Temporary CT Inspection Safes Production Ramp-Ups

Authors: Prof. Dr. Lutz Hagner | CEO, Dr. Robin Höhne | Head of NDT, Benjamin Schlosser | Senior Software Engineer (Microvista GmbH)

Despite ongoing digitization, the casting process remains complex and difficult to fully control. Lightweight construction and functional integration further increase the demands for process stability and transparency. Typical risks, particularly during early phases, include tight development timelines that require rapid feedback on component quality – yet often without sufficient inspection capacity. In many cases, customers block parts due to uncertain quality, even though replacements are urgently needed to maintain production flow.

In such scenarios, temporary CT inspection can offer a viable solution – provided it is rapidly deployable, configurable to specific needs, and economically justifiable.

Requirements for a Temporary CT System

Computed tomography has become a well-established inspection method, and many foundries operate their own systems. However, these are usually designed for laboratory analyses, involve manual evaluations, and require extensive expertise. They are not intended for rapid inspection workflows – or if they are, they are typically integrated into specific production lines. A flexible alternative must be mobile and immediately operational, adaptable to different components and defect focal points, and capable of automated, user-friendly operation. Furthermore, it must be compatible with existing quality assurance systems and economically viable.

Implementation is achieved using a 20-foot container (Figure 1) equipped with integrated radiation shielding, a spacious measuring chamber, and easy commissioning. The system is operated via an intuitive user interface. Evaluation is based on modular software with predefined analysis modules, including image enhancement, CAD comparison, pore and channel extraction, wall thickness analysis, and automated result reporting.

Case Study 1: Wall Thickness Analysis in a Stator Housing

Despite extensive preparation, simulation, prototyping, and pilot series production, unexpected quality issues arose after start of production (SOP) for a stator housing with integrated cooling channels. Core misalignment led to unacceptable wall thicknesses, and core breakage resulted in burrs and chips inside the cooling channels (Figure 2). As a result, a temporary 100% inspection was necessary.

Following a brief training, production staff were able to operate the system. A barcode scan identifies the appropriate fixture, automatically loads the correct inspection program, and processes only the relevant areas – in this case, twelve predefined zones for minimum wall thickness measurement. Evaluation of these zones occurs in parallel with the CT scan. Since analysis is slightly faster than scanning, cycle time is determined by the scan duration. As a result, a complete inspection of each stator housing is achieved every 100 seconds.

Thanks to flexible data processing, the inspection program was enhanced with burr and chip detection – without increasing the overall cycle time. Results are displayed immediately in a viewer for go/no-go decisions. For more detailed analysis, measurement data are made available via an online portal (Figure 3).

Case Study 2: Burr and Core Residue Detection in a Cylinder Head

For a newly developed cylinder head module featuring a complex channel layout, the risk of burr formation and core residue was significant. When a planned flow test system was not delivered on time, a mobile CT solution was deployed as an interim measure.

The main challenge was posed by thick walls and wide component tolerances, which impeded accurate CAD alignment due to limited image quality. An intelligent algorithm generates a “skeleton” through the channels and evaluates volumetric elements along its path. For each segment, material coverage and the minimum cross-section perpendicular to the channel axis are determined.

Evaluation is performed in comparison to CAD specifications. Expert reassessment via an online portal is possible – for instance, in cases of differing tolerance interpretations. This automated evaluation allows for nuanced and rapid inspection decisions (Figure 4).

Cloud-Based Evaluation as a Key to Scalability

Temporary CT inspection often needs to scale quickly – for example, during production ramp-ups or recalls. Satellite and 5G connectivity enable the establishment of secure, stable network links within minutes. Depending on data volume and complexity, evaluation is performed in the cloud. There, virtually unlimited resources are available for parallel processing, AI-assisted evaluation, and statistical analysis.

The evaluation solutions presented are not limited to a mobile CT system. They are generally based on completed CT reconstructions and can be adapted to any CT system – provided the data are available in a standardized format. This opens up a wide range of application scenarios, independent of location or system type.

Mobile CT systems with automated evaluation provide new flexibility for quality assurance during high-risk production phases. They combine the benefits of modern CT technology with high adaptability, short cycle times, and scalable computing power – locally and in the cloud.

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