Mold parameter determination method and electronic device

Abstract

The present disclosure relates to a mold parameter determination method and an electronic device, and relates to the technical field of simulation. The mold parameter comprises a forming cold machining model of a forming mold. The method comprises: obtaining a product three-dimensional model of a target product and forming mold material parameters; determining an initial forming mold model of the forming mold according to the product three-dimensional model; performing thermal-solid coupling finite element analysis of the forming mold according to the initial forming mold model and the forming mold material parameters, to determine a forming expansion amount of the forming mold in a forming process; and determining a forming cold machining model of the forming mold according to the forming expansion amount and the initial forming mold model. The method can accurately determine mold parameters.

Description

Technical Field

[0001] This disclosure relates to the field of simulation technology, and more specifically, to a method for determining mold parameters and an electronic device. Background Technology

[0002] In the field of hot pressing and deep drawing of thin plates, the determination of mold size in existing technologies needs to take into account the thermal expansion and contraction effect of the product and the mold. Usually, the target size is gradually approached by reserving the tolerance of the upper and lower molds and adjusting through multiple trial molding and mold opening.

[0003] This method has several drawbacks: First, due to the lack of precise quantitative methods, engineers often need to conduct multiple trial moldings to determine reasonable mold tolerances and thermal expansion compensation amounts, resulting in a development cycle that can last for several months and significantly increasing time and economic costs. Second, during the mold heating process, uneven heating due to factors such as the layout of heating rods leads to non-uniform thermal expansion. However, relevant technologies lack effective quantitative analysis methods for this, making it difficult to accurately predict the actual expansion of different parts of the mold, which is a key factor affecting the final mold dimensional accuracy. Summary of the Invention

[0004] One objective of this disclosure is to provide a new technical solution for mold parameter design, in order to solve the problems of long development cycles and low accuracy in determining mold parameters in related technologies.

[0005] According to a first aspect of this disclosure, a method for determining mold parameters is provided, the mold parameters including a cold-working model of a forming mold, the method comprising: Obtain the 3D model of the target product and the material parameters of the molding die; Based on the product's three-dimensional model, determine the initial molding mold model; Based on the initial molding die model and the molding die material parameters, a thermo-solid coupled finite element analysis of the molding die is performed to determine the molding expansion amount of the molding die during the molding process. Based on the molding expansion amount and the initial molding mold model, the molding cold processing model of the molding mold is determined.

[0006] Optionally, the step of performing a thermo-mechanical coupled finite element analysis of the molding die based on the initial molding die model and the molding die material parameters to determine the molding expansion of the molding die during the molding process includes: Based on the initial molding die model and the molding die material parameters, a thermo-solid coupled finite element model is established; Thermal boundary conditions and mechanical boundary conditions are set for the thermo-mechanical coupled finite element model; Based on the thermal boundary conditions and the mechanical boundary conditions, the process of heating the initial molding mold model from the initial temperature to the target molding temperature is simulated by the thermo-mechanical coupling finite element model to obtain the heating time required for the initial molding mold model to be heated to the target molding temperature. Based on the thermo-solid coupling solution results of the thermo-solid coupling finite element model at the corresponding time of the heating time and the initial molding mold model, the hot-state cavity three-dimensional model of the initial molding mold model at the target molding temperature is determined. The deviation between the geometric contours of the hot cavity 3D model and the initial molding mold model is used as the molding expansion amount.

[0007] Optionally, the molding expansion includes internal cavity thermal expansion, external thermal expansion, punch thermal expansion, and die thermal expansion. Determining the cold-state molding model of the molding die based on the molding expansion and the initial molding die model includes: Based on the initial forming punch working surface of the initial forming mold model, the thermal expansion of the inner cavity, and the thermal expansion of the punch, the cold processing surface of the forming punch of the forming mold is determined. Based on the initial forming cavity surface of the initial forming mold model, the thermal expansion of the outer shape, and the thermal expansion of the cavity, the cold processing surface of the forming mold cavity is determined. Based on the cold-processed surface of the forming punch, the cold-processed surface of the forming die, and the structural parts of the initial forming die model, a cold-processed model of the forming die is generated.

[0008] Optionally, the mold parameters further include a cold-working model of the forming mold, and the method further includes: Obtain the target process parameters and the material parameters of the forming mold; Based on the product's three-dimensional model, determine the initial shaping mold model; Based on the cold forming processing model, the material parameters of the sheet, and the target process parameters, thermoforming simulation is performed to obtain the target simulation product model corresponding to the target process parameters; Based on the target simulation product model, the initial forming mold model, and the forming mold material parameters, the forming cold processing model of the forming mold is determined.

[0009] Optionally, determining the cold-working model of the forming mold based on the target simulation product model, the initial forming mold model, and the forming mold material parameters includes: The total interference is determined based on the first coefficient of thermal expansion in the forming mold material parameters, the second coefficient of thermal expansion in the sheet material parameters, the product feature dimensions of the target simulation product model, the forming temperature difference, and the preset interference coefficient. Based on the total interference and the working surface of the initial forming punch of the initial forming die, the cold-processing surface of the forming punch of the forming die is determined. Based on the total interference and the initial forming die working surface of the initial forming die, the cold processing surface of the forming die is determined. Based on the cold-processed surface of the forming punch, the cold-processed surface of the forming die, and the initial forming die model, the cold-processed model of the forming die is determined.

[0010] Optionally, obtaining the target process parameters includes: Based on the aforementioned cold forming processing model, sheet material parameters, and current process parameters, thermoforming simulation is performed to obtain a simulated product model; The current process parameters are optimized based on the simulated product model until the simulated product model meets the preset conditions, thereby obtaining the target process parameters.

[0011] Optionally, the step of performing thermoforming simulation based on the cold forming model, sheet material parameters, and current process parameters to obtain a simulated product model includes: The cold forming process model is used as the constraint boundary for sheet deformation to establish a hot forming finite element model; Obtain the thermoforming conditions and sheet material parameters of the target product, as well as the current process parameters; Based on the thermoforming conditions, the material parameters of the sheet, and the current process parameters, the thermoforming finite element model is used to simulate the thermoforming process of the sheet model in the cold forming processing model to obtain the simulated product model.

[0012] Optionally, the material parameters of the sheet include true stress-strain data at different strain rates and temperatures, anisotropy parameters, elongation at break, density, and second coefficient of thermal expansion.

[0013] Optionally, the target process parameters include target stamping speed, target friction coefficient, target sheet thickness, target blank holder clearance, target temperature, and target blank holder force.

[0014] According to a second aspect of this disclosure, an electronic device is also provided, including a memory and a processor, the memory being used to store a computer program; the processor being used to execute the computer program to implement the method according to a first aspect of this disclosure.

[0015] This disclosure embodiment obtains a 3D model of the product and the material parameters of the molding die. Based on the 3D model, an initial molding die model is determined. Then, the molding expansion is determined through thermo-mechanical coupled finite element analysis. Finally, a cold-state processing model is determined based on the molding expansion and the initial molding die model. This solution achieves quantitative prediction of the thermal expansion of the molding die and accurate determination of the cold-state processing model on a computer. It uses the heated cavity as a reference to deduce the cold-state processing dimensions, solving the problem of relying on trial and error due to a lack of quantitative methods in related technologies. This significantly improves the design accuracy of the molding die and shortens the development cycle.

[0016] Other features and advantages of the embodiments of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the disclosure.

[0018] Figure 1 This is a schematic diagram of the structure of an electronic device that can apply the mold parameter determination method of the present disclosure embodiments.

[0019] Figure 2 This is a flowchart illustrating a method for determining mold parameters provided in an embodiment of this disclosure.

[0020] Figure 3 This is a flowchart illustrating another method for determining mold parameters provided in this embodiment. Detailed Implementation

[0021] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present disclosure.

[0022] The following description of at least one exemplary embodiment is merely illustrative and is not intended to limit the scope of this disclosure or its application or use.

[0023] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0024] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0025] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0026] It should be noted that all data acquisition actions in this disclosure were carried out in compliance with the relevant data protection laws and policies of the country where the data is located, and with the authorization of the relevant equipment owner.

[0027] This disclosure relates to a method for determining mold parameters. Figure 1 This is a schematic diagram of the structure of an electronic device that can apply the mold parameter determination method of the present disclosure embodiments.

[0028] Electronic devices are essentially computers, which can be manifested as high-performance tower workstations, rack servers, or small computing clusters composed of interconnected servers, without further limitation here.

[0029] like Figure 1 As shown, the electronic device 100 may include a processor 1100, a memory 1200, an interface device 1300, a communication device 1400, a display device 1500, an input device 1600, a speaker 1700, a microphone 1800, etc. The processor 1100 may be a central processing unit (CPU), a microprocessor (MCU), etc. The memory 1200 may include, for example, ROM (Read-Only Memory), RAM (Random Access Memory), or non-volatile memory such as a hard disk. The interface device 1300 may include, for example, a USB interface, a headphone jack, etc. The communication device 1400 may be capable of wired or wireless communication. The display device 1500 may be, for example, a liquid crystal display (LCD), a touch screen, etc. The input device 1600 may include, for example, a touch screen, a keyboard, etc. Users can input / output voice information through the speaker 1700 and the microphone 1800.

[0030] In one embodiment, the electronic device 100 includes a memory for storing a computer program and a processor for executing the computer program to implement the methods described in any embodiment of this disclosure.

[0031] exist Figure 1In the electronic device shown, the related technology relies primarily on engineers' practical experience and repeated trial molding to determine mold dimensions when designing thin-plate hot-pressing molds. Specifically, this technology suffers from the following shortcomings: First, determining mold dimensions requires considering the thermal expansion and contraction effects of the product and the mold, but lacks precise quantitative methods. Typically, the target dimensions are gradually approximated by allowing tolerances for the upper and lower molds and through multiple trial moldings and adjustments. Engineers often need to conduct multiple trial moldings to determine reasonable mold tolerances and thermal expansion compensation amounts, resulting in a development cycle that can last for several months, significantly increasing time and economic costs. Second, uneven heating during the mold heating process, caused by factors such as the layout of heating rods, leads to non-uniform thermal expansion. However, the related technology lacks effective quantitative analysis methods for this, making it difficult to accurately predict the actual expansion of different parts of the mold, a key factor affecting the final mold dimensional accuracy. Due to these shortcomings, the mold development cycle is long, the cost is high, and the product dimensional accuracy is difficult to guarantee.

[0032] To this end, this embodiment first obtains the three-dimensional model of the target product and the material parameters of the molding die to establish the input basis for simulation analysis. Then, based on the three-dimensional product model, an initial molding die model is determined as the geometric object for subsequent thermo-mechanical coupling analysis. Next, a thermo-mechanical coupling finite element analysis of the molding die is performed based on the initial molding die model and the molding die material parameters, achieving precise quantification of the non-uniform thermal expansion of the die during heating due to factors such as the layout of heating rods. Finally, based on this molding expansion, the cavity surface of the initial molding die model is compensated by reverse offset to determine the cold-state processing model of the molding die. This method replaces the traditional experience-based trial-and-error method with computer simulation, allowing mold designers to accurately determine the thermal expansion compensation amount and cold-state processing dimensions of the mold without multiple physical molding trials, thus significantly shortening the development cycle. Simultaneously, due to the precise quantification of the non-uniform thermal expansion of various parts of the mold, the accuracy of mold parameter determination and the dimensional accuracy of the final product are effectively improved.

[0033] <First Embodiment> The mold parameters include the cold processing model of the forming mold. Figure 2 This is a flowchart illustrating a method for determining mold parameters provided in an embodiment of this disclosure. Figure 2 As shown, the method may include steps S210 to S240.

[0034] Step S210: Obtain the 3D model of the target product and the material parameters of the molding die.

[0035] In this embodiment, the target product refers to a specific product that needs to be hot-pressed, such as a deep-drawn sheet metal part or a hot-stamped sheet metal part.

[0036] The 3D model of the target product is a three-dimensional geometric model obtained by digitally modeling the target product. This 3D model includes the product's design geometric contour, the working surface of the product's punch, and the surface of the product's concave cavity. The product's design geometric contour refers to the overall external boundary of the target product at room temperature. The working surface of the product's punch refers to the geometry of the target product's inner surface. The surface of the product's concave cavity refers to the geometry of the target product's outer surface.

[0037] The molding die material parameters refer to the primary thermophysical and mechanical parameters required by the die material under the target molding process. The primary thermophysical parameters include primary thermal conductivity, primary specific heat capacity, primary convective heat transfer coefficient, and primary density. The primary mechanical parameters include primary elastic modulus, primary Poisson's ratio, and primary coefficient of thermal expansion.

[0038] In one example, the target product is a deep-drawn part made of 6061 aluminum alloy sheet. The 3D model of the product is created using 3D modeling software and exported as an STP format file. The forming die material is H13 hot work die steel, and the material parameters of the forming die are obtained by consulting the material's high-temperature performance handbook or through high-temperature performance experiments. These parameters can be expressed as functions or curves of temperature and stored in the form of a structured database.

[0039] Step S220: Determine the initial molding mold model based on the product's three-dimensional model.

[0040] In this embodiment, the initial molding die model is a preliminary three-dimensional model of the mold structure designed based on the product's three-dimensional model. The initial molding die model includes a molding punch, a molding die, a mold base, and heating rods, etc. Specifically, the initial working surface of the molding punch is determined based on the working surface of the product punch in the product's three-dimensional model. The initial cavity surface of the molding die is also determined based on the cavity surface of the product cavity in the product's three-dimensional model. The mold base is used to fix and support the molding punch, molding die, and other components, and provides rigidity support for the entire molding die. The heating rods serve as a fixed heat source for heating the molding die, and their placement and power directly affect the temperature field distribution inside the molding die.

[0041] In one example, determining the initial molding die model includes: first, determining the parting surface position and demolding direction based on the product design geometry of the 3D product model; then, determining the initial molding punch working surface of the molding die based on the product punch working surface of the 3D product model, and determining the initial molding cavity surface of the molding die based on the product cavity surface of the 3D product model; next, determining the mold frame structure and heating rod layout of the molding die based on the set molding die installation method and set heating requirements; finally, combining the above parts to form the initial molding die model.

[0042] In one example, the initial molding die model can be an STP format file for subsequent finite element simulation analysis.

[0043] The geometric accuracy of the initial mold model directly affects the calculation accuracy of subsequent thermo-mechanical coupling analysis.

[0044] In one example, the initial mold model needs to retain structural details such as heating rod holes, cooling channels, and mounting holes to ensure the accuracy of thermal boundary condition settings. For auxiliary structures that are not involved in the thermo-mechanical coupling analysis (such as lifting holes, nameplate slots, etc.), appropriate geometric simplification can be performed to reduce the computational scale.

[0045] Step S230: Based on the initial molding die model and molding die material parameters, perform a thermo-solid coupled finite element analysis of the molding die to determine the molding expansion amount of the molding die during the molding process.

[0046] In this embodiment, the molding expansion refers to the change in geometric dimensions of the molding die due to temperature increase during the heating process. The molding expansion is determined through thermo-mechanical coupled finite element analysis.

[0047] In one embodiment, step S230, which involves performing a thermo-solid coupled finite element analysis of the molding die based on the initial molding die model and the molding die material parameters, to determine the molding expansion amount of the molding die during the molding process, may include the following steps S2311 to S2315.

[0048] Step S2311: Establish a thermo-solid coupled finite element model based on the initial molding die model and the molding die material parameters.

[0049] In this embodiment, the establishment of the thermo-solid coupling finite element model includes: discretizing the geometry of the initial molding mold model into a finite element mesh, dividing it into a finite number of elements and nodes.

[0050] Then, the thermophysical and mechanical properties of the mold material are set according to the mold material parameters. Specifically, the mold material parameters include thermophysical parameters and mechanical parameters. Thermophysical parameters include thermal conductivity, specific heat capacity, convective heat transfer coefficient, and density. Mechanical parameters include elastic modulus, Poisson's ratio, and coefficient of thermal expansion. Thermophysical parameters serve as the thermophysical properties of the mold material, while mechanical parameters serve as the mechanical properties of the mold material. Thermophysical parameters are used as material property inputs for the thermal analysis of the thermo-structure coupled finite element model, and are used to solve for the temperature field. Mechanical parameters are used as material property inputs for the mechanical analysis of the thermo-structure coupled finite element model, and are used to solve for thermal deformation.

[0051] In one example, the mesh of the thermo-structure coupled finite element model uses tetrahedral or hexahedral elements. For areas of interest such as the working surface of the punch and the cavity surface of the die, local mesh refinement is performed to improve computational accuracy.

[0052] Step S2312: Set thermal boundary conditions and mechanical boundary conditions for the thermo-solid coupled finite element model.

[0053] In this embodiment, thermal boundary conditions are used to simulate the thermal load on the molding die during the actual heating process.

[0054] In one example, thermal boundary conditions may include simulating the heating rod as a stationary heat source and setting a convective heat transfer environment. The heating rod is simulated as a stationary heat source, and its heat generation rate is determined based on the rated power of the heating rod and its actual operating conditions. The convective heat transfer environment is used to simulate the heat exchange between the mold surface and the surrounding air, including natural convection and radiative heat dissipation from the outer surface of the mold.

[0055] Mechanical boundary conditions include setting mechanical constraints. These conditions are used to simulate the constraint state of the molding die during actual installation, including the fixed constraints on the bottom surface of the molding die and the guiding constraints on the guide pillars.

[0056] In one example, the heating rod is simulated by assigning a heat generation rate load to the elements in the region where the heating rod is located. This heat generation rate is calculated based on the heating rod's rated power, resistance value, and actual operating voltage. The convective heat transfer coefficient of the outer surface of the molding die is set according to the molding die material, surface condition, and environmental conditions, for example, from 10 W / (m²·K) to 50 W / (m²·K). The mechanical constraints on the bottom surface of the molding die are simulated as fixed constraint boundary conditions, restricting all degrees of freedom of the bottom surface of the molding die.

[0057] Step S2313: Based on the thermal boundary conditions and mechanical boundary conditions, the process of heating the initial molding mold model from the initial temperature to the target molding temperature is simulated by the thermo-solid coupling finite element model, and the heating time required for the initial molding mold model to be heated to the target molding temperature is obtained.

[0058] In this embodiment, the heating time refers to the time required for the forming mold to heat from an initial temperature (e.g., ambient temperature 20°C) to a target forming temperature (e.g., the hot forming temperature of aluminum alloy is 450°C). The heating time is determined by applying thermal boundary conditions in a thermo-mechanical coupled finite element model, solving for the change of the temperature field of the forming mold over time, and recording the time when the surface temperature of the forming mold cavity reaches the target forming temperature, which is the heating time.

[0059] Heating time depends on multiple factors, including heating rod power, molding die quality, molding die thermophysical parameters, and heat dissipation conditions.

[0060] Step S2314: Based on the thermo-solid coupling solution results of the thermo-solid coupling finite element model at the corresponding time of heating and the initial molding mold model, determine the three-dimensional hot cavity model of the initial molding mold model at the target molding temperature.

[0061] In this embodiment, the hot-state cavity 3D model refers to the actual geometric shape of the cavity of the molding die under the stable state of the target molding temperature. At the corresponding moment of the heating time, the temperature field of the molding die has reached the target molding temperature. Steady-state thermo-mechanical coupling solution is performed at this temperature to obtain the thermal deformation result of the molding die. The cavity geometry of the initial molding die model is superimposed with the thermal deformation result to obtain the hot-state cavity 3D model.

[0062] The hot-state cavity 3D model reflects the actual cavity geometry of the molding die at the target molding temperature, including the non-uniform thermal expansion effect caused by factors such as heating rod layout and uneven die structure. This hot-state cavity 3D model is the core basis for thermal expansion compensation calculation.

[0063] Step S2315: The deviation between the geometric contours of the hot cavity 3D model and the initial molding mold model is used as the molding expansion amount.

[0064] In this embodiment, the deviation between the geometric contours of the hot cavity 3D model and the initial molding die model represents the amount of thermal expansion generated by the molding die during the heating process. This deviation is a non-uniformly distributed quantity; different parts of the molding die cavity experience varying amounts of expansion due to uneven temperature distribution and differences in structural stiffness.

[0065] In one example, the forming expansion includes the internal cavity thermal expansion, the external shape thermal expansion, the punch thermal expansion, and the die thermal expansion. Specifically, the internal cavity thermal expansion refers to the thermal expansion corresponding to the working surface of the initial forming punch in the initial forming mold model; the external shape thermal expansion refers to the thermal expansion corresponding to the cavity surface of the initial forming die model; the punch thermal expansion refers to the thermal expansion of the working part of the punch itself in the initial forming mold model; and the die thermal expansion refers to the thermal expansion of the cavity part itself in the initial forming mold model.

[0066] As can be seen from steps S2311 to S2315 above, this embodiment establishes a thermo-mechanical coupled finite element model, sets thermal and mechanical boundary conditions, simulates the transient process of the mold heating from the initial temperature to the target molding temperature to obtain the heating time, and then determines the three-dimensional model of the hot cavity at the corresponding time of the heating time. Finally, the deviation between the geometric contour of the hot cavity three-dimensional model and the initial molding mold model is used as the molding expansion amount. This scheme realizes the quantitative calculation of the non-uniform thermal expansion of the molding mold, provides a data foundation for determining the cold processing model of the molding mold, and solves the problem of inaccurate mold size determination caused by the lack of quantitative means for the non-uniform thermal expansion of the molding mold in related technologies.

[0067] Step S240: Determine the cold processing model of the molding die based on the molding expansion amount and the initial molding die model.

[0068] In this embodiment, the cold forming processing model refers to the three-dimensional mold model obtained by reverse offsetting and compensating for the forming expansion amount to the cavity surface of the initial forming mold model. The cold forming processing model is a three-dimensional model actually used to guide mold processing. Its cavity dimensions are processed at room temperature, and then expand to the design geometry of the target product at the target forming temperature.

[0069] In embodiments where the corresponding molding expansion includes the internal cavity thermal expansion, the external shape thermal expansion, the punch thermal expansion, and the die thermal expansion, step S240, based on the molding expansion and the initial molding die model, determines the molding cold processing model of the molding die, which may include the following steps S2411 to S2413.

[0070] Step S2411: Determine the cold processing surface of the forming punch of the forming mold based on the working surface of the initial forming punch and the thermal expansion of the inner cavity and the thermal expansion of the punch of the initial forming mold model.

[0071] In this embodiment, since the dimensions of the punch of the forming mold at room temperature are smaller than its dimensions at hot temperature, the forming mold needs to fit snugly against the inner cavity of the target product after thermal expansion. Therefore, taking the initial forming punch working surface of the initial forming mold model as a reference, the initial forming punch working surface of the initial forming mold model corresponds to the inner cavity geometry of the forming mold at room temperature. By superimposing this initial forming punch working surface with the inner cavity thermal expansion, the inner cavity geometry of the forming mold in the hot state is obtained. Then, the thermal expansion of the punch is subtracted to obtain the surface geometry of the forming mold punch that should be machined at room temperature, which serves as the cold-state machining surface of the forming punch of the forming mold.

[0072] In this way, after the punch of the forming mold is processed at room temperature according to the cold-processed surface of the forming punch, when heated to the target forming temperature, its hot surface exactly matches the actual size of the inner cavity of the target product in the hot state.

[0073] Step S2412: Determine the cold processing surface of the forming die cavity based on the initial forming die cavity surface and the thermal expansion of the initial forming die model, as well as the thermal expansion of the die cavity.

[0074] In this embodiment, since the dimensions of the die cavity at room temperature are smaller than those at hot temperature, the die cavity needs to conform to the shape of the target product after thermal expansion. Therefore, the initial die cavity surface of the initial die model is used as a reference, which corresponds to the external geometry of the die cavity at room temperature. This initial die cavity surface is superimposed with the external thermal expansion to obtain the external geometry of the die cavity at hot temperature. Subtracting the external thermal expansion yields the surface geometry of the die cavity to be machined at room temperature, which serves as the cold-processing surface of the die cavity.

[0075] In this way, after the die cavity of the molding die is processed at room temperature according to the cold-processed surface of the die cavity, when it is heated to the target molding temperature, its hot-state surface exactly matches the actual size of the target product in the hot state.

[0076] Step S2413: Generate the cold processing model of the forming mold based on the cold processing surface of the forming punch, the cold processing surface of the forming die, and the structural parts of the initial forming mold model.

[0077] In this embodiment, the cold-processed surfaces of the forming punch and forming die obtained from the above calculations are combined with the structural parts in the initial forming mold model that do not involve surface changes to generate a cold-processed model of the forming mold. This cold-processed model can be directly used to guide the CNC machining of the forming mold.

[0078] In the example above, by superimposing the thermal expansion of the internal cavity and the external shape with the thermal expansion of the punch and the die respectively, the cold-processed surfaces of the punch and die of the forming mold are determined separately. This method takes into account the differences in thermal expansion coefficients and temperature distribution between the target product and the forming mold, and can accurately calculate the required cold-state compensation for each of the punch and die of the forming mold. Compared with the traditional method of uniformly reserving tolerances, this scheme can accurately compensate for the non-uniform thermal expansion of various parts of the forming mold cavity, significantly improving the dimensional accuracy of the forming mold design.

[0079] As can be seen from steps S210 to S240 above, this embodiment obtains the product's 3D model and the molding die material parameters, determines the initial molding die model based on the product's 3D model, determines the molding expansion amount through thermo-mechanical coupled finite element analysis, and finally determines the cold processing model based on the molding expansion amount and the initial molding die model. This scheme realizes the quantitative prediction of the molding die's thermal expansion amount and the accurate determination of the cold processing model on a computer. It uses the heated cavity as a reference to deduce the cold processing dimensions, solving the problem of relying on experience and trial and error due to the lack of quantitative means in related technologies. This significantly improves the design accuracy of the molding die and shortens the development cycle.

[0080] <Second Embodiment> Based on the first embodiment described above, the mold parameters may also include the cold-processing model of the forming mold. Figure 3 This is a flowchart illustrating another method for determining mold parameters provided in this embodiment of the disclosure. Figure 3 As shown, the method for determining mold parameters may further include steps S310 to S340.

[0081] Step S310: Obtain the target process parameters and the forming mold material parameters.

[0082] In this embodiment, the target process parameters refer to the set of process parameters determined through simulation optimization that enable the molding quality to meet preset conditions. The target process parameters include target stamping speed, target friction coefficient, target sheet thickness, target blank holder clearance, target molding temperature, and target blank holder force. Specifically, the target stamping speed determines the deformation rate of the sheet during molding, affecting its flow behavior and molding quality. The target friction coefficient reflects the friction state between the sheet and the molding die surface, affecting the sheet's flow resistance and molding force. The target sheet thickness is a fundamental geometric parameter affecting the sheet's flow behavior and molding limits. The target blank holder clearance is a key parameter for preventing sheet wrinkling and controlling sheet flow. The target molding temperature determines the sheet's plastic flow properties and the mechanical properties of the final product. The target blank holder force is used to control the sheet's flow resistance during molding, preventing wrinkling and cracking.

[0083] A sheet material refers to a plate-shaped raw material used in thermoforming processes. Its shape and size are determined based on the unfolded geometry of the target product. The sheet material undergoes plastic deformation during thermoforming and ultimately becomes the target product.

[0084] The material parameters of the forming die refer to the second thermophysical parameters and second mechanical parameters required by the die material under the target forming process. The second thermophysical parameters include the second thermal conductivity, the second specific heat capacity, the second convective heat transfer coefficient, and the second density. The second mechanical parameters include the second elastic modulus, the second Poisson's ratio, and the first coefficient of thermal expansion.

[0085] The material of the shaping mold can be the same as or different from that of the forming mold; there is no limitation here.

[0086] In one embodiment, step S310, obtaining the target process parameters, may include steps S410 to S420.

[0087] Step S410: Based on the cold forming processing model, the material parameters of the sheet, and the current process parameters, perform thermoforming simulation to obtain the simulated product model.

[0088] In this embodiment, thermoforming simulation refers to simulating the thermoforming process of a sheet material within the cavity of a molding die using the finite element method. The cold-forming model serves as the geometric boundary of the molding die, defining the deformation constraints of the sheet material. The sheet material parameters define the material behavior of the sheet material at high temperatures. The current process parameters define the process control conditions during the forming process.

[0089] In one example, step S410, based on the cold forming processing model, the material parameters of the sheet, and the current process parameters, performs thermoforming simulation to obtain a simulated product model, which may include the following steps S4111 to S4113.

[0090] Step S4111: Use the cold forming processing model as the constraint boundary for the deformation of the sheet material to establish a hot forming finite element model.

[0091] In this embodiment, the thermoforming finite element model is established based on the cold forming processing model determined in the first embodiment. This cold forming processing model includes the cold forming surface of the forming punch and the cold forming surface of the forming die. In the thermoforming simulation, the cold forming surface of the forming punch and the cold forming surface of the forming die together constitute the contact constraint surface of the sheet material during the deformation process. That is, the sheet material is subject to contact constraint in the normal direction and friction constraint in the tangential direction during the mold closing process of the forming punch and forming die.

[0092] The surface geometry of the cold forming model is imported into the finite element environment, and a hot forming finite element model is built on this basis.

[0093] Step S4112: Obtain the thermoforming conditions and sheet material parameters of the target product, as well as the current process parameters.

[0094] In this embodiment, thermoforming conditions refer to the temperature boundaries and initial contact states that need to be set in thermoforming simulation. Specifically, thermoforming conditions may involve placing the sheet material model on the molding cavity of the cold-processing model and heating the cold-processing model to the target molding temperature. The initial placement position of the sheet material corresponds to the initial position of the sheet material in the molding die during actual production. The target molding temperature corresponds to the operating temperature of the molding die during actual production and is the thermal environment required for the sheet material to undergo plastic deformation.

[0095] Sheet material parameters refer to the material properties of a sheet at high temperatures. These parameters include true stress-strain data at different strain rates and temperatures, anisotropy parameters, elongation at break, density, and the second coefficient of thermal expansion. True stress-strain data at different strain rates and temperatures reflect the plastic flow behavior of the sheet under different deformation conditions and temperatures, and are core parameters describing the sheet's forming performance. Anisotropy parameters reflect the differences in the sheet's deformation capacity in different directions within the sheet plane, and are important for predicting wrinkling and cracking defects during the forming process. Elongation at break is a criterion for sheet fracture at high temperatures, used to determine whether cracking will occur during the forming process. Density and the second coefficient of thermal expansion are used for temperature field calculations and thermo-mechanical coupling analysis in thermoforming simulations.

[0096] Current process parameters refer to the initial process parameter settings that have not yet been optimized. Current process parameters include current stamping speed, current coefficient of friction, current sheet thickness, current blank holder clearance, current temperature, and current blank holder force.

[0097] Step S4113: Based on the thermoforming conditions, sheet material parameters, and current process parameters, the thermoforming finite element model is used to simulate the thermoforming process of the sheet model in the cold forming processing model to obtain the simulated product model.

[0098] In this embodiment, based on the thermoforming finite element model established in step S4111, the thermoforming conditions, sheet material parameters and current process parameters obtained in step S4112 are used as inputs to perform thermoforming finite element solution.

[0099] The solution process simulates the entire process of a sheet material moving from its initial position towards the forming cavity of the forming die under the drive of the forming punch. The sheet undergoes plastic deformation under the combined constraints of the cold-processed surfaces of both the forming punch and the forming cavity. Throughout the solution process, the temperature field of the sheet material changes over time, and its stress-strain state is dynamically updated during deformation. Current process parameters influence the deformation behavior of the sheet material through contact algorithms and the material constitutive model. The material constitutive model is a mathematical model established based on the true stress-strain data at different strain rates and temperatures obtained in step S4112. This model describes the quantitative relationship between flow stress, strain, strain rate, and temperature during high-temperature forming, and is the core basis for calculating the sheet material's deformation resistance and predicting cracking risk in the finite element method for thermoforming.

[0100] After the solution is completed, the final geometric shape of the output material is used as the simulation product model.

[0101] Step S420: Optimize the current process parameters based on the simulation product model until the simulation product model meets the preset conditions, and obtain the target process parameters.

[0102] In this embodiment, the simulated product model includes information such as the geometry, wall thickness distribution, and stress-strain state of the formed sheet, which can be used for molding quality assessment. If the simulated product model does not meet the preset conditions, the current process parameters need to be adjusted and steps S4111 to S4113 need to be re-executed until the simulated product model meets the preset conditions.

[0103] The preset conditions refer to the criteria for judging whether the molding quality of the simulated product model meets the requirements. These preset conditions may include that the product is free of cracks and wrinkles, has uniform wall thickness distribution, and meets dimensional accuracy requirements.

[0104] In one example, optimizing the current process parameters based on the simulated product model includes: obtaining the defect assessment results of the simulated product model. These defect assessment results include crack assessment results (i.e., whether cracks exist) and wrinkle assessment results (i.e., whether wrinkles exist). If the defect assessment results indicate the presence of cracks or wrinkles, the simulated product model does not meet the preset conditions. At least one of the current process parameters is then adjusted, and the thermoforming simulation is re-executed until the defect assessment results of the simulated product model meet the preset conditions. The current process parameters corresponding to meeting the preset conditions are then used as the target process parameters.

[0105] In one example, the optimization of the blank holder gap in the process parameters can be achieved through a series of simulations within a preset value range and with a preset gradient. For instance, the preset value range for the blank holder gap can be 0.15mm to 0.25mm, and the preset gradient can be 0.05mm. By simulating the forming process with blank holder gaps of 0.15mm, 0.20mm, and 0.25mm respectively, the defect assessment results under different gaps are evaluated, and the target blank holder gap is determined with the goal of minimizing the wrinkle content in the defect assessment results.

[0106] As shown in steps S410-S420 above, by establishing a thermoforming finite element model for process simulation, a simulated product model is obtained. Based on the molding quality reflected by this model, the current process parameters are optimized and iterated until the simulated product model meets preset conditions. The process parameters corresponding to these conditions are then determined as the target process parameters, thus achieving quantitative determination of process parameters. Compared to traditional physical trial-and-error methods, this approach eliminates the need for actual mold prototyping and physical experiments, allowing for the optimization and iteration of process parameters on a computer. This significantly reduces the number of experiments and development costs, and improves the efficiency and accuracy of process parameter determination. Furthermore, by quantifying the molding quality judgment criteria as whether the simulated product model meets preset conditions, the reliability and repeatability of the target process parameters are ensured.

[0107] Step S320: Determine the initial shaping mold model based on the product's three-dimensional model.

[0108] In this embodiment, the initial forming mold model is a preliminary three-dimensional model of the forming mold structure designed based on the product's three-dimensional model. The initial forming mold model includes a forming punch, a forming die, a mold base, a guiding mechanism, and an mounting structure. Specifically, the initial working surface of the forming punch is determined based on the working surface of the product punch in the product's three-dimensional model, and the initial cavity surface of the forming die is determined based on the cavity surface of the product's three-dimensional model. The mold base, guiding mechanism, and mounting structure of the initial forming mold model are non-surface components.

[0109] The method for determining the initial forming mold model is similar to that for determining the initial forming mold model in the first embodiment: the initial forming punch working surface of the forming punch is determined based on the working surface of the product punch of the product three-dimensional model, and the initial forming die cavity surface of the forming die is determined based on the cavity surface of the product die of the product three-dimensional model. Then, the mold frame structure and guiding mechanism of the forming mold are designed to form a complete initial forming mold model.

[0110] Step S330: Based on the cold forming processing model, the material parameters of the sheet, and the target process parameters, perform thermoforming simulation to obtain the target simulation product model corresponding to the target process parameters.

[0111] In this embodiment, the target simulation product model refers to the three-dimensional geometric model of the product obtained after performing thermoforming simulation using the target process parameters. The difference between the target simulation product model and the simulation product model in step S410 is that the simulation product model in step S410 is obtained using the current process parameters (unoptimized initial parameters), while the target simulation product model is obtained using the target process parameters (optimized optimal parameters).

[0112] The target simulation product model contains geometric information about the product after molding, including springback, warpage, changes in wall thickness distribution, and radius deformation. This target simulation product model directly reflects the geometric state of the target product after actual molding.

[0113] It should be noted that the specific implementation of step S330 is basically the same as that of step S410, and will not be elaborated here.

[0114] Step S340: Based on the target simulation product model, the initial forming mold model, and the forming mold material parameters, determine the forming cold processing model of the forming mold.

[0115] In this embodiment, the cold-working model refers to the three-dimensional model of the forming mold obtained after compensating for the interference fit onto the surface of the initial forming mold model. The cold-working model is the actual three-dimensional model used to guide the processing of the forming mold.

[0116] In one embodiment, step S340, which determines the cold-state processing model of the forming mold based on the target simulation product model, the initial forming mold model, and the forming mold material parameters, may include the following steps S3411 to S3414.

[0117] Step S3411: Determine the total interference amount based on the first thermal expansion coefficient in the forming mold material parameters, the second thermal expansion coefficient in the sheet material parameters, the product feature dimensions of the target simulation product model, the forming temperature difference, and the preset interference coefficient.

[0118] In this embodiment, the total interference fit refers to the amount of interference fit required between the forming mold and the target product under hot conditions.

[0119] The product feature dimensions of the target simulation product model reflect the dimensions of the contact surfaces between the forming mold and the product in a specific direction. Their extraction location corresponds to the area where the forming punch and die of the forming mold have an interference fit with the product. The specific values ​​of the product feature dimensions depend on the product shape and the mating parts of the forming mold.

[0120] For example, the characteristic dimension of a rotating product can be the inner diameter or the outer diameter, while the characteristic dimension of a non-rotating product can be the width or length in the mating direction.

[0121] The total interference is determined using a step-by-step calculation method: The first step is to determine the interference amount per unit dimension based on the difference between the second and first coefficients of thermal expansion, the forming temperature difference, and the preset interference coefficient. The interference amount per unit dimension reflects the interference between the product and the forming mold per unit length due to the difference in their coefficients of thermal expansion. The preset interference coefficient is greater than 1, ranging from 1.05 to 1.15, and is used to compensate for stress relaxation and creep effects during the hot-holding process, ensuring the dimensional stability of the product after forming.

[0122] The second step is to determine the total interference based on the unit size interference and the product feature dimensions.

[0123] For example, assume that the sheet material of the target product is aluminum alloy 6061 (the second coefficient of thermal expansion of this sheet material α_product = 23.5 × 10⁻⁶). -6 / ℃), the forming die material is Cr12MoV (the first coefficient of thermal expansion of this forming die material α_mold=12.5×10 ℃), and the forming die material is Cr12MoV (the first coefficient of thermal expansion of this forming die material α_mold=12.5×10 ℃). -6 / ℃), the product's feature dimension is 100mm, the forming temperature difference is 430℃ (heating from 20℃ to 450℃), and the preset interference coefficient is 1.1. Therefore, the interference per unit dimension = (23.5 × 10) -6 - 12.5×10 -6 ) × 430 ×1.1 = 0.005203mm / mm, total interference = 0.005203 × 100 = 0.5203mm.

[0124] Step S3412: Determine the cold machining surface of the forming punch of the forming mold based on the total interference and the working surface of the initial forming punch of the initial forming mold.

[0125] In this embodiment, the initial working surface of the initial forming punch of the initial forming die is the initial working surface of the forming punch preliminarily designed based on the three-dimensional model of the product. This surface does not yet include the interference fit amount. The cold-processed surface of the forming punch is the final surface that the forming punch should actually be processed at room temperature.

[0126] The method for determining the cold-processed profile of the forming punch is as follows: based on the initial working profile of the forming punch, the total interference is reduced inwards to obtain the cold-processed profile of the forming punch. After the cold-processed profile of the forming punch determined in this way is processed at room temperature, it expands under heat at the forming temperature. Its hot dimensions exactly form the required interference fit with the hot inner cavity of the product, thereby generating sufficient forming pressure to eliminate springback and residual stress deformation at the R-corners of the product.

[0127] In other words, the total interference determines the amount of indentation of the cold-machined profile of the forming punch relative to the initial working profile of the forming punch, and this indentation directly determines the tightness of the interference fit in the hot state.

[0128] Step S3413: Determine the cold processing surface of the forming die cavity of the forming mold based on the total interference and the initial forming die working surface of the initial forming mold.

[0129] In this embodiment, the initial working surface of the initial forming die is the initial working surface of the forming die preliminarily designed based on the product's three-dimensional model. This surface does not yet include the interference fit. The cold-processed surface of the forming die is the final surface that the forming die should actually be processed at room temperature. The cold-processed surface of the forming die is determined by expanding the initial working surface of the forming die outwards and adding the total interference fit.

[0130] The cold-processed die profile determined by this method, after being processed at room temperature, expands under heat at the forming temperature. Its hot-state cavity dimensions precisely match the hot-state shape of the product, forming the required interference fit and applying uniform forming pressure to the product from the outside. The total interference determines the outward expansion of the cold-processed die profile relative to the initial working die profile, and this outward expansion determines the tightness of the forming die's grip on the product's outer surface under hot conditions.

[0131] Step S3414: Determine the cold processing model of the forming die based on the cold processing surface of the forming punch, the cold processing surface of the forming die, and the initial forming die model.

[0132] In this embodiment, the cold-processed surface of the forming punch determined in step S3412 and the cold-processed surface of the forming die determined in step S3413 are combined with the structural parts of the initial forming mold model that do not involve surface changes to generate a complete cold-processed forming model.

[0133] The initial forming mold model includes non-surface components such as the mold base, guiding mechanism, and mounting structure. These components do not directly contact or form the product during the forming process, therefore no surface correction is required.

[0134] By combining the modified cold-processed surfaces of the forming punch and the forming die with the original structural parts of the initial forming mold model, a complete cold-processing model for forming can be obtained. This model can be directly used to guide the CNC machining of the forming mold.

[0135] In one example, the forming die uses a tooling structure with the forming punch at the bottom and the forming die at the top. This tooling structure facilitates the placement and removal of the target product, while also helping to ensure positioning accuracy during the forming process.

[0136] As can be seen from steps S3411 to S3414 above, this embodiment first determines the total interference based on the difference in thermal expansion coefficients between the product material and the forming die material, the product feature dimensions, the forming temperature difference, and the preset interference coefficient. Then, based on the initial forming punch working surface and the initial forming die working surface, the total interference is subtracted or added to determine the cold-processing surface of the forming punch and the cold-processing surface of the forming die, respectively. Finally, the modified surfaces are combined with the structural parts of the initial forming die model to generate the cold-processing model of the forming die, thus realizing the precise design of the cold-processing model of the forming die. This solution solves the problem of the interference of the forming die being set based on experience and the effect being unstable in related technologies. It can ensure that sufficient forming pressure is generated under hot conditions, and improve the forming accuracy and dimensional stability of the product's R-angle features.

[0137] As can be seen from steps S310 to S340 above, this embodiment adds a shaping mold design step to the molding mold design. First, the target process parameters and the corresponding target simulation product model are obtained through thermoforming simulation and process parameter optimization. Then, based on the target simulation product model, the total interference is determined according to the difference in thermal expansion coefficients between the product and the mold. The initial shaping mold surface is then modified to generate a shaping cold processing model, realizing a full-process simulation design from molding mold design to process parameter optimization and then to shaping mold design. This solution solves the problems of lack of theoretical basis in shaping mold design and interference set by experience in related technologies, improving the design accuracy of the shaping mold and the forming quality of the product's R-angle features.

[0138] This disclosure also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the mold parameter determination method in any embodiment of this disclosure. Optionally, the computer-readable storage medium may be a non-transitory storage medium, but is not limited thereto; it may also be a temporary storage medium.

[0139] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0140] This disclosure may be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having a computer-readable program loaded thereon for causing a processor to implement any of the methods in the foregoing embodiments of this disclosure.

[0141] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media may include, for example, electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), static random access memory (SRAM), compact disc-read-only memory (CD-ROM), digital versatile disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any combination thereof. The computer-readable storage medium used herein is not to be interpreted as a transient signal itself, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0142] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include one or more of copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to computer-readable storage media in the respective computing / processing device.

[0143] The computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source or object programs written in any combination of one or more programming languages, including object-oriented programming languages ​​(such as Smalltalk, C++, etc.) and conventional procedural programming languages ​​(such as the "C" language or similar programming languages). The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network (e.g., a local area network or a wide area network), or it may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays, or programmable logic arrays, can execute computer-readable program instructions to implement various aspects of the embodiments of this disclosure by utilizing state information from the computer-readable program instructions.

[0144] Various aspects of this disclosure are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus, and computer program products according to embodiments of this disclosure. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0145] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0146] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions that execute on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0147] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions. It should be noted that implementation in hardware, implementation in software, and implementation using a combination of software and hardware are all equivalent.

[0148] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein. The scope of this disclosure is defined by the appended claims.

Claims

1. A method for determining mold parameters, characterized in that, The mold parameters include the cold processing model of the forming mold, and the method includes: Obtain the 3D model of the target product and the material parameters of the molding die; Based on the product's three-dimensional model, determine the initial molding mold model; Based on the initial molding die model and the molding die material parameters, a thermo-solid coupled finite element analysis of the molding die is performed to determine the molding expansion amount of the molding die during the molding process. Based on the molding expansion amount and the initial molding mold model, the molding cold processing model of the molding mold is determined.

2. The method according to claim 1, characterized in that, The step of performing a thermo-mechanical coupled finite element analysis of the molding die based on the initial molding die model and the molding die material parameters to determine the molding expansion during the molding process includes: Based on the initial molding die model and the molding die material parameters, a thermo-solid coupled finite element model is established; Thermal boundary conditions and mechanical boundary conditions are set for the thermo-solid coupled finite element model; Based on the thermal boundary conditions and the mechanical boundary conditions, the process of heating the initial molding mold model from the initial temperature to the target molding temperature is simulated by the thermo-mechanical coupling finite element model to obtain the heating time required for the initial molding mold model to be heated to the target molding temperature. Based on the thermo-solid coupling solution results of the thermo-solid coupling finite element model at the corresponding time of the heating time and the initial molding mold model, the hot-state cavity three-dimensional model of the initial molding mold model at the target molding temperature is determined. The deviation between the geometric contours of the hot cavity 3D model and the initial molding mold model is used as the molding expansion amount.

3. The method according to claim 1, characterized in that, The molding expansion includes internal cavity thermal expansion, external thermal expansion, punch thermal expansion, and die thermal expansion. Determining the cold-state processing model of the molding die based on the molding expansion and the initial molding die model includes: Based on the initial forming punch working surface of the initial forming mold model, the thermal expansion of the inner cavity, and the thermal expansion of the punch, the cold processing surface of the forming punch of the forming mold is determined. Based on the initial forming cavity surface of the initial forming mold model, the thermal expansion of the outer shape, and the thermal expansion of the cavity, the cold processing surface of the forming mold cavity is determined. Based on the cold-processed surface of the forming punch, the cold-processed surface of the forming die, and the structural parts of the initial forming die model, a cold-processed model of the forming die is generated.

4. The method according to claim 1, characterized in that, The mold parameters also include a cold-processing model for the forming mold, and the method further includes: Obtain the target process parameters and the material parameters of the forming mold; Based on the product's three-dimensional model, determine the initial shaping mold model; Based on the cold forming processing model, the material parameters of the sheet, and the target process parameters, thermoforming simulation is performed to obtain the target simulation product model corresponding to the target process parameters; Based on the target simulation product model, the initial forming mold model, and the forming mold material parameters, the forming cold processing model of the forming mold is determined.

5. The method according to claim 4, characterized in that, The step of determining the cold-state processing model of the forming mold based on the target simulation product model, the initial forming mold model, and the forming mold material parameters includes: The total interference is determined based on the first thermal expansion coefficient in the forming mold material parameters, the second thermal expansion coefficient in the sheet material parameters, the product feature dimensions of the target simulation product model, the forming temperature difference, and the preset interference coefficient. Based on the total interference and the working surface of the initial forming punch of the initial forming die, the cold-processing surface of the forming punch of the forming die is determined. Based on the total interference and the initial forming die working surface of the initial forming die, the cold processing surface of the forming die is determined. Based on the cold-processed surface of the forming punch, the cold-processed surface of the forming die, and the initial forming die model, the cold-processed model of the forming die is determined.

6. The method according to claim 4, characterized in that, The acquisition of target process parameters includes: Based on the aforementioned cold forming processing model, sheet material parameters, and current process parameters, thermoforming simulation is performed to obtain a simulated product model; The current process parameters are optimized based on the simulated product model until the simulated product model meets the preset conditions, thereby obtaining the target process parameters.

7. The method according to claim 6, characterized in that, The process of performing thermoforming simulation based on the cold forming model, sheet material parameters, and current process parameters to obtain a simulated product model includes: The cold forming process model is used as the constraint boundary for sheet deformation to establish a hot forming finite element model; Obtain the thermoforming conditions and sheet material parameters of the target product, as well as the current process parameters; Based on the thermoforming conditions, the material parameters of the sheet, and the current process parameters, the thermoforming finite element model is used to simulate the thermoforming process of the sheet model in the cold forming processing model to obtain the simulated product model.

8. The method according to claim 4, characterized in that, The material parameters of the sheet include true stress-strain data at different strain rates and temperatures, anisotropy parameters, elongation at break, density, and second coefficient of thermal expansion.

9. The method according to claim 4, characterized in that, The target process parameters include target stamping speed, target friction coefficient, target sheet thickness, target blank holder clearance, target temperature, and target blank holder force.

10. An electronic device, characterized in that, It includes a memory and a processor, the memory being used to store a computer program; the processor being used to execute the computer program to implement the method according to any one of claims 1-9.

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