Avery important stage in the manufacturing and production cycle of a part is designing and verifying a prototype. Very often in the medical, automotive, or aerospace industries, very expensive and valuable parts are cut open to locate internal failures or to retrieve internal measurements. Such parts are left destroyed and can no longer be functional after the testing process.

3D X-ray of a medical component.
Industrial computed tomography (CT) scanning is a nondestructive testing method that can accurately inspect parts internally and externally in 3D. This non-contact, X-ray technology allows an object to be scanned in Free State form, leaving the part available for use after testing. Traditionally, CT is primarily used to scan the human body to retrieve internal bodily data. The method proves to be useful and effective for scanning objects in industrial applications as well.

A CT machine consists of three main parts: a rotary table, an X-ray source, and a detector panel. An object or part is placed on the rotary table. As it spins 360 degrees, the X-ray source shoots through the part, toward the detector panel, which captures several thousands of 2D X-ray images. These images are then re-constructed into a 3D model using software. Without damaging or cutting open the part, the viewer can retrieve internal measurements or locate internal defects. The inspection can be taken further by applying different types of analysis to the resulting scan.

An example of void/inclusion analysis performed by CT scanning one part and evaluating the internal porosity or inclusions within a part.
Industrial CT scanning provides many routes in terms of accessibility of different types of data. Apart from scanning for simple fit and function purposes, one can also acquire a CAD model from scratch through the CT process for reverse engineering solutions, or compare a CAD model of the part with the scanned results to ensure the credibility of the part is not compromised. Further, the technology can be used to locate, measure, and view internal porosity/voids and inclusions with very high accuracy. A user can also scan and compare multiple identical parts for a comparison analysis or retrieve general dimensions and tolerances. This technology can even be used to measure wall thickness for parts or scan to inspect fibers. Almost any type of material can be scanned, including micro-sized parts.

CT scanning can reduce potential operational costs by minimizing time allocated toward pre-production design and production. This method of inspection aims to enhance product quality and provides a high level of accuracy that would be difficult to assume with any other nondestructive testing method. Most importantly, it is a fast and easy internal inspection method that leaves the part intact.

This work was done by Jesse Garant & Associates Inc. For more information, Click Here " target="_blank">http://info.hotims.com/49751-122.

NASA Tech Briefs Magazine

This article first appeared in the November, 2014 issue of NASA Tech Briefs Magazine.

Read more articles from this issue here.

Read more articles from the archives here.