Adjustment and control method for angle compensation technology of flanging machine

Abstract

The invention relates to the technical field of flanging machines, in particular to a regulation and control method for an angle compensation technology of a flanging machine. Comprising the following steps: determining an angle deviation influence factor of the flanging machine; performing factor experiment design and working condition analysis; simulation and test data correction; establishing a polynomial response surface compensation model; according to the method, accurate forming can ensure that the angle deviation of a flanging product meets the precision requirement, so that the overall quality of the product is improved, material waste and the requirement for secondary machining are reduced, the production cost is reduced, and the economic benefit and the production efficiency are improved.

Description

Technical Field

[0001] This invention relates to the field of folding machine technology, and more specifically to a method for controlling the angle compensation technology of a folding machine. Background Technology

[0002] Currently, folding machines on the market suffer from the following problems: 1. Due to the promotion and widespread adoption of lightweight structures, some machine tools lack rigidity, making them prone to deformation under heavy loads, thus affecting forming accuracy. 2. The sheer variety and specifications of sheet metal make forming accuracy susceptible to material springback and hardness, and current theoretical models are not applicable to all processed materials, resulting in low angular accuracy. Both of these issues significantly impact overall product quality, leading to material waste and secondary processing, thus increasing production costs. Therefore, how to accurately control the angle compensation of folding machines is a technical problem that needs to be solved. Summary of the Invention

[0003] The problem to be solved by the present invention is to provide a control method for angle compensation technology of a bending machine, which has a fast control cycle and high compensation accuracy.

[0004] To address the shortcomings of existing technologies, the technical solution adopted by this invention is: a method for controlling the angle compensation technology of a folding machine, comprising the following steps:

[0005] S1. Determine the factors affecting the angle deviation of the bending machine:

[0006] Based on the clamping force Y, folding force F, sheet width b, sheet thickness t, target angle D, gap multiple N, and material yield strength σ b Elastic modulus E, hardening index E p Establish a correlation model between angular deviation and folding force F;

[0007] S2. Factor Experimental Design and Operating Condition Analysis:

[0008] Sample points are selected and value ranges are set for the clamping force Y, sheet width b, and sheet thickness t to generate test groups, labeled h, h = 1, 2, ..., Q, where Q is the total number of tests required;

[0009] S3. Simulation and Test Data Correction:

[0010] Finite element analysis was performed on the folding machine model using forming simulation software to obtain the folding force F and angle compensation P under each working condition, and the simulation results were corrected in reverse by combining the measured data.

[0011] S4. Establish a polynomial response surface compensation model:

[0012] The model of the folding force F and the angle compensation P is fitted based on the orthogonal polynomial selection method;

[0013] S5. Model Verification and Compensation Implementation: Import the compensation model into the control system, verify the model accuracy through initial calibration conditions, and realize angle compensation control for different plate widths and thicknesses based on the calibration values.

[0014] Preferably, in step S1, the correlation model of the folding force F further includes the material yield strength σ. b Elastic modulus E, hardening index E p The target angle D and the clearance multiple N are defined by the following proportional relationship:

[0015] Folding force F∝(b,t,D,N,σ) b E, E p ).

[0016] Preferably, in step S4: the polynomial response surface selects significant terms using an orthogonalization method, and defines the error reduction ratio (ERR). i Filter key terms, the contribution rate (ERR) of the i-th orthogonal polynomial to the error function. i The expression is:

[0017]

[0018] Among them, h i Let f(k) be the orthogonal coefficient of the i-th term, f(k) be the target response value calculated in the k-th sampling, k = 1, 2, ..., L, where L is the total number of samplings; p i f(k) represents the orthogonal term under the k-th sampling, which can be obtained through the orthogonal transformation of f(k), preserving ERR. i Items exceeding the set threshold.

[0019] Preferably, in step S5: the input parameters for initializing the calibration working condition include the sheet thickness t, the sheet width b, and the target angle D, and the output is the folding force F and the angle compensation amount P, and the parameters are dynamically adjusted through the control system interface.

[0020] Preferably, in step S3: the boundary conditions for the forming simulation software to perform finite element analysis on the bending machine model include fixing the clamping die (1) and applying bending load to the contact surface of the sheet metal (2). The mesh division adopts an adaptive densification strategy to improve the calculation accuracy of the stress concentration area.

[0021] The preferred model for the bending force F and the angle compensation amount P is as follows:

[0022] F=(((A×b×(t×N×1.1) 2 ×σ b 3 ) / (E×D 4 ×π 2))+2×((b×E p ×π×t 3 ×D / 4320 / (t×N×1.1))+(b×t 2 ×σ b / 8)-(b×E p ×t 2 ×σ b / 8 / E)-(B×b×(t×N×1.1) 2 ×σ b 3 / (E×D 4 ×π 2 ))+(C×b×E p ×(t×N×1.1) 2 ×σ b 3 / (E×D 4 ×π 2 ) / D))) / (t×N×1.1);

[0023] P=k1×b+k2×t+k3×F-k4×Y-k5-k6×b×t-k7×b×F+k8×b×Y+k9×t×Fk 10 ×t×Yk 11 ×F×Y+k 12 ×b 2 -k 13 ×t 2 -k 14 ×F 2 +k 15 ×Y 2 +k 16 ×b×F×Y;

[0024] Where D is the target angle, N is the gap multiple, and σ b E is the yield strength of the material (unit: MPa), and E is the elastic modulus. p The hardening index is represented by A, B, and C, which are the fitting coefficients for calculating the bending force; t is the sheet thickness; b is the sheet width; F is the bending force; and Y is the clamping force. i There are 16 fitting coefficients in total; in the formula, b (sheet width), t (sheet thickness), F (folding force), and Y (clamping force) have all been normalized according to the benchmark value, and the unit of angle compensation P is degrees.

[0025] The beneficial effects of this invention are as follows: This invention utilizes a combination of multi-factor experimental design and simulation with testing to develop a control method for the angle compensation model of a bending machine based on a polynomial response surface function. This invention significantly improves the precision of bending machine parts, reduces sample costs, and can efficiently and reliably meet processing requirements. The method of this invention has significant practical research value for controlling the forming precision of bending machines. Precise forming ensures that the angle deviation of the bent product meets accuracy requirements, thereby improving the overall quality of the product, reducing material waste and the need for secondary processing, thus reducing production costs and improving economic efficiency and production efficiency. Furthermore, high-precision bending forming can support more complex and innovative product designs, broaden product design space, and enhance market competitiveness. Attached Figure Description

[0026] Figure 1 This is a flowchart of the control method for the angle compensation technology of the folding machine provided by the present invention;

[0027] Figure 2 A flowchart illustrating the practical application of the folding machine angle compensation model provided by this invention;

[0028] Figure 3 This invention relates to the interaction between the clamping die and the folding die.

[0029] Figure 4 This is a schematic diagram of the sheet metal bending forming method involved in this invention;

[0030] Explanation of reference numerals in the attached drawings: 1. Pressing die; 2. Sheet material; 3. Folding die. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

[0032] To address the problems mentioned in the background art, this invention provides a method for controlling the angle compensation technology of a folding machine, such as... Figure 1 The diagram shows the flowchart of the adjustment method for the angle compensation technology of a folding machine, which includes the following steps:

[0033] S1. Determination of factors affecting the angle deviation of the folding machine:

[0034] According to the working principle of the folding machine, the angle forming process mainly relies on the interaction between the clamping die 1 and the folding die 3, such as Figure 3 The diagram illustrates the interaction between the clamping die 1 and the folding die 3. The clamping die 1 is located above the sheet metal 2, primarily serving to fix the sheet metal 2 and prevent displacement or deformation during the folding process. The folding die 3 is located below the sheet metal 2, mainly responsible for bending the sheet metal 2 to form the desired folded shape. The clamping die 1 and the folding die 3 work together to achieve the target angle. Therefore, the factors affecting the angle deviation mainly include:

[0035] Angular deviation ∝ (Y, F, b, t);

[0036] Where Y is the clamping force, F is the bending force, b is the sheet width, and t is the sheet thickness. The main factors affecting the bending force include:

[0037] Folding force F∝(b, t, D, N, σ) b E, E p );

[0038] Where D is the target angle, N is the gap multiple, and σ b E is the yield strength of the material, and E is the elastic modulus. p This is the hardening index.

[0039] S2. Test condition analysis based on multi-factor experimental design:

[0040] Based on the three adjustable variable parameters (clamping force Y, sheet width b, and sheet thickness t) obtained in step S1 above, the number of sample points and the range of values ​​for different variables are determined, and an experimental table is established accordingly. Various different working condition test groups are obtained and labeled as h, h = 1, 2, ..., Q, where Q is the total number of tests required.

[0041] S3. Solving for compensation values ​​based on simulation and test data:

[0042] Based on the various working condition test groups with different forming angles determined in step S2 above, simplified models of the clamping device and folding device of the folding machine are imported into SimufactForming software for forming simulation analysis. The simplified model is meshed automatically. In preprocessing, the forming trajectory of the folding die 3 and the required load for the clamping force are applied. According to each working condition in the test table, the corresponding folding force F and angle compensation P are obtained based on the simulation software, where h = 1, 2, ..., Q, and Q is the total number of tests. Based on this, the testing method based on folding angle forming is used to select some working conditions for testing and verification. The experimental and simulation error values ​​are then used to correct the finite element calculation results to ensure the accuracy and reliability of the simulation data modeling.

[0043] S4. Establishment of a polynomial response surface angle deviation compensation model:

[0044] Based on the parameters of different working condition combinations determined in step S2, and combined with the simulation solution of the bending force and angle compensation amount corresponding to each working condition in step S3, the bending force F and angle compensation amount P corresponding to different working conditions are fitted with polynomial response surface functions in numerical analysis software.

[0045] A polynomial response surface expresses the response function as a complete polynomial combination of n parameters, i.e.

[0046]

[0047] In the formula, u i (x) is a variable x = (x1, x2, ... x2) n A complete polynomial of ); a i The coefficients are undetermined; N is the total number of terms, and the expression for N is: In the formula, m is the highest order of the polynomial f(x) (for example, when m=2, it is a quadratic polynomial), and n is the number of independent variables.

[0048] The significance of each term in f(x) is evaluated using a polynomial selection method. Based on the concept of the optimal error reduction ratio, effective polynomial terms are selected, redundant terms are removed, and the optimal polynomial response surface is obtained.

[0049] To determine the polynomial model and its coefficients, f(x) is transformed into orthogonal set form, i.e.:

[0050]

[0051] In the formula, f(k) is the target response value calculated in the k-th sampling, k = 1, 2, ..., L, where L is the total number of samplings; p i (k) represents the orthogonal term under the k-th sampling, which can be obtained through the orthogonal transformation of f(k); h i These are the coefficients of the orthogonal terms.

[0052] Based on the orthogonal relationship between the terms in f(k), we can derive:

[0053]

[0054] Gram-Schmidt orthogonalization is used, p i (k) is represented as:

[0055]

[0056] In the formula, i = 1, 2, ..., N-1; j is the order preceding i (for example, if i is 1, j is 0; if i is 2, j is 1); u i(k) represents the k-th sampling polynomial; the orthogonal polynomial coefficients α ij It can be represented as:

[0057]

[0058] Define the error function MSE as follows:

[0059]

[0060] For MSE h i Taking the derivative and setting it equal to 0, it can be expressed as:

[0061]

[0062] h i Substitute p i In (k), based on p i (k) All terms are orthogonal, and h0 is a constant. The error function MSE can be expressed as:

[0063]

[0064] The maximum value of MSE is orthogonal term p i (k) contributes to the reduction in MSE as follows: Therefore, the error reduction ratio ERR is defined. i To quantify the contribution rate of each orthogonal term to the reduction of the error function MSE, i.e., the contribution rate ERR of the i-th orthogonal polynomial to the error function. i Represented as:

[0065]

[0066] In the formula, i = 0, 1, ..., N-1. i is the index of the number of terms in the polynomial, h... i Let f(k) be the coefficient of the i-th orthogonal term, k be the experimental sample number, k = 1, 2, ..., L, L be the total number of samplings, f(k) be the target response value calculated in the k-th sampling, and p i (k) represents the orthogonal term under the k-th sampling.

[0067] After each orthogonal transformation, calculate the contribution rate (ERR) of each term to the reduction of MSE. i Select the term with the largest error reduction rate, and repeat the above method until the remaining terms have the largest ERR. i If the value is less than a set threshold, discard the remaining terms. Then solve for h. i ERR is obtained through arccross transformation. i Coefficients of the retained terms.

[0068] Based on the influencing factors of angle deviation in step S1, and combined with the compensation values ​​obtained from testing and simulation calculations in step S3, a folding force calculation model is established based on the above polynomial fitting method (Note: Polynomial fitting is a mathematical method that approximates data points by constructing a polynomial function model, and therefore differs somewhat from theoretical derivation):

[0069] F=(((A×b×(t×N×1.1) 2 ×σb 3 ) / (E×D 4 ×π 2 ))+2×((b×E p ×π×t 3 ×D / 4320 / (t×N×1.1))+(b×t 2 ×σ b / 8)-(b×E p ×t 2 ×σ b / 8 / E)-(B×b×(t×N×1.1) 2 ×σ b 3 / (E×D 4 ×π 2 ))+(C×b×E p ×(t×N×1.1) 2 ×σ b 3 / (E×D 4 ×π 2 ) / D))) / (t×N×1.1);

[0070] Where D is the target angle, N is the gap multiple, and σ b E is the yield strength of the material (unit: MPa), and E is the elastic modulus. p t is the hardening index, A, B, and C are the fitting coefficients for calculating the folding force, t is the sheet thickness, and b is the sheet width.

[0071] The above-mentioned folding force F is converted to units (from N to ton), and an angle deviation compensation model is established based on polynomial fitting:

[0072] P=k1×b+k2×t+k3×F-k4×Y-k5-k6×b×t-k7×b×F+k8×b×Y+k9×t×Fk 10 ×t×Yk 11 ×F×Y+k 12 ×b 2 -k 13 ×t 2 -k 14 ×F 2 +k 15 ×Y2 +k 16 ×b×F×Y;

[0073] Where t is the sheet thickness, b is the sheet width, F is the bending force, Y is the clamping force, and k is the bending force. i (i is the subscript number) represents the angle deviation fitting coefficients, totaling 16. In the formula, b (sheet width), t (sheet thickness), F (folding force), and Y (clamping force) have all been normalized to baseline values, and k... i (i is the subscript number) represents the angle deviation fitting coefficient, and the unit of the angle compensation amount P is degrees.

[0074] S5. Verification and correction based on the compensation model:

[0075] The angle compensation model is encapsulated and imported into the control system. Based on the polynomial response surface function fitting in step S4 above, the bending force F and angle compensation amount P corresponding to a single working condition (i.e., the initial calibration working condition) for a single model are obtained. The required initial calibration value is solved. The angle compensation switch is turned on in the operation interface, and the calibration value is input into the system interface. Based on the calibration value, the calculation of different plate widths under the same thickness can be realized.

[0076] The parameters mentioned above are as follows: Y: clamping force; F: folding force; b: sheet width; t: sheet thickness; D: target angle; N: gap multiple; σ b E: Yield strength of material; E: Elastic modulus; E p Hardening index; P: Angle compensation amount; a i : Undetermined coefficients; p i (k): The orthogonal term under the k-th sampling; h i : Orthogonal coefficients; α ij Orthogonal polynomial coefficients; ERR i : The contribution rate of the i-th orthogonal polynomial to the error function; A, B, C: Fitting coefficients for calculating the folding force; k i : Angle deviation fitting coefficient.

[0077] Taking a bending machine as an example, this document describes the practical application procedure of the compensation model under the condition of a plate thickness of 1.5mm. Before applying the angle compensation model, it is necessary to ensure that the machine tool has been debugged and inspected and is ready for normal delivery and use. Before the initial calibration test, all angle compensation settings in the system must be turned off to ensure the accuracy of the initial calibration results. Taking the condition of a plate thickness t of 1.5mm and a plate width b of 1000mm as an example, firstly, the required clamping force Y is obtained as 88% through load debugging. Secondly, the angle deviation P is measured and calculated using an angle gauge. 偏差The initial calibration value is 3.55°. Subtracting the angle deviation from the modeling data value for a sheet thickness of 1.5mm, we obtain an initial calibration value of -1.87°. Finally, the angle compensation switch is turned on, -1.87 is entered in the system interface, and an appropriate clamping force is selected according to different sheet widths. After all this is completed, bending begins. Using this compensation technology, the angle deviation is reduced from ±5° to ±1°. When the compensation model fails (the compensated forming angle fails to meet the accuracy requirements), the angle compensation switch can be turned off, and higher precision edge forming can be achieved by manually changing the angle deviation.

[0078] This invention provides a method for angle compensation control of a folding machine based on multi-factor experimental design and a polynomial response surface model. By systematically analyzing the factors influencing angle deviation and combining simulation and measured data for correction, a high-precision compensation model is constructed. This method significantly improves the angle accuracy of folding, reducing the deviation from ±5° in traditional methods to ±1°, effectively reducing material waste and secondary processing requirements, and lowering production costs. Through dynamic parameter adjustment and model verification, this invention can be adapted to different sheet metal specifications and processing scenarios, supporting complex product designs and enhancing market competitiveness. Furthermore, the modular compensation model design simplifies system maintenance and has broad industrial application prospects.

Claims

1. A method for controlling the angle compensation technology of a folding machine, characterized in that, Includes the following steps: S1. Determine the factors affecting the angle deviation of the bending machine: Based on the clamping force Y, folding force F, sheet width b, sheet thickness t, target angle D, gap multiple N, and material yield strength σ b Elastic modulus E, hardening index E p Establish a correlation model between angular deviation and folding force F; S2. Factor Experimental Design and Operating Condition Analysis: Sample points are selected and value ranges are set for the clamping force Y, sheet width b, and sheet thickness t to generate test groups, labeled h, h = 1, 2, ..., Q, where Q is the total number of tests required; S3. Simulation and Test Data Correction: Finite element analysis was performed on the folding machine model using forming simulation software to obtain the folding force F and angle compensation P under each working condition, and the simulation results were corrected in reverse by combining the measured data. S4. Establish a polynomial response surface compensation model: A model of the folding force F and the angle compensation P was fitted based on the orthogonal polynomial selection method. S5. Model Verification and Compensation Implementation: Import the compensation model into the control system, verify the model accuracy through initial calibration conditions, and realize angle compensation control for different plate widths and thicknesses based on the calibration values.

2. The control method for the angle compensation technology of the folding machine according to claim 1, characterized in that, In step S1: the correlation model of the folding force F further includes the material yield strength σ. b Elastic modulus E, hardening index E p The target angle D and the clearance multiple N are defined by the following proportional relationship: Folding force F∝(b,t,D,N,σ) b E, E p ).

3. The control method for the angle compensation technology of the folding machine according to claim 2, characterized in that, In step S4: the polynomial response surface selects significant terms using an orthogonalization method, and defines the error reduction ratio (ERR). i Filter key terms, the contribution rate (ERR) of the i-th orthogonal polynomial to the error function. i The expression is: Among them, h i Let f(k) be the orthogonal coefficient of the i-th term, f(k) be the target response value calculated in the k-th sampling, k = 1, 2, ..., L, where L is the total number of samplings; p i f(k) represents the orthogonal term under the k-th sampling, which can be obtained through the orthogonal transformation of f(k), preserving ERR. i Items exceeding the set threshold.

4. The control method for the angle compensation technology of the folding machine according to claim 1, characterized in that, In step S5: the input parameters for initializing the calibration working condition include the sheet thickness t, the sheet width b, and the target angle D. The output is the bending force F and the angle compensation amount P, and the parameters are dynamically adjusted through the control system interface.

5. The control method for the angle compensation technology of the folding machine according to claim 1, characterized in that, In step S3: the boundary conditions for the forming simulation software to perform finite element analysis on the bending machine model include fixing the clamping die (1) and applying bending load to the contact surface of the sheet metal (2). The mesh division adopts an adaptive densification strategy to improve the calculation accuracy of the stress concentration area.

6. The control method for the angle compensation technology of the folding machine according to claim 3, characterized in that, The model for the bending force F and the angle compensation P is as follows: F=(((A×b×(t×N×1.1) 2 ×σ b 3 ) / (E×D 4 ×π 2 ))+2×((b×E p ×π×t 3 ×D / 4320 / (t×N×1.1))+(b×t 2 ×σ b / 8)-(b×E p ×t 2 ×σ b / 8 / E)-(B×b×(t×N×1.1)2×σ b 3 / (E×D 4 ×π 2 )+(C×b×E p ×(t×N×1.1) 2 ×σ b 3 / (E×D 4 ×π 2 ) / D))) / (t×N×1.1); P=k1×b+k2×t+k3×F-k4×Y-k5-k6×b×t-k7×b×F+k8×b×Y+k9×t×F-k 10 ×t×Y-k 11 ×F×Y+k 12 ×b 2 -k 13 ×t 2 -k 14 ×F 2 +k 15 ×Y 2 +k 16 ×b×F×Y; Where D is the target angle, N is the gap multiple, and σ b E is the yield strength of the material (unit: MPa), and E is the elastic modulus. p The hardening index is represented by A, B, and C, which are the fitting coefficients for calculating the bending force; t is the sheet thickness; b is the sheet width; F is the bending force; and Y is the clamping force. i There are 16 fitting coefficients in total; in the formula, b (sheet width), t (sheet thickness), F (folding force), and Y (clamping force) have all been normalized according to the reference value, and the unit of angle compensation P is degrees.

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