JP2016193455A - Metal plate bending forming control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal plate bending forming control method capable of controlling highly accurately a plate bending angle.SOLUTION: A metal plate bending forming control method includes steps for: (1) establishment of a relational database between a material parameter, a forming angle, a spring back quantity and an upper die pressing quantity; (2) reverse engineering of blanking and the material parameter; (3) comparison between the material parameter in the relational database and the material parameter of a metal plate to be processed obtained by the reverse engineering; and (4) a bending forming operation.SELECTED DRAWING: Figure 1

Description

  This method relates to a metal plate material processing technique, and specifically is a method of improving the bending accuracy of the metal plate material.

  Bending is one of the important sheet metal production methods for industrial production. In the production process of the sheet metal member, the angle of the sheet metal increases due to the recovery of the elastic deformation of the metal material itself. In addition, the wave motion in the performance of raw materials of different manufacturers and different specifications is large, the amount of spring back after bending deformation of the material is different, and the molding accuracy of the structural member becomes unstable. For this reason, it is very important to effectively avoid the springback and improve the molding accuracy during the molding process.

  On the other hand, in Patent Document 1, a new V-shaped component bending die is designed to reduce the springback and improve the molding accuracy of the stamping component. However, such a method has a great limitation, Only one bending angle of the molding angle is supported, and the size of the molded product is constant. When the molding angle of the molded product changes or the size of the molded product increases, the mold cannot be used and a set of molds with the corresponding angle and size must be reworked. Thereby, the production cycle is too long and the cost is very high.

  In Patent Document 2, a V-shaped 90 ° self-supporting bending springback angle capable of adjusting the bending springback amount and performing angle compensation is provided. Includes an upper mold base, and an adjustment angle side plate capable of adjusting a stamping angle of a lower end of the punch is connected to both ends of the upper mold base, the adjustment angle side plate is shaft-coupled by a bending radius, and the die is a lower mold The left and right self-supporting plates are hingedly connected to the upper end of the lower mold base including the base.

  The patent compensates by adjusting the molded angle, but repeats the angle adjustment process to perform bending experiments, test the molded angle, estimate the springback amount, and then adjust the mold angle. There is also a need to compensate. This method requires too many manual operations and cannot realize automated control. In addition, the mold used in such a method is complicated, and if used for a long time, the mold will be deformed, and at the same time, if a large bending member is bent, a large mold is required. However, the rigidity of the designed mold cannot be guaranteed, and the mold itself may be bent or deformed during the molding process, which may affect the molding quality.

  Therefore, the present invention does not directly control the magnitude of the springback amount, and based on the principle that the bending springback amount varies depending on the material's own characteristics, the bending process is simulated by the CAE simulation technique, thereby making the springback amount of the metal plate material. And get relational database between bending angle, material performance, plate thickness. The amount of springback of the material can be known before actual bending, and accuracy requirements can be met by precompensating and primary forming the bending member. It is possible to automatically control the forming angle and there is no need to manually measure and adjust the grinding device. The degree of automation is high and the molding accuracy is high. The method can meet the molding demands of different material performance, different plate thickness, different molding angles, and can process products to meet accuracy requirements.

CN203140585U CN201020102617

  It is an object of the present invention to provide a metal plate material bending forming control method capable of controlling a plate material bending angle with high accuracy.

The present invention provides a metal plate bending control method,
(1) Based on the structural parameters of the mold used for bending, a finite element simulation model for bending is established, and the material parameters of the metal sheet for simulation are input to the finite element simulation model for bending. Simulating the bending process of the metal sheet for simulation, obtaining the magnitude of the simulation springback amount corresponding to the forming angle, and setting the simulation springback amount as a springback amount to be added to the relational database; ,
After measuring the material parameters of the different metal plates, the bending process of the different metal plates is simulated based on the obtained finite element simulation model of the bending, and for each metal plate of the different metal plates Establishing the relational database between material parameters, forming angle, springback amount, upper die pressing amount of the mold,
Including the process of establishing a relational database between material parameters, forming angle, springback amount, upper die pressing amount, and
(2) blanking a workpiece metal plate to obtain a blank;
Obtain the experimental load-stroke curve in the blanking experiment of the workpiece metal plate by measurement, establish the finite element simulation model by the method of reverse engineering the actual physical parameters of the plate material, perform the blanking simulation, Repetitively reverse engineering material parameters of the workpiece metal plate material,
Blanking, reverse engineering of material parameters,
(3) comparing the material parameters in the relational database with the material parameters of the metal sheet to be processed;
When there is a reference material parameter having an error between the relational database and a material parameter of the metal sheet to be processed smaller than a second threshold value, a bending operation is performed,
If there is no reference material parameter with an error between the relational database and the material parameter of the workpiece metal plate smaller than a second threshold value, the material parameter of the workpiece metal plate obtained by the reverse engineering is obtained. Simulate the bending process in the same way as the process of establishing the relational database by using the material parameters, forming angle, springback amount, upper die pressing amount of the workpiece metal plate obtained by simulation. In addition to the relational database, the material parameter of the processed metal plate material obtained by the reverse engineering is a reference material parameter of the processed metal plate material in the relational database, and then bending forming Performing the operation,
Including comparing the material parameters in the relational database with the material parameters of the workpiece metal plate obtained by reverse engineering,
(4) inputting a bending angle;
Based on the relational expression between the forming angle corresponding to the reference material parameter and the upper die pressing amount of the mold of the bending machine that performs the bending operation, the required upper die pressing amount is calculated and the required upper Transmitting a mold pressing amount to the bending machine, and controlling the bending machine to bend the blank;
Including a step of bending forming operation.

  Using the above method, the present invention does not directly control the magnitude of the springback amount, but based on the principle that the bending springback amount varies depending on the material's own characteristics, the bending process is simulated by the CAE simulation technique. Obtain a relational database between the springback amount and bending angle of the plate, material performance, and plate thickness. The amount of springback of the material can be known before actual bending, and accuracy requirements can be met by precompensating and primary forming the bending member. It is possible to automatically control the forming angle and there is no need to manually measure and adjust the grinding device. The degree of automation is high and the molding accuracy is high. The method can meet the molding demands of different material performance, different plate thickness, different molding angles, and can process products to meet accuracy requirements.

  The present invention provides a metal plate bending control method, and the structural parameters of the mold used for bending include an upper drawing angle radius and a lower opening of the mold.

  Establish a finite element simulation model for bending with the upper die angle radius and lower die opening as structural parameters of the mold, and obtain a finite element simulation model that highly simulates actual bending conditions with fewer parameters Improve the efficiency of establishing a finite element simulation model.

  The present invention provides a metal sheet bending control method, and when the bending finite element model is established, the bending test is performed to acquire the actual springback amount of the simulation metal sheet, and A difference between the magnitude of the actual springback amount and the magnitude of the simulation springback amount is calculated, and when the difference exceeds a first threshold, the grid size of the finite element simulation model is refined, and the difference is calculated. Simulate again until is less than the first threshold.

  Using the above method, the accuracy of simulating the bending process by CAE simulation technology can reach 98%, and the predicted value is almost equal to the actual value. Thereby, it is guaranteed that the accuracy requirement can be satisfied by further forming the bending member first. It is possible to automatically control the forming angle and there is no need to manually measure and adjust the grinding device. The degree of automation is higher and the molding accuracy is higher.

  The present invention provides a metal sheet bending control method, and when establishing a relational database among material parameters, forming angle, springback amount, and upper die pressing amount, the material parameter used is used to detect a material. 3 is a material performance parameter and a flow stress curve measured in a tensile test.

  When a finite element simulation is performed by bending a flow stress curve as a material parameter, high simulation accuracy and efficiency can be obtained.

  The present invention provides a metal plate bending control method, wherein the first threshold is 2%.

  The present invention provides a metal sheet bending control method, simulates the bending process, records the relationship between different bending angles θ ′ and pressing amount ΔH, and then uses the finite element simulation model. Thus, by predicting the magnitude of the springback amount Δθ corresponding to the different bending angles θ ′, the relationship between the different bending angles θ ′ and the springback amount Δθ is obtained, and the forming angle θ and the bending angle θ ′ are obtained. And the relationship between the forming angle θ and the pressing amount ΔH is obtained based on the relationship θ = θ ′ + Δθ between the spring back amount Δθ.

  The present invention provides a metal plate bending control method, wherein the second threshold is 1%.

  The present invention provides a metal plate bending control method, and if the reference material parameter having an error between the material parameter of the workpiece metal plate smaller than the second threshold does not exist in the relational database, the reverse engineering is performed. By inputting the material parameters of the processed metal plate material obtained in this way into the finite element simulation model and simulating the bending process, the forming angle θ and the pressing amount ΔH of the processed metal plate material are obtained. And the relationship between the forming angle θ of the metal plate to be processed and the pressing amount ΔH is transmitted to the relational database.

  Step (1) can be performed before bending to test and simulate different manufacturers, different specifications, different batches, different thickness materials. If the type, use, and batch of materials in the database are more complete, the relationship between the forming angle and the pressing amount of the corresponding material can be directly checked from the database during bending, and control is performed at high speed and with high accuracy. Realize that. If the database is not rich, it may not be possible to find a material that is similar to the workpiece, and the first bend needs to perform a bending simulation on the workpiece, and then the relationship between the forming angle and the pressing amount Thus, one additional bending simulation time is required.

  Hereinafter, in order to make the above contents of the present invention easier to understand, a particularly preferred embodiment will be illustrated and described in detail with reference to the drawings.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
It is a flowchart which shows the database establishment of this invention. It is a flowchart which shows the blanking and bending forming of this invention. It is a flow stress curve of a common cold rolled steel plate. It is a finite element simulation model of bending. It is a bending simulation schematic diagram. This is a comparison between the simulation springback amount and the experimental springback amount. It is a schematic diagram of the relationship between the upper die pressing amount at the time of bending and the bending angle. It is a relationship (about 86o-96o) between the obtained bending angle and the upper die pressing amount when simulating the bending process. This is the relationship (about 86o-96o) between the obtained bending angle and the amount of springback when simulating the bending process. It is the relationship (about 86o-98o) between the forming angle of materials A and B and the upper die pressing amount. The relationship between the molding angle of the material X and the upper die pressing amount (about 84o-98o). It is a schematic diagram of a bending die.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(Establish database)
The present invention provides a metal plate bending control method,
(1) Based on the structural parameters of the mold used for bending, a finite element simulation model for bending is established, and the material parameters of the metal sheet for simulation are input to the finite element simulation model for bending, Simulating the bending process of the metal sheet for simulation, obtaining the magnitude of the simulation springback amount corresponding to the forming angle, and making the simulation springback amount a springback amount to be added to the relational database;
After measuring the material parameters of different metal sheets, the process of bending the different metal sheets is simulated based on the obtained finite element simulation model of bending, the material parameters for each metal sheet of different metal sheets, Establishing a relational database between the forming angle, springback amount, upper die pressing amount of the mold,
Including the process of establishing a relational database between material parameters, forming angle, springback amount, upper die pressing amount, and
(2) blanking a workpiece metal plate to obtain a blank;
Measure and obtain the experimental load-stroke curve in the blanking experiment of the metal plate to be processed, establish a finite element simulation model by reverse engineering the actual physical parameters of the plate, perform blanking simulation, Repetitively reverse-engineering the material parameters of the metal sheet to be processed;
Including blanking, material parameter reverse engineering process,
(3) comparing the material parameters in the relational database with the material parameters of the metal sheet to be processed;
If there is a reference material parameter in the relational database that has an error between the material parameter of the metal sheet to be processed that is smaller than the second threshold value, execute a bending operation,
If there is no reference material parameter in the relational database that has an error between the material parameters of the processed metal sheet that is less than the second threshold, the relational database is used using the material parameters of the processed metal sheet obtained by reverse engineering. Similar to the process of establishing a database, the bending process is simulated, and the relation between the material parameters, forming angle, springback amount, and upper die pressing amount of the processed metal sheet material obtained by the simulation is stored in a relational database. In addition, the material parameter of the processed metal sheet obtained by reverse engineering is a reference material parameter of the processed metal sheet in the relational database, and then performing a bending operation;
A process of comparing material parameters in a relational database with material parameters of a processed metal sheet obtained by reverse engineering,
(4) inputting a bending angle;
Based on the relationship between the forming angle corresponding to the reference material parameter and the upper die pressing amount of the mold of the bending machine that performs the bending operation, the required upper die pressing amount is calculated, and the required upper die pressing force is calculated. Transmitting a quantity to a bending machine and controlling the bending machine to bend the blank.

  The structural parameters of the mold used for bending include the upper mold drawing angle radius and the lower mold opening.

  When establishing a bend forming finite element model, a bending test is performed to obtain the actual springback amount of the metal plate for simulation, and the actual springback amount and the simulation springback amount When the difference exceeds the first threshold value, the grid size of the finite element simulation model is refined, and the simulation is performed again until the difference is smaller than the first threshold value.

  When establishing a relational database between material parameters, forming angle, springback amount, upper die pressing amount, the material parameters used are material performance parameters and flow stress curve measured in tensile test when detecting material It is.

  The bending process is simulated to record the relationship between the different bending angles θ ′ and the pressing amount ΔH, and then using the finite element simulation model, the springback amount Δθ corresponding to the different bending angles θ ′. The relationship between the different bending angles θ ′ and the springback amount Δθ is obtained by predicting the magnitude of the angle, and the relationship between the forming angle θ, the bending angle θ ′, and the springback amount Δθ is θ = θ ′ + Based on Δθ, the relationship between the forming angle θ and the pressing amount ΔH is acquired.

  If there is no reference material parameter in the relational database that has an error between the material parameter of the processed metal plate material that is smaller than the second threshold, the material parameter of the processed metal plate material obtained by reverse engineering is calculated using a finite element simulation model. To obtain the relationship between the forming angle θ of the metal plate material to be processed and the pressing amount ΔH, and the forming angle θ of the metal plate material to be processed and the pressing amount ΔH. Send the relationship between to a relational database.

  Hereinafter, embodiments of the present invention will be described with reference to specific numerical values. In this example, similar low carbon steel plates of two different manufacturers with a plate thickness of 1.2 mm are studied, and the numbers are A and B, respectively. Using a SHIMADZU universal tensile tester, two materials A and B are subjected to a tensile test at room temperature to obtain load displacement curves of the two materials A and B, and two materials based on the theoretical formula The flow stress curve and the mechanical performance parameter corresponding to are calculated and used as input parameters for characterizing the mechanical properties of the material when simulating bending. The obtained flow stress curve is shown in FIG. Differences in similar material flow stress curves produced by different manufacturers are very large and explain the differences in material performance. It shows the situation where the difference in performance of materials is large.

  In actual industrial production, since 90 degree bending is considered to be the most common processing method, this embodiment will be described by taking 90 degree bending as an example. Depending on the thickness of the object to be bent, parameters such as the upper die aperture angle radius and lower die opening of the required bending mold change according to the thickness, and the thin plate selects the lower die aperture radius and lower die opening, For thicker plates, choose a larger upper aperture radius and lower aperture. In this embodiment, since a plate material having a bending thickness of 1.2 mm will be described as an example, a general parameter suitable for bending a plate material having a thickness of 1.2 mm is selected for the mold, as shown in FIG. The upper mold depression angle is 86 degrees, the aperture angle radius is 1.2 mm, and the lower mold opening is 8 mm. As shown in FIG. 4, it is simplified using finite element simulation software -LS-DYNA, based on the parameters of the actual bending mold, that is, the upper mold depression angle of 86 degrees, the aperture angle radius of 1.2 mm, and the lower mold opening of 8 mm. Established bend forming finite element simulation model. In the finite element simulation model, a mold is defined as a rigid body, that is, a non-deformable one, and a flow stress curve measured in a tensile experiment is used as input data for the finite element simulation model. A finite element simulation is performed during the bending process of the plate material, and as shown in FIG. 5, the plate material after being bent at 90 degrees is simulated, and then the simulation springback corresponding to the bending angle by reusing the finite element method Simulate the magnitude of the quantity. In this embodiment, a 90-degree bending process, a sheet material bending with a thickness of 1.2 mm, an upper mold depression angle of 86 degrees, a drawing angle radius of 1.2 mm, and a lower mold opening of 8 mm are taken as examples. The numerical values are only for explaining the present invention, and the present invention is not limited to the above specific numerical values, and is arbitrary numerical values according to actual needs.

  In order to verify the accuracy of the established finite element simulation model, in the present invention, the materials A and B are bent using the mold shown in FIG. 12 according to the actual production state. Next, the upper die is removed, the angle θ after the spring back is measured, and both are subtracted to calculate the actual spring back amount Δθ. When the actual springback amount and the simulated springback amount are compared, and the error between the two is smaller than the first threshold, for example, 2%, the accuracy of the established bending finite element simulation model can be ensured. If the error between the two is greater than 2%, the grid size of the finite element simulation model is reasonably fine until the error between the simulation springback amount and the experimental springback amount is less than 2% so as to improve the simulation calculation accuracy. Turn into. In this example, the finite element simulation model is refined, and the influence on the simulation accuracy of the finite element grid size in the thickness direction of the plate material is the greatest. The thinner the grid in the thickness direction, the higher the accuracy and the thickness direction. When the grid is reduced to 1/7 of the thickness of the plate material, the size continues to be reduced and the improvement in accuracy is limited, but the simulation time becomes very long because the grid is too thin. Therefore, the optimal grid size in the thickness direction in this example is 1/7 of the plate thickness. FIG. 6 shows a comparison between simulation results and experimental results of the two materials A and B in this example, and the springback simulation errors of the two materials A and B are 1% and 1.5%, respectively. Since the simulation accuracy satisfies the requirement that the error is less than 2%, the bending finite element simulation model is used as a universal model for the simulation prediction of other subsequent materials. In the present invention, the first threshold value is 2%, but the first threshold value is not limited to the specific numerical value and can be arbitrarily changed according to actual needs.

  In the bending process, there is a relationship between the bending angle and the upper die pressing amount. Therefore, as shown in FIG. 7, the bending angle of the metal plate material is controlled by controlling the upper die pressing amount of the servo bending machine. Can be controlled. Based on the previously established bending finite element simulation model, the entire bending process of material A is simulated, and the upper die pressing amount with different drift and the corresponding bending angle are recorded, so that different bending angles and upper die pressing are recorded. You can get the relationship between quantity. Since the bending target in this example is 90 degrees, the bending state of about 90 degrees is emphasized, the relationship between the obtained bending angle and the upper die pressing amount (about 86o-96o), the amount of springback at the angle bending 8 shows the relationship between the different bending angles and the amount of springback, which is shown in FIG. 9 (about 86o-96o).

  Based on the relationship between the forming angle θ, the bending angle θ ′ and the springback amount Δθ, θ = θ ′ + Δθ, the relationship between the forming angle and the upper die pressing amount can be obtained, and after performing a linear analysis, The relationship between the forming angle θ of the material A and the upper die pressing amount ΔH is shown by line A in FIG. 10 in accordance with θ = −36.719 × ΔH + 169.02. Similarly, a finite element simulation of bending molding is performed for the material B, and a relationship θ = −36.656 × ΔH + 170.03 between the molding angle θ of the material B and the upper die pressing amount ΔH is obtained. This is shown by line B in FIG.

  According to this method, different manufacturers, different specifications, different batches of material can be tested to establish a relational database between material performance, forming angle, springback amount, upper die pressing amount. For materials with different thicknesses, it is possible to establish a finite element simulation model of bending of the upper die angle and the lower die opening corresponding to the thickness of the object to be bent, and material performance, forming angle, springback amount, upper die Establish a relational database between the pressing amount. In this way, the database can include bending issues for different manufacturers, different specifications, different batches, and different thickness materials.

(Blanking)
When blanking the metal sheet X, measuring and recording the blanking mold force received by the plate during the blanking process and the displacement of the blanked part, and recording the actual blank Get the load-stroke curve and the blank before bending. A finite element simulation model of the blanking process is established by a method described in a conventional patent (application of application number 201310680718.5), material mechanical performance parameters are set in advance on the blanking plate material, and the finite element for the blanking process is finite. Perform element simulation. Based on the actual blanking load-stroke curve, the established blanking finite element simulation is combined, and the mechanical performance parameters of the plate X are iteratively reverse engineered for each process and analyzed. As a result of iterating about 30 processes, the load-stroke curve simulation value basically overlaps the actual blanking load-stroke curve, the error between them is less than 1%, then reverse engineered The obtained material mechanical performance is output and the corresponding flow stress curve is drawn. Reference is made to the earlier application, application number 201310680718.5, for a detailed material performance reverse engineering method.

(Bending molding example 1)
The performance parameter of the material C obtained by reverse engineering is transmitted to the control unit of the bending machine. The control unit draws a flow stress curve based on the mechanical parameters of the workpiece, and compares it with the flow stress curve of the material in the database. The second threshold, e.g., is less than 1%, explaining that material A in the database is similar to material C, and the material parameter of material A is the reference material parameter of material C. Since the bending performance of the material depends on the mechanical performance of the material, the bending performance of the C material should be similar to the bending performance of the A material. In the present invention, the second threshold value is 1%, but the second threshold value is not limited to the specific numerical value, and can be arbitrarily changed according to actual needs.

  Then, the processing condition of the material C can be determined by the relationship between the molding angle of the material A and the upper die pressing amount, θ = −36.719 × ΔH + 169.02. A molding angle request is input, and in this example, the molding angle is 90 degrees. The angle is substituted into the relational expression, and the required upper mold pressing amount ΔH = (169.02-90) /36.719=2.15 mm. Can be calculated.

  Next, a command of upper die pressing amount = 2.15 mm is transmitted to the bending machine, the bending machine bends the blank of material C for which blanking is completed, and the forming angle after the spring back is 90.04. Measured to be degrees. The molding accuracy is much higher than the industrial requirement of 90 ± 0.5 degrees processing accuracy of molded products.

  Refer to Bending Example 2 when no material matching the error requirement is found in the database.

(Bending molding example 2)
The performance parameter of the material X obtained by reverse engineering is transmitted to the control unit of the bending machine. The control unit draws a flow stress curve based on the mechanical parameters of the workpiece, compares it with the flow stress curve of the material in the database, and does not find a material that meets the error requirements in the database, i.e., the workpiece metal plate in the relational database. If there is no reference material parameter whose error between the material parameter of X is smaller than the second threshold, the difference in performance between the material and the work material X in the relational database is very large. The bending process must be simulated by reusing the finite element simulation model of bending.

  The flow stress curve of the workpiece X obtained by reverse engineering is transmitted to the bending molding finite element simulation model, the bending molding is simulated, and the relationship between the molding angle of the workpiece X and the upper die pressing amount is determined. Obtained and shown in FIG. In addition, the relation between the performance of the work material and the corresponding molding angle and the upper die pressing amount is transmitted to the database, and the contents of the relational database are completed. As a result, when the flow stress curve of the metal plate M to be processed basically matches the flow stress curve of the material X, the material parameters of the metal plate X to be processed obtained by the reverse engineering are calculated in the relational database. It is a reference material parameter of the metal plate material M of processing. Next, the control unit determines an appropriate processing condition based on the relationship between the forming angle corresponding to the workpiece X in the relational database and the upper die pressing amount. Furthermore, when bending the plate material X, the control unit can directly find the X material from the relational database, and the processing conditions can be determined by the relationship between the corresponding molding angle and the upper die pressing amount, The method refers to Bending Example 1.

  Thus, the richer the material in the relational database, the easier it is to find a material with a very good fit with the performance of the material to be processed from the relational database. Is more suitable for the workpiece, the accuracy of the processed bent molded product is high, and it is not necessary to perform a finite element simulation calculation at the time of bending, and the control speed is faster. Even without finding a material with the same performance from the material database, the control system performs a bending forming simulation using the material parameters reverse-engineered during blanking to determine the forming angle of the workpiece and the upper die pressing amount. The relational database can be completed, and it is not necessary to use the data in the relational database directly for the next bending of the same material and to perform simulation.

  The above-described embodiments are merely illustrative of the principle of the present invention and its effects, and do not limit the present invention. For those skilled in the art, the above-described embodiments can be modified or changed without departing from the spirit and scope of the present invention. For this reason, all equivalent modifications or changes completed without departing from the spirit and technical idea disclosed in the present invention by those skilled in the art should be included in the claims of the present invention.

Claims (8)

A metal plate bending control method,
(1) Based on the structural parameters of the mold used for bending, a finite element simulation model for bending is established, and the material parameters of the metal sheet for simulation are input to the finite element simulation model for bending. Simulating the bending process of the metal sheet for simulation, obtaining the magnitude of the simulation springback amount corresponding to the forming angle, and setting the simulation springback amount as a springback amount to be added to the relational database; ,
After measuring the material parameters of the different metal plates, the bending process of the different metal plates is simulated based on the obtained finite element simulation model of the bending, and for each metal plate of the different metal plates Establishing the relational database between material parameters, forming angle, springback amount, upper die pressing amount of the mold,
Including the process of establishing a relational database between material parameters, forming angle, springback amount, upper die pressing amount, and
(2) blanking a workpiece metal plate to obtain a blank;
Obtain the experimental load-stroke curve in the blanking experiment of the workpiece metal plate by measurement, establish the finite element simulation model by the method of reverse engineering the actual physical parameters of the plate material, perform the blanking simulation, Repetitively reverse-engineering material parameters of the metal sheet to be processed;
Including blanking, material parameter reverse engineering process,
(3) comparing the material parameters in the relational database with the material parameters of the metal sheet to be processed;
If there is a reference material parameter with an error between the relational database and the material parameter of the workpiece metal plate material less than a second threshold, performing a bending operation;
If there is no reference material parameter with an error between the relational database and the material parameter of the workpiece metal plate smaller than a second threshold value, the material parameter of the workpiece metal plate obtained by the reverse engineering is obtained. Simulate the bending process in the same way as the process of establishing the relational database by using the material parameters, forming angle, springback amount, upper die pressing amount of the workpiece metal plate obtained by simulation. In addition to the relational database, the material parameter of the processed metal plate material obtained by the reverse engineering is a reference material parameter of the processed metal plate material in the relational database, and then bending forming Performing the operation,
Including comparing the material parameters in the relational database with the material parameters of the workpiece metal plate obtained by reverse engineering,
(4) inputting a bending angle;
Based on the relational expression between the molding angle corresponding to the reference material parameter and the upper mold pressing amount of the mold of the bending machine that performs the bending operation, the required upper mold pressing amount is calculated, and the required upper mold is calculated. Transmitting a pressing amount to the bending machine, and controlling the bending machine to bend the blank;
A metal plate material bending forming control method comprising:   The metal plate material bending forming control method according to claim 1, wherein the structural parameters of the mold used for bending forming include an upper mold drawing angle radius and a lower mold opening of the mold.   When establishing a bending finite element model, the bending test is performed to obtain the actual springback amount of the simulation metal plate, and the actual springback amount and the simulation springback are obtained. Calculating a difference between the magnitude of the quantity, and if the difference exceeds a first threshold, refining the grid size of the finite element simulation model until the difference is smaller than the first threshold. The metal sheet bending forming control method according to claim 1, wherein   When establishing a relational database between material parameters, forming angle, springback amount, upper die pressing amount, the material parameters used are material performance parameters and flow stress measured in tensile test when detecting material The metal sheet bending forming control method according to claim 1, wherein the method is a curve.   The metal sheet bending forming control method according to claim 1, wherein the first threshold value is 2%.   The bending process is simulated to record the relationship between the different bending angles θ ′ and the pressing amount ΔH, and then the springback amount corresponding to the different bending angles θ ′ using the finite element simulation model. By predicting the magnitude of Δθ, the relationship between different bending angles θ ′ and springback amount Δθ is obtained, and the relationship between forming angle θ, bending angle θ ′ and springback amount Δθ is θ = θ ′. 2. The metal sheet bending forming control method according to claim 1, wherein a relationship between the forming angle θ and the pressing amount ΔH is acquired based on + Δθ.   The metal sheet bending forming control method according to claim 1, wherein the second threshold value is 1%.   If the reference material parameter having an error between the material parameter of the metal plate to be processed is smaller than the second threshold does not exist in the relational database, the material of the metal plate to be processed obtained by the reverse engineering By inputting parameters to the finite element simulation model and simulating the bending process, the relationship between the forming angle θ and the pressing amount ΔH of the metal sheet to be processed is obtained, and the processing 8. The method for controlling the bending of a metal plate material according to claim 7, wherein a relationship between the forming angle θ of the metal plate material and the pressing amount ΔH is transmitted to the relational database.