Shearography Joint Inspection Using Thermal Deformation
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Solution Overview
Problem
Existing methods for testing joint connections, especially in metallic materials, face challenges due to high rigidity, requiring small deformation measurements that are difficult and time-consuming, and often necessitate mechanical stress application, which is uneconomical, especially in high-volume production processes like resistance spot welding.
Innovation Solution
A method utilizing thermally induced deformation during the joining process, measured by shearography, eliminates the need for mechanical stress and allows for quick quality assessment of joints by leveraging heat generated during processes like welding, clinching, or riveting, using induction heating for additional heat input if necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical stress is applied to metallic joining partners for quality testing, then measurement can be performed, but the high rigidity of metallic materials requires very small deformation measurements that are difficult and time-consuming
Solution Approach 1:
The patent changes the parameter used for inducing deformation from mechanical stress to thermal energy. By applying heat to the joining partners, the material expands and deforms without requiring mechanical force application. This thermal-induced deformation is sufficient for shearography measurement and avoids the time-consuming mechanical stress application and measurement of very small deformations in rigid metallic materials.
2Reliability
If mechanical stress is applied to each joint connection for quality assurance, then defect detection is possible, but the process time increases considerably making it uneconomical for high-volume production
Solution Approach 1:
The patent replaces the mechanical stress application system with a thermal energy system. Instead of applying mechanical force to each joint connection for quality assurance, heat is applied to induce deformation that can be measured by shearography. This substitution eliminates the need for time-consuming mechanical testing while maintaining defect detection capability, thereby preserving production efficiency in high-volume manufacturing.
3Measurement precision
If laser heating is used to generate deformation for shearography measurement, then measurement can be performed, but the process time and operating costs increase making it uneconomical
Solution Approach 1:
The patent utilizes the heat already present in the joining partners after the joining process (such as welding or riveting) to induce deformation for shearography measurement. Instead of applying additional laser heating, the residual heat from the joining operation itself is used for quality inspection. This self-service approach eliminates the need for separate heating equipment and additional process time, making the measurement economical for high-volume production.
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 rapid and efficient quality inspection of joints during production, reducing process time and costs, making it suitable for 100% inspection in high-volume manufacturing without significantly prolonging the production cycle.
Implementation Method 1
the test means is designed to measure a thermally induced deformation of the joining partners by means of a shearography
Implementation Method 2
the joining device has a heat input means, with which the joining partners can be heated in a chronological sequence before the thermally induced deformation of the joining partners is measured
Data Source
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AI summary
The invention relates to a method for producing and testing a joint (10) between a first joining partner (1) and at least one second joining partner (2), wherein the joint (10) is produced using a joining device (100), and wherein a testing device (20) is provided with which the produced joint (10) is tested using shearography, the method comprising at least the following steps: producing the joint (10) with the joining device (100) while heating the joining partners (1, 2) and measuring a thermally induced deformation (3) of the joining partners (1, 2) with the testing device (20) using shearography. The invention further relates to the joining device (100) for carrying out the method.