In laser cladding and laser remanufacturing applications, the objects to be processed are often irregularly shaped workpieces or have uneven surfaces. The laser cladding nozzle needs to maintain a certain distance from the workpiece surface to maintain stable process quality. Therefore, in actual engineering applications, long-term programming work is often required, which affects work efficiency and extends the construction period. For the robot laser cladding system, it is mainly reflected in the heavy robot teaching and schooling work. Normally, robot teaching relies entirely on manual operation, which requires high operator experience and is error-prone. It is a bottleneck in achieving high-efficiency, high-precision laser cladding and repair applications.

Adaptive conformal laser cladding is an effective method to solve the above problems, which mainly includes the following three basic steps:

1. Use sensors for online detection: sensors can be contact type, machine vision, laser displacement, etc., and the corresponding relationship between the sensor measurement coordinate system and the robot laser cladding tool coordinate system must be established;

2. Automatic data processing: including data filtering, reconstruction, modeling, etc. Some applications also need to implement intelligent algorithms such as automatic model matching and defect identification;

3. Automatic path generation and process parameter configuration: Based on the model established by automatic data processing, layered slicing is performed, filling trajectories are generated, and process parameters are automatically selected and optimized according to the defect type.

The adaptive conformal laser cladding function has three typical application scenarios:

1. Significantly reduce manual teaching work, shorten programming time, and improve calibration accuracy;

2. Automatically establish the workpiece coordinate system or user coordinate system, so that the robot path generated by offline programming can be quickly and accurately applied to the workpiece, improving the production cycle; it can replace the conventional feature point positioning method, and can also solve some scenes that cannot be detected manually. Positioning issues;

3. It has a simple 3D scanning function, combined with automatic identification algorithm and slice path generation algorithm, which can achieve rapid defect location and on-site adaptive repair; although the general measurement accuracy is lower than that of conventional 3D measurement systems, it is sufficient and efficient for laser repair High and low cost.

Applications

1. Conformal laser cladding of turbine blades

Turbine blades have relatively complex profiles, and there is usually no high-precision model available for repair. Moreover, after long-term service, the blades will have certain deformations and uneven wear on the surface. Therefore, offline programming methods cannot be used and must be Robot programming is completed using intensive manual teaching. Taking the interval of 50mm as an example, manual teaching of 400 points needs to be completed within 1 square meter. Calculated based on 1 minute for each point, it takes nearly 7 hours, seriously affecting the engineering efficiency, and because it must be completed manually, on-site work is required. The labor intensity is high, and workpieces and equipment may be damaged due to accidental collisions.

Using the adaptive conformal laser cladding function developed by Huirui, in actual production, only four corner points of the cladding area need to be manually taught, and the middle point is automatically scanned and measured by the laser displacement sensor installed on the side of the laser cladding head. The measured data is used to establish the topography of the blade area to be cladded, and then the robot program and host computer software automatically complete partitioning, interpolation, filling, parameter setting, etc. to generate usable robot laser cladding paths. It only takes less than 20 minutes to complete the measurement and path generation work within a 1 square meter curved surface, saving more than 95% of manual time. Moreover, after correcting the robot path through laser displacement measurement, the distance error between the cladding head nozzle and the workpiece surface is within 0.1mm, which perfectly fits the complex and distorted surface of the blade, and the process consistency is very high. In practice, the adaptive conformal laser cladding function is very suitable for this large-area curved surface cladding application needs.

2. Adaptive repair of sprocket components

As the main transmission component of the scraper conveyor, the sprocket chain nest bears huge alternating loads and additional impact loads during the meshing process with the circular chain. At the same time, the working conditions are harsh and filled with coal-water mixture. As a pair Every time the kinematic pair meshes, it will have a high-intensity impact on the sprocket, which will produce sliding friction and abrasive wear. To increase the service life of the sprocket, it requires strong toughness, excellent comprehensive performance, high strength and hardness, and good wear resistance.

Using laser to repair sprocket components can achieve higher strength, hardness and wear resistance than the base material, greatly extending the service life. Moreover, the use of laser repair has high precision and can achieve "near net shape" repair. After adding materials, it is basically close to the size of the original workpiece, without the need for time-consuming and laborious subsequent processes such as grinding and machining, saving materials and man-hours. Significant economic benefits. The key to achieving "near net shape" repair is adaptive laser repair. The following pictures illustrate the main processes of adaptive laser repair.