Laser Cutting Acoustic Sensing for Real-Time Quality Control
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Solution Overview
Problem
Existing laser cutting technologies face challenges in accurately assessing cutting quality due to limitations in detecting and interpreting airborne sound signals, which are often masked by strong process gas streams, and require complex modifications to access the space under the workpiece.
Innovation Solution
Arranging directional microphones below the workpiece to detect airborne sound signals during the cutting process, combined with machine learning algorithms to analyze these signals for real-time quality estimation and parameter adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If airborne sound sensors are arranged above the workpiece to detect cutting quality, then the detection is straightforward, but the strong process gas streams mask the sound signals and reduce measurement precision
Solution Approach 1:
The patent inverts the conventional sensor arrangement by placing airborne sound sensors below the workpiece instead of above it. This inversion allows the sensors to detect cutting quality sounds without interference from process gas streams, which flow downward from the cutting zone. The sound signals propagate through the workpiece and are captured from the opposite side, effectively eliminating gas stream masking effects.
Solution Approach 2:
The patent transitions the sensor detection dimension from above-the-workpiece to below-the-workpiece spatial arrangement. By detecting sound signals from the opposite dimension, the system accesses the sound field that has passed through the workpiece, providing a different detection pathway that avoids gas stream interference while maintaining measurement capability.
2Measurement precision
If sensors are placed below the workpiece to avoid gas stream interference, then measurement precision improves, but device complexity increases due to required machine modifications
Solution Approach 1:
The patent makes the laser cutting machine's bridge structure multi-functional by integrating both optical sensors and airborne sound sensors into the same moving platform. The bridge, which already supports the cutting head and optical sensors, is extended to carry sound sensors below the workpiece, allowing a single structural element to serve multiple detection functions without requiring separate support systems.
Solution Approach 2:
The patent merges the optical detection system and acoustic detection system into a unified sensor platform mounted on the bridge. Both types of sensors share the same mounting structure and movement mechanism, consolidating what could have been separate systems into one integrated arrangement, thereby reducing overall device complexity.
3Measurement precision
If multiple sensors and complex evaluation systems are used to assess cutting quality, then measurement precision improves, but ease of operation deteriorates due to complex signal interpretation
Solution Approach 1:
The patent implements a feedback system where airborne sound sensors continuously monitor cutting quality and automatically generate control signals that are fed back to the laser cutting machine's control unit. This closed-loop feedback mechanism enables real-time quality adjustment without requiring manual signal interpretation, as the system automatically processes sensor data and adjusts cutting parameters to maintain optimal quality.
Solution Approach 2:
The patent enables the laser cutting machine to perform self-diagnosis and self-adjustment of cutting quality through integrated sensors and automated evaluation algorithms. The system monitors its own performance in real-time and automatically corrects deviations without external intervention, allowing the machine to service its own quality control functions.
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
Provides reliable, efficient, and real-time cutting quality assessment with minimal machine modifications, enabling precise control of cutting parameters to achieve desired quality standards.
Implementation Method 1
detecting airborne sound that is to be evaluated; at least one airborne sound sensor is used to detect airborne sound
Data Source
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AI summary
The present invention relates to a method for providing a quality assessment result and a laser cutting machine (L) for cutting workpieces (13) at a processing point (100). The laser cutting machine is designed as having - a laser cutting head (3) which is mounted so as to be movable at least in an X-direction and defines a beam propagation direction (E) of a laser beam; - a storage device (14) for storing the workpiece to be cut (13); - a machine frame (5) with at least one frame part (7, 7'); - at least one airborne sound sensor (11), which can be moved in the X-direction relative to the frame part (7, 7'), wherein the at least one airborne sound sensor (11) is arranged in the beam propagation direction (E) after, in particular below, the processing point (100) and oriented towards it.