Thermographic Weld Defect Detection for Subsurface Flaw Inspection
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Solution Overview
Problem
Conventional laser beam welding processes face limitations in detecting subsurface weld defects, particularly 'false friends' defects, due to the requirement for large clearance and the inability to penetrate deeply, while remote laser beam welding lacks bridgeability for larger gaps, necessitating a method to detect both visible and subsurface defects in real-time without removing the welded assembly.
Innovation Solution
A portable system comprising a computing device, a thermographic sensor, and a heating source that determines a detection protocol based on weld material and thickness, communicates with the sensor to record and analyze thermographic data, enabling the detection of defects through thermal contour correlation or cooling rate analysis, and allows for onsite re-welding if defects are found.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional laser beam welding is used to ensure good bridgeability, then welding capability is improved, but large clearance is required which reduces applicability
Solution Approach 1:
The patent introduces a portable heating source as an intermediary device that applies thermal energy to the weld area, enabling the weld material to flow and bridge gaps without requiring large clearance. This thermal mediator allows the welding process to adapt to various joint configurations while maintaining reliable bridgeability.
Solution Approach 2:
The patent changes the thermal parameters of the weld area by applying external heating, which modifies the material properties and enables better bridgeability. By controlling temperature parameters, the system achieves reliable welding across different clearance conditions without requiring large gaps.
2Adaptability or versatility
If remote laser beam welding is used to weld from high above the joint surface, then adaptability to various joints is improved, but inability to detect subsurface defects occurs
Solution Approach 1:
The patent merges the remote laser beam welding capability with a portable heating source and thermographic sensor system. This combination allows the system to maintain joint accessibility while adding subsurface defect detection through thermal imaging, resolving the contradiction between adaptability and detection capability.
Solution Approach 2:
The thermographic sensor acts as an intermediary detection device that captures thermal radiation from the weld area. By analyzing thermal patterns, the system can detect subsurface defects without compromising the remote welding capability or joint accessibility.
3Ease of operation
If two-dimensional optic review is used to detect visible defects, then detection simplicity is improved, but inability to detect false friends defects occurs
Solution Approach 1:
The patent replaces the mechanical/optical direct observation system with a thermal field-based detection system. By substituting visual inspection with thermographic imaging, the system maintains operational simplicity while achieving the ability to detect subsurface defects and false friends that are invisible to two-dimensional optic review.
4Measurement precision
If weld defect detection is performed by removing the welded assembly, then detection thoroughness is improved, but manufacturing efficiency is reduced
Solution Approach 1:
The patent performs defect detection in-situ at the welding station before the assembly is removed or moved to another location. By conducting the thermographic inspection immediately after welding while the assembly is still in position, the system achieves thorough defect detection without sacrificing manufacturing efficiency or requiring additional handling steps.
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 efficient detection and repair of weld defects within the welding station, ensuring high-quality welds without moving the assembly, thereby improving manufacturing efficiency and quality control by identifying both visible and subsurface defects.
Implementation Method 1
heating a weld with the portable heating source according to the detection protocol
Implementation Method 2
recording thermographic data from the weld with the portable thermographic sensor according to the detection protocol
Implementation Method 3
The portable thermographic sensor is an infrared (IR) sensor, wherein the thermographic data includes an IR image or IR images
Data Source
AI summary
Methods and systems for detecting weld defects, and methods for manufacturing vehicles using such methods or systems, are provided. An exemplary method includes receiving an input indicating a weld material and material thickness by a portable computing device and determining, with the portable computing device, a detection protocol for the weld material and material thickness. Further, the method includes communicating the detection protocol from the portable computing device to a portable heating source and to a portable thermographic sensor, heating a weld with the portable heating source according to the detection protocol, and recording thermographic data from the weld with the portable thermographic sensor according to the detection protocol. Also, the method includes communicating the thermographic data from the portable thermographic sensor to the portable computing device, and analyzing the thermographic data to detect whether the weld includes a defect and/or determine type, dimension and location of the defect.