A device and method for real-time detection of tool fracture in friction stir welding

Abstract

The application discloses a kind of stir friction welding tool fracture real-time detection device and method, the working of welding structure is controlled by central control component, and real-time record welding structure working data, according to the real-time data of central control component, welding structure working data is analyzed, handled, and according to the working data comparison of two time points in sampling period, it is determined whether stir friction welding tool is fractured and fails, and this kind of real-time monitoring and determination mechanism can significantly improve the security and stability of welding process.

Description

Technical Field

[0001] This invention relates to the field of friction stir welding technology, and specifically to a real-time detection device and method for friction stir welding tool fracture. Background Technology

[0002] Friction stir welding (FSW) is a new solid-state welding method invented by the Welding Institute (TWI) in the UK in 1991. During the welding process, a friction stir welding tool is inserted into the materials to be welded. The rotating FSW tool heats the materials to a plasticized state, and under the stirring action of the tool, a dense joint structure is formed, thus achieving the weld. Figure 1 As shown. Friction stir welding involves materials that have not reached their melting point, making it a solid-state welding process. It has advantages such as being environmentally friendly, requiring no filler material, and exhibiting minimal post-weld deformation, making it suitable for welding lightweight alloys, especially aluminum alloys.

[0003] Static shoulder friction stir welding is a new welding technology developed based on conventional friction stir welding. During welding, the shoulder and stirring pin of the friction stir welding tool are separate structures. The shoulder does not rotate with the stirring pin, but only slides on the surface of the sample being welded. Since the static shoulder does not participate in the heat generation of rotational friction, the surface of the sample after welding is smooth and there is no burr in the weld of conventional friction stir welding, saving the subsequent burr removal process. In addition, the static shoulder does not participate in the heat generation during the welding process, only the stirring pin generates heat, which optimizes the heat input in the thickness direction of the weld and reduces the deformation after welding.

[0004] Dual-shoulder friction stir welding (FSW) is an advanced welding technology based on the traditional FSW principle, but with a unique dual-shoulder design: upper and lower shoulders connected by a stirring pin. During welding, the lower shoulder replaces the rigid support on the weld back in conventional FSW, simplifying the welding tooling. Simultaneously, dual-shoulder FSW completely solves the problems of incomplete root penetration or weak connections found in conventional single-shoulder FSW. The symmetrical distribution of the upper and lower shoulders works together to alleviate uneven heat input in the weld thickness direction, reducing post-weld deformation.

[0005] With the large-scale promotion and application of friction stir welding in industrial manufacturing fields such as aerospace, rail trains, shipbuilding, and new energy vehicles, some problems that urgently need to be solved have also been exposed. With the continuous improvement of automation level, the demand for real-time online detection of whether friction stir welding tools break during the welding process is becoming more and more urgent. Summary of the Invention

[0006] The purpose of this invention is to provide a real-time detection device and method for fracture of friction stir welding tools.

[0007] To achieve the above objectives, the technical solution provided by the present invention is as follows: The first aspect of this application provides a real-time detection device for fracture of friction stir welding tools, including a welding structure and a central control component, wherein the central control component is used to control the operation of the welding structure and record the working data of the welding structure in real time. The welding structure includes a friction stir welding tool, a drive motor for rotating the friction stir welding tool, a spindle, and a tool holder. The output shaft of the spindle is connected to the tool holder. One end of the tool holder has a tapered structure for insertion into the center hole of the end face of the spindle output shaft. The other end of the tool holder is used to mount the friction stir welding tool. The tapered structure enables automatic centering within the tool holder, reducing damage between the friction stir welding tool and the workpiece to be welded. The input shaft of the spindle is connected to the drive motor, and the drive motor transmits torque to the tool holder through the spindle. The central control unit determines whether the friction stir welding tool has broken by comparing the rate of change of the welding structure working data at two time points before and after the sampling period; the central control unit issues an alarm signal after determining that the friction stir welding tool has broken.

[0008] The friction stir welding tools include conventional friction stir welding tools, stationary shoulder friction stir welding tools, and double shoulder friction stir welding tools.

[0009] The conventional friction stir welding tool includes a clamping part, a shoulder, and a conventional stirring pin. The clamping part is inserted into the central hole at the lower end of the tool holder and is fixed by a side set screw. The shoulder is located at the lower part of the clamping part, and its lower end face is in close contact with the upper surface of the workpiece during welding. The conventional stirring pin is an approximately conical structure used to insert into the interior of the workpiece during welding.

[0010] The described stationary shoulder friction stir welding tool includes a connecting sleeve, a stationary shoulder, and a stationary shoulder stirring pin. The connecting sleeve is an approximately trapezoidal structure, with its upper end face in close contact with the lower end face of the main shaft and fixed thereto by screws. Its lower end face is in close contact with the upper end face of the stationary shoulder and fixed thereto by screws. The stationary shoulder is a bowl-shaped structure, with its upper end face connected and fastened to the lower end face of the connecting sleeve. The central hole on its lower end face is for the stirring pin to pass through. The upper end of the stationary shoulder stirring pin is inserted into the tool holder and fastened thereto. Its lower end passes through the central hole on the lower end face of the stationary shoulder and is inserted into the sample to be welded. During welding, the lower end face of the stationary shoulder is in close contact with the upper surface of the sample to be welded.

[0011] The aforementioned dual-shoulder friction stir welding tool includes an upper shoulder, a lower shoulder, and a dual-shoulder stirring pin. The dual-shoulder stirring pin is fixedly connected between the upper shoulder and the lower shoulder. A gap is provided between the upper shoulder and the lower shoulder for the workpiece to be welded to pass through. The lower end face of the upper shoulder is in close contact with the upper surface of the material to be welded, and the upper end face of the lower shoulder is in close contact with the lower surface of the material to be welded. The dual-shoulder stirring pin can perform friction stir welding on the material to be welded under the action of the upper shoulder and the lower shoulder.

[0012] The conventional friction stir welding tool has a threaded lower end face of the shoulder, typically a double ring, involute, or Archimedean curve. This thread enhances the agitation of the material on the upper surface of the welded specimen to obtain a defect-free weld joint. The conventional stirring pin has a right-hand threaded surface to enhance the material flow inside the welded specimen, forming a defect-free joint. The clamping part, shoulder, and conventional stirring pin are an integral structure.

[0013] The lower end face of the stationary shoulder of the described stationary shoulder friction stir welding tool is a smooth plane. During welding, it only slides relative to the upper surface of the welded specimen. The surface of the stationary shoulder stirring pin is machined with a right-hand thread to enhance the material flow inside the welded specimen and form an excellent joint.

[0014] The upper shoulder of the dual-shoulder friction stir welding tool has a threaded hole at its lower end for engagement with the threaded upper part of the dual-shoulder stirring needle; the center of the upper end of the lower shoulder has a threaded hole for engagement with the threaded lower part of the dual-shoulder stirring needle, ensuring a secure connection between the stirring needle and the upper and lower shoulders, while facilitating replacement and maintenance. The dual-shoulder stirring needle has a threaded section in its center, with a right-hand thread closer to the upper shoulder and a left-hand thread closer to the lower shoulder, using the center of the thickness direction of the workpiece as the boundary. This thread is used to generate frictional heat and plasticize the workpiece during welding, driving the flow of the plasticized material to form a superior weld. This structure also increases the friction between the stirring needle and the workpiece, improving weld quality.

[0015] The conventional stirring pin, stationary shoulder stirring pin, and double shoulder stirring pin have a thread inclination angle of 15°~35°, a thread depth of 0.2~0.35mm, and a welding pin length d. 焊接针长 =d 板厚 - (0.2~0.3) mm to ensure that the conventional stirring pin, stationary shoulder stirring pin, and double shoulder stirring pin have sufficient strength and wear resistance.

[0016] The upper shoulder of the dual-shoulder friction stir welding tool is inserted into the tool holder at one end. A key is provided on the side of the upper shoulder, and a keyway is provided inside the tool holder. Torque is transmitted between the tool holder and the upper shoulder through the key, and the upper shoulder and the tool holder can move axially.

[0017] The central control unit analyzes and compares the collected data based on its criteria. If the criteria are met, it is determined that the friction stir welding tool broke at that moment. The criteria are: T n+2 <T n+1 Fx n+2 <Fx n+1 Fy n+2 <Fy n+1 Fz n+2 <Fz n+1 |T n+1 -T n+2 | / T n+1 ≥a% |Fx n+1 -Fx n+2 | / Fx n+1 ≥b% |Fy n+1 -Fy n+2 | / Fy n+1 ≥c% |Fz n+1 -Fz n+2 | / Fz n+1 ≥d% |ω n+1 -ω n+2 | / ω n+1 ≤e% |υ n+1 -υ n+2 | / υ n+1 ≤f% Where T is the torque of the drive motor, ω is the rotational speed of the friction stir welding tool, υ is the feed speed of the friction stir welding tool, a, b, c, d, e, and f are all positive numbers greater than or equal to 0, n+1 and n+2 represent the (n+1)th and (n+2)th times respectively, and n+1 and n+2 are two time points before and after one sampling period, with n+1 time point first and n+2 time point second; T n+2 T is the torque of the drive motor at time n+2. n+1 Fx represents the drive motor torque at time n+1. n+2 Fx is the force exerted by the welding material on the friction stir welding tool in the X direction at time n+2. n+1 Fy represents the force exerted by the welding material on the friction stir welding tool in the X direction at time n+1. n+2 Fy represents the Y-direction force exerted by the welding material on the friction stir welding tool at time n+2. n+1Fz represents the Y-direction force exerted by the welding material on the friction stir welding tool at time n+1. n+2 Fz is the Z-direction force exerted by the welding material on the friction stir welding tool at time n+2. n+1 Let T be the Z-direction force exerted by the welding material on the friction stir welding tool at time n+1. n+1 Let T be the torque of the drive motor at time n+1. n+2 Let ω be the torque of the drive motor at time n+2. n+1 Let ω be the rotational speed of the friction stir welding tool at time n+1. n+2 υ is the rotational speed of the friction stir welding tool at time n+2. n+1 υ is the feed rate of the friction stir welding tool at time n+1. n+2 The feed rate of the friction stir welding tool at time n+2.

[0018] The second aspect of this application provides a real-time detection method for fracture of friction stir welding tools. The method involves controlling the operation of the welding structure and recording the working data of the welding structure in real time through a central control component. Based on the real-time data collected by the central control component, the working data of the welding structure is analyzed and processed. The method then compares the working data at two different time points within the sampling period to determine whether the friction stir welding tool has fractured and failed.

[0019] The real-time detection method for fracture of friction stir welding tools includes the following steps: First, select the appropriate friction stir welding tool based on the thickness, material, and welding trajectory model of the parts to be welded, and determine the D... 上轴肩 D 下轴肩 d 针长 The process involves determining the rotational speed ω and feed speed υ of the friction stir welding tool, along with parameters a, b, c, d, e, and f in the criteria. Next, the digital model of the welding trajectory of the parts to be welded is input into the central control unit to generate the corresponding welding trajectory for precise trajectory control during the welding process. Then, the welding operation begins by moving the friction stir welding tool to the starting position of the parts to be welded and performing welding according to the preset rotational speed ω and feed speed υ. During this process, the central control unit collects the drive motor torque T in real time according to the set sampling period and frequency. n ω, the spindle rotation speed of the friction stir welding tool n Friction stir welding tool feed rate υ n The force Fx exerted on the friction stir welding tool in the X direction by the welding material. n The Y-direction force Fy applied by the welding material to the friction stir welding tool n The Z-direction force Fz applied by the welding material to the friction stir welding tool nSubsequently, the central control unit processes the collected data, including noise reduction and normalization, to improve the accuracy and reliability of the data. Based on set criteria, it performs real-time analysis of the data, comparing data changes between two consecutive time points within the sampling period to determine if the friction stir welding tool has broken. If the criteria are met, indicating a breakage, the central control unit issues an alarm and calculates the specific location of the breakage using welding trajectory data, displaying it in real-time on the interface so operators can take timely countermeasures. Regardless of whether a breakage occurs during welding, the central control unit records all key data from the welding process in the database and marks the data accordingly based on the breakage result. This data can be used for subsequent quality traceability, fault analysis, and process optimization.

[0020] Compared with the prior art, the beneficial effects of the present invention are: This invention controls the operation of the welding structure and records the welding structure's working data in real time through a central control component. Based on the real-time data collected by the central control component, the welding structure's working data is analyzed and processed. The system then compares the working data from two different time points within the sampling period to determine whether the friction stir welding tool has broken or failed. This real-time monitoring and determination mechanism can significantly improve the safety and stability of the welding process.

[0021] This invention, by setting a series of criteria (such as the rate of change of torque, rotational speed, and feed rate), can accurately determine the breakage of the stirring tool and issue an alarm in a timely manner. These criteria are based on data changes during the actual welding process, ensuring high reliability and accuracy. Attached Figure Description Figure 1 A schematic diagram of the friction stir welding process and the forces acting upon it.

[0022] Figure 2 This is a schematic diagram of a conventional welding tool detection device in this embodiment.

[0023] Figure 3 This is a schematic diagram of the device for detecting the static shoulder welding tool in this embodiment.

[0024] Figure 4 This is a schematic diagram of the detection device for the dual-shoulder welding tool in this embodiment.

[0025] Explanation of reference numerals in the attached drawings: 111 Conventional welding tool; 1111 Conventional welding tool stirring pin; 112 Stationary shoulder friction stir welding tool; 1122 Stationary shoulder; 1123 Stationary shoulder friction stir welding tool stirring pin; 113 Double shoulder welding tool; 1131 Upper shoulder; 1132 Lower shoulder; 1133 Double shoulder welding tool stirring pin; 120 Drive motor; 130 Spindle; 140 Tool holder; 200 Central control component. Detailed Implementation

[0026] The present invention will be further described in detail below through embodiments, but it should not be construed as limiting the scope of the subject matter of the present invention to the following embodiments. All technologies implemented based on the above content of the present invention fall within the scope of the present invention.

[0027] This application provides a real-time detection device for fracture of friction stir welding tool, including a welding structure and a central control component. The central control component is used to control the operation of the welding structure and record the working data of the welding structure in real time. The welding structure includes a friction stir welding tool, a drive motor for rotating the friction stir welding tool, a spindle, and a tool holder. The output shaft of the spindle is used to connect with the tool holder. One end of the tool holder has a tapered structure for insertion into the center hole of the end face of the spindle output shaft. The other end of the tool holder is used to mount the friction stir welding tool. The tapered structure enables automatic centering within the tool holder, reducing damage between the friction stir welding tool and the workpiece to be welded. The input shaft of the spindle is used to connect with the drive motor, which transmits torque to the tool holder through the spindle. The central control unit determines whether the friction stir welding tool has broken by comparing the rate of change of the welding structure working data at two different time points within the sampling period; the central control unit issues an alarm signal after detecting that the friction stir welding tool has broken.

[0028] This application also provides a real-time detection method for fracture of friction stir welding tools. The method controls the operation of the welding structure and records the working data of the welding structure in real time through a central control component. Based on the real-time data collected by the central control component, the working data of the welding structure is analyzed and processed. The method then compares the working data at two different time points within the sampling period to determine whether the friction stir welding tool has fractured and failed.

[0029] This application also provides a method for determining central control components. Friction stir welding (FSW) is a process involving force-thermal coupling. An external actuator (drive motor) applies torque to the FSW tool, causing it to rotate and feed at a set speed. The FSW tool overcomes the reaction forces (Z-axis, X-axis, and Y-axis resistance) exerted by the workpiece, driving it to move along the X, Y, and Z axes, thus forming a weld. During welding, the FSW tool is the only component in contact with and interacting with the workpiece. It is subjected to forces from the workpiece in the X, Y, and Z directions (Fx, Fy, and Fz), respectively. Simultaneously, to execute the program according to the set rotation and feed speeds, the FSW tool also experiences a torque T transmitted from the external motor, thus overcoming the forces of Fx, Fy, and Fz to achieve equilibrium.

[0030] The magnitudes of the forces Fx, Fy, and Fz exerted on the friction stir welding tool are closely related to the material being welded, the weld thickness, and the welding process parameters. When the welding material and thickness remain constant, changes in the welding parameters will also affect the magnitudes of these forces. For example, when the rotational speed increases, the welding temperature rises, the material softens, and Fx, Fy, and Fz decrease. Conversely, when the feed rate increases, the heat input per unit length decreases, the welding temperature decreases accordingly, and the material hardens, thus increasing Fx, Fy, and Fz.

[0031] When a friction stir welding tool breaks, the volume of its driving material decreases significantly, which reduces the forces of Fx, Fy, and Fz. In order to maintain the set rotational and feed speeds, the externally input torque will also decrease, thus achieving a new equilibrium.

[0032] In this article, the fracture of the friction stir welding tool refers to the detachment of the stirring pin from the shoulder. Generally, during normal welding, the material driven by the stirring pin accounts for 70-80% of the material driven by the friction stir welding tool. If the stirring pin detaches from the shoulder, the volume of the material driven by the friction stir welding tool will decrease by 70-80%, and the forces Fx, Fy, and Fz will undergo a sudden change in value.

[0033] This mutation value can be used to determine whether the stirring pin has broken or detached from the shoulder during the welding process.

[0034] For static shoulder friction stir welding, the volume of material driven by the stirring pin accounts for 95% or more of the total volume of material driven by the friction stir welding tool. If the stirring pin detaches from the shoulder, the volume of material driven by the friction stir welding tool will decrease by 95% or more, and the forces of Fx, Fy and Fz will undergo a sudden change in value.

[0035] During the double-shoulder friction stir welding process, the Z-direction force is zero due to the cancellation of the upper and lower shoulders. In the normal welding process, the material driven by the stirring pin accounts for 60-70% of the material driven by the friction stir welding tool. If the stirring pin detaches from the shoulder, the volume of the material driven by the friction stir welding tool will decrease by 60-70%, and the Fx and Fy forces will undergo a sudden change in value.

[0036] In some embodiments, a conventional friction stir welding tool includes a clamping part, a shoulder, and a conventional stirring pin; the clamping part is inserted into the central hole at the lower end of the tool holder and is fixedly clamped by a side set screw; the shoulder is located at the lower part of the clamping part, and its lower end face is in close contact with the upper surface of the workpiece during welding; the conventional stirring pin is a conical structure used to insert into the interior of the workpiece during welding.

[0037] In some embodiments, the stationary shoulder friction stir welding tool includes a connecting sleeve, a stationary shoulder, and a stationary shoulder stirring pin. The connecting sleeve is a trapezoidal structure, with its upper end face in close contact with the lower end face of the spindle and fixed thereto by screws. Its lower end face is in close contact with the upper end face of the stationary shoulder and fixed thereto by screws. The stationary shoulder is a bowl-shaped structure, with its upper end face connected and fastened to the lower end face of the connecting sleeve. The central hole on its lower end face is for the stirring pin to pass through. The upper end of the stationary shoulder stirring pin is inserted into the tool holder and fastened thereto. Its lower end passes through the central hole on the lower end face of the stationary shoulder and is inserted into the sample to be welded. During welding, the lower end face of the stationary shoulder is in close contact with the upper surface of the sample to be welded.

[0038] In some embodiments, the dual-shoulder friction stir welding tool includes an upper shoulder, a lower shoulder, and a dual-shoulder stirring pin; the dual-shoulder stirring pin is fixedly connected between the upper shoulder and the lower shoulder, and a gap is provided between the upper shoulder and the lower shoulder for the workpiece to be welded to pass through. The lower end face of the upper shoulder is in close contact with the upper surface of the material to be welded, and the upper end face of the lower shoulder is in close contact with the lower surface of the material to be welded. The dual-shoulder stirring pin can perform friction stir welding on the material to be welded under the action of the upper shoulder and the lower shoulder.

[0039] In some embodiments, the lower end face of the shoulder of a conventional friction stir welding tool is machined with threads, typically double rings, involutes, or Archimedes' curves. The threads are used to enhance the agitation of the material on the upper surface of the welded specimen to obtain a defect-free weld joint. The surface of the conventional stirring pin is machined with right-hand threads to enhance the material flow inside the welded specimen and form a defect-free joint. The clamping part, the shoulder, and the conventional stirring pin are integral structures.

[0040] In some embodiments, the lower end face of the stationary shoulder of the stationary shoulder friction stir welding tool is a smooth plane, and during welding, it only slides relative to the upper surface of the specimen being welded. The surface of the stationary shoulder stirring pin is machined with a right-hand thread to enhance the material flow inside the specimen being welded and form an excellent joint.

[0041] In some embodiments, the lower end of the upper shoulder of the dual-shoulder friction stir welding tool is threaded to mate with the thread on the upper part of the dual-shoulder stirring pin; the center of the upper end of the lower shoulder is threaded to mate with the thread on the lower part of the dual-shoulder stirring pin, so that the stirring pin can be firmly connected between the upper and lower shoulders, while facilitating replacement and maintenance; the middle of the dual-shoulder stirring pin is threaded, with the center of the workpiece in the thickness direction as the boundary, the thread closer to the upper shoulder is right-handed and the thread closer to the lower shoulder is left-handed. The threads are used to generate frictional heat and plasticize the workpiece during welding, and to drive the flow of the plasticized material, thereby forming an excellent weld. This structure can also increase the friction between the stirring pin and the workpiece, improving the welding quality.

[0042] In some preferred embodiments, the thread inclination angle of conventional stirring pins, stationary shoulder stirring pins, and double shoulder stirring pins is 15°~35°, the thread depth is 0.2~0.35mm, and the welding pin length d is... 焊接针长 =d 板厚 - (0.2~0.3) mm to ensure that the conventional stirring pin, stationary shoulder stirring pin, and double shoulder stirring pin have sufficient strength and wear resistance.

[0043] The upper shoulder of the double-shoulder friction stir welding tool is inserted into the tool holder at one end. A key is provided on the side of the upper shoulder, and a keyway is provided inside the tool holder. Torque is transmitted between the tool holder and the upper shoulder through the key, and the upper shoulder and the tool holder can move axially.

[0044] The present invention will be further described in detail below with reference to specific embodiments: Example 1 The following combination Figure 1 This application will be described in further detail below. This application discloses a real-time fracture detection device for a conventional friction stir welding tool, referring to... Figure 1 .

[0045] The implementation steps are as follows: S1: Select the appropriate conventional friction stir welding tool based on the thickness, material, and welding trajectory model of the parts to be welded, and determine D. 轴肩 , d 针长The rotational speed ω, feed speed υ, and parameters a, b, c, d, e, and f in the criteria are determined during welding. An example is a long straight weld seam on a 15-meter-long, 1000mm-wide, and 6mm-thick 5083 aluminum alloy extruded profile. The selected shoulder diameter D of the stirring tool is... 轴肩 =18mm, the length d of a standard welding tool stirring pin 1111 针长 =5.8mm, feed rate during stable welding υ=300mm / min, rotation speed ω=800rpm; criteria a=30, b=30, c=30, d=30, e=2, f=2.

[0046] S2: Input the welding trajectory digital model of the part to be welded into the central control computer to generate the corresponding welding trajectory.

[0047] S3: Input the parameters selected in step S1 into the central control unit, and input parameters a, b, c, d, e, f, etc. into the judgment software.

[0048] S4: Fix the parts to be welded and determine the start and end positions of the welding; S5: Welding begins. The conventional welding tool 111 enters the workpiece directly above it and welds according to the set rotation speed ω, feed speed υ, and welding direction. In this embodiment, the rotation speed ω is 800 rpm; the feed speed υ is 300 mm / min.

[0049] S6: The central control unit collects data such as motor torque Tn, spindle rotation speed ωn, and feed speed υn in real time according to the sampling period and frequency, and sends the above data to the judgment software.

[0050] S7: After receiving the data sent by the central control unit S6, the judgment software performs noise reduction and normalization on the data, and analyzes and compares the collected data according to the criteria. If the criteria are met, the software determines that the stirring tool is broken at that moment and sends the alarm information to the central control unit. The specific criteria are as follows: T n+2 <T n+1 |T n+1 -T n+2 | / T n+1 ≥a% |Fx n+1 -Fx n+2 | / Fx n+1 ≥b% |Fy n+1 -Fy n+2 | / Fy n+1 ≥c% |Fz n+1-Fz n+2 | / Fz n+1 ≥d% |ω n+1 -ω n+2 | / ω n+1 ≤e% |υ n+1 -υ n+2 | / υ n+1 ≤f% For example, T 18.24 >T 18.22 , and |T 18.24 -T 18.22 | / T 18.22 ≥30%, |Fx 18.22 -Fx 18.24 | / Fx 18.22 ≥30% |Fy 18.22 -Fy 18.24 | / Fy 18.22 ≥30%, |Fz 18.22 -Fz 18.24 | / Fz 18.22 ≥30%, |ω 18.24 -ω 18.22 | / ω 18.22 ≤2%, |υ 18.24 -υ 18.22 | / υ 18.22 ≤2%; then the judgment is made at t 18.24 If the stirring tool breaks at this moment, then if the above criteria are not met, then data collection and analysis will continue.

[0051] S8: After receiving the alarm information from the judgment software, the central control unit calculates the location of the fracture based on the welding trajectory and displays the location information on the interface to remind the operator to handle it.

[0052] S9: If the fracture result is true, then record the above parameters into the database and mark the data. If the fracture result is false, then similarly record the above parameters into the database and mark the data accordingly. As the amount of data increases, the accuracy of the criterion continues to improve.

[0053] Example 2 The following combination Figure 2 This application will be described in further detail below. This application discloses a real-time detection device for fracture of a static shoulder friction stir welding tool, referring to... Figure 2 .

[0054] The implementation steps are as follows: S1: Select the appropriate stationary shoulder friction stir welding tool 112 based on the thickness, material, and welding trajectory model of the parts to be welded, and determine the center hole diameter D of the stationary shoulder friction stir welding tool 112. 中心孔 Outer diameter D 外径 , d 针长 The rotational speed ω, feed speed υ, and parameters a, b, c, d, e, and f in the criteria are determined during welding. Taking a long straight weld of a 15-meter-long, 1000mm-wide, and 6mm-thick 5083 aluminum alloy extruded profile as an example, the selected center hole diameter D of the stationary shoulder friction stir welding tool 112 is... 中心孔 =6.5mm, outer diameter D 外径 =14.5mm, the length d of the stirring pin 1123 of the stationary shaft shoulder friction stir welding tool. 针长 =5.8mm, feed rate during stable welding υ=350mm / min, rotation speed ω=1200rpm; criteria a=15, b=15, c=15, d=15, e=2, f=2.

[0055] S2: Input the welding trajectory digital model of the part to be welded into the central control computer to generate the corresponding welding trajectory.

[0056] S3: Input the parameters selected in step S1 into the central control unit, and input parameters a, b, c, d, e, f, etc. into the judgment software.

[0057] S4: Fix the parts to be welded and determine the start and end positions of the welding; S5: Welding begins. The stationary shoulder welding tool 112 enters the part to be welded directly above it and welds according to the set rotational speed ω, feed speed υ, and welding direction. In this embodiment, the rotational speed ω is 1200 rpm; the feed speed υ is 350 mm / min.

[0058] S6: The central control unit collects data such as motor torque Tn, spindle rotation speed ωn, and feed speed υn in real time according to the sampling period and frequency, and sends the above data to the judgment software.

[0059] S7: After receiving the data sent by the central control unit S6, the judgment software performs noise reduction and normalization on the data, and analyzes and compares the collected data according to the criteria. If the criteria are met, the software determines that the stirring tool is broken at that moment and sends the alarm information to the central control unit. The specific criteria are as follows: T n+2 <T n+1 |T n+1 -T n+2 | / T n+1 ≥a% |Fx n+1 -Fx n+2 | / Fx n+1 ≥b% |Fy n+1 -Fy n+2 | / Fy n+1 ≥c% |Fz n+1 -Fz n+2 | / Fz n+1 ≥d% |ω n+1 -ω n+2 | / ω n+1 ≤e% |υ n+1 -υ n+2 | / υ n+1 ≤f% For example, T 18.24 >T 18.22 , and |T 18.24 -T 18.22 | / T 18.22 ≥15%, |Fx 18.22 -Fx 18.24 | / Fx 18.22 ≥15% |Fy 18.22 -Fy 18.24 | / Fy 18.22 ≥15%, |Fz 18.22 -Fz 18.24 | / Fz 18.22 ≥15%, |ω 18.24 -ω 18.22 | / ω 18.22 ≤2%, |υ 18.24 -υ 18.22 | / υ 18.22 ≤2%; then the judgment is made at t 18.24 If the stirring tool breaks at this moment, then if the above criteria are not met, then data collection and analysis will continue.

[0060] S8: After receiving the alarm information from the judgment software, the central control unit calculates the location of the fracture based on the welding trajectory and displays the location information on the interface to remind the operator to handle it.

[0061] S9: If the fracture result is true, then record the above parameters into the database and mark the data. If the fracture result is false, then similarly record the above parameters into the database and mark the data accordingly. As the amount of data increases, the accuracy of the criterion continues to improve.

[0062] Example 3 The following is in conjunction with the appendix Figure 3 and 4 This application will be described in further detail.

[0063] This application discloses a real-time detection device for fracture of a dual-shoulder friction stir welding tool. It includes: a welding structure for welding workpieces; and a central control unit 200 for controlling the operation of the welding structure and for recording the welding structure's operational data in real time.

[0064] Reference Figure 3 The welding structure includes a double-shoulder welding tool 113, a drive motor 120 for rotating the double-shoulder welding tool 113, and a drive component for transmitting torque from the drive motor 120 to the double-shoulder welding tool 113. The drive motor 120 has a rotational speed of 100-10000 rpm, a power of 14-50 kW, a rated speed of 1500 rpm, and a torque of 10-100 Nm. The drive motor 120 transmits torque to the double-shoulder welding tool 113 via the drive component, thereby driving the double-shoulder welding tool 113 to operate.

[0065] Reference Figure 4 The dual-shoulder welding tool 113 in this embodiment is a floating dual-shoulder welding tool, and its specific structure is as follows: the dual-shoulder welding tool 113 includes an upper shoulder 1131; a lower shoulder 1132; and a dual-shoulder welding tool stirring needle 1133.

[0066] A stirring pin 1133 of a double-shoulder welding tool is fixedly connected between an upper shoulder 1131 and a lower shoulder 1132. A gap is provided between the upper shoulder 1131 and the lower shoulder 1132 for the workpiece to be welded to pass through. The lower end face of the upper shoulder 1131 is in close contact with the upper surface of the material to be welded, and the upper end face of the lower shoulder 1132 is in close contact with the lower surface of the material to be welded. The diameter D of the upper shoulder 1131 is... 上轴肩 and the diameter D of the lower shoulder 1132 下轴肩 They can be the same or different; generally, D 上轴肩 =D 下轴肩 ≈ (2.5~3)d 板厚 ; This implementation uses long, straight extruded profiles or sheet metal parts as an example. During welding, the dual-shoulder friction stir welding tool enters from the side to begin welding and detaches from the part from the other side after welding, achieving simultaneous welding of both the upper and lower surfaces of the part. The feed rate during welding is generally 100-3000 mm / min.

[0067] The stirring pin 1133 has threads machined on its upper, middle, and lower parts. The upper thread inserts into the hole on the lower end face of the upper shoulder 1131, and the lower thread inserts into the hole on the upper end face of the lower shoulder 1132. The lower end of the upper shoulder 1131 has a thread machined in its hole to mate with the thread on the upper part of the stirring pin 1133; the upper end of the lower shoulder 1132 has a center thread machined to mate with the thread on the lower part of the stirring pin 1133. The thread in the middle of the stirring pin 1133 is used to generate frictional heat and plasticize the parts being welded during welding, and to drive the flow of the plasticized material, thereby forming a superior weld. To further improve welding quality, the thread in the middle of the stirring pin 1133 is divided by the center of the thickness direction of the parts to be welded: a right-hand thread near the upper shoulder 1131 and a left-hand thread near the lower shoulder 1132. The inclination angle of the thread of the stirring pin 1133 is 15°~35°, the thread depth is 0.2-0.35mm, and the welding pin length d is... 焊接针长 =d 板厚 - (0.2~0.3) mm. These parameters ensure that the stirring pin 1133 has sufficient strength and wear resistance. The material of the floating double-shoulder friction stir welding tool is generally H13 mold steel, high-speed steel, etc., but it can also be MP159 or tungsten rhenium alloy.

[0068] Reference Figure 3 The drive unit includes a spindle 130, whose output shaft is used to connect to a welding tool, and the input shaft of the spindle 130 is used to connect to a drive motor 120, which transmits torque to the welding tool through the spindle 130.

[0069] The drive unit also includes a tool holder 140. One end of the tool holder 140 has a tapered structure for insertion into the center hole of the output shaft end face of the spindle 130, enabling automatic centering within the tool holder 140. The other end of the tool holder 140 is used to mount a double-shoulder friction stir welding tool, with the following specific structure: a keyway is provided inside the tool holder 140. One end of the upper shoulder 1131 passes through the tool holder 140, and a key is provided on the side of the upper shoulder 1131. Torque is transmitted between the tool holder 140 and the upper shoulder 1131 via the key, and the upper shoulder 1131 and the tool holder 140 can move axially. The key connection transmits torque to the floating double-shoulder friction stir welding tool mounted on it, enabling the floating double-shoulder friction stir welding tool and the keyway to float up and down. The floating double-shoulder tool can dynamically adjust the height position of the stirring tool according to the thickness of the target part, making it suitable for welding large-size extruded profiles.

[0070] The central control unit 200 includes a data acquisition module for reading real-time data from sensors and converting it into digital signals for subsequent processing. The sensors are a high-precision torque sensor installed in the welding structure to detect the torque of the drive motor 120, a speed sensor to detect the rotational speed of the drive motor 120, and a speed sensor to test the feed speed of the welding tool. The rotational speed of the stirring tool is calculated using the transmission ratio of the drive motor 120.

[0071] The central control unit 200 also includes a data processing module for receiving and processing real-time data from the data acquisition module. This module measures the rate of change of torque, rotational speed, and feed speed at two consecutive time points (n+1 and n+2) within the sampling period. It then makes a judgment based on preset criteria; typically, the sampling period is 0.02s and the judgment time is 0.01s.

[0072] The specific criteria are as follows: T n+2 <T n+1 Fx n+2 <Fx n+1 Fy n+2 <Fy n+1 |T n+1 -T n+2 | / T n+1 ≥a% |Fx n+1 -Fx n+2 | / Fx n+1 ≥b% |Fy n+1 -Fy n+2 | / Fy n+1 ≥c% |ω n+1 -ω n+2 | / ω n+1 ≤e% |υ n+1 -υ n+2 | / υ n+1 ≤f% Where a, b, c, e, and f are thresholds set according to the actual application scenario, and a, b, c, e, and f are all positive numbers greater than or equal to 0.

[0073] The hollow component 200 also includes an alarm module. When the data processing module determines that the stirring tool is broken based on the criteria, the alarm module will be triggered, and the alarm information will be displayed on the hollow platform to remind the operator to pay attention to the information.

[0074] In this embodiment, the central control system is developed using Windows software, is compatible with Siemens control systems, Beckhoff control systems, and several self-developed software programs, and includes an HMI interface. It can be used at certain intervals. Simultaneously, it collects data such as the torque T of the spindle drive motor 120, the spindle motor rotation speed ω, the feed speed υ, and the welding time. By pre-inputting a 3D model or AutoCAD model of the welding trajectory, it automatically generates welding trajectory information, which is used by operators to quickly locate the breakage position of the tool.

[0075] This application discloses a method for real-time detection of fracture in a dual-shoulder friction stir welding tool, comprising the following steps: S1: Select the appropriate floating biaxial shoulder friction stir welding tool based on the thickness, material, and welding trajectory model of the parts to be welded, and determine D. 上轴肩 D 下轴肩 d 针长 The rotational speed ω, feed speed υ, and parameters a, b, and c in the criteria are determined during welding. Taking a long straight weld of a 15-meter-long, 1000mm-wide, and 6mm-thick 5083 aluminum alloy extruded profile as an example. The selected upper shoulder diameter D of the stirring tool is 111. 上轴肩 =16mm, lower shoulder diameter D 112 下轴肩 =16mm, length d of stirring needle 113 针长 =5.8mm, feed rate during stable welding υ=400mm / min, rotation speed ω=500rpm; criteria a=40, b=40, c=40, e=2, f=2.

[0076] S2: Input the welding trajectory digital model of the part to be welded into the central control computer to generate the corresponding welding trajectory.

[0077] S3: Input the parameters selected in step S1 into the central control unit, and input parameters a, b, c, e, f, etc. into the judgment software.

[0078] S4: Fix the parts to be welded and determine the start and end positions of the welding; S5: Welding begins. The floating dual-shoulder welding tool 113 enters the part to be welded from the side and welds according to the set rotation speed ω, feed speed υ, and welding direction. In this embodiment, the rotation speed ω is 500 rpm; the feed speed υ is 400 mm / min.

[0079] S6: The central control unit collects data such as motor torque Tn, spindle rotation speed ωn, and feed speed υn in real time according to the sampling period and frequency, and sends the above data to the judgment software.

[0080] S7: After receiving the data sent by the central control unit S6, the judgment software performs noise reduction and normalization on the data, and analyzes and compares the collected data according to the criteria. If the criteria are met, the software determines that the stirring tool is broken at that moment and sends the alarm information to the central control unit. The specific criteria are as follows: T n+2 <T n+1 Fx n+2 <Fx n+1 Fy n+2 <Fy n+1 |T n+1 -T n+2 | / T n+1 ≥a% |Fx n+1 -Fx n+2 | / Fx n+1 ≥b% |Fy n+1 -Fy n+2 | / Fy n+1 ≥c% |ω n+1 -ω n+2 | / ω n+1 ≤e% |υ n+1 -υ n+2 | / υ n+1 ≤f% For example, T 18.24 >T 18.22 , and |T 18.22 -T 18.24 | / T 18.22 ≥40%, |Fx 18.22 -Fx 18.24 | / Fx 18.22 ≥40% |Fy 18.22 -Fy 18.24 | / Fy 18.22 ≥40%, |ω 18.22 -ω 18.24 | / ω 18.22 ≤2%, |υ 18.22 -υ 18.24 | / υ 18.22 ≤2%; then the judgment is made at t 18.24 If the stirring tool breaks at this moment, then if the above criteria are not met, then data collection and analysis will continue.

[0081] S8: After receiving the alarm information from the judgment software, the central control unit calculates the location of the fracture based on the welding trajectory and displays the location information on the interface to remind the operator to handle it.

[0082] S9: If the fracture result is true, then record the above parameters into the database and mark the data. If the fracture result is false, then similarly record the above parameters into the database and mark the data accordingly. As the amount of data increases, the accuracy of the criterion continues to improve.

[0083] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent substitutions, and improvements made by those skilled in the art to the above embodiments without departing from the scope of the technical solution of the present invention, based on the technical essence of the present invention, shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for real-time detection of fracture in friction stir welding tools, characterized in that: The welding structure is controlled by a central control unit, which records the welding data in real time. Based on the real-time data collected by the central control unit, the welding data is analyzed and processed. A comparison of the data from two different time points within the sampling period is used to determine whether the friction stir welding tool has broken or failed. This process includes the following steps: First, based on the thickness, material, and welding trajectory model of the parts to be welded, the appropriate friction stir welding tool is selected, and the D... 上轴肩 D 下轴肩 d 针长 The process involves determining the rotational speed ω and feed speed υ of the friction stir welding tool, along with parameters a, b, c, d, e, and f in the criteria. Next, the digital model of the welding trajectory of the parts to be welded is input into the central control unit to generate the corresponding welding trajectory for trajectory control during welding. Then, the welding operation begins, moving the friction stir welding tool to the starting position of the parts to be welded and welding υ according to the preset rotational speed ω and feed speed υ. During this process, the central control unit collects the drive motor torque T in real time according to the set sampling period and frequency. n ω, the spindle rotation speed of the friction stir welding tool n Friction stir welding tool feed rate υ n The force Fx exerted on the friction stir welding tool in the X direction by the welding material. n The Y-direction force Fy applied by the welding material to the friction stir welding tool n The Z-direction force Fz applied by the welding material to the friction stir welding tool n Subsequently, the central control unit performs noise reduction and normalization operations on the collected data, and analyzes the data in real time according to the set criteria. By comparing the data changes at two time points before and after the sampling period, it determines whether the friction stir welding tool has broken. The criteria include: T n+2 <T n+1 Fx n+2 <Fx n+1 My n+2 <Fy n+1 Fz n+2 <Fz n+1 |T n+1 -T n+2 | / T n+1 ≥a% |Fx n+1 -Fx n+2 | / Fx n+1 ≥b% |My n+1 -My n+2 | / My n+1 ≥c% |Fz n+1 -Fz n+2 | / Fz n+1 ≥d% |oh n+1 -oh n+2 | / h n+1 ≤e% |u n+1 -u n+2 | / u n+1 ≤f%; in: T represents the torque of the drive motor, ω represents the rotational speed of the friction stir welding tool, υ represents the feed speed of the friction stir welding tool, a, b, c, d, e, and f are all positive numbers greater than or equal to 0, n+1 and n+2 represent the (n+1)th and (n+2)th times respectively, which are two consecutive time points within a sampling period, with n+1 occurring first and n+2 occurring later; T n+2 T is the torque of the drive motor at time n+2. n+1 Fx represents the drive motor torque at time n+1. n+2 Fx is the force exerted by the welding material on the friction stir welding tool in the X direction at time n+2. n+1 Fy represents the force exerted by the welding material on the friction stir welding tool in the X direction at time n+1. n+2 Fy represents the Y-direction force exerted by the welding material on the friction stir welding tool at time n+2. n+1 Fz represents the Y-direction force exerted by the welding material on the friction stir welding tool at time n+1. n+2 Fz is the Z-direction force exerted by the welding material on the friction stir welding tool at time n+2. n+1 Let T be the Z-direction force exerted by the welding material on the friction stir welding tool at time n+1. n+1 Let T be the torque of the drive motor at time n+1. n+2 Let ω be the torque of the drive motor at time n+2. n+1 Let ω be the rotational speed of the friction stir welding tool at time n+1. n+2 υ is the rotational speed of the friction stir welding tool at time n+2. n+1 υ is the feed rate of the friction stir welding tool at time n+1. n+2 The feed rate of the friction stir welding tool at time n+2; If the criteria are met, i.e., the friction stir welding tool is determined to have broken, the central control unit will issue an alarm message and calculate the specific location of the breakage based on the welding trajectory data, and display it on the interface in real time so that the operator can take timely countermeasures. Regardless of whether a breakage occurs during the welding process, the central control unit will record all key data of this welding process into the database and mark the data accordingly based on the breakage result.

2. The real-time detection method for fracture of friction stir welding tools according to claim 1, characterized in that: The real-time detection device for fracture of friction stir welding tools includes a welding structure and a central control component. The central control component is used to control the operation of the welding structure and record the working data of the welding structure in real time. The welding structure includes a friction stir welding tool, a drive motor for driving the friction stir welding tool to rotate, a spindle, and a tool holder. The output shaft of the spindle is used to connect with the tool holder. One end of the tool holder has a tapered structure for inserting into the center hole of the end face of the output shaft of the spindle, and the other end of the tool holder is used to mount the friction stir welding tool. The input shaft of the spindle is used to connect with the drive motor, and the drive motor transmits torque to the tool holder through the spindle. The central control unit determines whether the friction stir welding tool has broken by comparing the rate of change of the welding structure working data at two time points before and after the sampling period; the central control unit issues an alarm signal after determining that the friction stir welding tool has broken.

3. The real-time detection method for fracture of friction stir welding tools according to claim 2, characterized in that: The friction stir welding tools include conventional friction stir welding tools, stationary shoulder friction stir welding tools, and double shoulder friction stir welding tools.

4. The real-time detection method for fracture of friction stir welding tools according to claim 3, characterized in that: The conventional friction stir welding tool includes a clamping part, a shoulder, and a conventional stirring pin. The clamping part is inserted into the central hole at the lower end of the tool holder and is fixed by a side set screw. The shoulder is located at the lower part of the clamping part, and its lower end face is in close contact with the upper surface of the workpiece during welding. The conventional stirring pin is a conical structure used to insert into the interior of the workpiece during welding.

5. The real-time detection method for fracture of friction stir welding tools according to claim 3, characterized in that: The described stationary shoulder friction stir welding tool includes a connecting sleeve, a stationary shoulder, and a stationary shoulder stirring pin. The connecting sleeve is a trapezoidal structure, with its upper end face in close contact with the lower end face of the main shaft and fixed thereto by screws. Its lower end face is in close contact with the upper end face of the stationary shoulder and fixed thereto by screws. The stationary shoulder is a bowl-shaped structure, with its upper end face connected and fastened to the lower end face of the connecting sleeve. The central hole on its lower end face is for the stirring pin to pass through. The upper end of the stationary shoulder stirring pin is inserted into the tool holder and fastened thereto. Its lower end passes through the central hole on the lower end face of the stationary shoulder and is inserted into the sample to be welded. During welding, the lower end face of the stationary shoulder is in close contact with the upper surface of the sample to be welded.

6. The real-time detection method for fracture of friction stir welding tools according to claim 3, characterized in that: The aforementioned dual-shoulder friction stir welding tool includes an upper shoulder, a lower shoulder, and a dual-shoulder stirring pin. The dual-shoulder stirring pin is fixedly connected between the upper shoulder and the lower shoulder. A gap is provided between the upper shoulder and the lower shoulder for the workpiece to be welded to pass through. The lower end face of the upper shoulder is in close contact with the upper surface of the material to be welded, and the upper end face of the lower shoulder is in close contact with the lower surface of the material to be welded. The dual-shoulder stirring pin can perform friction stir welding on the material to be welded under the action of the upper shoulder and the lower shoulder.

7. The real-time detection method for fracture of friction stir welding tools according to claim 4, characterized in that: The conventional friction stir welding tool has a threaded lower end face of the shoulder, which is used to enhance the material agitation on the upper surface of the welded specimen to obtain a defect-free weld joint; the conventional stirring pin has a right-hand threaded surface to enhance the material flow inside the welded specimen to form a defect-free joint; the clamping part, the shoulder and the conventional stirring pin are integral structures.

8. The real-time detection method for fracture of friction stir welding tools according to claim 5, characterized in that: The lower end face of the stationary shoulder of the described stationary shoulder friction stir welding tool is a smooth plane. During welding, it only slides relative to the upper surface of the welded specimen. The surface of the stationary shoulder stirring pin is machined with a right-hand thread to enhance the material flow inside the welded specimen.

9. The real-time detection method for fracture of friction stir welding tools according to claim 6, characterized in that: The upper shoulder of the dual-shoulder friction stir welding tool has a threaded hole at the lower end of the upper shoulder for engagement with the threaded upper part of the dual-shoulder stirring needle; the center of the upper end of the lower shoulder has a threaded hole for engagement with the threaded lower part of the dual-shoulder stirring needle, so that the stirring needle can be firmly connected between the upper and lower shoulders; the middle of the dual-shoulder stirring needle is provided with a thread, with the center of the thickness direction of the part to be welded as the boundary, the thread is right-handed near the upper shoulder and left-handed near the lower shoulder. The thread is used to generate frictional heat and plasticize the part to be welded during welding, and to drive the flow of the plasticized material, and can also increase the friction between the stirring needle and the material to be welded.

10. The real-time detection method for fracture of friction stir welding tools according to claim 7, 8 or 9, characterized in that: The conventional stirring pin, stationary shoulder stirring pin, and double shoulder stirring pin have a thread inclination angle of 15°~35°, a thread depth of 0.2~0.35mm, and a welding pin length d. 焊接针长 =d 板厚 - (0.2~0.3) mm.

11. The real-time detection method for fracture of friction stir welding tools according to claim 6 or 9, characterized in that: The upper shoulder of the dual-shoulder friction stir welding tool is inserted into the tool holder at one end. A key is provided on the side of the upper shoulder, and a keyway is provided inside the tool holder. Torque is transmitted between the tool holder and the upper shoulder through the key, and the upper shoulder and the tool holder can move axially.

12. The real-time detection method for fracture of friction stir welding tools according to claim 2, characterized in that: The central control unit analyzes and compares the collected data. If the criteria are met, the friction stir welding tool is determined to have broken at that moment.

Images