Intelligent stamping forming control method and system based on aluminum single plate

Abstract

The application provides an intelligent stamping forming control method and system based on aluminum single plate, relates to the aluminum single plate forming control technical field, and the method comprises the following steps: obtaining the aluminum single plate brand, the measured thickness, the surface flatness and the initial temperature, and pre-flattening; setting the heating temperature, the holding time and the mold heating rod and cooling water channel cooperative temperature control according to the thickness and the brand; the servo press operates in the segmented mode according to the contact downward, the pre-forming, the fine forming and the pressure maintaining; collecting the cavity pressure, the plate surface temperature and the strain gauge data, predicting the yield and hardening of each micro area, dynamically modulating the electric signal amplitude, the pulse width, the frequency and the phase difference, and actively reshaping the strain energy distribution; selecting the constant pressure, the variable pressure or the temperature control compensation according to the cavity pressure and the springback force during the pressure maintaining; determining whether manual aging is needed according to the punch springback force threshold before demolding, collecting the plate surface image after rewarming to judge the waste; and the system comprises stamping stroke segmented driving modules and the like, so that the average springback angle is reduced to 1.2 DEG, the thinning rate is 12.5%, and the corner cracking and the straight edge wrinkling are inhibited.

Description

Technical Field

[0001] This invention relates to the field of aluminum panel forming control technology, and in particular to an intelligent stamping forming control method and system based on aluminum panels. Background Technology

[0002] Aluminum single-layer panels are widely used in building curtain walls and irregular decorative components due to their light weight, strong weather resistance, and good surface decoration effect. Actual production is typically characterized by multiple varieties and small batches. The same workshop needs to frequently switch between various grades such as AA6016-T4 and 3003-H24. Incoming material thicknesses cover specifications such as 2.5 mm, 3.0 mm, and 4.0 mm. The flatness of the incoming panels may exhibit waviness of 0.4~0.8 mm / m, and the thickness tolerance at the beginning and end of the same roll can reach ±0.05 mm. Fluctuations in incoming material directly affect the quality of subsequent stamping. Most existing aluminum single-layer panel stamping production lines operate using mechanical presses with fixed process cards. During model changeovers, operators input constant blank holder force and constant slide speed according to a table based on the grade; the mold is only set to a fixed temperature via heating rods, lacking zoned temperature feedback; after the panels enter the furnace, they are heated according to a uniform temperature curve, and the temperature transfer relies on manual spot temperature gun checks, making it difficult to accurately reflect the overall temperature distribution of the panels. The aforementioned fixed parameter control method has revealed several prominent problems during the deep drawing process of rectangular box-shaped parts and irregularly shaped parts. During the contact descent stage, the slider descends at a uniform idle speed and contacts the sheet metal with a fixed blank holder force. For 6-series aluminum alloy sheets with a thickness of 3.0 mm or more and a high yield strength, early concentrated deformation is easily generated at the corner radius R10 mm. During the pre-forming and finishing stages, the existing blank holder force remains constant during stamping. However, due to different geometric constraints, the metal flows radially faster at the corners and slower at the straight edges, easily inducing wrinkling. On-site solutions often involve stopping the machine to adjust the mechanical limit or increasing the overall blank holder force. However, while increasing the overall blank holder force can suppress wrinkling, it further increases the corner thinning rate, leading to a passive compromise where cracking and wrinkling are mutually exclusive. During the pressure holding and shaping stage, the existing process sets a constant pressure based on experience, without collecting cavity pressure distribution data or monitoring punch springback force. When the elastic energy storage in the later stages of pressure holding for 6-series plates is insufficiently released, the original pressure is maintained, resulting in springback angles on the sidewalls often reaching 5°~9° after demolding. Hyperbolic parts require trial molding and surface rework. Meanwhile, during continuous production, when the mold temperature rises above 190°C, it is controlled only by manual water valve adjustment, resulting in a delayed response. If the surface temperature drops below 240°C after sheet transfer, the fixed speed and downward pressure cannot be automatically compensated. Often, the line is only stopped and parameters reset after the first piece's 3D scan reveals excessive springback, causing rework of the entire batch. Therefore, the root cause of these problems is not insufficient press capacity, but rather the failure to input stamping process data into the aluminum alloy elastoplastic physical model for real-time calculation. The servo valve electrical signal only operates in an open-loop manner, unable to dynamically reconstruct the blank holder force amplitude, timing, and phase according to changes in strain energy in various micro-regions of the sheet. Consequently, it is difficult to simultaneously suppress wrinkling, cracking, springback, and quality fluctuations caused by temperature fluctuations. Therefore, there is an urgent need in the market for a new intelligent stamping and forming control method and system based on aluminum single panels. Summary of the Invention

[0003] The purpose of this invention is to provide a smart stamping forming control method and system based on aluminum single-panel sheets, to solve the following problems in the existing technology: fixed process parameters cannot adapt to fluctuations in incoming material grade, thickness, and flatness; thick plates are prone to early concentrated deformation at the corners; the blank holder force is constant and cannot be adjusted in real time by zone; differences in metal inflow between corners and straight edges cause wrinkling; overall pressure increase exacerbates corner thinning, leading to a trade-off between wrinkling and cracking; the lack of cavity pressure and springback force monitoring during the holding pressure stage results in insufficient release of elastic energy and a large springback angle after demolding; continuous production temperature drift of the mold and temperature drop during sheet transfer lack automatic compensation, requiring line stoppage and rework; and the servo valve electrical signal only performs open-loop execution, unable to dynamically reconstruct the blank holder force amplitude, timing, and phase according to micro-area strain energy. The specific technical solution is as follows: This invention provides a method for intelligent stamping and forming control based on aluminum single-panel, comprising: S10: Obtain the basic information of the aluminum single-panel material to be stamped and perform pre-processing before stamping. The basic information includes the grade of the sheet material, the measured thickness, the surface flatness and the initial temperature. Determine the impact force and pressing speed of the processing punch based on the basic information. When the measured surface flatness exceeds the preset flatness threshold, perform pre-flattening treatment on the sheet material through a parallel die. S20, heat the pre-treated sheet material, determine the heating temperature and holding time according to the sheet material grade and actual thickness, and adjust and maintain the temperature of the stamping die within the preset die temperature range. When the sheet material temperature reaches the target heating temperature, transfer it to the stamping station. The die temperature is controlled by the die built-in heating rod and cooling water channel. S30, the mechanical servo press is started to drive the processing punch to move downward. The stamping stroke is divided into the contact downward section, the pre-forming section, the fine forming section and the pressure holding and shaping section. In the contact downward section, the processing punch moves down from the top dead point of the slide to the contact plate surface at a constant pressing speed, and the blank holder force is maintained at a low pressure value. S40, in the preforming and finishing sections, the data acquisition unit acquires in real time the temperature data of the sheet surface, the pressure data fed back by the pressure sensors arranged in the blank holder and the mold cavity, and the strain data fed back by the strain gauges arranged on the sheet surface. Based on the physical model of the elastic-plastic response of aluminum alloy, the yield evolution and hardening trajectory of each micro-region of the sheet are predicted in real time. The amplitude, pulse width, frequency and phase difference of the servo valve electrical signal are dynamically modulated by the programmable logic controller, so that the blank holder force, pressing speed and electrical signal modulation parameters of each section are dynamically adjusted according to the real-time response state of the material, thereby actively reshaping the strain energy distribution of the sheet in the mold. S50, in the pressure holding and shaping section, the processing punch remains in the same position after reaching the bottom dead center. The pressure holding pressure is set to 85% of the rated pressure. The pressure holding time is preset according to the thickness and grade of the sheet material. During this stage, the electrical signal is switched to constant pressure closed-loop mode. The pressure holding pressure setting value is set according to the pressure distribution of the mold cavity and closed-loop correction is performed according to the preset allowable pressure fluctuation threshold. The actual pressure holding pressure is dynamically adjusted through the proportional servo valve so that the deviation of the actual pressure from the set value during the pressure holding period is within the preset allowable fluctuation range, so as to eliminate the time-varying effect of plastic springback. S60, after the pressure holding is completed, the processing punch remains in the same position until the stamped sheet material returns to room temperature. Based on the pressure sensor on the surface of the processing punch, the springback force of the stamped sheet material acting on the processing punch is collected. Based on the comparison result of the springback force and the preset threshold, it is determined whether to perform post-heat treatment. After the determination is completed, the processing punch is controlled to reset, and image data of the sheet material surface after stamping is collected. The image data is analyzed to determine whether the stamped sheet material is qualified. Qualified products are output to the next process, and unqualified products are marked with defect type and fed back to the process strategy layer for parameter correction.

[0004] Further, S10 specifically includes: conveying the sheet metal to the inspection station via an automatic feeding device; obtaining the actual thickness of the sheet metal using a non-contact laser thickness gauge; acquiring surface images of the sheet metal using a surface array camera and calculating the surface flatness using an image processing algorithm; simultaneously obtaining the material grade and rolling direction information by reading the electronic information attached to the sheet metal; inputting the measured thickness and grade information to the processing unit; the processing unit determining the impact force and pressing speed of the processing punch based on the thickness-impact force-pressing speed mapping relationship table stored in the material mechanism layer; comparing the measured surface flatness with a preset flatness threshold of 0.3 mm per meter; when the measured surface flatness exceeds the preset threshold, controlling the parallel die to perform pre-flattening treatment on the sheet metal at a pressing speed of 20 mm per second; and re-measuring the flatness after processing until the requirements are met.

[0005] Furthermore, S20 specifically includes: feeding the pre-treated sheet material into a multi-layer box furnace, determining the heating parameters based on the sheet material thickness; when the sheet material thickness is 3.0 mm, the heating temperature is set to 320 degrees Celsius and the holding time is set to 45 minutes; when the sheet material thickness is 2.5 mm, the heating temperature is set to 260 degrees Celsius and the holding time is set to 30 minutes; when the sheet material thickness is 4.0 mm, the heating temperature is set to 250 degrees Celsius and the holding time is set to 60 minutes; after heating is completed, the sheet material is transferred to the stamping station within 20 seconds. The mold temperature control system is activated simultaneously. The mold temperature is heated to 180 degrees Celsius by the built-in heating rod. When the mold temperature exceeds 190 degrees Celsius due to continuous production, the cooling water flow rate is automatically adjusted to 115% of the rated flow rate to bring the mold temperature back to the preset range. The temperature control accuracy is maintained at ±5 degrees Celsius. The mold temperature is fed back in real time by a thermocouple array arranged in nine temperature control zones of the mold.

[0006] Furthermore, S30 specifically includes: S301, the mechanical servo press receives a stroke command from the programmable logic controller and controls the processing punch to descend from the top dead center of the slide at a constant speed of 120 mm / s. During this stage, the electrical signal is output with a constant amplitude, the blank holder force is maintained at 8 MPa for 0.8 seconds, until the processing punch contacts the surface of the sheet. When the pressure sensor of the processing punch detects that the contact force has reached the preset contact threshold, the system confirms that the processing punch has contacted the surface of the sheet metal. At this stage, the trigger electrical signal simultaneously triggers the data acquisition unit to start recording pressure, temperature, displacement and strain data at a sampling frequency of 1 kHz.

[0007] Further, S40 specifically includes: S401, in the preforming section, the processing punch presses down from the contact plate surface to 40% of the total stroke for 1.1 seconds, the pressing speed is reduced to 45 mm / s, the blank holder force is increased to 15 MPa, the data acquisition unit transmits the electrical signals fed back by the pressure sensor, temperature sensor and strain gauge to the process strategy layer in real time, the process strategy layer calculates the equivalent stress and yield state of each micro-region of the plate according to the physical model of the elastic-plastic response of aluminum alloy stored in the material mechanism layer, and converts the electrical signal into a pulse width modulation signal and outputs it to the proportional servo valve of each zone blank holder cylinder, the modulation frequency is 2 kHz, and the duty cycle is dynamically adjusted between 30% and 70% according to the real-time feedback of the radial inflow resistance of the plate; S402, in the finishing section, the processing punch is pressed down from 40% to 85% of the total stroke for 0.9 seconds, and the pressing speed is further reduced to 20 mm / s. The partitioned blank holder force is distributed in a gradient around the sheet metal, with a blank holder force of 18 MPa in the corner area and 12 MPa in the straight edge area. The electrical signal is introduced with phase modulation at this stage, so that the servo valve response in the corner area leads the straight edge area by 15 milliseconds. In S403, during the entire S40 process, when the local strain increase rate fed back by the strain gauges arranged on the surface of the plate exceeds 15% of the predicted value of the material mechanism layer, the system superimposes a modulation wave with a frequency of 3 kHz and an amplitude attenuation of 20% into the control signal of the pressing cylinder corresponding to the area, and synchronously reduces the pressing speed of the area by 20% until the local strain increase rate falls back to the predicted value range.

[0008] Furthermore, S40 also includes a temperature compensation control strategy. When the data acquisition unit reports that the sheet temperature is below 240 degrees Celsius, the process strategy layer determines that the current thermal state has deviated from the optimal forming temperature window. The system automatically reduces the pressing speed of the main forming section by 20% from the current value and simultaneously increases the blank holder force of the finishing forming section from 12 MPa to 14 MPa. The electrical signal modulation depth is increased by 10% accordingly, that is, the upper limit of the pulse width modulation duty cycle is increased from 70% to 80%. The power of the mold heating rod is increased by 15%, and the sheet temperature is accelerated through contact heat transfer of the mold until the temperature sensor reports that the sheet temperature has risen back to above 240 degrees Celsius, at which point the original parameter chain is restored. In S40, a local strain equalization modulation strategy is also included. When the data acquisition unit reports that the equivalent plastic strain growth rate in the corner area of ​​the sheet metal exceeds 15% of the predicted value of the material mechanism layer, the system identifies the location number of the area with excessive strain growth rate, adjusts the control signal of the partitioned edge-pressing cylinder corresponding to the area to be output with a lag of 20 milliseconds, dynamically reduces the edge-pressing force corresponding to the area from 18 MPa to 15 MPa, and synchronously increases the edge-pressing force corresponding to the straight edge area adjacent to the area from 12 MPa to 14 MPa. The system continuously monitors the feedback of the strain gauges in the area, and when the strain growth rate falls back to within ±5% of the predicted value, the edge-pressing force and phase difference are restored to the original set values.

[0009] S40 also includes a wrinkling suppression modulation strategy. When the data acquisition unit reports a wrinkling tendency signal in the straight edge area of ​​the sheet metal, the system identifies the location number of the wrinkling tendency area, increases the pressing force corresponding to the area from 12 MPa to 16 MPa, decreases the pressing force of the adjacent corner area from 18 MPa to 16 MPa, reverses the phase modulation direction of the electrical signal, so that the servo valve response of the straight edge area is 10 milliseconds ahead of the corner area, and simultaneously reduces the pressing speed from 20 mm / s to 15 mm / s until the wrinkling tendency signal disappears and the original setting parameters are restored.

[0010] Furthermore, in S50, when the pressure distribution in the mold cavity is uniform and the holding pressure fluctuation is within a preset range, a constant pressure holding control strategy is adopted. Specifically, after the processing punch reaches the bottom dead center, the system switches to a constant pressure closed-loop control mode, and the holding pressure is set to 85% of the rated pressure; the holding time is 3.5 seconds, and the actual pressure fluctuation is controlled within ±0.5 MPa through the closed-loop adjustment of the proportional servo valve; during the holding period, the system continuously collects the pressure distribution data of the mold cavity and performs closed-loop correction on the holding pressure to eliminate the time-varying effect of plastic springback; at the end of the holding period, the system records the entire pressure-time curve and stores it in the database.

[0011] The S50 also includes a variable pressure holding control strategy. When the data acquisition unit reports that the rebound force data value shows an increasing trend during the pressure holding period, the system determines that the elastic energy stored inside the sheet material under the current pressure holding condition has not been effectively released. The pressure holding is increased from 85% to 90% of the rated pressure in the first stage and held for 1 second. Then, the pressure holding is reduced back to 80% of the rated pressure in the second stage and held for 1.5 seconds. Finally, the pressure holding is restored to 85% of the rated pressure and held for 1 second, and the pressure-rebound force relationship curve is recorded throughout the process.

[0012] The S50 also includes a temperature-controlled compensation pressure holding strategy. When the rate at which the sheet temperature drops during the pressure holding period, as reported by the data acquisition unit, exceeds the preset cooling rate, the system determines that the sheet material has reduced its stress relaxation efficiency due to excessive heat dissipation. The power of the mold heating rod is increased by 20% to allow the mold temperature to rise back to the preset temperature range within 10 seconds. The pressure holding pressure is simultaneously reduced to 80% of the rated pressure to match the change in load-bearing capacity caused by the softening effect of the sheet material after the temperature rises. After the temperature sensor reports that the sheet temperature has recovered to the target range, the pressure holding pressure is restored to 85% of the rated pressure and the remaining pressure holding time is completed.

[0013] Furthermore, in S60, when the springback force data value is less than the preset springback force threshold, it is determined that no post-heat treatment is required. Specifically, the processing punch remains in the same position until the plate returns to room temperature after stamping; the system reads the springback force data from the pressure sensor on the surface of the processing punch and compares the springback force data value with the preset springback force threshold. When the springback force data value is less than the preset threshold, it is determined that no post-heat treatment is required; the processing punch is controlled to reset to the top dead center at a speed of 20 mm / s; image data of the plate surface after stamping is collected and the image data is input into the defect recognition model. The defect recognition model outputs the defect type and position coordinates of the plate surface. When the plate is determined to be qualified, a qualified signal is output and the plate is transported to the next process. When the plate is determined to have defects, the corresponding defect type signal and plate position signal are output.

[0014] Furthermore, S60 also includes a post-heat treatment control strategy. When the springback force data value is greater than or equal to a preset springback force threshold, the system determines that the current springback force indicates a high level of residual stress inside the sheet metal. The system controls the built-in heating rod of the mold to raise the mold temperature to 180 degrees Celsius and performs artificial aging treatment on the formed part for 2 hours. After the aging treatment is completed, the cooling water channel inside the mold is opened to cool the sheet metal to room temperature at a cooling rate of 20 degrees Celsius per second. After cooling is completed, the processing punch is reset, the surface image data of the sheet metal is collected, and the image data is analyzed to determine whether the stamped sheet metal is qualified. When the sheet metal is determined to be qualified, a qualified signal is output. When the sheet metal is determined to have defects, the defect type is fed back and the model parameters of the material mechanism layer are updated.

[0015] This invention also provides an intelligent stamping and forming control system based on aluminum single-panel, used to implement the method described above. The system includes: The sheet material information acquisition and preprocessing module is used to obtain the grade, actual thickness, surface flatness and initial temperature of the aluminum sheet to be processed before stamping. The measured thickness and grade information are input into the processing unit. The initial stamping parameters are determined according to the mapping relationship between thickness and impact force and pressing speed. When the measured flatness exceeds the preset flatness threshold, the parallel mold is controlled to perform pre-flattening treatment on the sheet material. At the same time, the flatness is re-measured to ensure that the sheet material condition meets the forming requirements. The heating and mold temperature control module is used to set the heating temperature and holding time according to the sheet material grade and actual thickness, uniformly heat the pre-treated sheet material, and maintain the mold temperature within the preset range through the coordinated control of the heating rod array and cooling water channel arranged inside the mold. The temperature control accuracy does not exceed ±5 degrees Celsius. After the sheet material reaches the target temperature, it is transferred to the stamping station within a predetermined time. The stamping stroke segmented drive module is used to drive the mechanical servo press to drive the processing punch to run in the order of contact downward section, pre-forming section, fine forming section and pressure holding and shaping section. In the contact downward section, the no-stroke pressing is completed with constant speed and constant electrical signal amplitude. In the pre-forming section and fine forming section, the pressing speed and blank holder force are adjusted according to real-time feedback. In the pressure holding and shaping section, the module switches to closed-loop pressure control mode. The dynamic electrical signal modulation and strain energy reshaping module is used to receive high-frequency feedback signals from pressure sensors, temperature sensors and strain gauges, call the physical model of aluminum alloy elastic-plastic response to calculate the yield evolution and hardening trajectory of each micro-region of the sheet in real time, and generate dynamic electrical signals including amplitude modulation, pulse width modulation, frequency modulation and phase difference modulation. Through the proportional servo valve, the pressure cylinders and slider drive units of each zone are independently controlled, thereby actively changing the strain energy distribution of the sheet in the mold and suppressing local overstrain and instability wrinkling. The pressure holding and shaping and springback closed-loop control module is used to maintain the position of the punch after it reaches the bottom dead center. Based on the pressure distribution and springback force change trend of the mold cavity during the pressure holding period, it selects constant pressure holding, variable pressure pulse release or temperature control compensation pressure holding strategy. After the sheet material returns to room temperature, it collects springback force data and compares it with a preset threshold. Based on this, it determines whether post-heat treatment is required and outputs corresponding control commands. The post-heat treatment decision and quality assessment module is used to control the mold heating rod to raise the mold to the post-heat treatment temperature and hold it when it is determined that post-heat treatment is required. Then, it cools down at a set cooling rate. When it is determined that post-heat treatment is not required, it directly controls the processing punch to reset. Then, it collects image data of the plate surface after stamping, outputs the defect type and location coordinates through the defect recognition model, outputs qualified products to the next process, and feeds back the defect information of unqualified products to the process strategy layer to update the control parameters.

[0016] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, performs the steps of the method described herein.

[0017] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method.

[0018] The beneficial effects of this invention are as follows: This invention deeply integrates the elastic-plastic response mechanism of aluminum alloys, dynamic modulation of electrical signals during the stamping process, and hierarchical control logic. It achieves on-demand setting of initial parameters through measured calculations of incoming material thickness, flatness, and temperature before stamping. During stamping, it achieves coordinated reconstruction of the blank holder force and slide speed in each zone through real-time acquisition of pressure, temperature, and strain signals and amplitude, pulse width, and phase modulation of servo valve electrical signals. This allows for the active reshaping of the sheet metal strain energy distribution, thereby simultaneously suppressing concentrated deformation at thick plate corners, local thinning, and sidewall wrinkling, eliminating the trade-off between wrinkling and cracking in the process. The pressure holding and shaping stage employs constant or variable pressure closed-loop control and automatically decides on heat treatment based on the punch's springback force. This fully releases the stored elastic energy and avoids unnecessary heat treatment processes, effectively converging the springback angle. Complex curved parts can achieve good surface accuracy without repeated trial molding and surface finishing. In addition, the mold temperature zone feedback and sheet temperature drop automatic compensation mechanism eliminate the need for manual intervention in thermal drift during continuous production. Batch changeovers and batch fluctuations also do not require line stoppages for resetting, improving product dimensional consistency and pass rate, extending mold life, and realizing an effective transformation of aluminum single-panel stamping from experience-based trial and error to adaptive intelligent manufacturing.

[0019] 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

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the steps of an intelligent stamping and forming control method based on aluminum single-panel according to the present invention; Figure 2 This is a schematic diagram of the structure of an intelligent stamping and forming control system based on aluminum single-panel according to the present invention; Figure 3 This is a schematic diagram of the stamping stroke segmentation and dynamic modulation timing of electrical signals in an intelligent stamping forming control method based on aluminum single-panel according to the present invention. Figure 4 This is a comparison test result diagram of the springback angle distribution of an intelligent stamping and forming control method for aluminum single-panel according to the present invention; Figure 5 This is a block diagram of the algorithm model of an intelligent stamping and forming control method for aluminum single-panel according to the present invention; Figure 6 This is a sensor feedback logic block diagram of an intelligent stamping and forming control method for aluminum single-panel according to the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0023] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.

[0024] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" and "second" may explicitly or implicitly include at least one feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0025] In an embodiment of the present invention, a method for intelligent stamping and forming control based on aluminum single-panel is provided. Please refer to [link / reference]. Figure 1 The method includes the following steps: S10: Obtain the basic information of the aluminum single-panel material to be stamped and perform pre-processing before stamping. The basic information includes the grade of the sheet material, the measured thickness, the surface flatness and the initial temperature. Determine the impact force and pressing speed of the processing punch based on the basic information. When the measured surface flatness exceeds the preset flatness threshold, perform pre-flattening treatment on the sheet material through a parallel die. S20, heat the pre-treated sheet material, determine the heating temperature and holding time according to the sheet material grade and actual thickness, and adjust and maintain the temperature of the stamping die within the preset die temperature range. When the sheet material temperature reaches the target heating temperature, transfer it to the stamping station. The die temperature is controlled by the die built-in heating rod and cooling water channel. S30, the mechanical servo press is started to drive the processing punch to move downward. The stamping stroke is divided into the contact downward section, the pre-forming section, the fine forming section and the pressure holding and shaping section. In the contact downward section, the processing punch moves down from the top dead point of the slide to the contact plate surface at a constant pressing speed, and the blank holder force is maintained at a low pressure value. S40, in the preforming and finishing sections, the data acquisition unit acquires in real time the temperature data of the sheet surface, the pressure data fed back by the pressure sensors arranged in the blank holder and the mold cavity, and the strain data fed back by the strain gauges arranged on the sheet surface. Based on the physical model of the elastic-plastic response of aluminum alloy, the yield evolution and hardening trajectory of each micro-region of the sheet are predicted in real time. The amplitude, pulse width, frequency and phase difference of the servo valve electrical signal are dynamically modulated by the programmable logic controller, so that the blank holder force, pressing speed and electrical signal modulation parameters of each section are dynamically adjusted according to the real-time response state of the material, thereby actively reshaping the strain energy distribution of the sheet in the mold. S50, in the pressure holding and shaping section, the processing punch remains in the same position after reaching the bottom dead center. The pressure holding pressure is set to 85% of the rated pressure. The pressure holding time is preset according to the thickness and grade of the sheet material. During this stage, the electrical signal is switched to constant pressure closed-loop mode, and the pressure fluctuation is controlled within a certain range. During the pressure holding period, the pressure distribution of the mold cavity is continuously monitored, and closed-loop correction is performed on the pressure holding pressure to eliminate the time-varying effect of plastic springback. S60, after the pressure holding is completed, the processing punch remains in the same position until the stamped sheet material returns to room temperature. Based on the pressure sensor on the surface of the processing punch, the springback force of the stamped sheet material acting on the processing punch is collected. Based on the comparison result of the springback force and the preset threshold, it is determined whether to perform post-heat treatment. After the determination is completed, the processing punch is controlled to reset, and image data of the sheet material surface after stamping is collected. The image data is analyzed to determine whether the stamped sheet material is qualified. Qualified products are output to the next process, and unqualified products are marked with defect type and fed back to the process strategy layer for parameter correction.

[0026] The principle and effect of the above technical solution are as follows: This invention provides a method for intelligent stamping forming control based on aluminum single-panel, including obtaining basic information and pre-processing of sheet material, heating and mold temperature control, segmented descent, pre-forming and precision forming under dynamic electrical signal modulation, constant pressure closed-circuit pressing, and post-processing and quality judgment based on springback force. Its core lies in integrating the physical mechanism of the elastic-plastic response of aluminum alloy, the dynamic modulation of electrical signals during stamping, and a hierarchical control logic architecture. The electrical signal is no longer just a predetermined execution command, but serves as an active medium that can sense and guide the distribution of strain energy in the sheet material. At different stages and locations of the stamping stroke, the amplitude, pulse width, frequency, and phase difference of the electrical signal are dynamically adjusted according to the real-time yield and hardening state of the material, so that the plastic work absorption in each micro-region of the sheet material tends to be balanced. This method actively reshapes the strain energy distribution of the sheet metal within the mold, concentrating the springback within an extremely narrow range. This simultaneously alleviates the previously mutually restrictive contradictions of wrinkling and cracking, significantly widening the process window. Batch differences in aluminum sheets and environmental disturbances no longer easily disrupt production stability, reducing control blind spots and hidden strain energy imbalances in traditional processes.

[0027] In one embodiment, S10 includes: S101, the sheet material is transported to the inspection station by an automatic feeding device, the actual thickness of the sheet material is obtained by a non-contact laser thickness gauge, the surface image of the sheet material is captured by an area array camera and the surface flatness is calculated by an image processing algorithm, and the material grade and rolling direction information are obtained by reading the electronic information attached to the sheet material. S102, the measured thickness and grade information are input to the processing unit. The processing unit determines the impact force and pressing speed of the processing punch according to the thickness-impact force-pressing speed mapping relationship table stored in the material mechanism layer. At the same time, the measured surface flatness is compared with the preset flatness threshold of 0.3 mm per meter. When the measured surface flatness exceeds the preset threshold, the parallel mold is controlled to perform pre-flattening treatment on the sheet at a pressing speed of 20 mm per second. After the treatment is completed, the flatness is re-measured until the requirements are met. The principle and effect of the above technical solution are as follows: by performing precise geometric detection and material identification on the sheet metal before stamping, and determining the initial stamping parameters based on the measured data, the uncertainty of the initial conditions caused by the batch fluctuation of the sheet metal is eliminated, so that the subsequent dynamic modulation process is always based on the real material state, avoiding the batch quality drift caused by the traditional process of adhering to uniform set parameters.

[0028] In one embodiment, S20 includes: S201: The pre-treated sheet metal is fed into a multi-layer box furnace. The heating parameters are determined according to the sheet metal thickness. When the sheet metal thickness is 3.0 mm, the heating temperature is set to 320 degrees Celsius and the holding time is set to 45 minutes; when the sheet metal thickness is 2.5 mm, the heating temperature is set to 260 degrees Celsius and the holding time is set to 30 minutes; when the sheet metal thickness is 4.0 mm, the heating temperature is set to 250 degrees Celsius and the holding time is set to 60 minutes. After heating is completed, the sheet metal is transferred to the stamping station within 20 seconds. S202, synchronously starts the mold temperature control system, heats the mold temperature to 180 degrees Celsius through the built-in heating rod of the mold. When the mold temperature exceeds 190 degrees Celsius due to continuous production, the cooling water flow rate is automatically adjusted to 115% of the rated flow rate to make the mold temperature drop back to the preset range. The temperature control accuracy is maintained at ±5 degrees Celsius. The mold temperature is fed back in real time through the thermocouple array arranged in the nine temperature control zones of the mold. The principle and effect of the above technical solution are as follows: the differentiated setting of heating temperature allows aluminum alloy sheets of different thicknesses to be within the optimal forming temperature window, and the active zoning control of the mold temperature field eliminates the local chilling effect caused by excessive temperature difference between the sheet and the mold, laying a thermodynamic basis for subsequent uniform plastic deformation.

[0029] In one embodiment, S30 includes: The S301 mechanical servo press receives stroke instructions from the programmable logic controller and controls the processing punch to descend from the top dead center of the slide at a constant speed of 120 mm / s. During this stage, the electrical signal is output with a constant amplitude, and the blank holder force is maintained at 8 MPa for 0.8 seconds until the processing punch contacts the surface of the sheet metal. S302, when the pressure sensor of the processing punch detects that the contact force has reached the preset contact threshold, the system confirms that the processing punch has contacted the surface of the sheet metal. At this stage, the triggering electrical signal simultaneously triggers the data acquisition unit to start recording pressure, temperature, displacement and strain data at a sampling frequency of 1 kHz. The principle and effect of the above technical solution are as follows: by designing the contact downward section as a high-speed idle stroke, the auxiliary time for non-processing is shortened. At the same time, the constant low pressure edge clamping force avoids the initial local thinning caused by excessive impact force when the processing punch contacts the plate. The trigger electrical signal provides an accurate time reference for subsequent dynamic modulation.

[0030] In one embodiment, S40 includes: S401, in the preforming section, the processing punch presses down from the contact plate surface to 40% of the total stroke for 1.1 seconds, the pressing speed is reduced to 45 mm / s, and the blank holder force is increased to 15 MPa. The data acquisition unit transmits the electrical signals fed back by the pressure sensor, temperature sensor and strain gauge to the process strategy layer in real time. The process strategy layer calculates the equivalent stress and yield state of each micro-region of the plate according to the physical model of the elastic-plastic response of aluminum alloy stored in the material mechanism layer, and converts the electrical signal into a pulse width modulation signal and outputs it to the proportional servo valve of each zone blank holder cylinder. The modulation frequency is 2 kHz, and the duty cycle is dynamically adjusted between 30% and 70% according to the real-time feedback of the radial inflow resistance of the plate. S402, in the finishing section, the processing punch is pressed down from 40% to 85% of the total stroke for 0.9 seconds, and the pressing speed is further reduced to 20 mm / s. The partitioned blank holder force is distributed in a gradient around the sheet metal, with a blank holder force of 18 MPa in the corner area and 12 MPa in the straight edge area. The electrical signal is introduced with phase modulation at this stage, so that the servo valve response in the corner area leads the straight edge area by 15 milliseconds. In S403, during the entire S40 process, when the local strain increase rate fed back by the strain gauges arranged on the surface of the plate exceeds 15% of the predicted value of the material mechanism layer, the system superimposes a modulation wave with a frequency of 3 kHz and an amplitude attenuation of 20% into the control signal of the pressing cylinder corresponding to the area, and synchronously reduces the pressing speed of the area by 20% until the local strain increase rate falls back to the predicted value range.

[0031] The principle and effect of the above technical solution are as follows: by dividing the entire forming process into two stages, preforming and precision forming, and performing pulse width modulation and phase modulation of electrical signals according to the real-time response of the material in each stage, the strain energy distribution of the sheet metal during the deformation process is actively reshaped. The uneven inflow velocity caused by the difference in geometric constraints between the corner area and the straight edge area is dynamically compensated by the phase difference of the electrical signal. The superposition of modulation waves at the local overstrain points suppresses the initiation of concentrated deformation and hidden cracks, which cannot be achieved by relying solely on constant blank holder force and fixed speed in traditional processes.

[0032] In one specific embodiment, in S40, if the data acquisition unit reports that the sheet temperature is lower than the preset forming lower limit, a temperature rise compensation control strategy is adopted, and the specific steps are as follows: SA41: When the measured sheet temperature is below 240 degrees Celsius, the process strategy layer determines that the current thermal state has deviated from the optimal forming temperature window. SA42: The system will automatically reduce the pressing speed of the main forming section by 20% from the current value, and simultaneously increase the blank holder force of the finishing forming section from 12 MPa to 14 MPa to compensate for the increased deformation resistance due to the decrease in temperature. SA43: The electrical signal modulation depth is increased by 10%, that is, the upper limit of the pulse width modulation duty cycle is increased from 70% to 80%, so that the pressure cylinder can obtain more energy input per unit time. SA44: At the same time, the power of the mold heating rod increases by 15%, and the heat transfer through the mold accelerates the temperature rise of the sheet metal until the temperature sensor reports that the sheet metal temperature has risen back to above 240 degrees Celsius, at which point the original settings are restored.

[0033] The heating compensation strategy in the low-temperature scenario of S40 mentioned above enables the sheet to maintain a uniform plastic flow state when the temperature fluctuates, avoiding the lag adjustment and batch defects caused by relying on manual inspection to detect temperature drift in traditional processes.

[0034] In S40, if the data acquisition unit reports that the equivalent plastic strain growth rate in the corner region of the sheet metal exceeds 15% of the predicted value in the material mechanism layer, a local strain equalization modulation strategy is adopted. The specific steps of the local strain equalization modulation strategy are as follows: SB41: The system identifies the location number of the strain rate increase exceeding the tolerance area and adjusts the corresponding zone pressing cylinder control signal to be output with a lag of 20 milliseconds. SB42: The corresponding blank holder force in the region is dynamically reduced from 18 MPa to 15 MPa to reduce the radial inflow resistance in the region; SB43: The blank holder force corresponding to the straight edge region adjacent to the area is simultaneously increased from 12 MPa to 14 MPa to suppress excessive material accumulation in the straight edge direction that may be caused by the decrease in blank holder force in the corner region. SB44: The system continuously monitors the feedback from the strain gauges in the region. When the strain rate drops back to within ±5% of the predicted value, the blank holder force and phase difference are restored to the original set values.

[0035] The local strain equalization modulation strategy in the corner region of the above-mentioned S40, through the phase delay of the electrical signal and the spatial redistribution of the edge pressure force, orderly guides the high strain energy originally concentrated in the corner to the adjacent region, fundamentally avoiding local thinning and hidden cracking.

[0036] In S40, if the data acquisition unit reports a wrinkling tendency signal in the straight edge area of ​​the sheet metal, a wrinkling suppression modulation strategy is adopted. The specific steps of the wrinkling suppression modulation strategy are as follows: SC41: The system identifies the location number of the wrinkling tendency area and increases the corresponding edge pressure from 12 MPa to 16 MPa to enhance the constraint on the flow of sheet material. SC42: Reduce the blank holder force in adjacent corner areas from 18 MPa to 16 MPa to achieve a more balanced distribution of blank holder force; SC43: The phase modulation direction of the electrical signal is reversed, so that the servo valve response in the straight edge region is 10 milliseconds ahead of the corner region, so as to prioritize the establishment of the constraint force in the straight edge region in terms of timing; SC44: Synchronously reduce the pressing speed from 20 mm / s to 15 mm / s to decrease the dynamic inflow speed of the sheet material until the wrinkling tendency signal disappears, then restore the original setting parameters.

[0037] The wrinkling suppression modulation strategy in the straight edge region wrinkling scenario in S40 above suppresses the initiation of unstable wrinkling by equalizing the blank holder force and reversing the phase of the electrical signal, while maintaining the overall forming efficiency. This avoids the passive response of stopping the machine to adjust the blank holder force in traditional processes.

[0038] In one specific embodiment, in S50, if the pressure distribution in the mold cavity is uniform and the pressure holding fluctuation is within a preset range, a constant pressure holding control strategy is adopted, and the specific steps are as follows: SA51: After the processing punch reaches the bottom dead center, the system switches to constant pressure closed-loop control mode, and the holding pressure is set to 85% of the rated pressure; SA52: The pressure holding time is 3.5 seconds, and the actual pressure fluctuation is controlled within ±0.5 MPa through the closed-loop regulation of the proportional servo valve. SA53: During the holding pressure period, the system continuously collects the pressure distribution data of the mold cavity and performs closed-loop correction on the holding pressure to eliminate the time-varying effect of plastic springback; SA54: When the pressure holding period ends, the system records the entire pressure-time curve and stores it in the database as reference data for subsequent batch process optimization.

[0039] The control strategy in the constant pressure holding scenario of S50 mentioned above provides a stable mechanical environment for stress relaxation of the sheet at the end of the forming stage, so that elastic strain can be released to the maximum extent during the holding pressure period, thereby significantly reducing the amount of springback after demolding.

[0040] In S50, if the data acquisition unit reports that the rebound force data value shows an increasing trend during the pressure holding period, a variable pressure holding control strategy is adopted. The specific steps of the variable pressure holding control strategy are as follows: SB51: The system determines that the elastic energy stored inside the sheet metal has not been effectively released under the current pressure holding conditions, and the pressure holding pressure needs to be adjusted in stages; SB52: Increase the holding pressure from 85% to 90% of the rated pressure in the first stage and hold for 1 second to increase the driving force for the release of elastic energy storage; SB53: Then, the holding pressure is reduced to 80% of the rated pressure in the second stage and held for 1.5 seconds, so that the sheet material can fully release the elastic aftereffect during the pressure reduction process; SB54: Finally, restore the holding pressure to 85% of the rated pressure, hold for 1 second, and record the pressure-rebound force relationship curve throughout the process.

[0041] The variable pressure holding control strategy under the increasing rebound force trend in S50 above forms a pulsed release channel for elastic energy storage through the staged rise and fall of holding pressure. This breaks the bottleneck of slow elastic strain energy release rate under constant pressure, causing the rebound force to decrease significantly at the end of the holding pressure period, and further narrowing the rebound angle distribution after demolding.

[0042] In S50, if the rate at which the sheet temperature decreases during the holding pressure period, as reported by the data acquisition unit, exceeds a preset cooling rate, a temperature control compensation holding pressure strategy is adopted. The specific steps of the temperature control compensation holding pressure strategy are as follows: SC51: The system determines that the sheet metal has reduced stress relaxation efficiency due to excessive heat dissipation, and the mold temperature needs to be increased simultaneously to delay sheet metal cooling. SC52: The power of the mold heating rod is increased by 20% to allow the mold temperature to rise back to the preset temperature range within 10 seconds; SC53: The holding pressure is simultaneously reduced to 80% of the rated pressure to match the change in load-bearing capacity caused by the softening effect of the sheet after the temperature rises. SC54: After the temperature sensor indicates that the sheet temperature has returned to the target range, restore the holding pressure to 85% of the rated pressure and continue to complete the remaining holding time.

[0043] The temperature control compensation pressure holding strategy in the rapidly decreasing temperature scenario in S50 above maintains the stress relaxation efficiency of the sheet metal during the pressure holding stage by actively raising the mold temperature and coordinating the adjustment of the pressure holding pressure, thus avoiding the elastic strain energy being frozen inside the sheet metal due to excessively rapid cooling.

[0044] In one specific embodiment, in S60, if the rebound force data value is less than a preset rebound force threshold, it is determined that no post-heat treatment is required. The specific steps are as follows: SA61: The processing punch remains in the same position until the sheet metal returns to room temperature after stamping; SA62: The system reads the springback force data from the pressure sensor on the surface of the punch and compares the springback force data value with the preset springback force threshold. When the springback force data value is less than the preset threshold, it is determined that no post-heat treatment is required. SA63: Controls the machining punch to return to the top dead center at a speed of 20 mm / s; SA64: Collects image data of the sheet surface after stamping, inputs the image data into the defect recognition model, and outputs the defect type and location coordinates of the sheet surface. When the sheet is determined to be qualified, it outputs a qualified signal and transports the sheet to the next process. When the sheet is determined to have defects, it outputs the corresponding defect type signal and sheet position signal so that the operator can process the sheet accordingly based on the defect type signal and the sheet position signal.

[0045] The processing flow in the above S60 scenario where the rebound force is less than the threshold is based on the determination of the necessity of post-processing according to the measured rebound force data. Only the plates that really need heat treatment are subjected to post-processing. This significantly reduces energy consumption and production cycle time while ensuring forming accuracy and material properties.

[0046] In S60, if the rebound force data value is greater than or equal to a preset rebound force threshold, a post-heat treatment control strategy is adopted. The specific steps of the post-heat treatment control strategy are as follows: SB61: The system determines that the current rebound force indicates that the residual stress level inside the sheet is high, and it needs to be released through post-heat treatment. SB62: Control the built-in heating rod of the mold to raise the mold temperature to 180 degrees Celsius, and perform artificial aging treatment on the molded parts. The holding time is 2 hours. SB63: After the aging treatment is completed, open the cooling water channel in the mold and cool the sheet to room temperature at a cooling rate of 20 degrees Celsius per second; SB64: After cooling is complete, control the processing punch to reset, collect image data of the plate surface, analyze the image data to determine whether the stamped plate is qualified, output a qualified signal when the plate is qualified, and feed back the defect type and update the model parameters of the material mechanism layer when the plate is found to have defects.

[0047] The post-heat treatment control strategy in the above-mentioned S60 scenario where the springback force is greater than or equal to the threshold, through a combination of artificial aging and controllable cooling, effectively eliminates residual stress and restores the mechanical properties of the material without changing the mold surface, providing an integrated solution for the post-processing of high-strength aluminum plates such as 6-series aluminum alloys.

[0048] To verify the superiority of the intelligent stamping control method based on aluminum single-panel over the traditional constant blank holder force (Constant BHF) and fixed stroke control methods, this invention set up three sets of control experiments: Group A (this invention) applies the entire process S10-S60, including temperature compensation (SA4), local strain equalization (SB4), and variable pressure holding (SB5). Group B (semi-dynamic control) only uses constant blank holder force zone control, without dynamic modulation of electrical signals (PWM / PFM) and real-time strain feedback. Group C (traditional process) uses constant blank holder force and constant speed, without heating and pressure holding shaping stages.

[0049] Test conditions and material parameters: The material used is 6xxx series aluminum alloy (specifically AA6016-T4), with an initial yield strength of 120MPa and a thickness of mm. The die is a rectangular box-shaped drawing die (200mm long, 100mm wide, with a corner radius of R10mm). The environment is room temperature of 25℃, and the sheet metal was solution treated before stamping.

[0050] The testing equipment used was a non-contact 3D optical scanner (GOM ATOS) to measure the geometric contour after springback; a digital image correlation system (DIC) to record strain distribution; and a dynamic pressure sensor with a sampling frequency of 1kHz. After the pressure holding period ended, demolding was completed, and the parts cooled to room temperature, the 3D optical scanner was used to obtain the sidewall contour of the formed part, and the angle between the "sidewall centerline" and the "mold surface tangent" was measured as the springback angle. Five cross-sections were taken for each part, and the average value was calculated. The average value and fluctuation range of 100 parts in each group were statistically analyzed. The thickness change of the critical point (rounded corner) before and after forming was recorded using DIC. The thinning rate was obtained by dividing the difference between the original thickness and the thickness after forming by the original thickness. A thinning rate exceeding 25% was considered a fracture. During the pre-forming and precision forming stages, the PWM duty cycle, servo valve response timing, and partition blank holder force output by the PLC were recorded in real time, and the modulation effect was evaluated by comparing it with the real-time strain state of the material. The test results are shown in Table 1.

[0051] Table 1: Comparison of Molding Quality

[0052] Table 1 shows that Group A has an average springback angle of 1.2°, a maximum springback angle of 1.5°, a springback fluctuation standard deviation of 0.14°, and a sidewall thinning rate of 12.5%. Group B (semi-dynamic control) has corresponding values ​​of 3.5°, 5.1°, 0.43°, and 16.8%. Group C (traditional process) has corresponding values ​​of 6.8°, 9.5°, 1.21°, and 21.5%, and Group C exhibits localized cracking and wrinkling in the sidewall area. It is evident that this invention, through segmented stamping stroke and dynamic modulation of electrical signals, significantly reduces the springback amount and its fluctuation amplitude, while simultaneously suppressing thinning and wrinkling defects. This demonstrates that the method can effectively reshape the strain energy distribution of the sheet metal, improving forming accuracy and consistency. Figure 3 This is a schematic diagram of the stamping stroke segmentation and dynamic modulation of electrical signals according to an embodiment of the present invention. It shows the relationship between the punch displacement, pressing speed, blank holder force and electrical signal modulation parameters and time in the contact downward segment, pre-forming segment, precision forming segment and pressure holding and shaping segment. Figure 4 The test results comparing the rebound angle distribution under different control strategies are shown in box plot form, illustrating the rebound angle distribution range and dispersion of the method of this invention, semi-dynamic control, and traditional processes. Figure 3 and Figure 4 It can be seen that the present invention segments the stamping stroke and dynamically modulates the amplitude, pulse width, frequency and phase difference of the electrical signal according to the real-time response state of the sheet in the pre-forming section and the finishing section, so that the strain energy distribution of each micro-area of ​​the sheet is actively reshaped, the springback angle distribution is significantly narrowed and the mean value is significantly reduced, indicating that the method can effectively suppress springback and improve forming accuracy and consistency.

[0053] Accordingly, such as Figure 2 As shown, an intelligent stamping and forming control method based on aluminum single-panel is provided. This embodiment of the invention also provides an intelligent stamping and forming control system based on aluminum single-panel, implementing the intelligent stamping and forming control method based on aluminum single-panel of this invention. The system includes: The sheet material information acquisition and preprocessing module is used to obtain the grade, actual thickness, surface flatness and initial temperature of the aluminum sheet to be processed before stamping. The measured thickness and grade information are input into the processing unit. The initial stamping parameters are determined according to the mapping relationship between thickness and impact force and pressing speed. When the measured flatness exceeds the preset flatness threshold, the parallel mold is controlled to perform pre-flattening treatment on the sheet material. At the same time, the flatness is re-measured to ensure that the sheet material condition meets the forming requirements. The heating and mold temperature control module is used to set the heating temperature and holding time according to the sheet material grade and actual thickness, uniformly heat the pre-treated sheet material, and maintain the mold temperature within the preset range through the coordinated control of the heating rod array and cooling water channel arranged inside the mold. The temperature control accuracy does not exceed ±5 degrees Celsius. After the sheet material reaches the target temperature, it is transferred to the stamping station within a predetermined time. The stamping stroke segmented drive module is used to drive the mechanical servo press to drive the processing punch to run in the order of contact downward section, pre-forming section, fine forming section and pressure holding and shaping section. In the contact downward section, the no-stroke pressing is completed with constant speed and constant electrical signal amplitude. In the pre-forming section and fine forming section, the pressing speed and blank holder force are adjusted according to real-time feedback. In the pressure holding and shaping section, the module switches to closed-loop pressure control mode, so that the entire stamping process is always under hierarchical control. The dynamic electrical signal modulation and strain energy reshaping module is used to receive high-frequency feedback signals from pressure sensors, temperature sensors and strain gauges, call the physical model of aluminum alloy elastic-plastic response to calculate the yield evolution and hardening trajectory of each micro-region of the sheet in real time, and generate dynamic electrical signals including amplitude modulation, pulse width modulation, frequency modulation and phase difference modulation. Through the proportional servo valve, the pressure cylinders and slider drive units of each zone are independently controlled, thereby actively changing the strain energy distribution of the sheet in the mold and suppressing local overstrain and instability wrinkling. The pressure holding and shaping and springback closed-loop control module is used to maintain the position of the punch after it reaches the bottom dead center. Based on the pressure distribution and springback force change trend of the mold cavity during the pressure holding period, it selects constant pressure holding, variable pressure pulse release or temperature control compensation pressure holding strategy. After the sheet material returns to room temperature, it collects springback force data and compares it with a preset threshold. Based on this, it determines whether post-heat treatment is required and outputs corresponding control commands. The post-heat treatment decision and quality assessment module is used to control the mold heating rod to raise the mold to the post-heat treatment temperature and hold it when it is determined that post-heat treatment is required. Then, it cools down at a set cooling rate. When it is determined that post-heat treatment is not required, it directly controls the processing punch to reset. Then, it collects image data of the plate surface after stamping, outputs the defect type and location coordinates through the defect recognition model, outputs qualified products to the next process, and feeds back the defect information of unqualified products to the process strategy layer to update the control parameters.

[0054] It should be noted that the intelligent stamping and forming control system based on aluminum single-panel provided in this embodiment of the invention is used to execute all the process steps of the intelligent stamping and forming control method based on aluminum single-panel in the above embodiment. The working principle and beneficial effect of the two are one-to-one, so they will not be described again.

[0055] Figure 5 Here is a block diagram of the algorithm model. Figure 6 As shown in the sensor feedback logic block diagram, this invention achieves dynamic modulation and stable quality control of the aluminum single-panel stamping process by having the material mechanism layer, process strategy layer and control execution layer work together, and by combining multiple types of sensors to collect temperature, pressure, strain, thickness and image information in real time.

[0056] The technical principle and effect of the above technical solution are as follows: This system integrates sheet material sensing, heating temperature control, segmented driving, dynamic electrical signal modulation, pressure holding closed loop and post-processing decision-making into the same hierarchical control architecture. This makes the electrical signal no longer a preset fixed command, but an active medium connecting the material mechanism and the equipment execution layer. During the entire stamping process, the blank holder force, pressing speed and signal modulation parameters are adjusted in milliseconds according to the real-time yield and hardening state of the aluminum sheet. This actively reshapes the strain energy distribution inside the sheet material, and simultaneously suppresses defects such as wrinkling, cracking and springback that have long plagued the field. Ultimately, it significantly improves the dimensional accuracy, batch consistency and continuous production stability of aluminum single-panel stamping.

[0057] This invention also provides an electronic device, comprising: a processor, a memory, and a computer program stored in the memory and executable on the processor, such as an intelligent stamping and forming control program based on aluminum single-panel. When the processor executes the computer program, it implements the steps in each of the above embodiments of the intelligent stamping and forming control method based on aluminum single-panel, such as steps S10 to S60. Alternatively, when the processor executes the computer program, it implements the functions of each module / unit in the above system embodiments.

[0058] For example, the computer program may be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units may be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program in the electronic device.

[0059] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for intelligent stamping and forming control based on aluminum single-panel, characterized in that, include: S10: Obtain the basic information of the aluminum single-panel material to be stamped and perform pre-processing before stamping. The basic information includes the grade of the sheet material, the measured thickness, the surface flatness and the initial temperature. Based on the basic information, determine the impact force and pressing speed of the processing punch. When the measured surface flatness exceeds the preset flatness threshold, perform pre-flattening treatment on the sheet material through a parallel die. S20 heats the pre-treated sheet metal, determining the heating temperature and holding time based on the sheet metal grade and measured thickness. Simultaneously, the temperature of the stamping die is adjusted and maintained within the preset die temperature range. When the sheet metal temperature reaches the target heating temperature, it is transferred to the stamping station. The die temperature is controlled by the die's built-in heating rod and cooling water channel. S30, the mechanical servo press is started to drive the processing punch downward. The stamping stroke is divided into the contact downward section, the pre-forming section, the fine forming section and the pressure holding and shaping section. In the contact downward section, the processing punch moves down from the top dead point of the slide to the contact plate surface at a constant pressing speed, and the blank holder force is maintained at a low pressure value. S40, in the preforming and finishing sections, the data acquisition unit acquires in real time the temperature data of the sheet surface, the pressure data fed back by the pressure sensors arranged in the blank holder and the mold cavity, and the strain data fed back by the strain gauges arranged on the sheet surface. Based on the physical model of the elastic-plastic response of aluminum alloy, the yield evolution and hardening trajectory of each micro-region of the sheet are predicted in real time. The amplitude, pulse width, frequency and phase difference of the servo valve electrical signal are dynamically modulated by the programmable logic controller, so that the blank holder force, pressing speed and electrical signal modulation parameters of each section are dynamically adjusted according to the real-time response state of the material, thereby actively reshaping the strain energy distribution of the sheet in the mold. In the S50 pressure holding and shaping section, after the processing punch reaches the bottom dead center, it remains in the same position. The pressure holding is set to 85% of the rated pressure, and the pressure holding time is preset according to the sheet thickness and grade. During this stage, the electrical signal switches to constant pressure closed-loop mode. The pressure holding set value is set according to the pressure distribution of the mold cavity, and closed-loop correction is performed according to the preset allowable pressure fluctuation threshold. The actual pressure holding is dynamically adjusted through the proportional servo valve so that the deviation of the actual pressure from the set value during the pressure holding period is within the preset allowable fluctuation range, so as to eliminate the time-varying effect of plastic springback. S60, after the pressure holding is completed, the processing punch remains in the same position until the stamped sheet returns to room temperature. Based on the pressure sensor on the surface of the processing punch, the spring force of the stamped sheet acting on the processing punch is collected. Based on the comparison result of the spring force and the preset threshold, it is determined whether to perform post-heat treatment. After the determination is completed, the processing punch is controlled to reset, and image data of the surface of the stamped sheet is collected. The image data is analyzed to determine whether the stamped sheet is qualified. Qualified products are output to the next process, and unqualified products are marked with defect type and fed back to the process strategy layer for parameter correction.

2. The method as described in claim 1, characterized in that, S10 specifically includes: conveying the sheet metal to the inspection station via an automatic feeding device; obtaining the actual thickness of the sheet metal using a non-contact laser thickness gauge; acquiring surface images of the sheet metal using a surface array camera and calculating the surface flatness using an image processing algorithm; simultaneously obtaining the material grade and rolling direction information by reading the electronic information attached to the sheet metal; inputting the measured thickness and grade information to the processing unit; the processing unit determining the impact force and pressing speed of the processing punch based on the thickness-impact force-pressing speed mapping relationship table stored in the material mechanism layer; comparing the measured surface flatness with the preset flatness threshold of 0.3 mm per meter; when the measured surface flatness exceeds the preset threshold, controlling the parallel die to perform pre-flattening treatment on the sheet metal at a pressing speed of 20 mm per second; and re-measuring the flatness after processing until the requirements are met.

3. The method as described in claim 1, characterized in that, S20 specifically includes: feeding the pre-treated sheet material into a multi-layer box furnace, determining the heating parameters based on the sheet material thickness; when the sheet material thickness is 3.0 mm, the heating temperature is set to 320 degrees Celsius and the holding time is set to 45 minutes; when the sheet material thickness is 2.5 mm, the heating temperature is set to 260 degrees Celsius and the holding time is set to 30 minutes; when the sheet material thickness is 4.0 mm, the heating temperature is set to 250 degrees Celsius and the holding time is set to 60 minutes; after heating is completed, the sheet material is transferred to the stamping station within 20 seconds. The mold temperature control system is activated simultaneously. The mold temperature is heated to 180 degrees Celsius by the built-in heating rod. When the mold temperature exceeds 190 degrees Celsius due to continuous production, the cooling water flow rate is automatically adjusted to 115% of the rated flow rate to bring the mold temperature back to the preset range. The temperature control accuracy is maintained at ±5 degrees Celsius. The mold temperature is fed back in real time by a thermocouple array arranged in nine temperature control zones of the mold.

4. The method as described in claim 1, characterized in that, S30 specifically includes: S301, the mechanical servo press receives the stroke command from the programmable logic controller and controls the processing punch to descend from the top dead center of the slide at a constant speed of 120 mm / s. During this stage, the electrical signal is output with a constant amplitude, the blank holder force is maintained at 8 MPa for 0.8 seconds until the processing punch contacts the surface of the sheet. When the pressure sensor of the processing punch detects that the contact force has reached the preset contact threshold, the system confirms that the processing punch has contacted the surface of the sheet metal. At this stage, the trigger electrical signal simultaneously triggers the data acquisition unit to start recording pressure, temperature, displacement and strain data at a sampling frequency of 1 kHz.

5. The method as described in claim 1, characterized in that, S40 specifically includes: S401, in the preforming section, the processing punch presses down from the contact plate surface to 40% of the total stroke for 1.1 seconds, the pressing speed is reduced to 45 mm / s, the blank holder force is increased to 15 MPa, the data acquisition unit transmits the electrical signals fed back by the pressure sensor, temperature sensor and strain gauge to the process strategy layer in real time, the process strategy layer calculates the equivalent stress and yield state of each micro-region of the plate according to the physical model of aluminum alloy elastoplastic response stored in the material mechanism layer, and converts the electrical signal into a pulse width modulation signal and outputs it to the proportional servo valve of each zone blank holder cylinder, the modulation frequency is 2 kHz, and the duty cycle is dynamically adjusted between 30% and 70% according to the real-time feedback of the radial inflow resistance of the plate; In the S402 precision forming section, the processing punch is pressed down from 40% to 85% of the total stroke over a period of 0.9 seconds. The pressing speed is further reduced to 20 mm / s. The blank holder force is distributed in a gradient around the sheet metal, with a blank holder force of 18 MPa in the corner area and 12 MPa in the straight edge area. The electrical signal is phase-modulated at this stage, causing the servo valve response in the corner area to lead the response in the straight edge area by 15 milliseconds. In S403, during the entire S40 process, when the local strain increase rate fed back by the strain gauges arranged on the surface of the plate exceeds 15% of the predicted value of the material mechanism layer, the system superimposes a modulation wave with a frequency of 3 kHz and an amplitude attenuation of 20% into the control signal of the pressing cylinder corresponding to the area, and synchronously reduces the pressing speed of the area by 20% until the local strain increase rate falls back to the predicted value range.

6. The method as described in claim 5, characterized in that, The S40 also includes a temperature compensation control strategy. When the data acquisition unit reports that the sheet temperature is below 240 degrees Celsius, the process strategy layer determines that the current thermal state has deviated from the optimal forming temperature window. The system automatically reduces the pressing speed of the main forming section by 20% from the current value and simultaneously increases the blank holder force of the finishing forming section from 12 MPa to 14 MPa. The electrical signal modulation depth is increased by 10% accordingly, that is, the upper limit of the pulse width modulation duty cycle is increased from 70% to 80%. The power of the mold heating rod is increased by 15%, and the sheet temperature is accelerated through contact heat transfer of the mold until the temperature sensor reports that the sheet temperature has risen back to above 240 degrees Celsius, at which point the original parameter chain is restored. S40 also includes a local strain equalization modulation strategy. When the data acquisition unit reports that the equivalent plastic strain growth rate in the corner area of ​​the sheet metal exceeds 15% of the predicted value of the material mechanism layer, the system identifies the location number of the area with excessive strain growth rate, adjusts the control signal of the partitioned edge-pressing cylinder corresponding to the area to be output with a lag of 20 milliseconds, dynamically reduces the edge-pressing force corresponding to the area from 18 MPa to 15 MPa, and synchronously increases the edge-pressing force corresponding to the straight edge area adjacent to the area from 12 MPa to 14 MPa. The system continuously monitors the feedback of the strain gauges in the area, and when the strain growth rate falls back to within ±5% of the predicted value, the edge-pressing force and phase difference are restored to the original set values. The S40 also includes a wrinkling suppression modulation strategy. When the data acquisition unit reports a wrinkling tendency signal in the straight edge area of ​​the sheet metal, the system identifies the location number of the wrinkling tendency area, increases the pressing force corresponding to the area from 12 MPa to 16 MPa, decreases the pressing force of the adjacent corner area from 18 MPa to 16 MPa, reverses the phase modulation direction of the electrical signal, so that the servo valve response of the straight edge area is 10 milliseconds ahead of the corner area, and simultaneously reduces the pressing speed from 20 mm / s to 15 mm / s until the wrinkling tendency signal disappears and the original setting parameters are restored.

7. The method as described in claim 1, characterized in that, In S50, when the pressure distribution in the mold cavity is uniform and the holding pressure fluctuation is within a preset range, a constant pressure holding control strategy is adopted. Specifically, after the punch reaches the bottom dead center, the system switches to constant pressure closed-loop control mode, and the holding pressure is set to 85% of the rated pressure. The holding time is 3.5 seconds, and the actual pressure fluctuation is controlled within ±0.5 MPa through the closed-loop adjustment of the proportional servo valve. During the holding period, the system continuously collects the pressure distribution data of the mold cavity and performs closed-loop correction on the holding pressure to eliminate the time-varying effect of plastic springback. When the holding period ends, the system records the entire pressure-time curve and stores it in the database. The S50 also includes a variable pressure holding control strategy. When the data acquisition unit reports that the rebound force data value shows an increasing trend during the pressure holding period, the system determines that the elastic energy stored inside the sheet material under the current pressure holding condition has not been effectively released. The pressure holding is increased from 85% to 90% of the rated pressure in the first stage and held for 1 second. Then, the pressure holding is reduced back to 80% of the rated pressure in the second stage and held for 1.5 seconds. Finally, the pressure holding is restored to 85% of the rated pressure and held for 1 second, and the pressure-rebound force relationship curve is recorded throughout the process. The S50 also includes a temperature control compensation pressure holding strategy. When the rate at which the sheet temperature drops during the pressure holding period exceeds the preset cooling rate, the system determines that the sheet temperature has reduced stress relaxation efficiency due to excessive heat dissipation. The power of the mold heating rod is increased by 20% on the current basis, so that the mold temperature rises back to the preset temperature range within 10 seconds. The holding pressure is simultaneously reduced to 80% of the rated pressure to match the change in load-bearing capacity caused by the softening effect of the sheet after the temperature rises; after the temperature sensor indicates that the sheet temperature has recovered to the target range, the holding pressure is restored to 85% of the rated pressure and the remaining holding time is completed.

8. The method as described in claim 1, characterized in that, In S60, when the springback force data value is less than the preset springback force threshold, it is determined that no post-heat treatment is required. Specifically, the processing punch remains in the same position until the sheet metal returns to room temperature after stamping; the system reads the springback force data from the pressure sensor on the surface of the processing punch and compares the springback force data value with the preset springback force threshold. When the springback force data value is less than the preset threshold, it is determined that no post-heat treatment is required; the processing punch is controlled to reset to the top dead center at a speed of 20 mm / s; image data of the sheet metal surface is collected after stamping, and the image data is input into the defect recognition model. The defect recognition model outputs the defect type and location coordinates of the sheet metal surface. When the sheet metal is determined to be qualified, a qualified signal is output and the sheet metal is transported to the next process. When the sheet metal is determined to have defects, the corresponding defect type signal and sheet metal position signal are output.

9. The method as described in claim 1, characterized in that, The S60 also includes a post-heat treatment control strategy. When the springback force data value is greater than or equal to the preset springback force threshold, the system determines that the current springback force indicates that the residual stress level inside the sheet metal is high. The system controls the built-in heating rod of the mold to raise the mold temperature to 180 degrees Celsius and performs artificial aging treatment on the formed part for 2 hours. After the aging treatment is completed, the cooling water channel in the mold is opened to cool the sheet metal to room temperature at a cooling rate of 20 degrees Celsius per second. After cooling is completed, the system controls the processing punch to reset, collects the surface image data of the sheet metal, analyzes the image data to determine whether the stamped sheet metal is qualified, outputs a qualified signal when the sheet metal is qualified, and feeds back the defect type and updates the model parameters of the material mechanism layer when the sheet metal is found to have defects.

10. A smart stamping and forming control system based on aluminum single-panel, used to implement the method described in any one of claims 1-9, characterized in that, The system includes: The sheet material information acquisition and preprocessing module is used to obtain the grade, actual thickness, surface flatness and initial temperature of the aluminum sheet to be processed before stamping. The measured thickness and grade information are input into the processing unit. The initial stamping parameters are determined according to the mapping relationship between thickness and impact force and pressing speed. When the measured flatness exceeds the preset flatness threshold, the parallel mold is controlled to perform pre-flattening treatment on the sheet material. At the same time, the flatness is re-measured to ensure that the sheet material condition meets the forming requirements. The heating and mold temperature control module is used to set the heating temperature and holding time according to the sheet material grade and actual thickness, uniformly heat the pre-treated sheet material, and maintain the mold temperature within the preset range through the coordinated control of the heating rod array and cooling water channel arranged inside the mold. The temperature control accuracy does not exceed ±5 degrees Celsius. After the sheet material reaches the target temperature, it is transferred to the stamping station within a predetermined time. The stamping stroke segmented drive module is used to drive the mechanical servo press to drive the processing punch to run in the order of contact downward section, pre-forming section, fine forming section and pressure holding and shaping section. In the contact downward section, the no-stroke pressing is completed with constant speed and constant electrical signal amplitude. In the pre-forming section and fine forming section, the pressing speed and blank holder force are adjusted according to real-time feedback. In the pressure holding and shaping section, the module switches to closed-loop pressure control mode. The dynamic electrical signal modulation and strain energy reshaping module is used to receive high-frequency feedback signals from pressure sensors, temperature sensors and strain gauges, call the physical model of aluminum alloy elastic-plastic response to calculate the yield evolution and hardening trajectory of each micro-region of the sheet in real time, and generate dynamic electrical signals including amplitude modulation, pulse width modulation, frequency modulation and phase difference modulation. Through the proportional servo valve, the pressure cylinders and slider drive units of each zone are independently controlled, thereby actively changing the strain energy distribution of the sheet in the mold and suppressing local overstrain and instability wrinkling. The pressure holding and shaping and springback closed-loop control module is used to maintain the position of the punch after it reaches the bottom dead center. Based on the pressure distribution and springback force change trend of the mold cavity during the pressure holding period, it selects constant pressure holding, variable pressure pulse release or temperature control compensation pressure holding strategy. After the sheet material returns to room temperature, it collects springback force data and compares it with a preset threshold. Based on this, it determines whether post-heat treatment is required and outputs corresponding control commands. The post-heat treatment decision and quality assessment module is used to control the mold heating rod to raise the mold to the post-heat treatment temperature and hold it when it is determined that post-heat treatment is required. Then, it cools down at a set cooling rate. When it is determined that post-heat treatment is not required, it directly controls the processing punch to reset. Then, it collects image data of the plate surface after stamping, outputs the defect type and location coordinates through the defect recognition model, outputs qualified products to the next process, and feeds back the defect information of unqualified products to the process strategy layer to update the control parameters.

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