High-strength aluminum alloy sheet metal part hot forming parameter automatic control architecture and method

Abstract

The application discloses a kind of high-strength aluminum alloy sheet metal hot forming parameter automatic control architecture and method, it is related to sheet metal forming technical field, including hot stamping forming device and the control system based on multi-physical quantity model;Hot stamping forming device includes hot stamping press, hot stamping die being arranged in hot stamping press, sensor unit being arranged on hot stamping die and temperature control element being arranged on hot stamping die;Control system includes built-in model, built-in model includes the constitutive model of alloy, alloy forming limit model and alloy TTT model;Control system receives the information collected by sensor unit and carries out data analysis;A kind of high-strength aluminum alloy sheet metal hot forming parameter automatic control architecture and method provided by the application solve the problem of rigidification of prior art hot forming device parameter setting.

Description

Technical Field

[0001] This invention relates to the field of sheet metal forming technology, and in particular to an automatic control architecture and method for hot forming parameters of high-strength aluminum alloy sheet metal parts. Background Technology

[0002] In recent years, large-scale, long-life, high-performance, and high-reliability thin-walled metal components have been increasingly used in next-generation aerospace vehicles and ships, among other advanced equipment. The ability to manufacture precision, lightweight, thin-walled components is one of the core technologies for the development of high-end transportation equipment such as aerospace. Given the requirements for lightweight, large-scale, long-life, high-performance, and high-reliability components, it is essential to utilize integral structural components as much as possible. Non-isothermal thermoforming of high-strength aluminum alloy sheet metal parts is an important method for forming integral structural components.

[0003] However, existing high-strength aluminum alloy sheet metal hot forming equipment mainly relies on preset constant parameters or simple empirical adjustments, making it difficult to respond to temperature fluctuations in real time. During the forming process, the external environment is not constant; for example, temperature differences exist between different times and areas within the workshop, and air circulation varies. These environmental factors make it difficult to uniformly control the temperature of the slab during forming. Furthermore, the time it takes for the slab to transfer from one processing stage to the hot forming equipment is also difficult to ensure is completely consistent, which also results in varying temperatures when the slab enters the hot forming process. Operating with fixed forming pressure and speed parameters, if the actual temperature of the slab is lower than the target value, insufficient material plasticity can easily lead to cracking; if the temperature is too high, excessive thinning or excessive springback may occur due to low deformation resistance. Although some existing systems attempt to initially monitor temperature through infrared thermography, they lack deep coupling with forming parameters, and parameter adjustments still rely on manual experience, resulting in problems such as response lag and insufficient compensation accuracy, making it difficult to fundamentally solve forming defects caused by uneven temperature. Summary of the Invention

[0004] The purpose of this invention is to provide an automatic control architecture and method for hot forming parameters of high-strength aluminum alloy sheet metal parts, solving the problem of rigid parameter settings in existing hot forming devices.

[0005] To achieve the above objectives, the present invention provides an automatic control architecture for hot forming parameters of high-strength aluminum alloy sheet metal parts, including a hot stamping forming device and a control system based on a multi-physical quantity model.

[0006] The hot stamping forming apparatus includes a hot stamping press, a hot stamping die disposed in the hot stamping press, a sensor unit disposed on the hot stamping die, and a temperature control element disposed on the hot stamping die;

[0007] The control system includes a built-in model, which includes the constitutive model of the alloy, the forming limit model of the alloy, and the TTT model of the alloy; the control system receives information collected by the sensor unit and performs data analysis.

[0008] Preferably, the hot stamping press includes a slide block, and the hot stamping die is disposed below the slide block;

[0009] The hot stamping die includes an upper die, a lower die, a blank holder, and a blank. The upper die is positioned above the lower die, and the blank is placed between the upper and lower dies. The blank holder is positioned on the outer periphery of the upper die and cooperates with the lower die to clamp the blank. The upper die includes a first forming surface, which is located at the lower end of the upper die and protrudes downward. The lower die includes a second forming surface, which is located at the upper end of the lower die and is recessed downward. The sizes of the first forming surface and the second forming surface are matched.

[0010] The sensor unit includes a temperature sensor, a first pressure sensor, and a second pressure sensor; both the temperature sensor and the first pressure sensor are located at the bottom of the first forming surface, and the second pressure sensor is located at the bottom of the second forming surface; the temperature sensor is used to measure the temperature of the billet in real time; the first pressure sensor is used to determine the time when the billet enters the forming stage, and at the same time collects the mold closing pressure information of the hot stamping die during the quenching process; the second pressure sensor is used to determine the time when the billet ends the forming stage and begins quenching.

[0011] Temperature control elements are evenly spaced on the first forming surface and the second forming surface.

[0012] Preferably, the sensor unit transmits the collected temperature and pressure information to the control system, and the control system adjusts the parameters of the hot stamping forming device according to the information collected by the sensor unit to ensure the forming quality and mechanical properties of the workpiece.

[0013] Preferably, the temperature sensor's range includes the solution treatment temperature and the first aging temperature of the aluminum alloy; if a contact temperature sensor is used, a platinum resistance temperature sensor or a thermocouple sensor is preferred; if a non-contact temperature sensor is used, a thin-film optical temperature sensor is preferred.

[0014] The measuring range of the first pressure sensor and the second pressure sensor includes the clamping force range of the hot stamping die, and the first pressure sensor and the second pressure sensor are preferably piezoelectric sensors.

[0015] This invention also provides a method for automatically controlling the hot forming parameters of high-strength aluminum alloy sheet metal parts, comprising the following steps:

[0016] Step 1: System initialization;

[0017] Step 2: First-stage data collection and analysis;

[0018] Step 3: Calculate the forming speed;

[0019] Step 4: Second stage data collection and analysis;

[0020] Step 5: Calculate the clamping force;

[0021] Step 6, Quenching: The control system feeds back the clamping force to the hot stamping press, which performs in-mold quenching on the blank.

[0022] Step 7: When the slab temperature drops to the mold temperature At that time, the mold is opened and samples are taken; the mold temperature is the first aging temperature.

[0023] Preferably, in step 1: initial information is input into the control system, including the maximum strain of the billet deformation. Strain path and billet material; the maximum strain of billet deformation is determined by the target geometry; maximum strain Obtained through finite element simulation or empirical formulas.

[0024] Preferably, in step 2: when the upper die contacts the billet and triggers the first pressure sensor, the temperature sensor simultaneously collects the billet temperature in the first stage. ,Will Input control system, through and Obtain the strain rate ;

[0025] The strain rate was determined by the following method:

[0026] For the billet at the target temperature, the upper limit of strain rate is calculated using the built-in forming limit model. ,in This is the maximum strain rate corresponding to the FLD safety zone, i.e., the critical value that does not trigger necking;

[0027] A safety margin of ≥10%~15% is typically required to avoid fracture caused by edge effects; a strain rate with a safety margin of not less than 15% is selected for the FLD (Fluorescent Diode); the formula for calculating the safety margin is:

[0028] ;

[0029] In the formula, This represents the critical strain under the corresponding strain rate conditions.

[0030] Preferably, in step 3: the control system obtains the forming time through the strain rate and the maximum strain. Through forming time and the maximum depth of the part Obtain forming speed The control system will control the forming speed. The output is given to the hot stamping forming device; the calculation expressions are as follows:

[0031] ;

[0032] .

[0033] Preferably, in step 4: when the billet contacts the lower die and triggers the second pressure sensor, the temperature sensor simultaneously collects the second stage temperature of the billet. ,Will The input is processed by the control system, which obtains the results through the built-in TTT model. Critical cooling rate ,in Mold temperature;

[0034] The critical cooling rate is tangent to the nose point of the TTT model curve, and is determined by the following method:

[0035] Let the coordinates of the nose tip point of the TTT model be... ,in Temperature of the tip of the nose. The shortest phase transition time from the start of cooling to the nose tip temperature; when the cooling curve satisfies the condition that the temperature drops to... At that time, the time taken was exactly equal to If the cooling curve is tangent to the phase transition initiation curve at the nose tip on the TTT model, then the cooling rate... .

[0036] Preferably, in step 5: the relationship between cooling rate and mold closing pressure is obtained experimentally; different pressures are selected for quenching the material, the cooling rate is measured, and a pressure-cooling rate curve is plotted by fitting the formula; the relationship between cooling rate and mold closing pressure is then analyzed. The relationship is used to obtain the required mold closing pressure. The clamping force is calculated from the clamping pressure, and the expression is:

[0037] ;

[0038] In the formula, This represents the contact area between the blank and the mold.

[0039] Therefore, the present invention, employing the above-mentioned automatic control architecture and method for hot forming parameters of high-strength aluminum alloy sheet metal parts, has the following beneficial effects:

[0040] (1) Strong adaptability: No need to rely on fixed parameters. After initial input of information such as part strain and material, the system can automatically adapt to the forming requirements of different types of high-strength aluminum alloys and workpieces with different geometric shapes, and meet the needs of multi-variety and small-batch production.

[0041] (2) High quality and yield: The blank temperature and mold closing pressure are monitored in real time by sensors, and the forming speed, mold closing force and other parameters are dynamically adjusted by combining multi-physical quantity models to avoid defects such as cracking and excessive thinning caused by temperature fluctuations, thereby improving the forming quality and yield of parts.

[0042] (3) Low energy consumption and equipment wear: Dynamically adjust process parameters to avoid redundant energy consumption and excessive equipment load caused by fixed parameters. While ensuring quality, reduce energy waste and extend equipment service life.

[0043] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the automatic control architecture for hot forming parameters of high-strength aluminum alloy sheet metal parts according to the present invention.

[0045] Figure 2 This is a partial structural schematic diagram of an embodiment of the present invention;

[0046] Figure 3 This is an overall flowchart of a method for an automatic control architecture of hot forming parameters for high-strength aluminum alloy sheet metal parts according to the present invention.

[0047] Figure 4 This is the hot forming process of high-strength aluminum alloy sheet metal parts according to an embodiment of the present invention;

[0048] Figure 5 This is a curve showing the relationship between the mold clamping pressure and cooling rate of the high-strength aluminum alloy according to an embodiment of the present invention;

[0049] Figure 6 This is a schematic diagram illustrating the relationship between molding temperature and time in an embodiment of the present invention.

[0050] Figure Labels

[0051] 1. Hot stamping press; 11. Slider; 2. Hot stamping die; 21. Upper die; 22. Lower die; 23. Blanking ring; 24. Blank; 25. First forming surface; 26. Second forming surface; 3. Temperature sensor; 4. First pressure sensor; 5. Second pressure sensor; 6. Temperature control element; 7. Control system. Detailed Implementation

[0052] The following detailed description of embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0053] Please see Figure 1-2 An automatic control architecture for hot forming parameters of high-strength aluminum alloy sheet metal parts, including a hot stamping forming device and a control system based on a multi-physical quantity model 7.

[0054] The hot stamping forming apparatus includes a hot stamping press 1, a hot stamping die 2 disposed in the hot stamping press 1, a sensor unit disposed on the hot stamping die 2, and a temperature control element 6 disposed on the hot stamping die 2;

[0055] Hot stamping press 1 includes a slide block 11, and hot stamping die 2 is disposed below the slide block 11;

[0056] The hot stamping die 2 includes an upper die 21, a lower die 22, a blank holder 23, and a blank 24. The upper die 21 is positioned above the lower die 22, and the blank 24 is positioned between the upper die 21 and the lower die 22. The blank holder 23 is positioned on the outer periphery of the upper die 21 and cooperates with the lower die 22 to press the blank 24. The upper die 21 includes a first forming surface 25, which is positioned at the lower end of the upper die 21 and protrudes downward. The lower die 22 includes a second forming surface 26, which is positioned at the upper end of the lower die 22 and is recessed downward. The first forming surface 25 and the second forming surface 26 are adapted to each other in size.

[0057] The sensor unit includes a temperature sensor 3, a first pressure sensor 4, and a second pressure sensor 5. The temperature sensor 3 and the first pressure sensor 4 are both located at the bottom of the first forming surface 25, and the second pressure sensor 5 is located at the bottom of the second forming surface 26. The temperature sensor 3 is used to measure the temperature of the blank 24 in real time. The first pressure sensor 4 is used to determine the time when the blank 24 enters the forming stage, and at the same time collects the mold closing pressure information of the hot stamping die 2 during the quenching process. The second pressure sensor 5 is used to determine the time when the blank 24 ends the forming stage and begins quenching.

[0058] Temperature control elements 6 are equally spaced on the first forming surface 25 and the second forming surface 26;

[0059] The control system 7 includes a built-in model, which includes the constitutive model of the alloy, the forming limit model of the alloy, and the TTT model of the alloy; the control system 7 receives information collected by the sensor unit and performs data analysis.

[0060] The sensor unit transmits the collected temperature and pressure information to the control system 7. The control system 7 adjusts the parameters of the hot stamping forming device according to the information collected by the sensor unit to ensure the forming quality and mechanical properties of the workpiece.

[0061] The temperature sensor 3 has a range that includes the solution treatment temperature and the first aging temperature of the aluminum alloy. If a contact temperature sensor 3 is used, a platinum resistance temperature sensor 3 or a thermocouple sensor is preferred. If a non-contact temperature sensor 3 is used, a thin-film optical temperature sensor 3 is preferred.

[0062] The measuring range of the first pressure sensor 4 and the second pressure sensor 5 includes the clamping force range of the hot stamping die 2, and the first pressure sensor 4 and the second pressure sensor 5 are preferably piezoelectric sensors.

[0063] Please see Figure 3-4 A method for automatically controlling the hot forming parameters of high-strength aluminum alloy sheet metal parts includes the following steps:

[0064] Step 1, System Initialization: Input initial information into control system 7, including the maximum strain of billet 24 deformation. Strain path and billet 24 material; the maximum strain of billet 24 deformation is determined by the target geometry; maximum strain Obtained through finite element simulation or empirical formulas;

[0065] Step 2, First Stage Data Collection and Analysis:

[0066] When the upper mold 21 contacts the billet 24 and triggers the first pressure sensor 4, the temperature sensor 3 simultaneously collects the temperature of the billet 24 in the first stage. ,Will Input control system 7, through and Obtain the strain rate ;

[0067] The strain rate was determined by the following method:

[0068] For the billet 24 at the target temperature, the upper limit of strain rate is calculated using the built-in forming limit model. ,in This is the maximum strain rate corresponding to the FLD safety zone, i.e., the critical value that does not trigger necking;

[0069] A safety margin of ≥10%~15% is typically required to avoid fracture caused by edge effects; a strain rate with a safety margin of not less than 15% is selected for the FLD (Fluorescent Diode); the formula for calculating the safety margin is:

[0070] ;

[0071] In the formula, The critical strain under the corresponding strain rate condition;

[0072] Step 3: Calculate the forming speed;

[0073] Control system 7 obtains the forming time through strain rate and maximum strain. Through forming time and the maximum depth of the part Obtain forming speed The control system 7 will control the forming speed The output is given to the hot stamping forming device; the calculation expressions are as follows:

[0074] ;

[0075] ;

[0076] Step 4: Second stage data collection and analysis;

[0077] When the billet 24 contacts the lower die 22, triggering the second pressure sensor 5, the temperature sensor 3 simultaneously collects the second-stage temperature of the billet 24. ,Will Input to control system 7, which obtains the result through the built-in TTT model. Critical cooling rate ,in Mold temperature;

[0078] The critical cooling rate is tangent to the nose point of the TTT model curve, and is determined by the following method:

[0079] Let the coordinates of the nose tip point of the TTT model be... ,in Temperature of the tip of the nose. The shortest phase transition time from the start of cooling to the nose tip temperature; when the cooling curve satisfies the condition that the temperature drops to... At that time, the time taken was exactly equal to The cooling curve on the TTT model is tangent to the phase transition initiation curve at the nose tip. Please refer to [link / reference]. Figure 6 Then the cooling rate ;

[0080] Step 5: Calculate the clamping force;

[0081] The relationship between cooling rate and mold closing pressure was obtained experimentally. Different pressures were selected for material quenching, and the cooling rate was measured. The pressure-cooling rate curve was plotted by fitting the formula. (See also...) Figure 5 By cooling rate and mold closing pressure The relationship is used to obtain the required mold closing pressure. The clamping force is calculated from the clamping pressure, and the expression is:

[0082] ;

[0083] In the formula, This represents the contact area between the blank 24 and the mold;

[0084] Step 6, Quenching: The control system 7 feeds back the clamping force to the hot stamping press 1, and the hot stamping press 1 performs in-mold quenching on the blank 24;

[0085] Step 7: When the slab temperature drops to the mold temperature At that time, the mold is opened and samples are taken; the mold temperature is the first aging temperature.

[0086] Therefore, this invention adopts the above-mentioned automatic control architecture and method for hot forming parameters of high-strength aluminum alloy sheet metal parts. By using sensors to monitor the blank temperature and mold closing pressure in real time, and combining a multi-physical quantity model to dynamically adjust parameters such as forming speed and mold closing force, it avoids defects such as cracking and excessive thinning caused by temperature fluctuations, thereby improving the forming quality and yield of parts. It does not rely on fixed parameters. After initial input of information such as part strain and material, the system can automatically adapt to the forming requirements of different types of high-strength aluminum alloys and workpieces with different geometric shapes, meeting the needs of multi-variety, small-batch production. Dynamically adjusting process parameters avoids redundant energy consumption and excessive equipment load caused by fixed parameters, thereby reducing energy waste and extending equipment service life while ensuring quality.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An automatic control architecture for hot forming parameters of high-strength aluminum alloy sheet metal parts, characterized in that: This includes a hot stamping forming device and a control system based on a multi-physical model; The hot stamping forming apparatus includes a hot stamping press, a hot stamping die disposed in the hot stamping press, a sensor unit disposed on the hot stamping die, and a temperature control element disposed on the hot stamping die; Hot stamping press includes a slide block, and hot stamping die is located below the slide block; The hot stamping die includes an upper die, a lower die, a blank holder, and a blank. The upper die is positioned above the lower die, and the blank is placed between the upper and lower dies. The blank holder is positioned on the outer periphery of the upper die and cooperates with the lower die to clamp the blank. The upper die includes a first forming surface, which is located at the lower end of the upper die and protrudes downward. The lower die includes a second forming surface, which is located at the upper end of the lower die and is recessed downward. The sizes of the first forming surface and the second forming surface are matched. The sensor unit includes a temperature sensor, a first pressure sensor, and a second pressure sensor; both the temperature sensor and the first pressure sensor are located at the bottom of the first forming surface, and the second pressure sensor is located at the bottom of the second forming surface; the temperature sensor is used to measure the temperature of the billet in real time; the first pressure sensor is used to determine the time when the billet enters the forming stage, and at the same time collects the mold closing pressure information of the hot stamping die during the quenching process; the second pressure sensor is used to determine the time when the billet ends the forming stage and begins quenching. Temperature control elements are evenly spaced on the first forming surface and the second forming surface; The control system includes a built-in model, which includes the constitutive model of the alloy, the forming limit model of the alloy, and the TTT model of the alloy; the control system receives information collected by the sensor unit and performs data analysis. The method for automatically controlling the hot forming parameters of high-strength aluminum alloy sheet metal parts includes the following steps: Step 1: System initialization; Input initial information into the control system, including the maximum strain of the billet deformation. Strain path and billet material; The maximum strain of the billet deformation is determined by the target geometry; maximum strain Obtained through finite element simulation or empirical formulas; Step 2, First Stage Data Acquisition and Analysis: When the upper die contacts the billet and triggers the first pressure sensor, the temperature sensor simultaneously acquires the billet temperature in the first stage. ,Will Input control system, through and Obtain the strain rate ; Step 3: Calculate the forming speed; Step 4, Second Stage Data Acquisition and Analysis: When the billet contacts the lower die and triggers the second pressure sensor, the temperature sensor simultaneously acquires the billet's second-stage temperature. ,Will The input is processed by the control system, which obtains the results through the built-in TTT model. Critical cooling rate ,in Mold temperature; Step 5: Calculate the clamping force; this is done by considering the cooling rate and the clamping pressure. The relationship between the mold closing pressure and the pressure obtained is obtained. The clamping force is calculated from the clamping pressure, and the expression is: ； In the formula, This represents the contact area between the blank and the mold. Step 6, Quenching: The control system feeds back the clamping force to the hot stamping press, which performs in-mold quenching on the blank. Step 7: When the slab temperature drops to the mold temperature At that time, the mold is opened and samples are taken; the mold temperature is the first aging temperature.

2. The automatic control architecture for hot forming parameters of high-strength aluminum alloy sheet metal parts according to claim 1, characterized in that: The sensor unit transmits the collected information to the control system, which then adjusts the parameters of the hot stamping forming device based on the information collected by the sensor unit.

3. The automatic control architecture for hot forming parameters of high-strength aluminum alloy sheet metal parts according to claim 2, characterized in that: The temperature sensor's range includes the solution treatment temperature and the first aging temperature of the aluminum alloy. The measuring ranges of the first and second pressure sensors include the clamping force range of hot stamping dies.

4. The automatic control architecture for hot forming parameters of high-strength aluminum alloy sheet metal parts according to claim 1, characterized in that, In step 2: The strain rate was determined by the following method: For the billet at the target temperature, the upper limit of the strain rate is calculated using the built-in alloy forming limit model. ,in The maximum strain rate in the FLD safety zone; Select a strain rate with a safety margin of not less than 15% for the FLD; the formula for calculating the safety margin is: ； In the formula, This represents the critical strain under the corresponding strain rate conditions.

5. The automatic control architecture for hot forming parameters of high-strength aluminum alloy sheet metal parts according to claim 4, characterized in that, In step 3: the control system uses strain rate and maximum dependent variable Obtain the forming time Through forming time and the maximum depth of the part Obtain forming speed The control system will control the forming speed. The output is given to the hot stamping forming device; the calculation expressions are as follows: ； 。 6. The automatic control architecture for hot forming parameters of high-strength aluminum alloy sheet metal parts according to claim 5, characterized in that, In step 4: The critical cooling rate is tangent to the nose point of the TTT model curve, and is determined by the following method: Let the coordinates of the nose tip point of the TTT model be... ,in Temperature of the tip of the nose. The shortest phase transition time from the start of cooling to the nose tip temperature; when the cooling curve satisfies the condition that the temperature drops to... When, the time taken is equal to If the cooling curve is tangent to the phase transition initiation curve at the nose tip on the TTT model, then the cooling rate... .

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