Laser Cutting Process Imaging for Real-Time Burr Detection
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Solution Overview
Problem
Existing laser cutting technologies struggle to provide comprehensive, real-time monitoring of cutting quality, particularly in individual planes, such as burrs on the underside of cut workpieces, due to limitations in spatial and temporal resolution and directional dependence of current observation methods.
Innovation Solution
A method and device for laser cutting that utilize an image acquisition system with an array of microlenses, mirrors, and micropolarization filters to capture multiple partial images of the cutting process from different angles, focal lengths, and polarizations, enabling real-time detection of cutting quality features like burrs, scoring, and slag formation through a neural network analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If photodiodes are used for monitoring the cutting process, then real-time monitoring is enabled, but only point information with spatial integration is obtained, limiting detection capability
Solution Approach 1:
The patent segments the monitoring function by using multiple photodiodes arranged in arrays, where each photodiode captures light from a specific spatial location. This segmentation transforms single point information into distributed spatial information, enabling detection of cutting quality variations across different positions without losing spatial resolution.
Solution Approach 2:
The patent transitions from one-dimensional point monitoring to two-dimensional area monitoring by arranging photodiodes in spatial arrays. This dimensional expansion allows simultaneous capture of cutting process information across multiple locations, providing comprehensive spatial coverage while maintaining real-time monitoring capability.
2Loss of information
If cameras are used for observing the cutting process, then two-dimensional area information is obtained, but real-time monitoring capability is reduced due to computational requirements
Solution Approach 1:
The patent extracts only the essential light intensity information from the cutting process using photodiode arrays, eliminating the need for complex image processing. By taking out only the necessary monitoring data (light intensity at specific positions) rather than capturing full images, the system achieves real-time monitoring without computational overhead.
Solution Approach 2:
The patent replaces the mechanical/image processing system with an optical detection system using photodiode arrays. Instead of capturing and processing images computationally, the system directly converts light intensity variations into electrical signals for immediate analysis, substituting computational processing with direct optical measurement.
3Reliability
If comprehensive process sensor technology is used, then cutting breakage and quality degradations can be detected, but degradations in individual planes cannot be distinguished
Solution Approach 1:
The patent applies local quality monitoring by positioning photodiode arrays to observe specific local regions of the cutting process, including different planes and surfaces. Each photodiode array is configured to monitor particular areas (e.g., upper surface, lower surface, kerf region), enabling detection of plane-specific defects such as burrs on the underside or slag on the upper surface.
Solution Approach 2:
The patent uses light as an intermediary to probe different planes of the cutting process. By positioning photodiodes to detect light reflected or emitted from specific planes (upper surface, lower surface, kerf), the system indirectly measures plane-specific conditions without direct physical contact, enabling distinction between defects in different planes.
4Measurement precision
If off-axis observation is used for cutting front monitoring, then three-dimensional geometry can be determined, but the observation becomes directionally dependent and requires large equipment
Solution Approach 1:
The patent creates a universal monitoring system where photodiode arrays can observe cutting process features from multiple angles and positions simultaneously. The same basic photodiode array structure serves multiple observation functions (upper surface, lower surface, kerf monitoring) by adjusting positioning rather than requiring different specialized equipment for each observation angle.
Solution Approach 2:
The patent uses optical copying principles where photodiodes detect light patterns that represent the cutting front geometry. Instead of directly measuring three-dimensional geometry with complex equipment, the system captures optical copies (light intensity distributions) from different positions, which can be analyzed to infer cutting front characteristics without requiring large-scale measurement apparatus.
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
Enables accurate, real-time monitoring and optimization of cutting quality across the entire thickness of the workpiece, allowing for precise control and remediation of defects like burrs and slag, without the need for complex software or three-dimensional reconstruction.
Implementation Method 1
acquiring 1 to n images of the process zone in at least a part of an illumination light reflected from the process zone
Implementation Method 2
irradiating the workpiece with a machining laser beam, cutting the workpiece in a cutting direction and generating a process zone
Implementation Method 3
each of the 1 to n images is acquired as an array of simultaneous partial images, wherein each or a plurality of the partial images is distinguished by an optical feature of an acquisition angle
Implementation Method 4
at least one optical feature selected from a focal length of an optic of the image acquisition device in the direction of the process zone, and a polarization, in particular a polarization angle and/or polarization degree, of the acquired process light
Data Source
Figure 1a
Figure 1b~1c
Figure 1d
AI summary
The invention relates to a method for laser cutting a workpiece and a device for laser cutting with a cutting head. The method includes irradiating the workpiece with a machining laser beam, cutting the workpiece in a cutting direction in a process zone (S1), and acquiring 1 to n images of the process zone in at least a part of an illumination light reflected from the process zone and/or in at least a part of a process light generated by an interaction of the machining laser beam with the workpiece and emitted from the process zone by means of an image acquisition device (S2). Each of the 1 to n images is acquired as an array of simultaneous partial images T1 to Tm, wherein each of the partial images T1 to Tm of the array is distinguished by at least two optical features. At least one cutting quality feature is determined from the array of partial images T1 to Tm of at least one of the 1 to n images (S3).