded, including the changes in length, width and height. By analyzing these deformation data, combining the elastic modulus and Poisson's ratio of the material, and applying appropriate mechanical formulas, the residual stress of the peeled layer can be calculated.
[0046] The slit warping method is specifically as follows: a cutting tool is used to cut one or several fine slits on the surface of the plate, the warping deformation amount of the plate near the slit is measured, the warping data of multiple positions are recorded, and based on the warping measurement results, the internal residual stress of the slit area and the entire plate is calculated.
[0047] The crack compliance method is specifically as follows: one or more fine cracks are introduced on the plate using a tool, a displacement sensor is used to measure the opening displacement of the crack tip, the measurement results of the crack opening displacement are recorded, and by combining the change of the crack opening displacement with the known elastic theory model, the residual stress of the crack area and the surrounding material can be calculated.
[0048] The neutron diffraction method is specifically as follows: the plate is placed in a test position of a neutron diffractometer, the neutron diffractometer emits a neutron beam, and the neutron beam interacts with atomic lattices in the plate to generate diffraction patterns. By analyzing the diffraction patterns, the spacing of the lattices can be accurately determined. The existence of residual stress compresses or stretches the lattices, causing the spacing of the lattices to change. According to the change in the spacing of the lattices, the corresponding micro stress is calculated by applying physical principles such as the elastic constant and Bragg's law. The micro stress is directly related to the macro residual stress, and therefore the residual stress distribution in the plate can be calculated.
[0049] In an embodiment of the present application, when h i is positive, the warping deformation of the two sides of the milling surface towards the direction close to the milling cutter is positive deformation; when h i is negative, the warping deformation of the middle of the milling surface towards the direction close to the milling cutter is negative deformation.
[0050] In an embodiment of the present application, the difference between the predicted deflection of the plate and the actual deflection of the plate is -25.9-17.1.
[0051] The difference between the predicted deflection of the plate and the actual deflection of the plate is small, and therefore the method of the present application can effectively predict the degree of deformation of the plate after layer milling.
[0052] The present application The derivation process is as follows: it is assumed that the residual stress of the plate is uniformly distributed at the same thickness, and the residual stress only differs in thickness. In the absence of external force, the residual stress is in a state of balance. When the material is removed layer by layer, the original mechanical balance is broken, and the remaining residual stress will be redistributed, and the stress and moment reach a new balance. At this time, the force causing the deformation is equal in size and opposite in direction to the combined force and moment of the residual stress in the removed layer. By testing the distribution of the residual stress in the thickness, the deflection of the material can be calculated.
[0053] Before the material is removed, the stress on the cross section is in a state of balance. During the layer milling process, the bending of the plate will affect the residual stress of the un-bent part. After each layer of material is removed, the residual stress of the un-removed material part will be redistributed, and therefore needs to be corrected during the calculation of the subsequent passes.
[0054] As Figure 1 As shown in the front view structure diagram of the layer-milled plate, when the i-th pass is layer-milled, the layer-milling depth reaches i△x, and the neutral surface 1 has a curvature radius of R i At this time, the bending moment M i of the plate during the i-th pass on any cross section can be represented as:
[0055]
[0056] wherein, Ii Ii represents the inertia moment of the uncut part of the plate at the i-th pass.
[0057] According to the geometric relationship:
[0058] (R i -h i ) 2 +(l / 2) 2 =(R i ) 2 (2)
[0059] Therefore, R i can be expressed as:
[0060]
[0061] According to equations (1) and (3), the bending moment and the geometric relationship of the plate with a length of l can be expressed as:
[0062]
[0063] Therefore, the deflection h i can be expressed as:
[0064]
[0065] For the overall milling of the plate, the A-A cross section perpendicular to the l direction of the plate is a rectangle, as shown in Figure 2 The cross-sectional structure of the layer-cut plate of the present application is shown in the figure, and b is the width of the plate.
[0066] At this time, I i can be expressed as:
[0067]
[0068] M i is the accumulation of the residual stress of the 1st to i-th pass on the neutral plane 1. Assuming that j is a certain pass, the residual stress of the j-th pass relative to the distance t j of the neutral plane can be expressed as:
[0069]
[0070] Therefore, the influence of the residual stress on the bending moment M i can be expressed as:
[0071]
[0072] By substituting equation (8) into equation (5), the deflection h i generated by the overall layer-cutting of the plate can be calculated, that is,
[0073]
[0074] The beneficial effects of the present application will be further illustrated below in conjunction with examples.
[0075] Example 1
[0076] Predicted h i Data: the length l of the aluminum alloy 7050 plate is 400 mm, the width is 100 mm, the thickness s is 100 mm, the elastic modulus E is 69 GPa, the thickness of each layer cutting is 4 mm, the total number of layer cutting i is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, j is the middle number of layer cutting of the plate, the residual stress σ j at each layer cutting position in the thickness direction is tested by using the slit warping method residual stress testing technology, taking the horizontal plane of the plate to be layer cut as the starting point, and the residual stress distribution data along the thickness direction is obtained, as shown in Table 1.
[0077] Table 1
[0078]
[0079] The data in Table 1 is substituted into
[0080] to obtain the deflection h i of the plate after layer cutting for 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 times, and the results are shown in Table 2.
[0081] Actual h i Data: the same specification aluminum alloy 7050 plate as above is layer cut by using a numerical control milling machine, the total number of layer cutting i is 2, 4, 6, 8, 10 and 12, the thickness of each layer cutting is 4 mm, the bottom of the sample is tested by using a three-coordinate device, and the test position is as shown in Figure 4 Figure 4 , wherein P1, P2, P3, P4, P5, P6, P7, P8, P9, P10, P11, P12, P13, P14, P15, P16, P17, P18, P19, P20, P21, P22, P23, P24, P25, a total of 25 points, are distributed in Figure 4 , the average value of the warping deformation of the sample P1, P6, P11, P16, P21, P5, P10, P15, P20, P25 at 10 points is collected, the deflection h i after layer cutting for 2, 4, 6, 8, 10 and 12 times is calculated, and the predicted h i is calculated, and the difference between the actual h i , and the results are shown in Table 2.
[0082] Table 2
[0083]
[0084] Example 2
[0085] The difference from Example 1 is that the length l of the aluminum alloy 7050 plate is 1000 mm, the width is 200 mm, and the thickness s is 80 mm;
[0086] Prediction h i Data: The elastic modulus E is 69 GPa, the thickness of each layer is 4 mm, the total number of layer cuts i is 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10, j is the middle number of layer cuts of the plate, and the residual stress test technology of the slit warping method is used. Starting from the horizontal surface of the plate to be layer cut, the residual stress σ at the position where each layer cut is required is tested along the thickness direction. j The residual stress distribution data along the thickness direction are shown in Table 3.
[0087]
[0088] Substitute the data in Table 3 into
[0089] The deflection h of the plate after 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 times of layering is obtained. i , the results are shown in Table 4.
[0090] Actual h i Data: A CNC milling machine was used to cut the aluminum alloy 7050 plates of the same specifications as above. The total number of cuts i was 2, 4, 6, 8 and 10 respectively. The thickness of each cut was 4mm. The three-coordinate test was carried out on the bottom of the sample using a three-coordinate machine. The test parts were as follows: Figure 4 As shown, collection Figure 4 The average value of the warping deformation of 10 points at P1, P6, P11, P16, P21, P5, P10, P15, P20, and P25 of the specimen is used to calculate the deflection h after 2, 4, 6, 8, and 10 times of layer cutting. i , and calculate the predicted h i With actual h i The results are shown in Table 4.
[0091] Table 4
[0092]
[0093]
[0094] Example 3
[0095] The difference from Example 1 is that SS400 steel plate is used to replace the aluminum alloy 7050 plate;
[0096] Prediction h i Data: The length l of the SS400 steel plate is 300 mm, the width is 50 mm, the thickness s is 80 mm, the elastic modulus E is 210 GPa, the thickness △x of each layer is 4 mm, the total number of layer cuts i is 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10, j is the number of layer cuts in the middle of the plate, and the residual stress test technology of the slit warping method is used. Starting from the horizontal plane of the plate to be layered, the residual stress σ at each layer cut position is tested along the thickness direction. j The residual stress distribution data along the thickness direction are shown in Table 5.
[0097] Table 5
[0098]
[0099]
[0100] Substitute the data in Table 5 into
[0101] The deflection h of the plate after 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 times of layering is obtained. i , the results are shown in Table 6.
[0102] Actual h i Data: The SS400 steel plates with the same specifications as above were cut by CNC milling machine. The total number of cuts i was 2, 4, 6, 8 and 10 respectively. The thickness of each cut was 4mm. The bottom of the sample was tested by three-coordinate equipment. The test parts were as follows: Figure 4 As shown, collection Figure 4 The average value of the warping deformation of 10 points of the specimen P1, P6, P11, P16, P21, P5, P10, P15, P20, and P25 is used to calculate the deflection h after the layer is cut 2 times, 4 times, 6 times, 8 times, and 10 times. i , and calculate the predicted h i With actual h i The results are shown in Table 6.
[0103] Table 6
[0104]
[0105] Figure 3 The comparison diagram of the predicted deflection and the actual deflection with the change of the layer cutting depth in Example 1 of the present application is shown in FIG. Figure 3As can be seen from the figure, the test obtained sample deformation results at different milling depths are highly consistent with the predicted warping deformation results obtained by calculation.
[0106] Figure 5 For the warping deformation cloud chart of the plate as a whole when the layer milling depth reaches 1 / 2 of the thickness of the plate in Embodiment 1 of the present application, it can be seen from the figure that the sample as a whole presents a warping state at both ends.
[0107] As can be seen from the data in the table, the method of the present application can quickly predict the warping deformation of the plate at different processing depths according to the test obtained residual stress distribution.
[0108] As can be seen from the above description, the above-mentioned embodiments of the present application achieve the following technical effects:
[0109] The present application can calculate the deflection of the plate after different layer milling times by testing the residual stress in the thickness direction of the plate layer by layer and then substituting these data into the formula, which is helpful for estimating the deformation that may occur to the plate before processing so as to take corresponding preventive measures. The deformation in the plate processing process is one of the main reasons for causing the size deviation and irregular shape of the final product. The present application can make the operator or the automatic system adjust the processing parameters such as the cutting depth, the speed and the feed rate, and increase the stress compensation link when necessary, so as to help significantly reduce the processing error, thereby helping to improve the consistency and quality of the product, and reduce the processing cost and improve the processing efficiency.
[0110] The above is only an embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A method for predicting the degree of deformation of a plate after layer cutting, characterized in that: The method comprises: Step S1: Starting from the horizontal plane of the plate to be cut, the residual stress at each cutting position is measured along the thickness direction and recorded as σ j ; Step S2: the σ obtained in step S1 is tested j Substitute into the formula The deflection h of the plate after i-th layer cutting is obtained i ; Through the deflection h i Predict the deformation degree of the plate after layer cutting, the deflection h i The absolute value of is positively correlated with the degree of deformation after layer cutting; Among them, i is the total number of times the plate is layered, j is the middle number of times the plate is layered, △x is the thickness of the plate each time it is layered, E is the elastic modulus of the plate, s is the total thickness of the plate, l is the length of the plate, and the direction of the length is along the direction of layering.
2. The method for predicting the deformation degree of plate after layer cutting according to claim 1, characterized in that: The residual stress is measured by a method selected from any one of a peeling method, a slit warping method, a crack compliance method, and a neutron diffraction method.
3. The method for predicting the deformation degree of plate after layer cutting according to claim 1, characterized in that: When the h i When h is positive, the warping deformation on both sides of the milling surface toward the milling cutter is positive deformation; when h is positive, the warping deformation on both sides of the milling surface toward the milling cutter is positive deformation. i When it is a negative value, the warping deformation in the middle of the milling surface toward the milling cutter is negative deformation.
4. The method for predicting the deformation degree of plate after layer cutting according to claim 1, characterized in that: The i is 1 to 20 times; And / or, the △x is 1 to 5 mm.
5. The method for predicting the deformation degree of plate after layer cutting according to claim 4, characterized in that: The i is 1 to 12 times; And / or, the △x is 3 to 4 mm.
6. The method for predicting the deformation degree of plate after layer cutting according to claim 1, characterized in that: The l is 200 to 2000 mm; and / or the ratio of the width of the plate to the l is 1:(2 to 8); and / or the s is 50 to 200 mm.
7. The method for predicting the deformation degree of plate after layer cutting according to claim 4, characterized in that: The l is 300 to 1000 mm; and / or the ratio of the width of the plate to the l is 1:(4 to 6); and / or the s is 80 to 100 mm.
8. The method for predicting the deformation degree of a plate after layer cutting according to any one of claims 1 to 7, characterized in that: The E is 42 to 210 GPa.
9. The method for predicting the deformation degree of plate after layer cutting according to claim 8, characterized in that: The plate is any one of an aluminum alloy plate, a steel plate, a titanium alloy plate and a magnesium alloy plate.
10. The method for predicting the deformation degree of plate after layer cutting according to claim 9, characterized in that: When the plate is an aluminum alloy plate, E is 68 to 72 GPa; When the plate is a steel plate, E is 190 to 210 GPa; When the plate is a titanium alloy plate, E is 110 to 115 GPa; When the plate is a magnesium alloy plate, the E is 42-45 GPa.