Inspection of Defects in an Automotive Inverter Component with X-Ray Inspection System

Importance of the Topic

Electric vehicle inverters play a critical role in converting battery DC power into variable-frequency AC to drive traction motors. Their efficiency and reliability directly influence vehicle performance and range. Excessive heat generated by high currents can lead to component failure, making nondestructive inspection of internal structures essential for quality control and design optimization.

Objectives and Overview of the Study

This work demonstrates how the Xslicer™ SMX™-6010 microfocus X-ray inspection system can rapidly visualize and evaluate internal defects within an inverter’s insulated-gate bipolar transistor (IGBT) module. The study aims to compare planar fluoroscopic imaging with computed tomography (CT) to detect voids, assess defect morphology, and enable quantitative measurements for quality assessment.

Methodology

Fluoroscopic panoramic imaging was first used to generate a composite projection of the entire IGBT module housed in a resin case. Regions of interest were then examined at low and high magnifications to reveal internal voids. For three-dimensional analysis, CT scans produced cross-sectional slices, allowing clear differentiation of material densities and precise defect localization. Measurement functions calculated void dimensions, spatial orientation, and area ratios within selected regions.

Used Instrumentation

• Xslicer™ SMX™-6010 microfocus X-ray inspection system (Shimadzu)
• Fluoroscopic panoramic imaging module
• CT reconstruction and measurement software tools

Key Results and Discussion

Fluoroscopic images revealed bright regions corresponding to low-density voids within solder joints and bonding areas. High-magnification views localized individual voids but could not resolve multilayer depth information. CT cross sections overcame this limitation by distinguishing void shapes and heights across different slice positions. Quantitative analysis determined void area ratios below 3% and counted more than 20 discrete voids within the solder region. Angular and linear measurements further characterized defect geometry.

Benefits and Practical Applications

• Rapid, nondestructive inspection without disassembly accelerates production line quality control.
• Combined fluoroscopy and CT modes allow both overview and detailed defect analysis.
• Quantitative defect metrics support process improvements in soldering and component design.

Future Trends and Opportunities

Advances in detector sensitivity and reconstruction algorithms will reduce scan times and improve resolution for finer defect detection. Integration of automated defect recognition and AI-driven analysis could enable real-time quality monitoring. Expanding applications to other power electronics and battery modules will further enhance reliability in electric mobility and renewable energy systems.

Conclusion

The Xslicer SMX-6010 microfocus X-ray inspection system effectively visualizes and quantifies internal defects in automotive inverter components. The dual-mode approach of fluoroscopic panoramic imaging and CT provides comprehensive insights into void distribution and morphology. This methodology supports improved design, manufacturing process control, and product reliability in high-power electronic assemblies.