A quick connection system for thin aluminum alloy sheets

Abstract

This invention provides a rapid joining system for aluminum alloy thin sheets, relating to the field of material joining. It includes a conveying assembly, a shearing assembly, an auxiliary lifting assembly, a sensing system, and a heating device. The conveying assembly consists of two sets of conveying mechanisms with a shearing assembly positioned between them. Each set of conveying mechanisms comprises multiple conveying rollers. The shearing assembly includes an upper shearing head and a lower shearing head, with shearing grooves respectively formed in the center of the bottom surface of the upper shearing head and the center of the top surface of the lower shearing head. The auxiliary lifting assembly is located outside the two conveying rollers of one set of conveying mechanisms and includes two auxiliary lifting rollers and a lifting device. The sensing system is positioned corresponding to the shearing assembly. This system not only enables rapid and efficient joining of aluminum alloy thin sheets but also allows for real-time monitoring during the joining process using intelligent sensors such as temperature and pressure sensors, preventing joint defects caused by external environmental factors.

Description

Technical Field

[0001] This invention relates to the field of material joining technology, and more specifically to a rapid joining system for thin aluminum alloy plates. Background Technology

[0002] Aluminum and aluminum alloys possess advantages such as low density, high specific strength, and good corrosion resistance, making them widely used in aerospace, automotive, shipbuilding, and electronics industries. Aluminum alloy sheets, specifically plates with a thickness of 1-5 mm made from aluminum alloys, are lightweight, high-strength, highly corrosion-resistant, and have excellent thermal and electrical conductivity. However, welding and joining aluminum alloys has always been a challenge hindering the development of the aluminum industry. Due to the inherent properties of aluminum alloys, it is difficult to achieve the same weld strength as steel through fusion welding or laser welding. Currently, friction stir welding is widely used on aluminum alloys, but its low welding efficiency makes it unsuitable for large-scale, rapid production. In the production of aluminum alloy sheets and strips, because laser welding cannot be used, continuous production without stopping the machine is not possible like the endless rolling of steel sheets and strips. Aluminum sheets and strips are typically produced by "stitching" two aluminum coils together. However, this "stitching" usually requires a stoppage of several minutes, and the stitched portion is relatively large, requiring subsequent cutting and resulting in significant material waste.

[0003] Studies have shown that shear extrusion joining can achieve better bonding of thin aluminum alloy sheets, with bond strength exceeding that of friction stir welding and traditional welding and riveting methods (e.g., Journal of Materials Science & Technology, 2023, 164:168-178). Heated shear extrusion joining effectively avoids problems such as hot cracking, porosity, and softening of the heat-affected zone that occur during aluminum alloy welding. It (i.e., heated extrusion joining) achieves metallurgical bonding through shear force and plastic deformation, resulting in joints with high strength and good sealing. However, due to the difference in extrusion shrinkage at the joint during the extrusion process and the thinness of the aluminum alloy sheet, the overall flatness at the joint is poor during extrusion. Unavoidable problems such as burrs, flash, or unevenness occur at the joint, affecting not only the subsequent assembly performance and mechanical properties of the sheet but also easily causing scratches and damage on the production line. Furthermore, during the heated extrusion joining process of the aluminum alloy sheet, the plastic deformation of the sheet mainly depends on preheating and the extrusion shear force. The heating temperature is highly susceptible to external environmental influences, leading to sudden temperature changes (such as a rapid temperature drop), resulting in… During the joining process, the alloy material hardens rapidly and its plastic flow capacity decreases, leading to unwelded areas or brittle fracture at the joint. Severe temperature gradients in thin plate sections or joint areas can even cause thermal stress, ultimately resulting in thermal cracking. Increasing the preheating temperature can mitigate the impact of sudden temperature changes to some extent, but it can cause the aluminum alloy to exceed its recrystallization temperature, leading to brittle fracture at the joint due to coarse grains. Excessively high heating temperatures can even cause localized melting of the aluminum alloy, resulting in molten aluminum adhering to the extrusion head surface and hindering the normal extrusion process. Furthermore, sudden temperature changes combined with the simultaneous action of extrusion pressure (i.e., temperature-pressure parameter mismatch) can cause uneven thickness distribution or warping deformation, affecting not only the dimensional accuracy of the joint but also the overall mechanical properties of the joint, resulting in poor connection quality. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide a rapid connection system for aluminum alloy thin plates. This system not only enables rapid and efficient connection between aluminum alloy thin plates, but also allows for real-time monitoring of temperature and extrusion pressure during the connection process, effectively avoiding the problem of temperature sudden changes and connector defects caused by external environmental influences.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A rapid connection system for aluminum alloy thin plates includes a conveying assembly, a shearing assembly, an auxiliary lifting assembly, a sensing system, and a heating device. The conveying assembly consists of two sets of conveying mechanisms, with the shearing assembly positioned between them. Each set of conveying mechanisms comprises multiple conveying rollers, and the upper tangential surfaces of these rollers are located on the same horizontal plane. The shearing assembly includes an upper shearing head and a lower shearing head, with shearing grooves respectively formed in the middle of the bottom surface of the upper shearing head and the middle of the top surface of the lower shearing head. The shearing grooves of the upper and lower shearing heads are mirror-symmetrical (i.e., the upper shearing head rotates 180° around its center to perfectly align with the lower shearing head). The auxiliary lifting assembly is positioned outside the two conveying rollers of one set of conveying mechanisms and includes two auxiliary lifting rollers and a lifting device. The two auxiliary lifting rollers are arranged in parallel, with their ends connected to the lifting device, which controls the synchronous lifting and lowering of the two auxiliary lifting rollers. The sensing system is positioned corresponding to the shearing assembly.

[0007] Based on further optimization of the above scheme, the shearing groove is composed of two arc segments, including a small arc segment and a large arc segment. The small arc segment and the large arc segment are smoothly connected, and the shearing groove of the upper shearing head is conveyed by the conveying component in the order of the small arc segment and the large arc segment. The radius of the small arc segment is 3 times the thickness of the aluminum alloy sheet, and the radius of the large arc segment is 6 times the thickness of the aluminum alloy sheet.

[0008] Based on further optimization of the above scheme, the length of the shearing groove is no more than 5 times the thickness of the aluminum alloy sheet; the length of the flat section on both sides of the shearing groove is consistent and greater than 5 times the thickness of the aluminum alloy sheet.

[0009] Based on further optimization of the above scheme, the sensing system includes an infrared sensor, a temperature sensor, and a pressure sensor. The infrared sensor is located on the side of the shearing assembly near the auxiliary lifting assembly and includes an infrared emitting source and an infrared receiving source. The infrared emitting source and the infrared receiving source are respectively located on the lower shear head and the upper shear head, and the infrared emitting source and the infrared receiving source are correspondingly arranged. The temperature sensor is located on the bottom surface of the upper shear head on the side of the corresponding shearing groove near the auxiliary lifting assembly, and the temperature sensor is evenly distributed along the width direction of the upper shear head. The pressure sensor (e.g., a high-temperature strain gauge sensor) is located on the top surface of the lower shear head on the side of the corresponding shearing groove away from the auxiliary lifting assembly, and the pressure sensor is evenly distributed along the width direction of the lower shear head.

[0010] Based on further optimization of the above scheme, the heating device is located on the front and rear sides of the shearing assembly and is set at the overlapping part of the stacked aluminum alloy sheets. The heating device can clamp the aluminum alloy sheets. At the same time, an infrared thermal imager is set on the front and rear sides of the shearing assembly and above the heating device. The line of sight of the infrared thermal imager is opposite to the overlapping position of the aluminum alloy sheets.

[0011] A method for quick connection of aluminum alloy thin plates, employing the above-mentioned connection system, includes:

[0012] Step 1: Stacking Aluminum Alloy Sheets: Place the aluminum alloy sheets on the conveying assembly, allowing them to follow the assembly. When the tail of the first aluminum alloy sheet is in the middle of the shearing groove of the lower shear head, pause one side of the conveying mechanism (the one furthest from the auxiliary lifting assembly) and place the next aluminum alloy sheet on another conveying mechanism (the one equipped with the auxiliary lifting assembly). The next sheet then follows the conveying mechanism. When the end of the next aluminum alloy sheet is detected by the infrared sensor, the corresponding conveying mechanism stops, and the auxiliary lifting roller rises and rotates, lifting and continuously running the next aluminum alloy sheet until its end reaches the middle of the shearing groove of the upper shear head. At this point, the auxiliary lifting roller stops, the upper shear head moves down to its bottom surface and contacts the end face of the next aluminum alloy sheet, and the upper shear head pauses. Afterward, the auxiliary lifting roller descends and resets.

[0013] Step 2, Heating the aluminum alloy sheet: First, drive the front and rear heating devices to clamp the stacked aluminum alloy sheets; then, start the heating devices to heat the aluminum alloy sheets; after heating is completed, the front and rear heating devices release the clamps on the aluminum alloy sheets.

[0014] Step 3, Extrusion Connection: Simultaneously start the upper and lower shear heads and make them move towards each other to achieve the shear connection of the two aluminum alloy sheets; during the connection process, the temperature and pressure are monitored simultaneously to achieve pressure compensation and heating temperature optimization.

[0015] Based on further optimization of the above scheme, the diameter of the auxiliary lifting roller is 2 to 4 times the diameter of the conveying roller, and the lifting height of the auxiliary lifting roller is 1 to 3 times the thickness of the aluminum alloy sheet; in the initial state, the top of the auxiliary lifting roller is located 0.2 to 2 mm below the top of the conveying roller.

[0016] Based on the further optimization of the above scheme, step three involves monitoring temperature and pressure to achieve pressure compensation and heating temperature optimization, specifically as follows:

[0017] First, using the law of conservation of energy, predict the temperature of the connector at the next moment:

[0018]

[0019] In the formula: T(t+1) This indicates the predicted temperature for the next moment. T(t) Indicates the current temperature; Q f This represents the heat generated by friction during the extrusion process. Q e This indicates the amount of heat generated by external heating.Q l This indicates the heat loss; Indicates the density of the material. A c Indicates the contact area of ​​the connector. h Indicates the thickness of the aluminum alloy sheet. c p Indicates the specific heat capacity of the material; Indicates the time step between the next moment and the current moment;

[0020] in:

[0021]

[0022] In the formula: Indicates the internal frictional properties of an object; F(t) This represents a time-dependent extrusion pressure function; This indicates the extrusion head speed as it changes over time. H c Indicates the convective heat transfer coefficient; T n This indicates the measured temperature of the aluminum alloy sheet at a given moment. T a Indicates ambient temperature; A l Indicates the heat dissipation area; Indicates the emissivity of the material; This represents the Stefan-Boltzmann constant;

[0023] Then, by combining a temperature sensor with an infrared thermal imager, the actual temperature of the connector at the next moment is obtained. T 0; if T 0 and T(t+1) If the deviation is greater than the preset deviation threshold (the deviation threshold is set according to the time step), it indicates that a temperature change has occurred during the extrusion process and is compensated by changing the extrusion pressure; otherwise, it indicates that no temperature change has occurred.

[0024] Simultaneously, the initial temperature, actual temperature, and adjustment amount of extrusion pressure (if there is a temperature change) of each extrusion process are recorded, an objective function is constructed, and the initial temperature is optimized through machine learning.

[0025] Based on further optimization of the above scheme, the method for obtaining the actual temperature of the connector at the next moment is as follows:

[0026] First, the emissivity of the aluminum alloy sheet is calibrated using a pre-defined blackbody furnace calibration (since the surface emissivity of aluminum alloy is affected by factors such as oxidation and roughness, calibration can effectively reduce errors caused by oxidation and roughness).

[0027]

[0028] In the formula: Indicates the surface radiance of the aluminum alloy; Indicates the radiance of a blackbody; T Indicates the target temperature; H p Represents Planck's constant; c Represents the speed of light; Indicates the operating wavelength of the infrared thermal imager; k Represents the Boltzmann constant;

[0029] Then, based on the brightness difference between the heated area and the background radiation, the infrared thermal imager image is segmented using the Otsu algorithm to extract the initial ROI region; and the Canny operator is used to detect the edge of the heated area, combined with morphological operations (such as dilation, erosion, etc.) to remove noise, ensuring that the ROI region accurately covers the heated area.

[0030] Next, the measured brightness of each pixel within the ROI region is obtained. And perform environmental parameter corrections, including corrections for reflected radiation and atmospheric attenuation.

[0031] Correction for reflected radiation:

[0032]

[0033] In the formula: T a The ambient temperature is displayed, and the ambient brightness is obtained by combining the ambient temperature with Planck's law. ;

[0034] Atmospheric attenuation correction:

[0035]

[0036] In the formula: Indicates distance as D The atmospheric transmittance, i.e., the distance between the infrared thermal imager and the aluminum alloy heating zone, is... D ;

[0037] The corrected radiance is used to obtain the corresponding temperature value detected by the infrared thermal imager. T X :

[0038]

[0039] Because the infrared thermal imager detects the heating areas on the front and rear edges of the aluminum alloy sheet, while the heating area in the middle is blocked by the upper and lower shear heads, the infrared imaging temperature measurement will have a large deviation. Therefore, by coordinating the temperature sensors evenly distributed on the upper shear head with the infrared thermal imager's detection results, accurate temperature feedback can be achieved. Specifically:

[0040] The corresponding detection temperature is obtained in real time using temperature sensors on the front and rear sides of the upper shear head. T c-b And detect the temperature using a temperature sensor. T c-b Temperature detected by infrared thermal imager at the corresponding time T X Obtain the temperature of each temperature sensor point in the middle of the upper shear head. T c-ni ( i = 1,2,…,n-2 The corresponding actual temperature value T x-i ,in, n Indicates the number of temperature sensors on the upper shear head:

[0041]

[0042] Finally, the actual temperature values ​​at each point were fitted. T x-i and T X This refers to the actual temperature of the heating zone of the aluminum alloy sheet at the current moment. T 0.

[0043] Based on further optimization of the above scheme, the method of compensating for temperature abrupt changes by extrusion pressure is specifically as follows:

[0044] First, establish a temperature-compression pressure coupling model:

[0045]

[0046] In the formula: F Indicates compressive force. This indicates the flow stress of the aluminum alloy. f Indicates the friction factor; a , b m is a material constant (obtained from experimental data, n is usually 0.5 to 2), Q represents the deformation activation energy, and R represents the gas constant. Indicates strain rate (determined by extrusion rate). Represents the inverse hyperbolic sine function; L , d These represent the length and width of the connector area, respectively.

[0047] Based on the current real-time temperature T 0. The target value of extrusion pressure is obtained through a temperature-extrusion pressure coupling model. F m ;

[0048] Then, based on the temperature deviation Dynamic compensation of extrusion pressure is achieved using a PID controller:

[0049]

[0050]

[0051] In the formula: K p , K i , K d These represent the proportional coefficient, integral coefficient, and derivative coefficient of the PID controller, respectively.

[0052] Based on further optimization of the above scheme, the objective function is specifically as follows:

[0053]

[0054] In the formula: , These represent the weighting coefficients, which are set according to the actual situation. This represents the amount of pressure adjustment for the i-th time; T ci Indicates the first i The initial extrusion temperature recorded for this time; T best Indicates the historical best temperature;

[0055] By constructing intelligent models (such as random forests or deep neural network models), the optimal initial temperature is predicted. Input features include ambient temperature, plate thickness, and historical process parameters.

[0056] The following are the technical effects of the present invention:

[0057] This invention involves heating and extruding thin aluminum alloy sheets. Through a combination of heating, extrusion, shearing, and friction, the aluminum alloy sheets undergo plastic deformation, resulting in a tight bond between the two metals via metallic bonds. By incorporating double-arc shear grooves on both the upper and lower shear heads, this invention not only provides a buffer space for the plastically deformed aluminum alloy sheet connector, preventing abrupt stress concentration points after connection and thus reducing the joint's mechanical properties, but also ensures surface smoothness during extrusion. This prevents burrs and flash caused by warping of the sheet edges due to pressure, which can easily scratch the production line. Furthermore, the double-arc shear groove design enhances the rearrangement of metal atoms and grain refinement during extrusion, thereby improving the connector's strength and mechanical properties.

[0058] Meanwhile, this invention, through real-time monitoring and prediction by the sensing system and the establishment of a temperature-extrusion pressure coupling model, effectively prevents sudden temperature changes caused by external environmental influences through extrusion pressure compensation. This prevents problems such as rapid hardening of alloy materials, reduced plastic flow capacity, hot cracking caused by extrusion stress, and coarse grains in the alloy due to the molten state. It ensures the plastic deformation capacity and recrystallization capacity of the aluminum alloy sheet connection area in a short time, thus ensuring the quality and mechanical properties of the connector. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the structure of the aluminum alloy sheet quick connection system in an embodiment of the present invention.

[0060] Figure 2 for Figure 1 A magnified view of part A in the image.

[0061] Figure 3 for Figure 1 BB-direction sectional view.

[0062] Figure 4 This is a tensile curve diagram of the aluminum alloy sheet connection system of the present invention.

[0063] Figure 5 This is a microstructure diagram of the connection position after aluminum alloy thin plates are connected using the connection system of the present invention.

[0064] Among them, 10 is an aluminum alloy sheet; 11 is a conveying roller; 20 is a shearing groove; 21 is an upper shearing head; 22 is a lower shearing head; 31 is an auxiliary lifting roller; 411 is an infrared receiver; 412 is an infrared emitter; 42 is a temperature sensor; 43 is a pressure sensor; 51 is a heating device; and 52 is an infrared thermal imager. Detailed Implementation

[0065] The technical solutions in the embodiments of the present invention will be clearly and completely described below. In the following description, specific details such as specific system structures and technologies are presented for illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention.

[0066] Example 1:

[0067] A rapid connection system for aluminum alloy thin sheets includes a conveying assembly, a shearing assembly, an auxiliary lifting assembly, a sensing system, and a heating device 51. The conveying assembly consists of two sets of conveying mechanisms, with a shearing assembly (such as...) positioned between the two sets of conveying mechanisms. Figure 1 As shown), both sets of conveying mechanisms consist of multiple conveying rollers 11, and the upper tangent surfaces of the multiple conveying rollers 11 are located on the same horizontal plane (e.g., Figure 1 As shown, two conveyor rollers 11 are respectively arranged on the left and right sides of the shearing assembly. The number of conveyor rollers 11 on each side is set according to the actual length of the aluminum alloy sheet 10. The two conveyor rollers 11 in this embodiment are only for example and are not intended to limit the solution of the present invention. The shearing assembly includes an upper shearing head 21 and a lower shearing head 22, and shearing grooves 20 are respectively formed in the middle of the bottom surface of the upper shearing head 21 and the middle of the top surface of the lower shearing head 22 (e.g., Figure 1 As shown), the shearing groove 20 of the upper shear head 21 and the shearing groove 20 of the lower shear head 22 are mirror symmetrical (i.e., the upper shear head 21 rotates 180° around its center and is completely consistent with the lower shear head 22, as shown). Figure 1 (As shown); the shear groove 20 consists of two arc segments, including a small arc segment and a large arc segment (as shown). Figure 2 As shown), the small arc segment and the large arc segment are smoothly connected, and the shearing groove 20 of the upper shear head 21 is conveyed by the conveying assembly in the direction (i.e., Figure 1 (As shown from left to right) are small arc segments and large arc segments respectively (the shearing groove 20 of the lower shear head 22 is conveyed by the conveying assembly, i.e.) Figure 1 The diagram shows the large and small arc segments from left to right. The radius of the small arc segment is three times the thickness of the aluminum alloy sheet (e.g., ...). Figure 2 As shown, in this embodiment, assuming the thickness of the aluminum alloy sheet 10 is h, then the radius of segment bq is 3h, and the radius of the large arc segment is 6 times the thickness of the aluminum alloy sheet 10 (i.e., the radius of segment cq is 6h). The length of the shear groove 20 is no greater than 5 times the thickness of the aluminum alloy sheet 10 (i.e., the length of segment bc ≤ 5h); the lengths of the flat segments on both sides of the shear groove 20 are consistent (i.e., ab = cd, ef = gh) and greater than 5 times the thickness of the aluminum alloy sheet 10 (i.e., ab > 5h). Furthermore, if the thickness of the aluminum alloy sheet 10 is less than 1mm, then the lengths of the flat segments on both sides of the shear groove 20 (i.e., segments ab, ca, ef, and gh) are greater than 5mm.

[0068] The auxiliary lifting component is set in a set of conveyor mechanisms (i.e. Figure 1 The outer side of the two conveying rollers 11 of the set of conveying mechanisms on the left side includes two auxiliary lifting rollers 31 and a lifting device. The two auxiliary lifting rollers 31 are arranged in parallel and their two ends are respectively connected to the lifting device. The lifting device is used to control the synchronous lifting of the two auxiliary lifting rollers 31 (the lifting device can be a conventional hydraulic lifting device in the art, which is provided with brackets at the two ends of the auxiliary lifting rollers 31 and the two ends of the auxiliary lifting rollers 31 are respectively rotatably connected to the brackets, and the brackets are provided with motors that drive the auxiliary lifting rollers 31).

[0069] The sensing system is configured to correspond to the shearing assembly. The sensing system includes an infrared sensor, a temperature sensor 42, and a pressure sensor 43. The infrared sensor is located on the side of the shearing assembly closest to the auxiliary lifting assembly (i.e.,...). Figure 1 (As shown on the left), including an infrared emitter 412 and an infrared receiver 411, the infrared emitter 412 and the infrared receiver 411 are respectively set to correspond to the lower shear head 22 and the upper shear head 21, and the infrared emitter 412 and the infrared receiver 411 are set to correspond (e.g. Figure 1 (As shown); the temperature sensor 42 is located on the upper shear head 21 on the side of the corresponding shear groove 20 near the auxiliary lifting component (i.e. Figure 1 The bottom surface of the upper shear head 21 (as shown on the left side of the shear groove 20) and the temperature sensors 42 are evenly distributed along the width direction of the upper shear head 21 (e.g., Figure 3 As shown, the number of temperature sensors 42 is set according to the actual detection accuracy and the width of the upper shear head 21; the pressure sensor 43 (e.g., a high-temperature strain gauge sensor) is located on the lower shear head 22 on the side of the corresponding shear groove 20 away from the auxiliary lifting component (i.e., Figure 1 The pressure sensors 43 are evenly distributed along the width direction of the lower shear head 22, on the top surface corresponding to the right side of the shear groove 20 (as shown). Figure 3 As shown, the pressure sensor 43 is set according to the actual detection accuracy and the width of the lower shear head 22.

[0070] Heating device 51 is located on the front and rear sides of the shearing assembly (i.e. Figure 3 (as shown on the left and right sides) and corresponding to the overlapping parts of the stacked aluminum alloy sheets 10 (such as...) Figure 3 As shown), the heating device 51 can clamp the aluminum alloy sheet 10; at the same time, infrared thermal imagers 52 are installed on the front and rear sides of the shearing assembly and on the upper side of the heating device 51, and the line of sight of the infrared thermal imagers 52 is opposite to the overlapping position of the aluminum alloy sheet 10 (e.g., Figure 3 (As shown).

[0071] The tensile curve and microstructure after connection are obtained using the system in this embodiment, such as... Figure 4 and Figure 5 As shown. Among them, Figure 4The difference between process 1 and process 2 lies in the vertical distance between points b and g. In the actual process, points b and g are perpendicular lines, and their distance is adjusted according to the plate thickness. In this embodiment, after shearing and extrusion, the vertical distance between points b and g in process 1 is 0.8h, while in process 2 it is 1h.

[0072] Example 2:

[0073] A method for quick connection of aluminum alloy thin plates, employing the connection system described in Example 1, includes:

[0074] Step 1: Stacking of aluminum alloy sheets: Place the aluminum alloy sheets on the conveyor assembly, allowing the sheets to move along with the assembly (i.e., the aluminum alloy sheets 10 are moved by the conveyor rollers 11 as follows). Figure 1 (The direction shown is from left to right); when the tail of the current aluminum alloy sheet 10 is in the middle of the shearing groove 20 of the lower shear head, the side conveying mechanism is paused (i.e., Figure 1 The conveyor mechanism (located away from the auxiliary lifting assembly on the right) operates, i.e., it pauses the forward movement of the previous aluminum alloy sheet 10:

[0075] The operation and pause of the right-side transmission mechanism can be controlled via an infrared sensor.

[0076] When the aluminum alloy sheet 10 blocks the infrared sensor, the infrared receiver 411 cannot receive the signal from the infrared transmitter 412. As the aluminum alloy sheet 10 continues to be conveyed, its tail reaches the infrared sensor and continues to move. The signal emitted by the infrared transmitter 412 is no longer blocked by the aluminum alloy sheet 10 and is received by the infrared receiver 411. Timing starts from this moment, using the conveying speed of the conveyor roller 11. v The distance from the center of the shear groove 20 of the lower shear head 22 to the infrared sensor is used to obtain the pause time of the right-side conveyor mechanism. t 1:

[0077]

[0078] In the formula: l ef The length of segment ef. l fg The length of the shear groove segment fg;

[0079] The next aluminum alloy sheet 10 is placed in another conveying mechanism (i.e. Figure 1On the conveyor mechanism (shown on the left side, where an auxiliary lifting component is provided), the next aluminum alloy sheet 10 follows the conveyor mechanism. When the end of the next aluminum alloy sheet 10 is detected by an infrared sensor (i.e., when the next aluminum alloy sheet 10 is not present, the infrared receiver 411 continuously receives the signal from the infrared emitter 412; when the next aluminum alloy sheet 10 is present, the infrared emitter 412 is blocked, and this is used for timing), the corresponding conveyor mechanism stops, and the auxiliary lifting roller 31 is raised and rotated. The diameter of the auxiliary lifting roller 31 is 2 to 3 times the diameter of the conveyor roller 11. The lifting height of the auxiliary lifting roller 31 is 1 to 3 times the thickness of the aluminum alloy sheet 10 (the core of the auxiliary lifting roller 31 is made of steel pipe or steel rod, and the outer ring is made of flexible materials such as polyurethane and rubber to avoid scratching the aluminum sheet); in the initial state, the top of the auxiliary lifting roller 31 is located 0.2 to 2 mm below the top of the conveying roller 11; to achieve the lifting and continuous operation of the next aluminum alloy sheet 10, so that the end of the next aluminum alloy sheet 10 runs to the middle of the shearing groove 20 of the upper shear head 21, and is conveyed by the speed of the auxiliary lifting roller 31. v 2. The distance from the middle of the shear groove 20 of the upper shear head 21 to the infrared sensor is used to obtain the time at this moment. t 2:

[0080]

[0081] In the formula: l bc The length of the shear groove bc segment of the upper shear head 21;

[0082] At this time: the auxiliary lifting roller stops running, the upper shear head 21 moves down to the bottom surface and contacts the end face of the next aluminum alloy sheet 10, the upper shear head 21 stops running, and then the auxiliary lifting roller 31 descends to reset.

[0083] Step 2, Heating the aluminum alloy sheet: First, drive the front and rear heating devices 51 to operate (i.e., Figure 3 The heating devices 51 on both sides move towards each other to form a clamp on the stacked aluminum alloy sheet 10; then, the heating devices 51 are activated to heat the aluminum alloy sheet 10 (the heating time is about 1 minute and the target temperature is about 400℃); after the heating is completed, the front and rear heating devices 51 release the clamp on the aluminum alloy sheet 10.

[0084] Step 3, Extrusion Connection: Simultaneously activate the upper shear head 21 and the lower shear head 22 (via a hydraulic mechanism) to move them towards each other, achieving the shear connection of the two aluminum alloy sheets 10; during the connection process, monitor the temperature and pressure simultaneously to achieve pressure compensation and heating temperature optimization.

[0085] Specifically:

[0086] Step 3-1: Predict the temperature of the connector at the next moment using the law of conservation of energy.

[0087]

[0088] In the formula: T(t+1) This indicates the predicted temperature for the next moment. T(t) Indicates the current temperature; Q f This represents the heat generated by friction during the extrusion process. Q e This indicates the amount of heat generated by external heating. Q l This indicates the heat loss; Indicates the density of the material. A c Indicates the contact area of ​​the connector. h Indicates the thickness of the aluminum alloy sheet. c p Indicates the specific heat capacity of the material; Indicates the time step between the next moment and the current moment;

[0089] in:

[0090]

[0091] In the formula: Indicates the internal frictional properties of an object; F(t) This represents a time-dependent extrusion pressure function; This indicates the extrusion head speed as it changes over time. H c Indicates the convective heat transfer coefficient; T n This indicates the measured temperature of the aluminum alloy sheet at a given moment. T a Indicates ambient temperature; A l Indicates the heat dissipation area; Indicates the emissivity of the material; This represents the Stefan-Boltzmann constant;

[0092] Step 3-2: By combining a temperature sensor with an infrared thermal imager, obtain the actual temperature of the connector at the next moment. T 0, specifically:

[0093] The emissivity of the aluminum alloy sheet is calibrated using a pre-defined blackbody furnace calibration (since the surface emissivity of aluminum alloy is affected by factors such as oxidation and roughness, calibration can effectively reduce errors caused by oxidation and roughness).

[0094]

[0095] In the formula: Indicates the surface radiance of the aluminum alloy; Indicates the radiance of a blackbody; T Indicates the target temperature; H p Represents Planck's constant; c Represents the speed of light; Indicates the operating wavelength of the infrared thermal imager; k Represents the Boltzmann constant;

[0096] Based on the brightness difference between the heated area and the background radiation, the infrared thermal image is segmented using the Otsu algorithm (any conventional Otsu algorithm in this field can be used, and no further limitations are imposed in this embodiment), and the initial ROI region is extracted; the Canny operator is used to detect the edge of the heated area, and morphological operations (such as dilation, erosion, etc.) are combined to remove noise, ensuring that the ROI region accurately covers the heated area.

[0097] Obtain the measured brightness of each pixel within the ROI region. And perform environmental parameter corrections, including corrections for reflected radiation and atmospheric attenuation.

[0098] Correction for reflected radiation:

[0099]

[0100] In the formula: T a The ambient temperature is displayed, and the ambient brightness is obtained by combining the ambient temperature with Planck's law. ;

[0101] Atmospheric attenuation correction:

[0102]

[0103] In the formula: Indicates distance as D The atmospheric transmittance, i.e., the distance between the infrared thermal imager and the aluminum alloy heating zone, is... D ;

[0104] The corrected radiance is used to obtain the corresponding temperature value detected by the infrared thermal imager. T X :

[0105]

[0106] Because the infrared thermal imager detects the heating areas on the front and rear edges of the aluminum alloy sheet, while the heating area in the middle is blocked by the upper and lower shear heads, the infrared imaging temperature measurement will have a large deviation. Therefore, by coordinating the temperature sensors evenly distributed on the upper shear head with the infrared thermal imager's detection results, accurate temperature feedback can be achieved. Specifically:

[0107] The corresponding detection temperature is obtained in real time using temperature sensors on the front and rear sides of the upper shear head. T c-b And detect the temperature using a temperature sensor. T c-b Temperature detected by infrared thermal imager at the corresponding time T X Obtain the temperature of each temperature sensor point in the middle of the upper shear head. T c-ni ( i = 1,2,…,n-2 The corresponding actual temperature value T x-i ,in, n Indicates the number of temperature sensors on the upper shear head:

[0108]

[0109] Fit the actual temperature values ​​at each point T x-i and T X (Temperature fitting is performed by averaging or other similar linear fitting methods), which represents the actual temperature of the heating area of ​​the aluminum alloy sheet at the current moment. T 0.

[0110] Step 3-3, if T 0 and T(t+1) If the deviation exceeds a preset deviation threshold (the deviation threshold is specifically set according to the time step), it indicates that a sudden temperature change has occurred during extrusion. This is compensated for by changing the extrusion pressure. Specifically:

[0111] Establish a temperature-extrusion pressure coupling model:

[0112]

[0113] In the formula: F Indicates compressive force. This indicates the flow stress of the aluminum alloy. f Indicates the friction factor; a , b m is a material constant (obtained from experimental data, n is usually 0.5 to 2), Q represents the deformation activation energy, and R represents the gas constant. Indicates strain rate (determined by extrusion rate). Represents the inverse hyperbolic sine function; L , d These represent the length and width of the connector area, respectively.

[0114] Based on the current real-time temperature T 0. The target value of extrusion pressure is obtained through a temperature-extrusion pressure coupling model. F m ;

[0115] Based on temperature deviation Dynamic compensation of extrusion pressure is achieved using a PID controller:

[0116]

[0117]

[0118] In the formula: K p , K i , K d These represent the proportional coefficient, integral coefficient, and derivative coefficient of the PID controller, respectively.

[0119] Conversely, it indicates that no temperature change has occurred (connection can be performed according to the predetermined extrusion pressure).

[0120] Steps 3-4: Record the initial temperature, actual temperature, and pressure adjustment for each extrusion process (if there are temperature abrupt changes), and construct the objective function, specifically:

[0121]

[0122] In the formula: , These represent the weighting coefficients, which are set according to the actual situation. This represents the amount of pressure adjustment for the i-th time; T ci Indicates the first i The initial extrusion temperature recorded for this time; T best Indicates the historical best temperature; Minimize Indicates the goal of minimization;

[0123] Initial temperature optimization is achieved through machine learning, which involves building intelligent models (such as random forests or deep neural network models) to predict the optimal initial temperature. Input features include ambient temperature, sheet thickness, and historical process parameters.

Claims

1. A rapid attachment system for aluminum alloy sheet, characterized by: The application relates to an aluminum alloy sheet cutting device, which comprises a conveying assembly, a shearing assembly, an auxiliary lifting assembly, a sensing system and a heating device. The shearing assembly comprises an upper shearing head and a lower shearing head, and a shearing groove is arranged in the middle of the bottom surface of the upper shearing head and the top surface of the lower shearing head; the shearing groove of the upper shearing head is mirror-symmetric to the shearing groove of the lower shearing head.

2. An aluminum alloy sheet rapid joining system according to claim 1, characterized by: The shearing groove is composed of two circular arc segments, including a small circular arc segment and a large circular arc segment; the small circular arc segment and the large circular arc segment are smoothly connected, and the shearing groove of the upper shearing head is sequentially provided with the small circular arc segment and the large circular arc segment from the conveying direction of the conveying assembly; the radius of the small circular arc segment is 3 times the thickness of the aluminum alloy sheet; the radius of the large circular arc segment is 6 times the thickness of the aluminum alloy sheet; the length of the shearing groove is not greater than 5 times the thickness of the aluminum alloy sheet; the lengths of the flat segments on the two sides of the shearing groove are consistent and greater than 5 times the thickness of the aluminum alloy sheet; the sensing system comprises an infrared sensor, a temperature sensor and a pressure sensor; the infrared sensor is arranged on the side of the shearing assembly close to the auxiliary lifting assembly, and comprises an infrared emitter and an infrared receiver; the infrared emitter and the infrared receiver are arranged on the lower shearing head and the upper shearing head respectively; the temperature sensor is arranged on the bottom surface of the upper shearing head on the side close to the auxiliary lifting assembly and is uniformly distributed along the width direction of the upper shearing head; and the pressure sensor is arranged on the top surface of the lower shearing head on the side away from the auxiliary lifting assembly and is uniformly distributed along the width direction of the lower shearing head.

3. A method of connecting using the aluminum alloy sheet rapid connection system according to claim 2, characterized by: The heating device is arranged on the front side and the rear side of the shearing assembly and corresponds to the overlapping position of the aluminum alloy sheets; the heating device can clamp the aluminum alloy sheets; meanwhile, an infrared thermal imager is arranged on the upper side of the heating device on the front side and the rear side of the shearing assembly; the line-of-sight direction of the infrared thermal imager is opposite to the overlapping position of the aluminum alloy sheets. The application relates to an aluminum alloy sheet cutting device, which comprises a conveying assembly, a shearing assembly, an auxiliary lifting assembly, a sensing system and a heating device. Step one, aluminum alloy sheet stacking: place the aluminum alloy sheet on the conveying assembly, and make the aluminum alloy sheet follow the conveying assembly; when the tail of the previous aluminum alloy sheet is located in the middle of the shearing groove of the lower shearing head, stop the operation of one side of the conveying mechanism, and place the next aluminum alloy sheet on the other conveying mechanism; when the end of the next aluminum alloy sheet is sensed by the infrared sensor, the corresponding conveying mechanism stops, the auxiliary lifting roller lifts and rotates to realize the lifting and continuous operation of the next aluminum alloy sheet, and the end of the next aluminum alloy sheet runs to the middle of the shearing groove of the upper shearing head; at this time: the auxiliary lifting roller stops running, the upper shearing head moves down to the bottom surface and contacts the end surface of the next aluminum alloy sheet, and the upper shearing head stops running, and then the auxiliary lifting roller descends and resets; Step two, aluminum alloy sheet heating: first, drive the front and rear heating devices to run to form clamping of the stacked aluminum alloy sheet; then, start the heating device to heat the aluminum alloy sheet; after heating, the front and rear heating devices release the clamping of the aluminum alloy sheet; Step three, extrusion connection: simultaneously start the upper and lower shearing heads to move towards each other to realize the shearing connection of the two aluminum alloy sheets; during the connection process, the temperature and pressure are monitored synchronously to realize pressure compensation and heating temperature optimization.

4. The method of claim 3, wherein: The diameter of the auxiliary lifting roller is 2-4 times the diameter of the conveying roller, and the lifting height of the auxiliary lifting roller is 1-3 times the thickness of the aluminum alloy sheet; in the initial state, the top end of the auxiliary lifting roller is located 0.2-2mm below the top end of the conveying roller.

5. The method of claim 3, wherein: In step three, the temperature and pressure are monitored to realize pressure compensation and heating temperature optimization, which is specifically: First, predict the temperature of the next connection head through the law of conservation of energy: wherein: T(t+1) represents the predicted temperature at the next time instant, T(t) represents the temperature at the current time instant; Q f represents the heat generated by friction during extrusion, Q e represents the heat added externally, Q l represents the heat lost; represents the material density, A c represents the contact area of the joint, h represents the thickness of the aluminum alloy sheet, c p represents the specific heat capacity of the material; represents the time step between the next time instant and the current time instant; Where: wherein: represents the internal frictional properties of the object; F(t) represents a time-dependent extrusion force function; represents the running speed of the extrusion head as a function of time; H c represents the convective heat transfer coefficient; T n represents the measured temperature at a time instant on the aluminum alloy sheet, T a represents the ambient temperature; A l represents the heat dissipation area; represents the emissivity of the material; represents the Stefan-Boltzmann constant; After that, through the cooperation of temperature sensor and infrared thermal imager, the actual temperature of the connector at the next moment is obtained T 0; if T 0 and T(t+1) The deviation between the preset deviation threshold value indicates that the temperature mutation occurs during the extrusion process, and the extrusion force is changed to compensate; otherwise, it indicates that no temperature mutation occurs. At the same time, record the initial temperature, actual temperature and control amount of extrusion pressure of each extrusion process to construct a target function and realize optimization of the initial temperature through machine learning.

6. The method of claim 5, wherein: The actual temperature of the next connection head is obtained by: First, calibrate the material emissivity of the aluminum alloy sheet through pre-blackbody furnace calibration: wherein: represents the radiant luminance of the aluminum alloy surface; represents the blackbody radiant luminance; T represents the target temperature; H p represents the Planck constant; c represents the speed of light; represents the working wavelength of the infrared thermal imager; k represents the Boltzmann constant; Then, according to the brightness difference between the heating area and the background radiation, the infrared thermal imager image is segmented by Otsu algorithm to extract the initial ROI region; and the Canny operator is used to detect the edge of the heating area, and the morphological operation is used to remove noise to ensure that the ROI region accurately covers the heating area; Then, the measured brightness of each pixel in the ROI region is acquired and the environmental parameters are corrected, including the reflected radiation correction and the atmospheric attenuation correction, Reflective radiation correction: In the formula: T a represents the ambient temperature, the ambient brightness is obtained by combining the ambient temperature with Planck's law ; Atmospheric attenuation correction: wherein: represents the atmospheric transmissivity of the distance D , i.e. the distance between the infrared thermal imager and the aluminum alloy heating zone is D ; Using the corrected radiance, the temperature value corresponding to the infrared thermal imager detection is obtained T X : Through the uniform arrangement of temperature sensors on the upper shearing head and the detection results of the infrared thermal imager, accurate temperature feedback is realized, which is specifically: Real-time acquisition of corresponding detection temperature by temperature sensors on front and back sides of upper shear head T c-b And detecting temperature by temperature sensor T c-b And detecting temperature by temperature sensor T X Acquisition of temperature of each temperature sensor point in the middle of upper shear head T c-ni i = 1,2,…,n-2 Corresponding actual temperature value T x-i Wherein, n Indicates the number of temperature sensors on upper shear head:​​ Finally, the actual temperature values of each point are fitted T x-i With T X That is, the actual temperature of the aluminum alloy sheet heating area at the current time T 0.

Images