IGBT terminal ultrasonic welding equipment

Abstract

The invention provides IGBT terminal ultrasonic welding equipment which comprises an X-axis driving device, a Y-axis driving device, a Z-axis driving device and a controller, a 3D camera moving in the XY direction is fixed to the side edge of the Z-axis driving device, a laser heater moving in the XY direction is fixed to the front portion of the Z-axis driving device, an ultrasonic welding head assembly moving in the XYZ direction is fixed to the lower portion of the Z-axis driving device, and the controller is connected with the controller. The 3D camera, the laser heater and the ultrasonic welding head assembly are connected with the controller, and the 3D camera is used for conducting multi-angle scanning on IGBT terminal welding spots after welding is completed to obtain multiple pieces of point cloud data and sending the point cloud data to the controller; and the controller is used for carrying out defect detection on the IGBT terminal welding spots according to the point cloud data. Therefore, ultrasonic-laser hybrid welding and online quality detection are integrated, the pseudo soldering rate is reduced, and real-time defect recognition of the welding spots can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of device processing, and particularly to an IGBT terminal ultrasonic welding device. Background Art

[0002] At present, the IGBT terminal ultrasonic welding device has the following deficiencies:

[0003] Single energy control: The clamping device only relies on ultrasonic energy, and the welding efficiency is limited by the thermal conductivity of the material, and it is easy to produce false soldering.

[0004] Lagging quality inspection: Existing devices rely on manual visual inspection and cannot identify defects such as microcracks and welding beads in real time. Summary of the Invention

[0005] In order to solve one of the above technical problems, the present invention proposes the following technical solutions.

[0006] In a first aspect of an embodiment of the present invention, an IGBT terminal ultrasonic welding device is proposed, including an X-axis driving device, a Y-axis driving device, a Z-axis driving device and a controller. A 3D camera moving in the XY direction is fixed on the side of the Z-axis driving device, a laser heater moving in the XY direction is fixed in front of the Z-axis driving device, and an ultrasonic welding head assembly moving in the XYZ direction is fixed below the Z-axis driving device. The 3D camera, the laser heater and the ultrasonic welding head assembly are respectively connected to the controller. The 3D camera is used to perform multi-angle scanning on the IGBT terminal solder joints after welding under the control of the controller to obtain a plurality of point cloud data and send it to the controller; the controller is used to perform defect detection on the IGBT terminal solder joints according to the point cloud data.

[0007] In addition, the IGBT terminal ultrasonic welding device according to the above embodiment of the present invention may further have the following additional technical features.

[0008] According to an embodiment of the present invention, the controller performs defect detection on the IGBT terminal solder joints according to the point cloud data through the following steps: performing stitching processing on the point cloud data through a registration algorithm to obtain a three-dimensional model of the IGBT terminal solder joints; projecting the three-dimensional model onto a plurality of different planes to obtain a plurality of projection images; performing denoising, enhancement and balancing processing on the projection images in sequence and then inputting them into a ResNet-50 defect detection model to obtain the defect information of the IGBT terminal solder joints.

[0009] According to an embodiment of the present invention, position sensors are respectively fixed on the X-axis driving device and the Y-axis driving device. There is a 2D camera moving in the XY direction on the front side of the Z-axis driving device. The 2D camera is fixed on the X-axis slider. The lens of the 2D camera is fixed on the body of the 2D camera, and a light source is fixed below the lens of the 2D camera.

[0010] According to an embodiment of the present invention, the ultrasonic welding head assembly includes an ultrasonic transducer and a welding head, and the welding head is fixed below the ultrasonic transducer.

[0011] According to an embodiment of the present invention, a pressure sensor is fixed above the welding head. The pressure sensor is respectively connected to the Z-axis driving device and the controller. The controller is further configured to judge the offset of the IGBT terminal to be welded according to the output value of the pressure sensor, and adjust the downward pressure according to the offset.

[0012] According to an embodiment of the present invention, the working surface of the welding head has a gradient composite coating and a laser grooving array.

[0013] According to an embodiment of the present invention, the bottom layer of the gradient composite coating is a TiN wear-resistant layer, and the surface layer is a DLC friction-reducing layer.

[0014] According to an embodiment of the present invention, the laser grooving array includes V-shaped staggered grooves.

[0015] The technical solution of the embodiment of the present invention integrates ultrasonic-laser composite welding and on-line quality detection, reduces the rate of false soldering, and can realize real-time defect identification of solder joints. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of an IGBT terminal ultrasonic welding device according to an embodiment of the present invention.

[0017] Figure 2 It is a schematic structural diagram of a 2D camera according to an embodiment of the present invention.

[0018] Figure 3 It is a schematic structural diagram of an ultrasonic welding head assembly according to an embodiment of the present invention.

[0019] Figure 4 It is a principle block diagram of dynamic resonance compensation of the present invention.

[0020] Figure 5 It is a principle block diagram of on-line quality detection of the present invention.

[0021] Reference numerals: 1. X-axis driving device; 2. Y-axis driving device; 3. Z-axis driving device; 4. 3D camera; 5. Laser heater; 6. Ultrasonic welding head assembly; 61. Ultrasonic transducer; 62. Welding head; 71. X-axis grating scale; 72. Y-axis grating scale; 8. 2D camera; 81. Body of 2D camera; 82. Lens of 2D camera; 9. Light source. Detailed implementation manners

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0023] Figure 1 It is a schematic structural diagram of an IGBT terminal ultrasonic welding device according to an embodiment of the present invention.

[0024] As Figure 1 shown, the IGBT terminal ultrasonic welding device includes an X-axis driving device 1, a Y-axis driving device 2 ( Figure 1 two are shown in the figure), a Z-axis driving device 3 and a controller (not shown in the figure). A 3D camera 4 that moves in the XY direction is fixed to the side of the Z-axis driving device 3. A laser heater 5 that moves in the XY direction is fixed in front of the Z-axis driving device 3. An ultrasonic welding head assembly 6 that moves in the XYZ direction is fixed below the Z-axis driving device 3. The 3D camera 4, the laser heater 5 and the ultrasonic welding head assembly 6 are respectively connected to the controller.

[0025] The 3D camera 4 is used to perform multi-angle scanning on the welded IGBT terminal solder joints after welding under the control of the controller to obtain a plurality of point cloud data, and send it to the controller. The controller is used to perform defect detection on the IGBT terminal solder joints according to the point cloud data.

[0026] Among them, both the X-axis and Y-axis driving devices are built with linear motors, and the Z-axis driving device uses a ball screw module. The Y-axis is a double-sided double-drive linear motor. The Y-axis is installed on the body frame, the X-axis is installed on the mover of the Y-axis, and the Z-axis is installed on the mover of the X-axis.

[0027] Specifically, the composite energy welding method is adopted, combining the advantages of ultrasonic and laser. First, preheating is carried out through the laser heater 5: the copper terminal is preheated to 250 ± 10 °C with a 1064 nm pulsed laser (power 50 - 200 W); then the main welding is achieved through the ultrasonic welding head assembly 6: the frequency is 20 kHz, the amplitude is 30 μm, and the welding time is shortened to 60% of the traditional process. After welding, under the control of the controller, the IGBT terminal solder joints are scanned from multiple angles (accuracy ±2 μm) by the 3D camera 4 to obtain their point cloud data, and the data is sent to the controller. The controller can, based on the received point cloud data and the ResNet-50 defect detection model, perform quality inspection on the solder joints, identify defects such as microcracks and weld beads, realize real-time online identification and classification of solder joint defects, and the accuracy rate is ≥99.3%.

[0028] The IGBT terminal ultrasonic welding equipment of the present invention is applicable to the manufacture of high-power devices such as new energy vehicle IGBT modules and photovoltaic inverters. Through the laser heater 5 and the ultrasonic welding head assembly 6, composite energy welding is realized, solving the problem that the welding efficiency is limited by the thermal conductivity of the material and prone to false soldering, which can improve the welding efficiency and reduce the false soldering rate; through the 3D camera 4, online quality inspection of the solder joints is realized, solving the problem that existing equipment cannot identify defects online in real time, and can detect solder joint defects in real time.

[0029] Thus, the IGBT terminal ultrasonic welding equipment of the embodiment of the present invention integrates ultrasonic-laser composite welding and online quality inspection, reduces the false soldering rate, and can realize real-time defect identification of solder joints.

[0030] In one embodiment, the controller can perform defect detection on the IGBT terminal solder joints according to the following steps based on the point cloud data: the point cloud data is stitched through a registration algorithm to obtain a three-dimensional model of the IGBT terminal solder joints; the three-dimensional model of the IGBT terminal solder joints is projected onto multiple different planes to obtain multiple projection images; after the projection images are sequentially denoised, enhanced, and balanced, they are input into the ResNet-50 defect detection model to obtain defect information (defect classification, position, etc.) of the IGBT solder joints.

[0031] Specifically, the controller specifically realizes online quality inspection of the solder joints according to the following steps:

[0032] (1) Data acquisition

[0033] Ensure that the line laser scanner 3D camera is in a stable environment (reduce vibration, temperature fluctuations, and external light interference), and adjust the scanning speed and resolution to capture solder joint details. Multi-angle scanning: The solder joints are scanned from multiple perspectives to cover potential defect areas, and then the point cloud data is stitched through a registration algorithm (such as ICP) to form a complete three-dimensional model;

[0034] (2) Data preprocessing

[0035] Use statistical outlier removal or radius filtering to clean the point cloud noise. Project the three-dimensional model of the solder joint onto multiple planes (such as the front view, top view, side view) to generate multiple 2D images, focus on the solder joint area, reduce the amount of calculation, and retain key features;

[0036] (3) Data augmentation and balancing

[0037] Perform geometric transformations on the projected images, including rotation (±5°), translation (±10 pixels), and scaling (0.9 - 1.1 times), and add Gaussian noise to simulate scanner errors. Input the ResNet-50 defect detection model, and use oversampling (such as SMOTE) or adjust the loss function weights to improve the recognition ability of minority classes;

[0038] (4) Model adaptation and training

[0039] Modify the first layer convolution of ResNet-50 to adapt to the multi-channel projection input (such as 3 channels corresponding to three orthogonal views).

[0040] Load the ImageNet pre-trained weights, fine-tune the fully connected layer, and give priority to learning the solder joint features. Introduce the SE (Squeeze-and-Excitation) module to enhance the attention to the defect area;

[0041] (5) Training and optimization

[0042] Use cross-entropy loss and combine Focal Loss to alleviate class imbalance. Select AdamW and set the learning rate decay strategy.

[0043] (6) Deployment and real-time optimization

[0044] Apply pruning or quantization techniques to compress the model and improve the inference speed. Deploy using GPU or edge computing devices to meet the real-time detection requirements of the production line.

[0045] Through the above steps, combining the advantages of high-precision three-dimensional scanning and deep learning, solder joint defects can be efficiently identified, and the accuracy of quality inspection can be improved.

[0046] In one example, referring to Figure 1 , position sensors are respectively fixed on the X-axis drive device 1 and the Y-axis drive device 2, and a 2D camera 8 that moves in the XY direction is fixed on the front side of the Z-axis drive device 3. The position sensors can be the X-axis grating scale 71 and the Y-axis grating scale 72, that is, the position detection of the linear motor all uses grating scales for position feedback, with a resolution of 0.5μm.

[0047] Among them, referring to Figure 1, the 2D camera 8 is fixed on the X-axis slider and can move in the XY directions within the device. As Figure 2 shown, the lens 82 of the 2D camera 8 is fixed on the body 81 of the 2D camera, and a light source 9 is fixed below the lens 82 of the 2D camera. The light source 9 is fixed below the lens 82 through a bracket.

[0048] Specifically, the positioning before IGBT terminal welding is achieved through the position X-axis grating scale 71, Y-axis grating scale 72, and 2D camera 8 to ensure the accuracy of the welding position.

[0049] In one example, as Figure 3 shown, the ultrasonic welding head assembly 6 includes an ultrasonic transducer 61 and a welding head 62. The welding head 62 is fixed (by thread) below the ultrasonic transducer 61.

[0050] Among them, a pressure sensor (not shown in the figure) is fixed above the welding head 62. The pressure sensor is connected to the Z-axis driving device (by thread), and the pressure sensor is connected to the controller. The controller is also used to judge the offset of the IGBT terminal to be welded according to the output value of the pressure sensor and adjust the downward pressure according to the offset.

[0051] Specifically, a high-precision pressure sensor (range 0 - 1000N, resolution ±0.1N) is linked with the servo motor. The controller can predict the creep amount of the IGBT terminal based on the LSTM network, adjust the downward pressure in real time (response time ≤ 5ms), and achieve dynamic compensation.

[0052] There is a problem of insufficient positioning accuracy in the prior art: Although the traditional clamping mechanism can fix the IGBT module, it lacks dynamic compensation and is difficult to adapt to the offset caused by the deformation of the terminal. In the embodiment of the present invention, the offset of the terminal can be predicted through the pressure sensor, and dynamic compensation is performed to adjust the downward pressure in real time.

[0053] Thus, on the basis of fixing the IGBT terminal, dynamic compensation is performed to adapt to the offset caused by the deformation of the terminal, and the positioning accuracy is further improved.

[0054] In one example, the working surface of the welding head 62 has a gradient composite coating and a laser grooving array.

[0055] The bottom layer of the gradient composite coating is a TiN wear-resistant layer, and the surface layer is a DLC friction-reducing layer.

[0056] The laser grooving array includes V-shaped staggered grooves.

[0057] Specifically, on the basis of the traditional cemented carbide welding head, the working surface of the welding head adopts a gradient coating: the bottom layer is a TiN wear-resistant layer (thickness 50 - 80 μm), and the surface layer is a DLC friction-reducing layer (thickness 10 - 15 μm). The working surface of the welding head adopts a laser grooving design: V-shaped staggered grooves (depth-width ratio 1:3, groove depth 20 - 50 μm, spacing 200 μm), which can improve the energy transfer efficiency by 30%.

[0058] In a specific example, for laser-ultrasonic collaborative welding, the welding method can be selected according to the material properties. After welding, detection items such as real-time monitoring and off-line detection are carried out.

[0059] The principle of dynamic compensation is as Figure 4 shown. The pressure closed-loop is realized by the linkage of a pressure sensor and a servo motor, and the dynamic closed-loop control is realized through pressure detection, control, and feedback, and the downward pressure is adaptively adjusted.

[0060] The principle of quality detection is as Figure 5 shown. The controller collects data through a 3D camera, processes the collected point cloud data and analyzes it with an AI model to obtain whether the IGBT is qualified or abnormal. If it is qualified, a detection report is generated. If it is abnormal, defect information such as defect classification and location is output.

[0061] The detailed working process of welding using the IGBT terminal ultrasonic welding equipment of the present invention is as follows:

[0062] (1) Manual feeding and initialization

[0063] Manual operation: The operator places the product to be welded (such as an IGBT module) on the positioning platform and positions it through mechanical limit;

[0064] Equipment startup: After triggering the startup instruction, the system executes a self-check program, including sensor calibration (pressure / temperature / vision), and zero point of the motion axis;

[0065] (2) Visual positioning and path planning

[0066] Image acquisition: The industrial camera takes pictures of the product, combines with the light source to eliminate the reflection interference, and obtains the image of the terminal welding area;

[0067] Path generation: Based on the topological relationship of the bonding points, the optimal bonding sequence is generated to avoid the empty stroke of the robotic arm (such as "Z-shaped" or spiral path);

[0068] (3) Execution of the welding process

[0069] Parameter loading: According to the preset process recipe, the bonding parameters are called (ultrasonic power 50 - 200 W, pressure 200–500 N, time 10 - 150 ms), the welding head descends, reaches the welding position, and performs welding;

[0070] Real-time monitoring: The closed-loop feedback system monitors the welding force-displacement curve. Abnormal fluctuations (such as excessive pressure or insufficient ultrasonic energy) trigger alarms and suspend the process.

[0071] (4) Welding machine effect detection

[0072] Online inspection: After welding is completed, the 2D camera captures the surface texture, oxidation spots and tiny cracks of the solder joint, and the 3D camera reconstructs the three-dimensional morphology of the solder joint and quantifies the geometric parameters such as the height and offset of the welding pattern;

[0073] Result output: The test data is stored in the MES system, an SPC (statistical process control) report is generated, and the OK / NG judgment results and defect type classification are displayed through the HMI interface;

[0074] (5) Equipment stop and safety reset

[0075] Stop logic: After completing all welding points, the motion controller executes a safe stop sequence: the robot returns to a safe position;

[0076] Abnormal processing: If an abnormal result is detected, the device will trigger an audible and visual alarm and remain in a shutdown state, waiting for manual intervention and reinitialization according to the reset process.

[0077] For example, when welding an automotive IGBT module, the welding object is: 1200V / 300A IGBT module (terminal material is C194 copper alloy). Parameter comparison:

[0078] Welding strength (MPa): conventional process 220, the present invention 320;

[0079] Cold soldering rate: 1.2% for traditional process, 0.05% for the present invention;

[0080] Single point time consumption: 800ms for the traditional process and 450ms for the present invention.

[0081] In summary, the IGBT terminal ultrasonic welding equipment of the present invention solves the problems of low efficiency and unstable quality of traditional processes through ultrasonic-laser energy synergy, dynamic resonance compensation and online quality detection technology. Experiments show that the welding strength is increased by 45% and the defect rate is reduced to less than 0.05%, which is particularly suitable for the manufacture of high-power devices in the new energy field.

[0082] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. An IGBT terminal ultrasonic welding device, characterized in that, It includes an X-axis driving device, a Y-axis driving device, a Z-axis driving device and a controller. A 3D camera that moves in the XY direction is fixed to the side of the Z-axis driving device. A laser heater that moves in the XY direction is fixed in front of the Z-axis driving device. An ultrasonic welding head assembly that moves in the XYZ directions is fixed below the Z-axis driving device. The 3D camera, the laser heater and the ultrasonic welding head assembly are respectively connected to the controller. The 3D camera is used to perform multi-angle scanning on the IGBT terminal solder joints after welding under the control of the controller to obtain a plurality of point cloud data, and send it to the controller. The controller is used to perform defect detection on the IGBT terminal solder joints according to the point cloud data.

2. The IGBT terminal ultrasonic welding equipment according to claim 1, wherein The controller performs defect detection on the IGBT terminal solder joints according to the point cloud data through the following steps: The point cloud data are spliced and processed through a registration algorithm to obtain a three-dimensional model of the IGBT terminal solder joints. The three-dimensional model is projected onto a plurality of different planes to obtain a plurality of projection images. After the projection images are sequentially denoised, enhanced and balanced, they are input into a ResNet-50 defect detection model to obtain the defect information of the IGBT terminal solder joints.

3. The IGBT terminal ultrasonic welding equipment according to claim 1, characterized in that, Position sensors are respectively fixed on the X-axis driving device and the Y-axis driving device. There is a 2D camera that moves in the XY direction on the front side of the Z-axis driving device. The 2D camera is fixed on an X-axis slider. The lens of the 2D camera is fixed to the body of the 2D camera. A light source is fixed below the lens of the 2D camera.

4. The IGBT terminal ultrasonic welding equipment according to any one of claims 1-3, characterized in that, The ultrasonic welding head assembly includes an ultrasonic transducer and a welding head. The welding head is fixed below the ultrasonic transducer.

5. The IGBT terminal ultrasonic welding equipment according to claim 4, characterized in that, A pressure sensor is fixed above the welding head. The pressure sensor is respectively connected to the Z-axis driving device and the controller. The controller is also used to judge the offset of the IGBT terminal to be welded according to the output value of the pressure sensor, and adjust the downward pressure according to the offset.

6. The IGBT terminal ultrasonic welding equipment according to claim 4, characterized in that The working surface of the welding head has a gradient composite coating and a laser grooving array.

7. The IGBT terminal ultrasonic welding device according to claim 6, characterized in that, The bottom layer of the gradient composite coating is a TiN wear-resistant layer, and the surface layer is a DLC friction-reducing layer.

8. The IGBT terminal ultrasonic welding equipment according to claim 6, characterized in that, The laser grooving array includes V-shaped staggered grooves.

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