Defects in components often cause high costs in development processes, especially if they are detected late. With the help of our computer tomography, defects are identified early and without dismantling the component and can therefore be eliminated at an early stage, thus saving costs.
When it comes to computed tomography (CT), most people first think of the typical application in medical technology. This is also correct in principle.
Computer tomography essentially involves the measurement of spatially extended bodies, including their internal structures, using X-rays.
A spatial measurement is achieved with the aid of many 2D "images", also known as absorption profiles, which are combined to form a three-dimensional image of the body.
Compared to medical CT, there are some differences in the industrial sector, which mainly lie in the complexity of the components to be examined and in the structure of the computer tomograph. As a rule, the radiation exposure for the object to be examined does not pose a problem in industrial computed tomography, so that significantly higher radiation intensities and thus better resolutions can be achieved.
In order to produce a three-dimensional image of a body, many individual absorption profiles have to be superimposed.
Absorption profiles are created by irradiating the specimen with X-rays.
The required X-ray radiation is generated in an X-ray tube in which electrons are accelerated by a filament in a vacuum and then hit a cathode where they are strongly decelerated. This produces, among other things, X-rays.
The X-ray radiation is directed in the form of a conical steel onto the object and behind it hits an X-ray tomography sensor. A high-resolution CT scan requires several hundred to a few thousand such images from different perspectives. For this purpose, the object is placed on a turntable. Depending on the composition of the material, different levels of absorption occur. The X-ray radiation is directed onto the object in the form of a cone steel and hits an X-ray tomography sensor behind it. Up to several thousand such images from different perspectives are required for a high-resolution CT scan. For this purpose, the object is located on a turntable. Depending on the composition of the material, different levels of absorption occur. With the help of mathematical methods, the individual images can be superimposed and combined into a volume in special programs from the voxel data.
Voxels are volume image points, which contain information of the local radiation absorptions in a raster in space. Dark voxels represent areas with low absorption e.g. air, bright voxels indicate areas with high absorption.
One of the main applications for which a CT scan is used is the target/actual comparison. The target data (CAD) is compared with the CT data. Even internal or difficult to access geometries can be measured non-destructively and with high precision. At first glance, a false color comparison shows deviations in shape such as warpage or sink marks. The quality of the component can thus be evaluated quickly and inexpensively without a great deal of measuring effort.
Also an actual/actual comparison can be carried out by means of scan files. This serves to re-qualify the component quality after changing the process parameters, changing the machine or interrupting production for a longer period. An actual/actual comparison is also ideal for evaluating the wear of a certain component or wear in the tool after a longer period of use.
Another application of computed tomography is material analysis. This includes testing the material structure for fiber orientation and unwanted inclusions such as blowholes or bubbles. These defects, which are not visible from the outside, can be highlighted in color and analyzed.
Plastic parts are becoming thinner and thinner due to increasing demands in terms of weight optimization and material savings. As a result, wall thickness analysis is becoming more and more important. Computer tomography can be used to create a simple false-colour representation of the test specimen with regard to the wall thickness and immediately check whether the material thicknesses are being adhered to.
After transferring the scan data into the STL format, measurements including form and position tolerances can be carried out with the aid of control geometries. Compared to conventional coordinate measuring machines, component measurement using CT is significantly faster and therefore more cost-effective, as the measuring points are only touched virtually and the process paths of the machine are omitted. After evaluation of all results, an individual test report is generated.
Old components often lack CAD data sets or drawings. Reverse engineering describes the reversal of the development process from an existing part to the design data.
Using reverse engineering, the data sets generated in the CT can be converted into standard geometries and free-form surfaces so that the data is available again for further production or development steps.