Laser welding device and method for bearing retainer

Abstract

The invention discloses a laser welding device and method for a bearing retainer, and relates to the technical field of laser welding. The laser welding device comprises a welding part and a modulation part, the welding part comprises a laser generation module and a welding execution module, the laser generation module is provided with a laser emitting end, and the welding execution module is connected with the laser emitting end; the modulation part comprises a swing execution module, a direction detection module and a modulation module, the swing execution module is connected with the laser emitting end, the modulation module is connected with the laser generating module, the modulation module is in communication connection with the direction detection module, and the modulation module adjusts the duty ratio of the laser generating module in real time according to a received direction signal; therefore, the duty ratio of the laser beam during scanning along the first direction is higher than that during scanning along the second direction. According to the laser welding device and method, the defects of weld joints in the laser welding process can be reduced, the welding quality is improved, and the cracking risk of a welded joint in the service process is reduced.

Description

Technical Field

[0001] This application relates to the field of laser welding technology, and in particular to a laser welding apparatus and method for bearing cages. Background Technology

[0002] Laser welding, with its advantages of low energy consumption, high precision, and high speed, has been applied in fields such as automobile manufacturing. However, in actual welding processes, especially when dealing with short and thick welds such as bearing cages, several technical challenges remain: Firstly, a sudden increase in laser energy input within a short period can easily cause violent fluctuations in the molten pool or even localized overmelting, leading to weld collapse. Secondly, due to the highly concentrated energy of the laser beam, uneven heat conduction can easily cause defects such as porosity and incomplete fusion within the weld. These defects not only reduce weld quality but also significantly increase the risk of cracking during service. Summary of the Invention

[0003] The purpose of this application is to provide a laser welding apparatus and method for bearing cages, which can improve welding quality and reduce the risk of cracking of the welded joint during service.

[0004] To address the aforementioned technical problems, the embodiments of this application provide the following technical solutions: The first aspect of this application provides a laser welding apparatus for bearing cages, comprising: The welding section includes a laser generating module and a welding execution module. The laser generating module has a laser emitting end, and the welding execution module is connected to the laser emitting end. The modulation unit includes: A swing execution module is connected to the laser emitter. The orientation detection module is located near the swing execution module or integrated into the swing execution module; The modulation module is connected to the laser generation module and also communicates with the direction detection module. The welding execution module is used to move the laser emitting end to the preset position of the weld seam on the target workpiece. The laser emitter is used to emit a laser beam to initiate welding. The swing execution module is used to redirect the laser beam so that the redirected laser beam enters the weld position; The welding execution module is also used to drive the laser emitter and the oscillating execution module to move along the direction of weld extension during the welding process; The oscillation execution module is also used to oscillate at a set amplitude during the welding process so that the laser beam reciprocates along a first direction and a second direction, both of which are perpendicular to the direction of weld extension; The direction detection module is used to detect the scanning direction of the laser beam in real time and send the detected direction signal to the modulation module; The modulation module is used to adjust the duty cycle of the laser generating module in real time according to the received direction signal, so that the duty cycle of the laser beam when scanning along the first direction is higher than that when scanning along the second direction.

[0005] In some modified embodiments of this application, the modulation module is used to control the duty cycle of the laser beam to be 100% when scanning along the first direction and the duty cycle of the laser beam to be 30% to 70% when scanning along the second direction.

[0006] In some modified embodiments of this application, during the welding process, the welding execution module and the oscillation execution module are used to jointly control the spot of the laser beam to perform periodic reciprocating motion along a triangular wave trajectory in the weld area of ​​the target workpiece.

[0007] In some modified embodiments of this application, the direction detection module is specifically used to detect the current scanning direction of the beam in real time during the welding process, including: the direction detection module calculates the adjacent sampling points t k and t k-1 positional difference between To determine the instantaneous scanning direction of the laser beam; among which, The calculation formula is as follows:

[0008] If Δx > 0, the laser beam is determined to be scanning along the first direction; if Δx < 0, the laser beam is determined to be scanning along the second direction.

[0009] In some modified embodiments of this application, it also includes: The modulation module is specifically used to obtain the scanning speed of the laser beam as it scans along the second direction, and dynamically adjusts the duty cycle according to the scanning speed; the duty cycle of the laser beam as it moves along the second direction is calculated using the following formula:

[0010] in: This is the duty cycle when the laser beam moves along the second direction; This is the preset lower limit for the duty cycle; This is the preset upper limit for the duty cycle; This represents the instantaneous scanning speed of the current laser beam; This represents the maximum scan speed.

[0011] In some modified embodiments of this application, it also includes: The weld monitoring unit faces the weld position of the target workpiece and is connected to the control unit. During the welding process, the weld monitoring unit detects the weld status in real time and sends corresponding signals to the control unit. The control unit adjusts the welding parameters according to the weld status.

[0012] In some modified embodiments of this application, the welded portion further includes: Two gas delivery pipes are set on both sides of the laser emitting end, which are used to deliver argon and helium respectively. Two flow regulating valves are set on each of the two gas delivery pipes, and both flow regulating valves are connected to the control unit. If the weld monitoring unit detects that the center depression of the molten pool in the weld is greater than the second set value, the weld monitoring unit sends a corresponding signal to the control unit, and the control unit controls the flow regulating valve to increase the helium ratio.

[0013] In some modified embodiments of this application, the control unit includes: The multiphysics coupling simulation modeling unit is used to acquire the material and size data of the target workpiece, simulate the welding process, and select the optimal combination of welding process parameters. The path planning module is used to generate a preset welding trajectory path based on the weld position before welding; the control unit is also used to control the welding unit and the modulation unit to weld according to the optimal welding process parameters during the welding process, and the control unit controls the welding execution module and the swing execution module to control the laser beam spot to move along the preset welding trajectory path.

[0014] The service performance evaluation module is used to determine whether the target workpiece meets the long-term service requirements after welding. If the target workpiece meets the long-term service requirements, the control unit sends a signal to the operator to move the target workpiece to the finished product area. At the same time, the control unit packages the actual welding parameters, monitoring data, weld morphology and simulated residual stress data of the target workpiece together as a digital twin data file of the target workpiece and feeds it back to the process expert database.

[0015] A second aspect of this application provides a laser welding method for a bearing cage, and an apparatus for laser welding the aforementioned bearing cage, comprising: The welding execution module moves the laser emitter to the preset position of the weld seam on the target workpiece; The laser emitter emits a laser beam to begin welding. The swing execution module is used to redirect the laser beam so that the redirected laser beam enters the weld position. The welding execution module drives the laser emitter and the oscillating execution module to move along the direction of weld extension during the welding process; The oscillation execution module oscillates at a set amplitude during the welding process to make the laser beam reciprocate scanning along the first and second directions; The direction detection module detects the scanning direction of the laser beam in real time and sends the detected direction signal to the modulation module. The modulation module adjusts the duty cycle of the laser generator module in real time according to the received direction signal, so that the duty cycle of the laser light when scanning along the first direction is higher than the duty cycle when scanning along the second direction.

[0016] This disclosure involves a welding execution module that drives a laser generating module and an oscillating execution module to move along the weld seam extension direction. The oscillating execution module oscillates at a set amplitude to make the laser beam reciprocate along a first direction and a second direction, thereby distributing energy more evenly in the weld seam width direction. Furthermore, by detecting the beam movement direction in real time and dynamically adjusting the duty cycle of the laser in different scanning directions, the duty cycle is higher when scanning along the first direction and lower when scanning along the second direction. This provides a higher energy density on one side of the oscillation path (such as the forward direction), which helps to fully melt the base material and promotes feeding before solidification of the molten pool. On the other side (such as the return stroke), the energy input is reduced to avoid overheating and excessive metal vapor back pressure, thereby suppressing porosity formation. The combination of reciprocating scanning of the laser beam along the first and second directions and duty cycle control achieves dual optimization of spatial energy dispersion and temporal energy precision control. This reduces sudden changes in heat accumulation, avoids collapse caused by sudden energy increases, improves the wettability and fluidity of the molten pool, enhances sidewall fusion, reduces the risk of incomplete fusion, promotes metallurgical reactions and gas expulsion, and significantly reduces porosity. Ultimately, this results in a welded joint with uniform shape, dense internal structure, and stable mechanical properties, improving welding quality and reducing the risk of cracking during service. Attached Figure Description

[0017] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, with the same or corresponding reference numerals denoteing the same or corresponding parts, wherein: Figure 1 A schematic diagram of a laser welding apparatus for a bearing cage is shown. Figure 2 A schematic diagram of a portion of the welding section of a laser welding apparatus for a bearing cage is shown. Figure 3 A schematic diagram of a partial structure of a laser welding apparatus for a bearing cage is shown. Figure 4 A schematic diagram of narrow-gap laser filler wire welding is shown for a laser welding method of bearing cage; Figure 5A schematic diagram of a partial internal structure of a laser welding device for a bearing cage is shown. Figure 6 A schematic diagram illustrating the laser oscillating welding principle of a laser welding method for bearing cages is shown. Figure 7 A schematic diagram of the laser oscillation welding trajectory of a laser welding method for a bearing cage is shown. Figure 8 The diagram schematically illustrates the welding effect of a laser welding device for a bearing cage. Figure 9 The diagram schematically illustrates the weld seam effect of a laser welding device for a bearing cage; Figure 10 A schematic diagram of a laser welding method for bearing cages is shown.

[0018] Explanation of icon numbers: 1. Base; 2. Welding section; 21. Laser generating module; 211. Laser generating body; 212. Laser emitting end; 202. Welding execution module; 203. Gas delivery pipe; 204. Wire feeding assembly; 3. Modulation section; 31. Oscillating execution module; 4. Fixing section; 401. Roller; 402. Pneumatic clamp; 5. Positioning section; 6. Control section; 7. Weld monitoring section; 8. Target workpiece; 81. Weld; 9. Laser beam; 10. Triangular wave trajectory. Detailed Implementation

[0019] Exemplary embodiments of this application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this application and to fully convey the scope of this application to those skilled in the art.

[0020] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure pertains.

[0021] Laser welding, with its advantages of low energy consumption, high precision, and high speed, has been applied in fields such as automobile manufacturing. However, in actual welding processes, especially when dealing with short and thick welds such as those on bearing cages, several technical challenges remain: Firstly, a sudden increase in laser energy input within a short period can easily cause violent fluctuations in the molten pool or even localized overmelting, leading to weld collapse. Secondly, due to the highly concentrated energy of the laser beam, uneven heat conduction can easily cause defects such as porosity and incomplete fusion within the weld. These defects not only reduce weld quality but also significantly increase the risk of cracking during service.

[0022] To address the aforementioned technical problems, this application provides a laser welding method and apparatus for bearing cages, which can improve welding quality and reduce the risk of cracking of the welded joint during service.

[0023] like Figure 1 , Figure 2 and Figure 5 As shown, this application embodiment provides a laser welding device for a bearing cage, including a welding section 2 and a modulation section 3. The welding section 2 includes a laser generating module 21 and a welding execution module 202. The laser generating module 21 has a laser emitting end 212, and the welding execution module 202 is connected to the laser emitting end 212. The modulation section 3 includes a swing execution module 31, a direction detection module, and a modulation module. The swing execution module 31 is connected to the laser emitting end 212. The direction detection module is located near the swing execution module 31 or integrated into the swing execution module. The modulation module is connected to the laser generating module 21 and is communicatively connected to the direction detection module. The welding execution module 202 is used to move the laser emitting end 212 to a preset position of the weld seam 81 of the target workpiece 8; the laser emitting end 212 is used to emit a laser beam 9 to start welding; the oscillation execution module 31 is used to redirect the laser beam 9 so that the redirected laser beam 9 enters the position of the weld seam 81; the welding execution module 202 is also used to drive the laser emitting end 212 and the oscillation execution module 31 to move along the direction of extension of the weld seam 81 during the welding process; the oscillation execution module 31 is also used to oscillate at a set amplitude during the welding process so that the laser beam 9 reciprocates along a first direction and a second direction, both of which are perpendicular to the direction of extension of the weld seam 81; the direction detection module is used to detect the scanning direction of the laser beam 9 in real time and send the detected direction signal to the modulation module; the modulation module is used to adjust the duty cycle of the laser generating module 21 in real time according to the received direction signal so that the duty cycle of the laser beam 9 when scanning along the first direction is higher than its duty cycle when scanning along the second direction.

[0024] Welding unit 2 is the core functional unit responsible for generating laser light and performing the actual welding action. Welding unit 2 consists of a laser generating module 21 and a welding execution module 202. The laser generating module 21 is the core component in the laser welding device used to generate a high-energy laser beam; its essence is a laser source. That is, the laser generating module 21 is a functional unit that converts electrical energy (or other pump sources) into coherent light (laser), providing the energy required for welding. It can include basic structures such as a laser gain medium, pump source, and resonant cavity, and outputs a laser beam with a specific wavelength, power, and mode. The laser generating module 21 can be a fiber laser, which has high electro-optical efficiency, good beam quality, strong stability, and is maintenance-free, suitable for automotive manufacturing and welding of thin / thick metal plates. The laser generating module 21 can also be a semiconductor laser, which is small in size, has a long lifespan, and can be directly modulated, suitable for plastic welding, heat conduction welding, and auxiliary heating. The laser generating module 21 can also be a disk laser, which has high power, good heat dissipation, and excellent beam quality, suitable for high-end industrial welding (such as power batteries). For example, the laser generating module 21 uses a 6000W fiber laser with adjustable power, an output wavelength of 1080nm, and a modulation frequency shift rate of 20kHz. The output laser is connected to the modulation unit 3 via optical fiber. The laser emitting end 212 refers to the physical interface or exit point where the laser generating module 21 (i.e., the laser) outputs the laser beam. It is the starting point for the transmission of laser energy from inside the laser to the external optical path system. The laser emitting end 212 can also serve as the connection hub between the laser and the welding execution module 202 and the swing execution module 31. For example, the laser emitting end 212 is the final light-emitting position of the laser welding head or the laser output optical path within the welding head. The welding execution module 202 positions this light-emitting position by driving the welding head.

[0025] like Figure 1 As shown, the welding execution module 202 is an electromechanical integrated execution unit in the laser welding device responsible for precisely guiding the laser to the weld seam 81 of the workpiece and realizing the welding trajectory movement. It does not generate laser light, but rather carries, positions, and drives the laser output end to complete the actual processing action. The welding execution module 202 can be a robot-integrated structure, where the laser welding head can be mounted on the end effector of a six-axis industrial robot, flexibly realizing complex three-dimensional trajectories. The welding execution module 202 can also be a linear module structure, using servo motors, precision guide rails, and lead screws to drive the welding head (laser generating end) to move linearly along the X / Y / Z axes, offering high precision and fast response, suitable for battery modules, electronic devices, and planar weld seams. The welding execution module 202 can also be a gantry truss type, a large beam structure, allowing the welding head to move over a wide range in the XY plane with high rigidity. For example, the welding execution module 202 can be a multi-axis linkage robotic arm with a repeatability accuracy better than 0.1mm. The laser welding head (laser emitting end) is fixed to the end effector of the robotic arm via a flange, and the fiber optic interface of the laser welding head (laser emitting end) is connected to the fiber optic cable of the laser generating body 211. like Figure 2 As shown, in some modified embodiments of this application, the welding part 2 further includes two gas delivery pipes 203, which are disposed on both sides of the laser emitting end 212 and are used to deliver argon and helium respectively. Two flow regulating valves are respectively provided on the two gas delivery pipes 203, and both flow regulating valves are connected to the control part 6, so as to realize the adjustable mixing ratio of argon and helium. After the two gases are mixed, they should be output through a laminar flow nozzle to evenly cover the molten pool of the weld 81 and avoid disturbing the molten pool.

[0026] A gas delivery pipe is a conduit or nozzle structure used to deliver shielding gas from a gas source or mixing chamber to the welding area (such as near the molten pool). Its function is to guide and evenly distribute the shielding gas to isolate it from air, prevent oxidation, and influence molten pool cooling and plasma behavior. Gas delivery pipes can be straight-through metal tubes made of stainless steel or copper, resistant to high temperatures, and simple in structure. They can also be dual-sided independent nozzle tubes, symmetrically arranged, capable of delivering different gases separately.

[0027] A flow control valve is an actuator used to precisely control the flow rate of gas. It regulates the gas volume per unit time by adjusting the valve opening to change the flow cross-sectional area. It is controlled by a control unit and supports dynamic proportional regulation. It can be a mass flow controller, based on thermal or differential pressure sensing and solenoid valve closed-loop control, supporting analog or digital signals. In some implementations, the flow control valve can also be other types of valves such as proportional solenoid valves.

[0028] During use, if the weld monitoring unit 7 detects that the center depression of the molten pool in the weld 81 is greater than a second set value, the weld monitoring unit 7 sends a corresponding signal to the control unit 6, and the control unit 6 controls the flow regulating valve to increase the helium ratio. An excessively large depression usually indicates that the keyhole is too deep or unstable, the surface tension gradient of the molten pool is abnormal, the heat input is too high, or the cooling is insufficient, resulting in delayed molten metal reflow. Helium has a relatively stronger cooling effect on the molten pool; increasing the helium ratio can enhance cooling. High thermal conductivity helium accelerates heat dissipation from the edge of the molten pool, promotes metal reflow to fill the center, reduces laser energy loss, makes the energy distribution more stable, and avoids drastic keyhole fluctuations. In addition, the molten pool has better fluidity in a helium atmosphere, which helps to smooth the surface.

[0029] This modified implementation introduces an adjustable dual-gas protection system (argon + helium) and links it with real-time feedback from the weld monitoring unit, forming an intelligent control strategy that dynamically optimizes the protective gas ratio based on the molten pool condition. When excessive central depression of the molten pool is detected, the proportion of high thermal conductivity helium is automatically increased, effectively enhancing molten pool cooling, suppressing plasma shielding, and promoting metal reflow, thereby significantly improving weld formation quality and process stability.

[0030] The welding execution module 202 may also include a wire feeding assembly 204, which is located on one side of the welding head. The wire feeding assembly 204 can be adapted to welding wires of various materials, thereby realizing narrow-gap laser filler welding. The wire feeding assembly 204 may have a wire feeder with a servo motor power of 500W and a wire feeding speed adjustment range of 3.2 to 4.0 m / min.

[0031] like Figure 5 As shown, the modulation unit 3 is an intelligent control unit used to dynamically adjust the laser output characteristics (such as direction, power, and duty cycle) to optimize welding quality. In some embodiments, the modulation unit 3 can be integrated inside the welding unit 2. The oscillation execution module 31 refers to an optical-electromechanical execution unit in the laser welding device used to periodically deflect the propagation direction of the laser beam 9, causing it to reciprocate in a plane perpendicular to the extension direction of the weld seam 81. The oscillation execution module 31 can receive control signals to drive the beam deflection by setting the amplitude (deflection angle or displacement) and frequency; causing the laser beam 9 to continuously reciprocate between a first direction and a second direction (the first direction and the second direction are opposite directions on the same straight line, both perpendicular to the weld seam 81), and in conjunction with the forward movement of the welding execution module 202, form a composite weld seam trajectory such as a snake or triangular waveform. The oscillation execution module 31 can be a galvanometer-type oscillation module, which drives the reflector to deflect the laser beam through two high-speed galvanometer motors. It has a high scanning frequency (up to several kiloHz), flexible trajectory (straight line / circle / figure-eight, etc.), fast response, and high precision, and is suitable for precision welding (batteries, electronics, medical devices). The oscillation execution module 31 can also be a fiber-coupled oscillating head, with a built-in rotating prism or eccentric lens. Driven by a motor, the emitted beam oscillates around an axis, featuring a compact structure, direct fiber connection, and a oscillation trajectory that can be circular or linear, making installation simple. Alternatively, the oscillation execution module 31 can be a piezoelectric driven deflector, utilizing the micro-displacement of piezoelectric ceramics to drive a reflector or fiber end face. This is suitable for ultra-high response speeds (microseconds), has a small stroke, and is suitable for micro-amplitude oscillations. For example, a galvanometer-type oscillation module can be selected to achieve precise oscillation with an amplitude of 0-5mm and a frequency of 50-200Hz.

[0032] The direction detection module refers to the sensing and signal processing unit integrated into the modulation unit 3 of the laser welding device. It is used to perform high-frequency sampling (e.g., microsecond-level) of the position or angle of the oscillation execution module 31 (such as a galvanometer). By calculating the position difference between adjacent sampling points, it determines the instantaneous scanning direction of the beam deflection in real time (e.g., moving towards a first or second direction), and feeds the direction information back to the modulation module for synchronous adjustment of laser parameters (e.g., power, duty cycle). This achieves dynamic coupling control between the laser output parameters and the beam scanning direction; for example, increasing power when scanning to the left and decreasing it when scanning to the right to optimize weld seam 81 formation. The direction detection module can be a built-in encoder of the galvanometer, for example, a high-resolution optical / magnetic encoder can be integrated on the galvanometer motor shaft to directly output angular position signals. This provides high accuracy, fast response, and is integrated with the galvanometer, eliminating the need for external components. Alternatively, the direction detection module can be a high-precision position sensor, such as a laser displacement sensor or an eddy current sensor, to non-contactly measure the actual deflection angle of the reflector. The orientation detection module can also be an FPGA (Field-Programmable Gate Array) or a dedicated ASIC (Application-Specific Integrated Circuit). The real-time processing unit receives the raw position signal and performs microsecond-level differential calculations and orientation determination through hardware circuitry, with extremely low latency (<10 μs). It supports high-speed closed-loop control and is suitable for high-speed oscillating welding and dynamic modulation systems. The orientation detection module can adopt a combination of a galvanometer-embedded encoder and FPGA real-time processing, or a combination of a high-precision position sensor and FPGA real-time processing.

[0033] The modulation module is a control unit in a laser welding device that dynamically adjusts the output parameters (such as duty cycle, power, and frequency) of the laser generator module 21 based on the real-time motion direction signal provided by the direction detection module. The modulation module can receive beam scanning direction signals (such as "currently moving in the first direction") from the direction detection module, calculate and output modulation commands in real time, enabling the laser to have different energy output characteristics in different scanning directions. The modulation module can be an embedded controller type, based on a microcontroller (MCU) or FPGA, running real-time control algorithms and directly outputting analog / digital modulation signals. It is suitable for mainstream industrial equipment and supports complex logic and high-speed response. The modulation module can also be a PLC (Programmable Logic Controller) integrated type, where a direction-duty cycle mapping program can be written in the PLC to control the laser through a high-speed output module. This is suitable for automated production lines and allows for deep integration with the overall machine control system. For example, during use, the direction detection module determines that the beam is scanning along the first direction and sends a signal to the modulation module; after receiving the signal, the modulation module looks up a table or calculates the high duty cycle value; it sends the corresponding PWM (pulse width modulation) or analog voltage signal to the laser generation module 21; the laser outputs a high-energy pulse sequence; when the direction is switched to the second direction, the duty cycle automatically drops to a lower value.

[0034] like Figure 1 and Figure 3 As shown, in some modified embodiments of this application, the laser welding apparatus further includes a weld monitoring unit 7, which faces the weld 81 position of the target workpiece 8, and is used to detect the state of the weld 81 in real time during the welding process and adjust the welding parameters according to the state of the weld 81.

[0035] The weld monitoring unit 7 refers to a real-time sensing and feedback unit located in the laser welding device, facing the weld seam 81 area of ​​the target workpiece 8. It continuously collects weld seam 81 status information (such as molten pool morphology, temperature, plasma, keyhole depth, and weld seam 81 formation) during the welding process and dynamically adjusts welding parameters (such as laser power, speed, oscillation amplitude, and duty cycle) based on the analysis results to improve welding quality and stability. The weld monitoring unit 7 can employ a molten pool visual monitoring system to monitor the molten pool size, brightness, and flow state. It can consist of a high-speed industrial camera and a narrow-band filter (to suppress laser glare), suitable for thin-plate welding and precision component welding. The weld monitoring unit 7 can also employ infrared thermal imaging to monitor the temperature distribution of the molten pool and heat-affected zone. For example, it can be an infrared thermal imager (frame rate ≥ 100 Hz), suitable for thick-plate welding and heat input control.

[0036] In some modified embodiments of this application, the welding apparatus further includes a fixing part 4, a positioning part 5, and a control part 6. The fixing part 4 is used to fix the target workpiece 8 in a preset position; the positioning part 5 is disposed on one side of the fixing part 4 and is used to identify and position the weld 81; the welding part 2, the modulation part 3, the fixing part 4, and the positioning part 5 are respectively connected to the control part 6.

[0037] like Figure 1 As shown, the fixing part 4 is used to clamp, support, or constrain the workpiece to ensure its stable position during welding. The fixing part 4 can be a mechanical fixture (pneumatic / hydraulic / manual), a vacuum adsorption platform, a magnetic chuck (suitable for ferromagnetic materials), a customized fixture (for specific workpiece shapes), etc. The fixing part 4 can include a support adjustment assembly and a clamping assembly. The roller 401 of the support adjustment assembly has a diameter of 50mm and a movement range of 500mm, which can drive the target workpiece 8 (e.g., a bearing cage) to rotate and move 360°. The pneumatic clamp 402 of the clamping assembly has a maximum clamping force of 500N, a copper liner thickness of 5mm on the pneumatic clamp 402, and a distance recognition module with an accuracy of 0.05mm on the pneumatic clamp 402. A pressure sensor can be installed on the pneumatic clamp 402 of the fixing part 4 to measure the pressure of the pressure clamp. The pressure sensor is connected to the control unit 6. When the pressure reaches the set value, the control unit 6 controls the pneumatic clamp 402 to stop operating.

[0038] The positioning unit 5 is a sensing and measurement unit in the laser welding device used to automatically identify, detect, and accurately determine the spatial position of the weld 81 on the workpiece. It can provide the welding execution module 202 with accurate weld 81 trajectory coordinates or starting point information, realizing automated alignment where what you see is what you are welding. The positioning unit 5 can sense the geometric features of the workpiece surface, identify the weld 81 (such as gaps, bevels, splicing lines), and output the position, direction, depth, or three-dimensional contour data of the weld 81. The positioning unit 5 can be a machine vision positioning system, using an industrial camera and light source (ring light, coaxial light) to capture the weld 81 area, and identifying the weld 81 through image processing algorithms (such as edge detection, template matching), which is low-cost. The positioning unit 5 is suitable for high-contrast welds 81 (such as black and white), and is applicable to butt welding of planar thin plates and battery tab welding. The positioning unit 5 can also be a laser triangulation sensor, projecting a laser line onto the workpiece surface, receiving the reflected light, and calculating the height and position through triangulation to obtain a 3D contour. Installed in front of the welding head (front-mounted), it scans in advance and is coaxially integrated with the welding head (common optical path), allowing for simultaneous welding and measurement.

[0039] The control unit 6 refers to the hardware and software collaborative system integrated into the laser welding device, communicating with modules such as the welding unit 2, modulation unit 3, fixing unit 4, and positioning unit 5. The control unit 6 can realize workpiece status monitoring and clamping control, weld seam 81 position identification and path generation, dynamic modulation of laser output parameters (power, frequency, duty cycle), and coordinated control of actuator motion trajectory and swing strategy. For example, the control unit 6 can use an industrial-grade computer, with built-in welding path planning algorithms, multi-physics coupling simulation modeling units, and service performance evaluation modules. It can also analyze monitoring data, generate welding parameter adjustment commands, and control the collaborative work of various modules.

[0040] The control unit includes a multiphysics coupling simulation modeling unit and a path planning module. The multiphysics coupling simulation modeling unit is used to acquire the material and size data of the target workpiece before welding, simulate the welding process, and select the optimal combination of welding process parameters. The path planning module is used to generate a preset welding trajectory path based on the weld position before welding. During welding, the control unit controls the welding unit and the modulation unit to weld according to the optimal combination of welding process parameters. The control unit controls the welding execution module and the oscillation execution module to control the laser beam spot to move along the preset welding trajectory path.

[0041] The multiphysics coupled simulation modeling unit is a numerical simulation subsystem integrated within the control unit, based on a thermo-mechanical-other multiphysics coupled model. Before actual welding, it performs virtual simulations of the temperature field, molten pool flow, stress deformation, etc., during the laser welding process, based on input parameters such as the target workpiece material type, geometric dimensions, and joint type. It automatically selects the optimal combination of welding process parameters (including laser power, welding speed, oscillation frequency, duty cycle, etc.) according to preset quality indicators (such as weld penetration uniformity and residual stress minimization). The multiphysics coupled simulation modeling unit is an embedded or cloud-based process virtual verification engine, which can serve as a functional hardware or firmware module of the control unit (such as an industrial control computer or FPGA acceleration unit equipped with a dedicated solver).

[0042] The path planning module control unit is a functional unit used to generate welding motion trajectories. It can receive the actual position and direction information of the weld from the positioning unit, and combine the workpiece coordinate system and the kinematic model of the actuator to calculate and output a high-precision, smooth preset welding trajectory path for the welding execution module and the swing execution module to track together.

[0043] The above-mentioned scheme can predict defects (such as collapse, porosity, and cracks) through simulation, avoid undesirable parameters in advance, and ensure that the path accurately matches the actual weld, avoiding weld deviation caused by assembly errors and significantly improving the success rate of the first weld. In some implementations, the simulation can not only output parameters, but also provide feedback on the optimal swing strategy (such as whether an asymmetric duty cycle is required). Path planning can be combined with the distribution of the heat-affected zone to optimize the entry / exit points of the arc to reduce arc start and end defects.

[0044] In some modified embodiments of this application, the control unit further includes a service performance evaluation module, which is used to determine whether the target workpiece meets the long-term service requirements after welding. If the target workpiece meets the long-term service requirements, the control unit sends a signal to the operator to move the target workpiece to the finished product area. At the same time, the control unit packages the actual welding parameters, monitoring data, weld morphology and simulated residual stress data of the target workpiece together as a digital twin data file of the target workpiece and feeds it back to the process expert database.

[0045] The service performance evaluation module constructs multiphysics degradation models or machine learning prediction models based on weld morphology, residual stress distribution, and material properties. By building correlation models through this module, the service performance evaluation module predicts the service performance and lifespan of welded joints under complex operating conditions. This provides a theoretical basis for developing welding quality acceptance standards, improves product reliability, and achieves predictable quality and quantifiable lifespan. Instead of relying on destructive sampling inspections, it uses digital models to predict the long-term reliability of each product.

[0046] like Figure 1As shown, in some embodiments, the laser welding apparatus may also include a base 1, and the welding part 2, modulation part 3, fixing part 4, positioning part 5, etc. may all be disposed on the base 1.

[0047] like Figure 10 As shown, this application provides a laser welding method using a laser welding apparatus that applies at least a portion of the above-described bearing cage, comprising the following steps: S1: After the target workpiece 8 is placed in the preset position, the positioning unit 5 performs visual positioning of the target workpiece 8 and collects the weld information of the target workpiece 8.

[0048] The weld information includes the position and dimensions of weld 81. In use, the target workpiece 8 can be placed on roller 401, the positioning unit 5 is activated, and the contour of the target workpiece and the position of weld 81 are collected and transmitted to the main control unit (control unit 6). The positioning accuracy is better than ±0.1mm. The positioning unit 5 directly identifies the actual position of weld 81 and digitizes information such as the actual direction and gap width of weld 81. The control unit 6 can then dynamically plan the path and adjust the swing amplitude or power accordingly, laying the data foundation for subsequent intelligent control.

[0049] S2: The multiphysics coupling simulation modeling unit acquires the material and size data of the target workpiece 8, performs welding process simulation, and selects the optimal combination of welding process parameters.

[0050] The material type, geometric dimensions, and joint type of the target workpiece 8 can be obtained and input into the welding process simulation module built into the control unit 6. The simulation module is based on the thermal field-molten pool-stress coupling model (multi-physics field coupling simulation modeling unit) and performs virtual welding simulation for different combinations of laser power, welding speed, oscillation amplitude, and duty cycle. According to the preset evaluation index, the optimal welding process parameter combination that meets the forming quality requirements of weld 81 is selected, thereby significantly reducing the number of on-site trial weldings, reducing material and time costs, and predicting welding defects (such as collapse and porosity) in advance, thus improving the first-pass yield. It is compatible with different materials (copper / aluminum / steel) and structures (lap / butt / corner joint) and supports subsequent dynamic modulation, that is, the optimal duty cycle strategy of the simulation can be directly used for execution by the modulation unit 3.

[0051] For example, the material and dimensional data of the target workpiece 8 can be input into a multiphysics coupled simulation modeling unit, a parameter search space can be set, and the optimal combination of welding process parameters can be selected from the parameter search space. The parameter search space can include laser power of 4000–6000W, welding speed of 0.8–1.2m / min, oscillation amplitude of 0–5mm, oscillation frequency of 100–150Hz, and oscillation modulation parameters with an outward duty cycle of 100% and a return duty cycle of 30%–70% adaptive. By incorporating multiphysics coupled simulation modeling, the process parameters can be optimized through computer settings during welding, and the optimal combination of welding process parameters can be selected, thereby improving production efficiency.

[0052] The control system can select the laser welding mode based on the width of weld 81, including narrow-gap laser autofusion welding and narrow-gap laser filler wire welding. The computer adaptively adjusts the welding mode according to the width of weld 81. Narrow-gap laser autofusion welding is suitable for welds 81 with a width ≤ 2mm. Figure 4 As shown, narrow-gap laser filler wire welding is suitable for welds 81 with a width greater than 2mm, such as welds 81 with a width of 2mm to 5mm. The filler wire diameter can be 0.8 to 1.2mm. Both modes can perform multi-pass welding according to the depth.

[0053] S3: The control unit 6 controls the fixing unit 4 to fix the target workpiece 8 in a preset position.

[0054] For example, the control unit 6 controls the drive roller 401 of the fixing unit 4 to adjust the height of the target workpiece 8 so that the center of the roller 401 is coaxial with the pneumatic clamp 402. The control unit 6 controls the pneumatic clamp 402 of the fixing unit 4 to approach the outer edge of the target workpiece and maintain constant force clamping after the contact pressure reaches the set value. The path planning module of the control unit 6 generates a welding trajectory based on the point cloud data of the weld seam 81, and the trajectory closed-loop error is <0.1mm.

[0055] In some implementations, clamping stress should be ensured. Much lower than the yield strength of the target workpiece material 8 To avoid plastic deformation;

[0056] Wherein, F is the clamping force of the pneumatic clamp 402, which can be measured by the pressure sensor installed on the pneumatic clamp 402; This refers to the effective contact area between the fixture and the workpiece.

[0057] In some embodiments, when the target workpiece 8 is placed in a preset position, the fixing part 4 can be used to fix the target workpiece 8, thereby further improving the positioning accuracy.

[0058] S4: The control unit 6 generates a preset welding trajectory path based on the position of weld 81.

[0059] The control unit 6 generates a preset welding trajectory path based on the position of weld 81, which can avoid path deviation caused by workpiece assembly errors and improve welding accuracy and welding quality.

[0060] S5: The control unit 6 drives the welding execution module 202 to move the laser emitting end 212 to the preset position of the weld seam 81 of the target workpiece 8; During welding, the two protective gas delivery pipes 203 of the welding execution module 202 can provide a mixture of argon and helium gas, and the mixing ratio can be precisely adjusted to optimize the protection effect of the molten pool and control the heat input, thereby effectively suppressing welding defects.

[0061] The welding execution module 202 precisely aligns the laser focus with the preset starting point of the weld seam 81 (identified by the positioning unit 5 and planned by the control unit 6), avoiding welding offset, incomplete welding or burn-through caused by manual focusing or mechanical cumulative errors, thus improving the quality of the first weld, which is especially important for small weld seams 81 (such as battery tabs and sensor housings).

[0062] S6: The control unit 6 controls the laser generating module 21 to output the laser beam 9 according to the optimal welding process parameter combination. The laser beam 9 is turned by the swing execution module 31 and then shot into the weld 81 position.

[0063] The laser generating module 21 outputs laser based on the optimal parameter combination (such as power, frequency, and duty cycle) obtained from the multiphysics simulation in S2; the parameters are geometrically matched with the actual weld 81 to avoid overheating or insufficient penetration, resulting in a high success rate of welding on the first attempt, reducing trial and error costs, and making it suitable for manufacturing high-value products.

[0064] By integrating precise positioning, simulation-driven, and dynamic beam control into a three-in-one intelligent welding control, it effectively solves the three major pain points of traditional laser welding: inaccurate welding start, blind parameters, and poor forming. It significantly improves welding quality stability, process adaptability, and automation level, and is especially suitable for high-end manufacturing fields with stringent consistency requirements (such as new energy, medical, and electronics).

[0065] S7: During the welding process, the control unit 6 controls the welding execution module 202 to drive the laser emitter 212 and the swing execution module 31 to move along the direction of the weld seam 81 according to the preset welding trajectory path.

[0066] S8: The control unit 6 controls the swing execution module 31 to swing at a set amplitude so that the laser beam 9 reciprocates along the first direction and the second direction, both of which are perpendicular to the direction in which the weld 81 extends.

[0067] like Figure 6As shown, the laser beam 9 is repeatedly scanned along the first and second directions to stir the molten pool, promote gas escape, reduce porosity, expand the effective weld width, and improve the adaptability of the lap gap. Even if there is an assembly gap, the oscillating beam can still cover the entire joint to avoid incomplete fusion. For highly reactive materials (copper, aluminum) or dissimilar materials, the reciprocating scanning helps to stabilize the keyhole and improve welding stability.

[0068] like Figure 7 As shown, during the welding process, the welding execution module and the oscillation execution module jointly control the spot of the laser beam 9 to perform periodic reciprocating motion along the triangular wave trajectory 10 in the weld seam 81 region of the target workpiece 8. Its motion trajectory can be described by the following piecewise function:

[0069] Where x(t) is the offset of the laser beam in the transverse direction of weld 81 at time t, A is the oscillation amplitude, and T is the oscillation period (T=1 / f, f is the oscillation frequency). The triangular wave oscillation has a constant scanning speed (except at the instant of the turning point) and sharp turning characteristics, which makes the laser beam 9 stay in the central region of weld 81 for a shorter time and act on the side wall region for a relatively longer time. This can more effectively promote the fusion of the side wall and stir the molten pool more strongly through the linear "scraping" effect on the molten pool, thereby significantly improving the weld 81 formation, refining the grains, and reducing porosity.

[0070] S9: The direction detection module detects the scanning direction of the laser beam 9 in real time.

[0071] A high-resolution optical / magnetic encoder can be integrated onto the galvanometer motor shaft to directly output angular position signals. This provides high accuracy and fast response, and is integrated with the galvanometer, eliminating the need for an external encoder. The orientation detection module can also be a high-precision position sensor; for example, a laser displacement sensor or an eddy current sensor can be used to non-contactly measure the actual deflection angle of the reflector.

[0072] S10: The direction detection module sends the detected direction signal to the modulation module.

[0073] During detection, a high-precision encoder or analog voltage can be used to acquire the real-time position signal x(t) of the galvanometer. The position signal can be calculated by measuring adjacent sampling points t. k and t k-1 positional difference between To determine the instantaneous scanning direction of laser beam 9; The calculation formula is as follows:

[0074] The determination rule is as follows: if Δx > 0, then the laser beam 9 is determined to be scanning along the first direction; if Δx < 0, then the laser beam 9 is determined to be scanning along the second direction.

[0075] S11: The modulation module adjusts the duty cycle of the laser generating module 21 in real time according to the received direction signal so that the duty cycle of the laser beam 9 when scanning along the first direction is higher than the duty cycle when scanning along the second direction.

[0076] By real-time detection of the laser beam's movement direction and dynamic adjustment of the laser's duty cycle in different scanning directions, a higher duty cycle is achieved when scanning along the first direction, while a lower duty cycle is achieved along the second direction. This provides higher energy density on one side of the oscillating path (e.g., the forward direction), which helps to fully melt the base material and promotes feeding before solidification at the rear of the molten pool. On the other side (e.g., the return stroke), energy input is reduced to avoid overheating and excessive metal vapor back pressure, thereby suppressing porosity formation. The combination of reciprocating scanning of the laser beam 9 along the first and second directions with duty cycle control achieves dual optimization of spatial energy dispersion and temporal precise energy control. This reduces sudden changes in heat accumulation, avoids collapse caused by sudden energy increases, improves molten pool wettability and fluidity, enhances sidewall fusion, reduces the risk of incomplete fusion, promotes metallurgical reactions and gas expulsion, and significantly reduces porosity. Ultimately, this results in a welded joint with uniform shape, dense internal structure, and stable mechanical properties, improving welding quality and reducing the risk of cracking during service.

[0077] In some implementations, based on the direction detection result, the output power of the laser can be automatically switched by the FPGA state machine at the instant the scanning direction changes, with the delay controlled within one PWM cycle to ensure the continuity of light output.

[0078] The duty cycle of laser beam 9 is 100% when scanning along the first direction, and 30%–70% when scanning along the second direction. By setting an asymmetric energy distribution strategy of 100% duty cycle in the first direction and 30%–70% duty cycle in the second direction, active control of the molten pool flow is achieved. This significantly improves the surface quality of weld 81, suppresses porosity and undercut, and enhances adaptability to assembly errors and dissimilar materials while ensuring penetration and fusion. The 30% duty cycle in the second direction represents extremely low energy retracement, suitable for materials prone to burn-through; the 70% duty cycle in the second direction represents near-symmetrical oscillation, used in applications requiring high weld width uniformity.

[0079] The control unit 6 can obtain the scanning speed of the laser beam 9 as it scans along the second direction, and dynamically adjust the duty cycle according to the scanning speed to achieve more precise energy control; the duty cycle of the laser beam 9 as it moves along the second direction is calculated using the following formula:

[0080] in: The duty cycle of the laser beam 9 when it moves along the second direction; This is the preset lower limit for the duty cycle; This is the preset upper limit for the duty cycle; This represents the instantaneous scanning speed of the current laser beam 9; This is the maximum scanning speed. When the process requires changes to the oscillation amplitude A or frequency f, the system can automatically calculate the new... The return power is adjusted accordingly to ensure uniform and excellent weld formation under different oscillation parameters.

[0081] S12: The weld monitoring unit 7 monitors the status of weld 81 in real time and sends corresponding signals to the control unit 6; The sensing layer (weld monitoring unit 7) can collect real-time status information such as molten pool morphology, temperature, brightness, width, and spatter through high-speed vision, infrared thermal imaging, plasma sensing, and other means. By combining a real-time monitoring system with multiphysics coupling simulation modeling, process parameters can be optimized in real time during welding through computer settings, eliminating the need for extensive subsequent testing and correction, thus improving production efficiency.

[0082] S13: The control department adjusts the welding parameters according to the weld condition.

[0083] The decision-making layer (control unit 6) can determine whether the current welding deviates from the ideal state based on preset quality criteria (such as the weld pool width threshold and temperature gradient range); the execution layer (modulation module + laser generation module 21 + oscillation execution module 31) can dynamically adjust parameters such as laser power, duty cycle, frequency, oscillation amplitude, or welding speed. Through the real-time perception and closed-loop control of the weld pool state by the weld monitoring unit 7 during the welding process, a leap from experience-driven to data-driven approaches is achieved, which not only significantly improves the quality stability and defect tolerance of weld 81, but also endows the laser welding system with intelligent attributes that can autonomously adapt to complex working conditions.

[0084] In some embodiments, if the difference between the molten pool temperature in the weld 81 and the melting point of the target workpiece 8 is detected to be greater than a first set value, the laser power is reduced; for example, the first set value can be 100°C, and if the molten pool temperature is detected to exceed the material melting point of 100°C, the laser power can be automatically reduced by 5% to 10%; In some implementations, if a depression in the center of the weld pool in weld 81 is detected to be greater than a second preset value, the proportion of welding shielding gas is increased. For example, the second preset value can be 0.2 mm. If signs of collapse appear (depression in the center of the weld pool > 0.2 mm), the proportion of helium in the shielding gas is immediately increased.

[0085] S14: After welding is completed, the control unit 6 controls the laser generating module 21 to stop working; After the laser generating module 21 stops working, the protective gas can continue to be supplied for 5-10 seconds to ensure that the weld 81 cools and sets. High-temperature metals (especially aluminum, titanium, and stainless steel) are easily oxidized above 600°C. Delayed gas supply creates an inert atmosphere, ensuring the metallurgical quality of weld 81. Slow cooling reduces thermal stress and lowers the risk of solidification cracks; continuous gas flow also helps residual gas escape.

[0086] By using post-weld delay protection and automatic forming detection, the oxidation and deterioration of the weld seam are effectively prevented, and the objective quantification and closed-loop traceability of welding quality are realized, significantly improving product reliability and the level of production line intelligence.

[0087] S15: The weld monitoring unit 7 scans the weld 81 and inspects the weld 81.

[0088] Post-weld inspection results can be used to determine whether the part is qualified (online sorting), and fed back to the process database to optimize parameters for subsequent batches. During inspection, a surface depression of ≤0.1mm is considered qualified when weld 81 is formed.

[0089] S16: The service performance evaluation module determines whether the target workpiece 8 meets the long-term service requirements; If the target workpiece 8 meets the requirements for long-term service, the control unit 6 sends a signal to the operator to move the target workpiece to the finished product area. At the same time, it packages the actual welding parameters, monitoring data, weld morphology 81 and simulated residual stress data of the target workpiece 8 together as a digital twin data file of the target workpiece 8 and feeds it back to the process expert database. If the target workpiece 8 does not meet the long-term service requirements, the reasons can be analyzed and parameter suggestions can be generated. Based on the original simulation, key parameters can be locally adjusted (such as increasing power or changing the oscillation frequency). Welding and testing can then be carried out according to the subsequent steps until the target workpiece 8 meets the long-term service requirements.

[0090] For example, the service performance evaluation module can construct a performance degradation correlation model for the welded joint based on the actual morphology of weld 81, welding process monitoring data, simulated residual stress distribution, and material service environment model, predicting its fatigue life and reliability under complex working conditions. If the prediction results meet the preset long-term service requirements, the target workpiece 8 is moved to the finished product area, and its actual welding parameters, real-time monitoring data, weld 3D morphology, and simulated residual stress data are packaged to generate a digital twin data file of the workpiece, which is then uploaded to the process expert database. If the requirements are not met, the failure mode is analyzed, targeted parameter correction suggestions are generated, the welding process parameter combination is updated, and the process jumps to the welding execution stage after step S2 to re-weld and inspect until the workpiece passes the service performance evaluation.

[0091] Using a 304 stainless steel bearing cage as the target workpiece 8 to be welded, the laser welding method specifically includes the following steps: After a 200mm diameter bearing cage made of 304 stainless steel is placed on the roller 401 of the fixing part 4, the control part 6 activates the positioning part 5. Using a high-resolution industrial camera (2 megapixels) and a ring light source, when the weld 81 is detected, a signal is transmitted to the control part 6, which then stops the roller 401. The control part 6 then controls the positioning part 5 to acquire the cage profile and the features of the weld 81 (weld 81 length 20mm, width 3mm, depth 10mm). The control part 6 then calculates the center coordinates of the weld 81, achieving a positioning accuracy of ±0.05mm.

[0092] The control unit acquires the material parameters of 304 stainless steel (melting point 1390-1450℃, thermal conductivity 16.3W / (m·K), structural dimensions φ200mm×20mm; and calls the multiphysics coupling simulation modeling unit (thermal field-molten pool-stress).

[0093] The multiphysics coupling simulation modeling unit then set the parameter search space as follows: laser power 4000–6000 W, welding speed 0.8–1.2 m / min, oscillation amplitude 0–5 mm, oscillation frequency 100–150 Hz, and oscillation modulation parameters of 100% duty cycle for outgoing and 30%–70% duty cycle for return adaptively. After multiple simulation iterations by the multiphysics coupling simulation modeling unit, the optimal combination of welding process parameters was selected as follows: laser power 5200 W, welding speed 1.0 m / min, oscillation amplitude 1.2 m, oscillation frequency 120 Hz, 100% duty cycle for outgoing and 45% duty cycle for return (according to the adaptive calculation values ​​in Table 1 below).

[0094] Table 1

[0095] The control unit 6 adjusts the welding method to narrow gap laser filler wire welding according to the width of weld 81, sets the defocusing amount to +25mm, the wire feeding speed to 3.5m / min (welding wire material ER308L, diameter 1.0mm), the shielding gas ratio to Ar 87%+He 13%, and the flow rate to 12L / min.

[0096] The control unit 6 controls the roller 401 to adjust the height of the cage so that the center of the roller 401 is coaxial with the pneumatic clamp 402. The pneumatic clamp 402 (equipped with a pressure sensor) approaches the outer edge of the cage at a speed of 50 mm / s. After the control unit 6 detects that the contact pressure reaches 300 N, it maintains constant force clamping. The path planning module of the control unit 6 generates a welding trajectory based on the point cloud data of weld 81, sets the welding start phase angle to 15° (avoiding the assembly mark position), and the trajectory closed-loop error is <0.1 mm.

[0097] The control unit 6 controls the flow control valve to open the protective gas, and the gas flow rate is precisely controlled to 12L / min by the mass flow meter (flow control valve). After the pressure sensor detects that the pipeline pressure is stable at 0.3MPa, the laser generation module 21 is started after a delay of 500ms.

[0098] The control unit 6 controls the swing execution module 31 to drive the laser beam 9 to swing along a triangular wave trajectory 10, with the amplitude set to A = 1.2 mm and the frequency f = 120 Hz. Its scanning speed... = 4 1.2 120 = 576 mm / s.

[0099] The direction detection module calculates Δx in real time to clearly determine whether the beam is on the outgoing or returning path.

[0100] The modulation module dynamically adjusts the duty cycle and laser power according to the direction signal to achieve a total power of 5200W for the outgoing path and a total power of 2340W for the return path. The weld monitoring unit 7 acquires images of the molten pool at 1000fps and estimates the molten pool depth. The computer (control unit) analyzes the monitoring data in real time. When the system detects that the molten pool depth is less than 1.5 mm, it triggers a real-time control law for power compensation. The control unit controls the laser generating module 21 to increase the laser power from 4600W to 4700W within 100ms. Process parameter deviation events are also recorded. Simultaneously, if parameter deviations occur, the control unit 6 uses an adaptive algorithm to adjust the welding parameters.

[0101] After welding is completed, control unit 6 stops the laser, while the protective gas continues to be supplied for 8 seconds; Figure 8 and Figure 9 As shown, the weld monitoring unit 7 acquires images of weld 81, and the control unit 6 controls and determines that the surface flatness of weld 81 is ≤0.1mm and there are no depressions, which meets the standard.

[0102] The control unit 6 controls the pneumatic clamp 402 to release, and the roller 401 drives the retainer to retract, completing the welding. At the same time, the actual welding parameters, monitoring data, weld morphology 81 and simulation prediction residual stress data are packaged into a digital twin file and stored in the process expert database.

[0103] The service performance evaluation module performs quantitative evaluation based on simulation and testing data: fatigue life prediction is based on the crack propagation formula, using parameters such as stress intensity factor range and material constants to predict the number of cycles required for defects to propagate to the critical size. The critical defect size determination is based on fracture mechanics criteria, combining parameters such as material fracture toughness, geometric correction factor, and total stress (the sum of service load stress and welding residual stress), calculating that the critical porosity size of the joint can reach φ0.42mm under optimal parameters.

[0104] Reference Figure 8 and Figure 9 In this embodiment, a systematic comparative experiment was conducted to compare the welding quality of different oscillation modes. The experimental results are as follows: Table 2

[0105] As shown in Table 2, the directional modulation oscillation welding technology proposed in this invention achieves a leapfrog improvement in welding quality compared with the traditional non-oscillation and equal power oscillation modes: the porosity is reduced from 2.8% in the traditional mode to 0.2%, the risk of weld 81 collapse is reduced from 18% to below 1%, and the grain size is significantly refined to 12μm, with the overall pass rate increasing to 99.5%, fundamentally solving the welding quality bottleneck of high-end bearing cages.

[0106] Reference Figure 8 and Figure 9 In this embodiment, a systematic comparative experiment was conducted on mechanical performance testing, and the experimental results are shown in Table 3.

[0107] Table 3

[0108] This invention achieves a comprehensive breakthrough in mechanical properties: tensile strength is increased to 585MPa, yield strength reaches 425MPa, elongation is increased by 53%, and impact toughness is increased by 55%. All indicators far exceed the service requirements of high-end bearing cages.

[0109] This embodiment employs a novel narrow-gap laser filler wire welding method that meets the requirements for high-performance cage welding, overcoming the limitations of cage laser welding plate thickness, material, and welding defects.

[0110] The novel dual-shielded gas and direction-modulated oscillating laser welding method employed in this embodiment significantly improves welding efficiency and achieves a substantial leap in overall performance compared to traditional welding methods. Firstly, it simplifies the traditionally lengthy processing steps into three core steps: stamping, rounding, and welding, resulting in a production efficiency increase of over 30% and a 30% improvement in raw material utilization. Secondly, the average strength of the welded joint is increased by approximately 15%, and the defect detection rate is suppressed to below 0.3%, effectively controlling spatter and porosity defects. Ultimately, the weld seam 81 achieves a pass rate of 99.5%, and the surface roughness Ra of the weld cage is <0.1μm, fully meeting the stringent precision and reliability requirements of high-end bearings.

[0111] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A laser welding apparatus for a bearing cage, characterized in that, include: The welding unit (2) includes a laser generating module (21) and a welding execution module (202). The laser generating module (21) has a laser emitting end (212), and the welding execution module (202) is connected to the laser emitting end (212). Modulation unit (3), the modulation unit (3) includes: A swing execution module (31) is connected to the laser emitting end (212); A direction detection module is located near the swing execution module (31) or integrated into the swing execution module (31); The modulation module is connected to the laser generating module (21) and is communicatively connected to the direction detection module; The welding execution module (202) is used to move the laser emitting end (212) to a preset position of the weld (81) of the target workpiece (8); The laser emitting end (212) is used to emit a laser beam (9) to start welding; The swing execution module (31) is used to redirect the laser beam (9) so that the redirected laser beam (9) enters the weld (81) position; The welding execution module (202) is also used to drive the laser emitting end (212) and the swing execution module (31) to move along the direction of the weld (81) during the welding process; The swing execution module (31) is also used to swing at a set amplitude during the welding process so that the laser beam (9) reciprocates along a first direction and a second direction, both of which are perpendicular to the direction in which the weld (81) extends; The direction detection module is used to detect the scanning direction of the laser beam (9) in real time and send the detected direction signal to the modulation module; The modulation module is used to adjust the duty cycle of the laser generating module (21) in real time according to the received direction signal, so that the duty cycle of the laser beam (9) when scanning along the first direction is higher than the duty cycle when scanning along the second direction.

2. The laser welding apparatus for bearing cages according to claim 1, characterized in that, The modulation module is used to control the duty cycle of the laser beam (9) to be 100% when scanning along the first direction and 30% to 70% when scanning along the second direction.

3. The laser welding apparatus for bearing cages according to claim 1, characterized in that, The welding execution module (202) and the oscillation execution module (31) are used to jointly control the spot of the laser beam (9) to make periodic reciprocating motion along the triangular wave trajectory (10) in the weld seam (81) area of ​​the target workpiece (8) during the welding process.

4. The laser welding apparatus for bearing cages according to claim 1, characterized in that, The orientation detection module is specifically used to calculate adjacent sampling points t during the welding process. k and t k-1 positional difference between To determine the instantaneous scanning direction of the laser beam; among which, The calculation formula is as follows: ； If Δx > 0, the laser beam is determined to be scanning along the first direction; if Δx < 0, the laser beam is determined to be scanning along the second direction.

5. The laser welding apparatus for bearing cages according to claim 1, characterized in that, The modulation module is specifically used to obtain the scanning speed of the laser beam (9) when it scans along the second direction, and dynamically adjust the duty cycle according to the scanning speed; the duty cycle of the laser beam (9) when it moves along the second direction is calculated using the following formula: ； in: The duty cycle of the laser beam (9) when it moves along the second direction; This is the preset lower limit for the duty cycle; This is the preset upper limit for the duty cycle; The instantaneous scanning speed of the laser beam (9) is given. This represents the maximum scan speed.

6. The laser welding apparatus for bearing cages according to any one of claims 1-5, characterized in that, The welding apparatus further includes: Fixing part (4), the fixing part (4) is used to fix the target workpiece (8) in a preset position; Positioning part (5), which is disposed on one side of the fixing part (4) for identifying and positioning the weld (81). The control unit (6), the welding unit (2), the modulation unit (3), the fixing unit (4) and the positioning unit (5) are respectively connected to the control unit (6).

7. The laser welding apparatus for bearing cages according to claim 6, characterized in that, The laser welding apparatus also includes: Weld monitoring unit (7) is positioned facing the weld (81) of the target workpiece (8). The weld monitoring unit (7) is connected to the control unit (6). The weld monitoring unit (7) is used to detect the state of the weld (81) in real time during the welding process and send corresponding signals to the control unit (6). The control unit (6) adjusts the welding parameters according to the state of the weld (81).

8. The laser welding apparatus for bearing cages according to claim 7, characterized in that, The welded part (2) also includes: Two gas delivery pipes (203) are provided on both sides of the laser emitting end (212) for delivering argon and helium respectively. Two flow regulating valves are provided on the two gas delivery pipes (203) respectively, and both flow regulating valves are connected to the control unit (6). If the weld monitoring unit (7) detects that the center depression of the molten pool in the weld (81) is greater than the second set value, the weld monitoring unit (7) sends a corresponding signal to the control unit (6), and the control unit (6) controls the flow regulating valve to increase the helium ratio.

9. The laser welding apparatus for bearing cages according to claim 6, characterized in that, The control unit (6) includes: The multi-physics coupling simulation modeling unit is used to obtain the material and size data of the target workpiece (8), perform welding process simulation, and select the optimal combination of welding process parameters. The path planning module is used to generate a preset welding trajectory path based on the position of the weld (81); the control unit (6) is also used to control the welding unit (2) and the modulation unit (3) to weld according to the optimal welding process parameters during the welding process, and to control the welding execution module (202) and the swing execution module (31) to control the spot of the laser beam (9) to move along the preset welding trajectory path; The service performance evaluation module is used to determine whether the target workpiece (8) meets the long-term service requirements after welding. If the target workpiece (8) meets the long-term service requirements, the control unit (6) sends a signal to the operator to move the target workpiece (8) to the finished product area. At the same time, the control unit (6) packages the actual welding parameters, monitoring data, weld (81) morphology and simulation prediction residual stress data of the target workpiece (8) together as a digital twin data file of the target workpiece (8) and feeds it back to the process expert database.

10. A laser welding method for a bearing cage, applied to the laser welding apparatus for bearing cages as described in any one of claims 1-9, characterized in that, include: The welding execution module (202) moves the laser emitter (212) to the preset position of the weld (81) of the target workpiece (8); The laser emitting end (212) emits a laser beam (9) to begin welding; The swing execution module (31) is redirected to direct the laser beam (9) so that the redirected laser beam (9) enters the weld (81) position; The welding execution module (202) drives the laser emitting end (212) and the swing execution module (31) to move along the direction of the weld (81) during the welding process; The oscillation execution module (31) is oscillated at a set amplitude during the welding process so that the laser beam (9) reciprocates along the first direction and the second direction; The direction detection module detects the scanning direction of the laser beam (9) in real time and sends the detected direction signal to the modulation module. The modulation module adjusts the duty cycle of the laser generating module (21) in real time according to the received direction signal so that the duty cycle of the laser beam (9) when scanning along the first direction is higher than the duty cycle when scanning along the second direction.

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