CT Inspection of Self-Piercing Rivet Joints Without Destructive Sectioning
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Solution Overview
Problem
Current methods for inspecting self-piercing rivet joints in metal components require destructive processes, such as cutting and polishing, which are time-consuming and costly, and do not allow for accurate non-destructive quality control.
Innovation Solution
A computerized tomography (CT) scan system using x-rays at an energy level of at least 200 kV is employed to inspect the joint without destroying or modifying the assembly, enabling high-resolution imaging of the rivet's dimensions and features without creating scrap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If destructive inspection methods (cutting and polishing) are used to inspect rivet joints, then measurement precision can be achieved, but productivity decreases and loss of substance increases due to scrap creation
Solution Approach 1:
The patent replaces the mechanical destructive inspection system (cutting tools, polishing equipment) with a non-destructive imaging system using x-rays or neutrons. This substitution allows inspection without physical contact that destroys the sample, thereby maintaining measurement precision while dramatically improving productivity by eliminating time-consuming cutting and polishing steps.
Solution Approach 2:
The patent creates a digital copy (image) of the rivet joint interior structure through x-ray or neutron imaging, replacing the need to physically expose the cross-section through destruction. This copying approach preserves the original component while providing sufficient visual information for quality inspection, eliminating scrap and enabling faster inspection cycles.
2Measurement precision
If destructive inspection methods are used, then measurement precision can be achieved, but loss of substance increases due to creation of scrap
Solution Approach 1:
The patent replaces mechanical destruction with non-destructive imaging, substituting physical cutting and polishing processes with x-ray or neutron radiography. This eliminates the creation of scrap material while maintaining the ability to obtain precise measurements of rivet joint quality through digital imaging of the internal structure.
Solution Approach 2:
The patent creates a digital replica of the rivet joint's internal structure through imaging, replacing the need to physically destroy and expose the joint for inspection. This copying method provides complete visual information for quality assessment without removing any material or creating scrap, thereby eliminating substance loss entirely.
3Measurement precision
If destructive inspection methods are used, then measurement precision can be achieved, but use of energy increases due to additional processing steps
Solution Approach 1:
The patent replaces the energy-intensive mechanical processes of cutting, polishing, and handling destructive samples with a single non-destructive imaging operation. This substitution eliminates the cumulative energy consumption of multiple sequential steps (cutting machine operation, polishing machine operation, sample handling, cleaning) while achieving the same inspection objective through x-ray or neutron imaging.
Solution Approach 2:
The patent creates a digital copy of the rivet joint structure through imaging, eliminating the need for physical sample preparation steps that consume energy. By obtaining the inspection image directly from the intact component without cutting or polishing, the process removes multiple energy-consuming operations from the workflow, reducing overall energy usage while maintaining measurement precision.
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 method provides improved quality control with reduced costs and energy consumption, allowing for accurate inspection of assemblies without destruction, resulting in more efficient and cost-effective quality assurance.
Implementation Method 1
The system comprises a source of x-rays and an x-ray detector. The source of x-rays emits the x-rays toward a portion of the assembly which includes the rivet at an energy level of at least 200 kV.
Data Source
AI summary
A system and method for inspecting an assembly including components joined by self-piercing rivets by a computerized tomography (CT) scan of the joint is provided. The system includes a source of x-rays, a mounting unit for an assembly including the joint which is subject to the x-rays, and an x-ray detector disposed opposite the source for detecting the x-rays. The x-rays are provided at a high energy level of at least 200 kV to generate images having a resolution of at least 200 micrometers (μm). A computer stitches the images together to form reconstructive images which show details of the joint. The assembly to be inspected is not destroyed or modified prior to the inspection process. The resolution of the images generated by the x-rays is high enough to determine the presence of cracks, if any, the interlock (SH), minimum thickness (Tmin), and overall structure of the unmodified assembly.