3D CT Scan overview

Initially utilized for medical applications, 3D CT has been prevalent for industrial applications in recent years, due to technological advancements in computerized software and digital detectors. This technology has revolutionized the way industry leaders inspect, qualify and validate objects, using outsourced nondestructive testing labs for a quick and accurate 3D CT scan.

What is 3D CT?

Three dimensional Computed Tomography (CT), also known as computed tomography (CT) or computed axial tomography (CAT) scan, is based on a radiographic testing technique utilizing x-ray technology to inspect objects, internally and externally, without applying any external forces or pressure.

3D CT, also referred to 3D CAT scan, is a nondestructive testing method that is utilized commonly for medical and industrial applications.Since 3D CT is a process based on X-ray technology, various application for metallic and non-metallic components are viable. 3D CT has been a revolutionary technology for industrial use, as it has aided in qualifying, validating and inspecting objects for quality control processes.

Radiographic Testing Technique

There are several different radiographic testing techniques, including x-radiation, gamma radiation and neutron radiography. For the application of 3D Computed tomography, x-rays are utilized. X-rays rely on electricity to be powered; when an electron is accelerated and comes in contact with other atomic particles, it decelerates. This process develops an x-ray. The x-ray energy source is used to penetrate through the testing subject, which is on an axis of rotation, and a detector panel captures several 2D x-ray tomographic images at pre-determined intervals. Collectively, these images are reconstructed into a 3D model for extensive computed tomography scanned result analysis.

How does 3D CT work?

In order for 3D CT to work, a radiographer must be present to calibrate the system according to the material of the object being scanned. The radiographer must also ensure that the size of the part is within the detector panel size range, in order to capture the part in its entirety. 3D CT works using an x-ray source, a detector panel and a specialized software:

X-ray – an x-ray source should be positioned directly across the detector panel. The x-ray source shoots radiation toward the object being scanned, enabling the detector panel to capture 2D x-rays. The x-ray source energy is measured in electron volts, KeV. X-ray radiation can be detrimental to the body if there is high exposure.

Detector panel – a computerized or digital detector panel can be positioned directly across from the x-ray source. All the radiation that passes through the object and reaches the detector panel is captured in a 2D x-ray slice. Several 2D x-ray slices are captured on a pre-determined increment, as the part rotates.

Software – The several 2D x-ray tomographic images collected are transferred to a specialized software and reconstructed into a final 3D model.

What determines the image quality of a 3D CT scan?

There are a few very significant factors that determine the quality of a 3D industrial CT scan. Image quality is dependent on the size of the object being scanned, the material of the object, and the resolution desired by the user.

Size: The size of the object being scanned has to be paired with the appropriate CT system in regards to the size range of the detector panel. If the size of the object is larger than the detector panel, the resulting scan will not reflect the object in its entirety. When this is the case, multiple scans can be conducted to gather information of the entire object, and analyzed independently. Furthermore, if only a specific area is to be scanned, then the part can be placed closer to the x-ray source to gather data of that area.

Material: The quality of the image depends on the density of the material of the part to be scanned. The material has to be paired with enough x-ray energy source to enable the system to penetrate through the material for internal part data. If a part is of high density, increased x-ray energy is necessary to penetrate through that material for accurate and high quality results. If the part is of low density, low energy x-ray source can be utilized to access high quality images. If too much energy is exposed to low density material, the resulting scan will display scattered data. If not enough energy is exposed, the resulting scan will not display accurate data.

Resolution: The amount of 2D x-ray tomographic images to be captured can be pre-determined to ensure the resolution desired can be met, subject to the size and material of the part to be inspected.

When is 3D CT necessary?

3D CT becomes necessary when a user is looking to inspect an object internally, without destroying the part in its entirety. 3D Cat scanning can become highly useful in the following stages of an objects manufacturing cycle:

Applications of 3D CT

3D Computed Tomography can be applied across multiple industries for quality control purposes. Commonly used for industrial and medical applications, 3D CT has enabled users to access internal and external failures without damaging or destroying the part being scanned. Common applications of 3D CAT scanning include:

Benefits of 3D CT

Applying 3D CT for quality control of parts, users are able to avoid destroying their part, saving time and costs of manufacturing test components. The following are the common benefits of using 3D CT, regardless of the industry:

  • Nondestructive testing method
  • Internal and external part data
  • Save time and costs of manufacturing
  • Quick and accurate results
  • Quality management tool
  • Research and development tool
  • Reverse engineering with accuracy


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