Back to the articles

CT scan of components - a non-destructive and precise method for failure analysis

Measurement News from Q-Tech

CT scan of components - a non-destructive and precise method for defect analysis

The manufacturing processes for new components in industry must become ever faster and yet more precise. This increases the pressure on manufacturers. But despite time pressure and increasingly complex components, quality assurance and functional control during production must not be neglected. For a long time, the measurement and control of internal structures was a particular problem. Precise measurement was often only possible by destroying the individual products or components.

It wasn't until industrial computed tomography (CT) and CT scanning of components that this changed. 

What is behind a CT scan of components? This is a non-contact scanning process using X-rays. Special software calculates the outlines of the component from the images generated and uses them to create a 3D data set. In this, changes to the surface, air inclusions, small cracks and much more become visible.

Why is CT scanning of components so important today?

Today, the manufacturing industry is faced with ever shorter product life cycles and a growing variety of products. As a result, product development and production processes must become ever more cost- and time-efficient. In addition, thanks to improved machines and new production methods, increasingly complex components can also be produced. 

In this context, especially the development of additive manufacturing (3D printing) and the production of components with cavities has significantly advanced the development of industrial computed tomography. These cannot be readily produced using conventional methods and cannot be measured using tactile or optical coordinate measuring machines.

But this is precisely where the problem lies. On the one hand, advanced materials such as fiber-reinforced plastics and new manufacturing processes allow the development of innovative products. On the other hand, however, this requires different measuring and testing methods for quality assurance. 

What is the CT scan used for in components?

Only time-saving measurement techniques can reduce manufacturing costs to a minimum. This is exactly where industrial computed tomography (CT) and the CT scan of components come into play. With the CT scan, components and their inner workings can be visualized non-destructively. This enables fast and simple defect analysis. This is because the individual workpieces can be

  • Cracks, 
  • Cavities, 
  • Pores/Bubbles,
  • a too high/too low pore density and 
  • inclusions are examined. 

Particularly in the foundry or injection molding industry, CT scans of components are now the preferred method for quality assurance. 

But the scans are not only used for defect analysis. They can also be used to examine the material properties of a product. Typically, the fiber orientation, as well as the fiber density or also the pore size and pore density are analyzed here. 

In both cases, defect analysis and material property verification, the results are used to optimize the manufacturing process and reduce defects.

In conjunction with suitable software, virtual 3D models are created from the scanned components at the same time. Instead of a simple CAD file, the CT scan delivers a detailed image of the workpiece. 

The advantages of a CT scan for components summarized: 

  • With the scan, defects inside a workpiece can be detected, analyzed and corrected. 
  • The measurement of the workpieces is possible non-destructively thanks to CT scanning. 
  • Component measurement with the computer tomograph is often faster and more efficient than with conventional measurement methods.
  • Digitization also allows the components to be reproduced without a CAD model.
  • The generated 3D point cloud of the component creates a digital twin that also enables digital archiving and subsequent re-measurements.

The disadvantages of CT scans

Despite the numerous advantages, there are also disadvantages to industrial CT scanning of components. The most frequently cited in this context is the enormous cost of acquiring a CT scanner. Moreover, since this technology is more advanced than that of an optical or tactile scanner, the costs can even be several times higher than those of other 3D scanners. For this reason, many companies choose to hire an outside service provider, such as Q-Tech, for their CT scans.

In addition, many companies do not have suitable premises to safely operate an industrial CT scanner. This is because the scanners may only be operated in a radiation-impermeable chamber due to the X-rays they generate.

As far as the material is concerned, X-rays either take many times longer to penetrate materials with higher densities or the power of the existing X-ray source of the CT scanner is not sufficient to penetrate the material at all. This means that a CT scan of a component can sometimes take several hours or not even be possible in the first place or only provide insufficient quality of the component images.

How does an industrial CT scan of components work?

There is a wide range of industrial scanners in various designs and sizes suitable for different applications. Small tabletop models for laboratory use to full industrial floor models for use in factories or on the shop floor, as well as portable measuring arms that can be used as needed, are not uncommon these days.

In larger manufacturing operations, metrology is now often integrated into the production line to provide instant analysis of cast, stamped, welded or otherwise fabricated parts, as well as packaged goods. 

Much like a computed tomography (CT) scanner in a hospital allows medical personnel to "see" the inside of a patient, industrial CT scanning technology enables non-destructive measurement and inspection of the inside of a workpiece

In this method, an object (patient or part) is passed between an X-ray tube and a sensor, creating a point cloud that is then interpreted using software. However, whereas in a medical CT scanner the X-ray tube rotates around the patient, in industrial computed tomography the workpiece usually rotates slowly on a rotary table while the sensor records data at set intervals. 

But beyond the different configurations of the CT scanner itself, scanning a piece of metal and taking precise measurements requires additional different capabilities of the scanner. After all, metal parts have a greater tendency to absorb X-rays, a property that can affect the resolution of the image produced, especially when scanning parts with a high density. However, to maintain resolution on dense parts, industrial CT scanning systems must operate with a more powerful voltage source in the kV range than medical scanners. 

Typical CT scanners offer a wide range of measurement capabilities and functions. Sizes start with small tabletop models that meet the most stringent requirements and capture the smallest 3D details from 0.25 µm. They can be equipped with different X-ray powers, from 160 kV for nanometer resolution to 225 kV, 320 watts and even higher powers ,it voltage sources of 300 kV and more.

Larger scanners are available for extremely fast CT data acquisition of workpieces with a diameter of up to 500 mm and a height of up to 600 mm and weighing up to 50 kg. Typical functions that can be performed with such a system include 3D analysis of a scanned turbine blade, automatic analysis of the pore volume of an aluminum casting, and 3D measurements with target/actual comparisons on injection-molded plastic parts, such as the radio key of a passenger car. 

Which materials are suitable for scanning?

Industrial CT scans are suitable for almost all materials and are particularly good for:

  • Plastics
  • Carbon fiber reinforced plastics (CFRP)
  • Glass fiber reinforced plastics (GRP)
  • Aluminum

The resolution of the scan is a few micrometers (μm), depending on the material and size of the component.

If other materials, especially high-density materials, are to be subjected to nondestructive failure analysis, the following test methods may be more suitable: 

  • Radiography
  • Ultrasonic testing
  • Eddy current testing
  • Dye penetrant inspection
  • Magnetic particle testing
  • Dimensional test

What are the possible applications for industrial CT scans?

Industrial computed tomography has many applications: 


CT scans of components for defect analysis

By locating defects such as pores, voids, and inclusions, the CT scan can be used to

  • Tool optimization
  • Production control and optimization
  • Quality assurance and
  • error analysis can be used.

3D measurements and metrology

The precise 3D measurements of external and internal components enable metrological applications for: 

  • Preparation of a target/actual comparison or actual/actual comparisons.
  • Measurements of the wall thickness or the wall thickness.
  • Determination and verification of form and position tolerances.

Verification of assembly errors and connections

Assembly defects can be detected with industrial CT non-destructively and without disassembly of the component. Thus, the CT scan can also be used for:

  •     Final assembly inspection
  •     Position control of seals
  •     Analysis of solder joints
  •     Visualization of leakage and corrosion

CT scan of components and reverse engineering

A CT scan of existing components can be used to subsequently create technical drawings or generate missing CAD data sets. These are important for example for: 

  • The digitization of handmade prototypes.
  • The digitization of spare parts that are no longer available.

CT scans reveal defects in components

Industrial computed tomography (CT) works much like a medical CT machine - capturing the internal and external features of a component, assembly or material in amazing detail. 

It is the only technology that allows you to look beneath the surface without destroying it. That's why CT scanning of components is now one of the leading methods for non-destructive analysis and testing in industry.

Some of the most common uses of CT scans in industrial metrology include:

  • Reverse engineering
  • For defect analysis and quality control of workpieces 
  • Long range scanning for a detailed 360° 3D image of structures, bridges or plants.

As a rule, industrial CT scans are offered by external service providers and experts such as Q-Tech . This is because very few companies have the space and, in particular, appropriately trained personnel to operate an industrial CT scanner safely.