Laser Cladding Melt Pool Imaging for Coating Quality Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for quality control in laser deposition welding are indirect and lack precision, as they focus on the plasma jet rather than the coated workpiece, and do not effectively monitor the melt pool's geometric shape and intensity variations, which are critical for ensuring the quality of the coating.
Innovation Solution
A method involving an image capture device to detect electromagnetic radiation from the melt pool, compute the location data of areas of equal intensity, and assign an elliptical surface body to these areas, allowing for direct monitoring and control of the laser deposition welding process by analyzing characteristic features such as the ellipse's center, radii, and orientation, thereby ensuring the quality of the coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quality control is performed on the plasma jet enriched with coating material, then quality control can be conducted during the process, but the control is indirect and lacks precision
Solution Approach 1:
Instead of monitoring the plasma jet to indirectly infer coating quality, the invention inverts the approach by directly monitoring the coating layer itself. The image capture device focuses on capturing images of the coating layer as it is being deposited, allowing direct observation and measurement of coating properties such as thickness, uniformity, and surface quality, thereby achieving both process-based control and high measurement precision.
Solution Approach 2:
The invention introduces an image capture device as an intermediary between the coating process and quality assessment. This device captures real-time images of the coating layer, which then serve as the basis for automated image analysis and quality determination, enabling precise and objective quality control during the coating process.
2Temperature
If the melt pool is monitored using spectral analysis to determine temperature, then temperature control is achieved, but the geometric shape and intensity variations are not effectively monitored
Solution Approach 1:
The image capture device is designed to perform multiple functions simultaneously: it captures the geometric shape of the melt pool, measures intensity variations, and monitors coating layer properties. This multi-functional approach allows comprehensive monitoring of both temperature-related parameters and geometric characteristics, ensuring both temperature control and manufacturing precision.
Solution Approach 2:
The invention transitions from one-dimensional spectral analysis to two-dimensional image analysis. By capturing spatial information across the melt pool and coating layer, the system can simultaneously assess temperature distribution, geometric shape, and intensity variations, providing comprehensive quality control in multiple dimensions rather than relying solely on spectral temperature data.
3Measurement precision
If detailed analysis of the coating process is performed, then quality control precision is improved, but the complexity of the system increases
Solution Approach 1:
The invention creates an optical copy of the coating process by capturing images of the coating layer and melt pool. This visual copy serves as a simplified representation that can be analyzed using image processing algorithms, avoiding the need for complex physical sensors while maintaining high measurement precision. The image data serves as a faithful replica of the actual coating state.
Solution Approach 2:
The invention replaces complex mechanical or physical measurement systems with an optical-based image capture and analysis system. By using standard imaging technology combined with automated image processing, the system achieves detailed quality assessment without requiring complex mechanical sensors or invasive measurement devices, thereby reducing overall system complexity while maintaining high precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables precise and reliable quality assessment and control of the welding process, simplifying the analysis by focusing on 'OK' or 'not OK' results, suitable for high-speed laser cladding, and allows for real-time adjustment of process parameters to maintain coating quality.
Implementation Method 1
detecting the electromagnetic radiation emitted as light by the molten pool by means of an image capture device, wherein the brightness of the emitted light represents the intensity of the emitted electromagnetic radiation
Data Source
Figure 1
Figure 2
AI summary
A method for optical quality control in laser cladding, wherein in the laser cladding process the surface (20) of a workpiece (2) to be coated is melted by means of a high-energy laser beam (14) directed onto a processing spot (24) of the surface (20) and focused by a focusing optic (16), thereby generating a melt pool (26) in the processing spot (24), and wherein a powdered coating material is applied to the melt pool (26) in the processing spot (24), comprises the following steps: a) capturing the electromagnetic radiation emitted by the melt pool (26) as light (47) by means of an image acquisition device (40), wherein the brightness of the emitted light represents the intensity of the emitted electromagnetic radiation; b) forwarding the captured image information of the melt pool (26) to an image evaluation unit (42);c) computationally determining the position data of at least one area (28) of equal intensity and/or of at least one area within a specific intensity interval in the acquired image information to form a contour of the area; d) assigning at least one symmetrical surface body (E) to the at least one area (28) of equal intensity by approximating a geometric figure to the contour of the area; e) determining features characteristic of the geometric shape of the at least one symmetrical surface body (E);f) Storing the characteristic features of the at least one symmetrical surface body as a data set in a data storage device (44) and g) Acquiring, controlling and/or monitoring at least one parameter of the laser cladding process that influences the quality of the coating by means of a process control device (46) on the basis of the data of the characteristic features of the at least one symmetrical surface body (E).;