Industrial CT metrology: high-precision 3D measurements

X-ray tomography is revolutionizing the traditional approach to industrial metrology. This non-destructive technology enables complete three-dimensional reconstruction of your components, opening up new horizons for the most demanding dimensional measurements. Unlike conventional methods, tomography offers an integral view, enabling simultaneous characterization of internal and external geometries.

What is metrology?

Metrology is the science of measurement. It defines the concepts, methods and standards that guarantee the accuracy, repeatability and traceability of measurement results, with a clear expression of the associated uncertainty.

In the industrial environment, metrology is the cornerstone of quality control. It involves mastery of measurement units, assessment of uncertainties, implementation of calibration procedures, traceability of measurements, and compliance with international standards.

For computed tomography, practices are based in particular on R&R-type studies and recognized standards such as VDI/VDE 2630, which provide a framework for the implementation and comparability of results

Why combine metrology and computed tomography

Industrial computed tomography represents a natural and major evolution for metrology: used in measurement mode, it transforms the CT system into a CMM (Coordinate Measuring Machine) equipped with a volumetric sensor

The objective is no longer limited to inspection (defects, porosity, assemblies): it involves dimensional measurements and validation of tolerances on both internal and external surfaces, even in areas inaccessible to conventional probes or optical means, without damaging the part.

A single scan produces a complete 3D volume that serves as a single dataset for dimensional control and reporting, while enabling simultaneous analysis of even highly complex internal and external geometries.

Why choose industrial CT for your metrological measurements?

High-precision 3D inspection - indoors and out

Industrial computed tomography (CT) offers unrivalled capabilities for dimensional metrology:

Non-destructive, fully 3D measurements, including on internal features
High accuracy and repeatable results
A single scan replaces dozens of traditional measurements
Ideal for complex geometries
Ideal for checking assemblies, without disassembly, to measure positioning, clearances and dimensions under real constraints.
Ideal for comparing a part with its CAD file and validating a process
Non-contact: suitable for deformable parts
Suitable for transparent or shiny parts, without preparation (powdering, markers, etc.)

With RX-Solutions CT metrology solutions, benefit from a state-of-the-art CT platform, designed to deliver high-precision measurements every day.

Metrological applications using X-ray system

Metrologie dimensionnelle par tomographie

Coordinate Measurement

Determination of component's geometries with an ultra-high accuracy in a single and fast scan

Regardless of the complexity of the shapes, CT generates a high-density 3D point cloud from which all traditional measurements can be made: geometric and positional tolerances (parallelism, perpendicularity, circularity, concentricity, coaxiality, etc.).

Non-contact and non-destructive, the method is suitable for a wide range of industrial components. With results down to the micron depending on the configuration, CT becomes essential for qualifying and inspecting complex parts and assemblies.

Nominal to Actual Comparison

Comparison between CAD nominal and CT scanned data

A typical task fulfilled by the use of a metrology-certified tomograph is the 3D comparison between nominal and realized by visualizing the geometric deviations between the data extracted from a scan of a part and its digital model.

This comparative metrological analysis enables :

Rapid sample qualification, with deviation mapping at all points and colorimetric visualization of deviations
Continuous improvement of production processes (injection, 3D printing, machining)
Complete metrological traceability for quality certification
Validation of tolerances on complex parts impossible to measure otherwise
Correction of molds or CAD for additive manufacturing, thanks to calculation models that take into account the actual deformations of the parts produced.

Deviations are color-coded, providing an immediate and precise overview of the differences between the parts being compared, facilitating decision-making and optimization of production parameters.

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FOIRE AUX QUESTIONS

Can computed tomography (CT) really measure, or just “see inside”?

Yes. Industrial CT is more than an image: it provides a complete 3D volume in a single scan, from which dimensional measurements can be made on internal and external surfaces, with tolerances and GD&T.

How reliable is CT scan for 3D measurements?

Reliability depends on the system, settings and metrological procedures. RX Solutions “Metrology series” CT Systems specify a VDI/VDE 2630-compliant BEP, and enable task-specific uncertainty to be calculated. With periodic calibration and verification, repeatable and traceable measurements are obtained.

Does CT replace CMM?

CT complements CMM. CT measures inaccessible geometries (cavities, assemblies, internal zones) without contact; tactile CMM remains relevant for certain critical dimensions and tight material/geometry tolerances. In practice, CT + CMM are often combined.

What are the advantages of CT over a CMM or optical vision?

We move from point-by-point inspection to analysis of a complete volume:

access to hidden geometries without cutting,
a single scan replaces several operations,
dense point cloud for all dimensions and CAD/scan comparison,
less preparation/clamping, more speed on complex parts.

How long does a CT scan/measurement take?

This depends on the size, material/density, thickness and resolution required. Count on a few minutes to over an hour.

Do artifacts (rings, beam hardening) distort measurements?

They can. We can reduce them with the right parameters (kV, filters), trajectories and software corrections. We then validate the residual effect using measurement uncertainty and standard parts to guarantee metrological accuracy.

How is the nominal/realized (CAD ↔ scan) comparison carried out?

The scanned part is aligned with the CAD (best-fit / DRF), 3D deviations are calculated, a colored deviation map is displayed and GD&T dimensions are extracted. The results are plotted in reports (PDF/CSV/QIF) and integrated into the SPC.