Laser Cutting Acoustic Sensing for Cut Quality Detection
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Solution Overview
Problem
Existing laser cutting technologies face challenges in accurately detecting and assessing cutting quality, particularly due to the limitations of relying solely on optical signals and the difficulty in accessing the space under the workpiece.
Innovation Solution
The implementation of airborne sound sensors, preferably directional microphones, positioned below the processing area on a moving cutting bridge, allows for the detection of airborne sound signals in the space below the processing point, enabling effective quality estimation of the laser cutting process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If optical sensors are used to detect cutting quality, then visual information can be obtained, but the detection is limited and cannot capture acoustic information
Solution Approach 1:
The patent transitions from two-dimensional optical detection (camera viewing the cut from above) to three-dimensional acoustic detection by placing sensors below the workpiece. This dimensional change allows capture of acoustic information that propagates through the workpiece and support structure, providing a new perspective on cutting quality that complements optical methods.
Solution Approach 2:
The patent uses the workpiece and support structure as acoustic intermediaries to transmit cutting information to sensors positioned below the workpiece. The acoustic waves generated during cutting travel through the workpiece material and support structure, allowing indirect detection of cutting quality parameters without direct contact with the cut zone.
2Measurement precision
If sound sensors are placed above the workpiece, then acoustic signals can be detected, but the process gas jet masks the sound signals
Solution Approach 1:
Instead of placing sound sensors above the workpiece where they would be exposed to the process gas jet, the patent inverts the sensor position and places them below the workpiece. This inversion allows the sensors to detect acoustic signals that have already passed through the workpiece, effectively avoiding the harmful gas jet interference that occurs during cutting.
3Ease of operation
If the space under the workpiece is accessed for sensor placement, then acoustic detection is enabled, but the space is difficult to access
Solution Approach 1:
The patent integrates the sound sensors into the existing machine structure below the workpiece, making the sensor placement a permanent fixture rather than a temporary addition. This multi-functional approach allows the same structural elements to serve both as support for the workpiece and as mounting locations for the acoustic sensors, eliminating the need for separate access mechanisms.
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 provides a reliable and efficient method for estimating cutting quality by capturing valuable acoustic information that was previously masked by process gas jets, leading to improved monitoring and control of the laser cutting process.
Implementation Method 1
at least one airborne sound sensor, which can be moved in the X-direction relative to the frame part, wherein the at least one airborne sound sensor is arranged in the beam propagation direction after, in particular below, the processing point and oriented towards it
Data Source
AI summary
The present disclosure relates to a method for providing a quality assessment result and a laser cutting machine for cutting workpieces at a processing point. The laser cutting machine is designed as having: a laser cutting head which is mounted so as to be movable at least in an X-direction and defines a beam propagation direction of a laser beam; a storage device for storing the workpiece to be cut; a machine frame with at least one frame part; at least one airborne sound sensor, which can be moved in the X-direction relative to the frame part, wherein the at least one airborne sound sensor is arranged in the beam propagation direction after, in particular below, the processing point and oriented towards the latter.