100% Inline Quality Assurance for Ex- and Pultruded Products through Innovative and Novel X-ray Inspection Systems

In-line quality assurance of continuously manufactured products such as extruded pipes, hoses, profiles, and seals is challenging because established inspection methods (e.g., terahertz, ultrasound) are limited to rotationally symmetric or planar geometries and do not provide complete 3D information on defects. This paper presents the development of a novel, cost-effective X-ray computed tomography (CT) system for in-line inspection of extruded and pultruded profiles. The system employs a circular arrangement of multiple X-ray sources and detectors around the extrusion line; the profile under test traverses the measurement setup during production, enabling continuous monitoring at production speed. As the target profiles belong to a margin-sensitive segment, the system design was strictly oriented toward economic feasibility and relies on commercially available off-the-shelf components. The prototype comprises 34 X-ray sources (max. 80 keV) and 10 detectors; target specifications include a maximum envelope diameter of approximately 150 mm and a theoretical spatial resolution of 0.1 mm. Compared with conventional CT systems, data quality is constrained by the limited number of projections (34) and a lower signal-to-noise ratio resulting from high acquisition speed. Consequently, multiple 3D reconstruction algorithms (algebraic, iterative, AI-based) are evaluated to reduce artifacts and enhance feature detectability. For the following defect detection (voids, cracks, deformed geometry), an AI-based method is planned as the project progresses. The paper discusses the system concept, design decisions, and performance limits for industrial in-line inspection.