Laser Weld Quality Detection Using Optical Reflection
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Solution Overview
Problem
Existing methods for monitoring the quality of laser transmission welding in plastics parts are complex and not suitable for mass production, limiting detection precision and reaction time.
Innovation Solution
The method involves determining the location and thickness of the joint plane before and after welding using a reference point, employing laser beam or ultrasonic measurements to assess the weld seam penetration and total thickness, allowing for rapid and precise evaluation of welding quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radiation detection sensors are used to detect burns during laser transmission welding, then thermal damage detection capability is improved, but device complexity increases and mass production suitability deteriorates
Solution Approach 1:
The patent replaces complex radiation detection sensors with a simple optical sensor that detects light reflection changes. Instead of using elaborate radiation detection equipment to monitor thermal damage, the invention uses basic optical principles where a laser beam reflects off the plastic part surface, and changes in reflection intensity indicate burn conditions. This substitution dramatically simplifies the device while maintaining detection capability.
2Measurement precision
If elaborate detection methods are used to monitor welding quality, then detection precision is improved, but productivity decreases due to complex construction
Solution Approach 1:
The patent implements a self-service detection system where the welding process itself generates the detection signal. The laser beam used for welding also serves as the detection probe, and the plastic part's surface characteristics (burns, weld quality) automatically modulate the reflected light. This eliminates the need for separate complex detection equipment and enables real-time monitoring that keeps pace with mass production speeds.
3Reliability
If complex detection devices are used to ensure welding quality, then reliability of quality control is improved, but ease of operation deteriorates
Solution Approach 1:
The patent implements immediate feedback control where the optical sensor continuously monitors the welding process and provides real-time information about weld quality and thermal damage. The system compares the reflected light intensity against predetermined thresholds and automatically signals when quality standards are met or violated. This continuous feedback loop ensures reliable quality control while maintaining simple operation through automatic monitoring and clear signal output.
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 rapid and precise determination of welding quality, identifying flaws such as shrinkage holes or incomplete bonds, facilitating efficient quality control in mass production.
Implementation Method 1
a welding process is performed by a laser beam that melts the interfaces of the parts in the region of the joint plane
Implementation Method 2
melts the interfaces of the parts in the region of the joint plane
Implementation Method 3
the radiation originating from the burn is detected by a corresponding element (sensor)
Implementation Method 4
the ascertainment of the location of the joint plane and the thickness of the parts welded to one another is performed by a laser beam measurement
Data Source
AI summary
The invention relates to a method for determining whether two plastics components (1, 2) to be welded to each other in a joint plane are welded to each other after a welding process has been carried out, characterized in that the position of a reference plane is determined from a reference point before the welding process is carried out, then the welding process is carried out, and the position of the joint plane or the thickness of the components (1, 2) welded to each other is determined from the reference point during or after the welding process.