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CN-121491539-B - Intelligent laser head with molten pool monitoring function

CN121491539BCN 121491539 BCN121491539 BCN 121491539BCN-121491539-B

Abstract

The invention discloses an intelligent laser head with a molten pool monitoring function, and belongs to the technical field of laser welding. The invention relates to an intelligent laser head with a molten pool monitoring function, which comprises a device shell, an optical fiber laser and a molten pool detection head, wherein a clamping plate is arranged at the lower end of a positioning bracket, a magnetorheological fluid damper is arranged between the clamping plate and the positioning bracket, two micro-piezoelectric ceramic driving structures are arranged in the molten pool detection head, and a lens assembly is arranged in the molten pool detection head. The invention solves the problem that the existing laser welding head cannot ensure the long-term stability of the processing focus and the monitoring sight line in the state of heat engine, can change the angles and the positions of the lens component and the built-in lens, reversely finely adjusts the positions of the lens according to the real-time temperature, actively compensates the light path offset caused by thermal expansion, changes the passive bearing heat of the lens component into active real-time correction, ensures the long-term stability of the processing focus and the monitoring sight line of the lens component in the state of heat engine, and improves the working effect.

Inventors

  • SHI ZHONG

Assignees

  • 深圳欧斯普瑞智能科技有限公司

Dates

Publication Date
20260505
Application Date
20260114

Claims (8)

  1. 1. The intelligent laser head with the molten pool monitoring function comprises a device shell (1), an optical fiber laser (201) and a molten pool detection head (3), and is characterized in that the optical fiber laser (201) is arranged on two sides below the device shell (1), the molten pool detection head (3) is arranged on one side of the optical fiber laser (201), and the angles of the optical fiber laser (201) and the molten pool detection head (3) are identical; positioning brackets (104) are arranged on two sides below the device shell (1), a clamping plate (205) is arranged at the lower end of each positioning bracket (104), the fiber laser (201) penetrates through each clamping plate (205) and is embedded in each positioning bracket (104) to be clamped with each positioning bracket (104), and a magnetorheological fluid damper (204) is arranged between each clamping plate (205) and each positioning bracket (104); two micro-piezoelectric ceramic driving structures (305) are arranged in the molten pool detection head (3), a lens assembly (303) is arranged in the molten pool detection head (3), and the front end of the micro-piezoelectric ceramic driving structure (305) is movably connected with two sides of the lens assembly (303) through connecting lugs; The bottom of the device shell (1) is provided with a processing table (5), the upper end of the processing table (5) is provided with a positioning workbench (501), the upper end of the positioning workbench (501) is provided with a temperature sensor, and the temperature sensor is electrically connected with the micro-piezoelectric ceramic driving structure (305) through a plc module; the plc module is internally preset with a nonlinear compensation strategy based on a thermal engine coupling effect, and is configured to read real-time temperature data of the temperature sensor at a preset sampling frequency and calculate a real-time driving voltage applied to the micro-piezoelectric ceramic driving structure (305) by using the following thermal drift compensation formula : In the formula, For the calculated real-time driving voltage applied to the micro-piezoelectric ceramic driving structure (305); a zero bias voltage for the lens assembly (303) at standard focal length; an effective optical path physical length for the lens assembly (303) at a reference temperature; An equivalent linear coefficient of thermal expansion for the material of the device housing (1) and the lens assembly (303); A current real-time temperature acquired for the temperature sensor; a base reference temperature for system calibration; the number of layers of piezoelectric ceramic stacks inside the micro piezoelectric ceramic driving structure (305); A longitudinal inverse piezoelectric constant for the micro-piezoelectric ceramic drive structure (305) for characterizing voltage-displacement conversion efficiency; is a thermal inertia gain coefficient for compensating for thermal conduction induced time delays; Is a natural logarithmic function and is used for simulating nonlinear saturation characteristics of thermal stress accumulation; the absolute value of the temperature change rate in the current sampling period is given; The temperature change rate is normalized by the thermal response sensitivity threshold; The plc module performs active feed-forward compensation on the position of the lens assembly (303) through the thermal drift compensation formula when the temperature accumulation rise or the abrupt power change caused by continuous operation of the fiber laser (201) causes severe temperature fluctuation.
  2. 2. The intelligent laser head with molten pool monitoring according to claim 1, wherein a QBH interface (101) is installed on the device housing (1), the QBH interface (101) is connected with a fiber laser (201), the QBH interface (101) is electrically connected with an optical calibrator, and a laser positioning sensor is installed at the lower end of the device housing (1).
  3. 3. The intelligent laser head with the molten pool monitoring function according to claim 1, wherein radiators (102) are fixedly connected to two sides of the device shell (1), the radiators (102) are attached to the inside of the device shell (1) through heat exchange tubes, a cooling fan (103) is installed at the lower end of the radiator (102), and the cooling fan (103) is connected with the radiators (102) through fixing screws.
  4. 4. An intelligent laser head with molten pool monitoring according to claim 3, characterized in that a positioning bracket (104) is installed on one side of the lower part of the device housing (1), the positioning bracket (104) is connected with the device housing (1) through a fixing bolt, an adjusting head (301) is arranged at the lower end of the positioning bracket (104), and the adjusting head (301) is fixedly connected with the lower end of the positioning bracket (104) through a locking piece.
  5. 5. The intelligent laser head with molten pool monitoring according to claim 1, characterized in that a laser emitting head (202) is installed at the lower end of the optical fiber laser (201), a side shaft protection air tap (4) is arranged on one side of the laser emitting head (202), the side shaft protection air tap (4) is fixedly connected with a device shell (1) through a connecting rod, the side shaft protection air tap (4) is used for leading cold air to cool the molten pool rapidly, a cleaning pipe (6) is arranged in the device shell (1), the position of an air blowing port of the cleaning pipe (6) corresponds to the welding position of the laser emitting head (202), and an air guiding port (601) is arranged at the upper end of the cleaning pipe (6).
  6. 6. The intelligent laser head with molten pool monitoring according to claim 1, wherein two ends of the magnetorheological fluid damper (204) are fixedly connected with the fastening frame (203) and the retainer (2) respectively, an exciting coil, a magnetic pole and a magnetorheological fluid filling cavity are arranged in the magnetorheological fluid damper (204), and the clamping plate (205) is clamped with the outside of the fiber laser (201) through a damping washer. ‌ A
  7. 7. The intelligent laser head with the molten pool monitoring function according to claim 1, wherein a fixed disc (302) is arranged outside the molten pool detection head (3), the fixed disc (302) is fixedly connected with the molten pool detection head (3) and the adjusting head (301) through fixed screws respectively, a built-in lens (304) is arranged at the front end of the lens assembly (303), and the built-in lens (304) extends out of the molten pool detection head (3) to be movably connected with the molten pool detection head (3); The two sides of the molten pool detection head (3) are provided with movable grooves, the upper end of the micro-piezoelectric ceramic driving structure (305) is provided with a connector (307), and the upper end of the micro-piezoelectric ceramic driving structure (305) is movably connected with the molten pool detection head (3) in the movable grooves through the connector (307); The internal mounting of molten pool detection head (3) has vision camera (306), vision camera (306) are including CCD camera, spectrum appearance and thermal infrared imager, install surveillance camera machine (7) in the middle of the inside of device casing (1), surveillance camera machine (7) and vision camera (306) are all connected with the terminal through transmission module.
  8. 8. The intelligent laser head with puddle monitoring of claim 7, wherein the terminal is further configured to perform a magnetorheological damping adaptive vibration suppression method based on visual acuity, the method comprising the steps of: step S1, the terminal receives a molten pool real-time video stream acquired by the vision camera (306) through the transmission module, and intercepts a region of interest (ROI) containing the edge of the molten pool from each frame of image; s2, the terminal carries out convolution operation on the region of interest by using the Laplacian operator, calculates the edge gradient amplitude average value of the current frame image, and defines the edge gradient amplitude average value as an image definition index ; Step S3, the terminal monitors the image definition index in real time When detecting When the value is lower than a preset definition threshold value, judging that the device shell (1) is interfered by micro-amplitude high-frequency vibration; Step S4, immediately starting an active vibration suppression optimizing mode by the terminal, sending an adjusting instruction to a controller connected with the magnetorheological fluid damper (204), and stepwise changing the current input to the exciting coil of the magnetorheological fluid damper (204) by a preset step length; step S5, after each change of the current, the terminal recalculates a new image definition index And comparing the current before and after the change Value change, reserve cause The direction of the current with increased value until The value reaches a local maximum value, so that the optimal damping rigidity capable of restraining the micro-amplitude vibration to the greatest extent under the current working condition is locked.

Description

Intelligent laser head with molten pool monitoring function Technical Field The invention relates to the technical field of laser welding, in particular to an intelligent laser head with a molten pool monitoring function. Background The laser directional energy deposition technology is an additive manufacturing technology which uses laser as a heat source to form a molten pool on a substrate, and uses a powder feeding device to convey powder to the molten pool for deposition according to a preset model. Although the laser directional energy deposition technology has a plurality of advantages, the laser, the powder and the metal matrix interact simultaneously in the deposition process, so that the chemical metallurgy and the thermophysical process are very complex, the rapid heating and rapid cooling fusion and solidification process easily causes the defects of microscopic cracks, air holes, spheroidization, splashing, collapse and the like of the workpiece, and the metallurgical defects and poor molding quality have serious influence on the microstructure and mechanical properties of the part, thus restricting the development of the technology. Therefore, the method has important significance in real-time monitoring of the parts in the laser directional energy deposition process. The molten pool is a tiny liquid metal area formed by laser acting on the surface of the material. Its state directly determines the quality of the final weld or print layer. The traditional laser processing is open-loop, namely, the laser processing is performed after the parameters are preset, so that tiny fluctuation in the processing process cannot be dealt with, and a molten pool needs to be monitored. In the prior art, the laser welding head cannot ensure the long-term stability of a processing focus and a monitoring sight line in a heat engine state in the actual use process, so that the existing requirements are not met, and an intelligent laser head with a molten pool monitoring function is provided. Disclosure of Invention The invention aims to provide an intelligent laser head with a molten pool monitoring function, which solves the problem that a laser welding head provided in the background art cannot ensure long-term stability of a processing focus and a monitoring sight line in a heat engine state in the actual use process. The intelligent laser head with the molten pool monitoring function comprises a device shell, an optical fiber laser and a molten pool detection head, wherein the optical fiber laser is arranged on two sides below the device shell, the molten pool detection head is arranged on one side of the optical fiber laser, the angle settings of the optical fiber laser and the molten pool detection head are the same, welding work is carried out on a welding point and a welding line by matching the optical fiber laser with a laser emission head, and the molten pool detection head carries out detection work on a molten pool of materials above a processing table and a positioning workbench; The device comprises a device shell, wherein a positioning support is arranged on two sides below the device shell, a clamping plate is arranged at the lower end of the positioning support, the optical fiber laser penetrates through the clamping plate and is embedded in the positioning support to be clamped with the positioning support, a magnetorheological fluid damper is arranged between the clamping plate and the positioning support, and high-frequency micro-amplitude vibration and workshop vibration from outside during high-speed movement of the robot can be effectively filtered through the magnetorheological fluid damper, so that a stable environment is provided for a precise optical and monitoring system inside the optical fiber laser, and definition of a monitoring image and stability of a processing beam during high-speed movement are ensured; the molten pool detection head is internally provided with two micro-piezoelectric ceramic driving structures, the molten pool detection head is internally provided with a lens assembly, the front end of the micro-piezoelectric ceramic driving structure is movably connected with two sides of the lens assembly through connecting lugs, when the molten pool detection head is used, the temperature around the molten pool is detected through a temperature sensor on a positioning workbench, after the detected temperature receives data through a plc module, the two micro-piezoelectric ceramic driving structures are adjusted through the micro-piezoelectric ceramic driving structure, the two micro-piezoelectric ceramic driving structures stretch and retract and are adjusted to different lengths, so that the angles and positions of the lens assembly and an embedded lens can be changed, in long-term work, laser welding work is carried out through an optical fiber laser, in the welding work, the optical fiber laser is fixed through a clamping plate and a retainer, and after the optical fib