A clear trend is emerging in the automotive industry: lightweight construction is the name of the game and it is one of the basic prerequisites for the competitiveness of German car manufacturers. To make vehicles lighter – and therefore more efficient – virtually all com- ponents have to be slimmed down. Of course, this slimming must not reduce safety, which is monitored via component testing. From a purely technological point of view, it has been possible for many years to test components even in the production line. However, most of these inline computed tomography systems are not yet commercially viable. The investment costs for these solutions amount to a high sixfigure sum. Additional costs for direct inte- gration into the process chain further elevate the investment to dizzying heights. Working together with the company Erhardt + Abt, researchers at the Development Center for X-ray Technology have therefore developed a new system concept that works very efficiently and cost effectively: “HeiDetect Inline CT Compact R”. One of the outstanding features of this compact system is its greatly simplified component handling. An industrial robot combines aspects of the manipulator and loading systems, removing the need for many additional individual components.
The system works in a way that is simple and effective in equal measure. Located next to the production line that conveys the objects to be tested is the box of the inline CT system. An adjacent industrial robot lifts a component from the production line, places it in the com- pletely radiation shielded box, and rotates it 360 degrees. While the component is rotating, the Xray components installed in the box create highly informative CT images in a matter of seconds. These images make it possible to clearly identify, locate, and evaluate defects. Specially developed algorithms effortlessly compensate for slight inaccuracies in the robot’s movement, ensuring that image quality is up to the required standard.
Whereas meter-high cladding was required for the systems used to date, the radiation shield- ing in the new system is considerably less voluminous. Compared to commercially available production-integrated CT systems, the shielding is some 60 percent more compact. This saves space and reduces costs. In addition, it cuts maintenance and repair costs significantly. With the “HeiDetect Inline CT Compact R,” the Fraunhofer researchers are striking out on new paths and showing that research does not have to be complicated. As well as saving time, unnecessary components, and valuable space, the system does what it is supposed to: it carries out reliable inline component testing.
Detectors play a key role in X-ray systems. They are responsible for capturing the X-rays penetrating the test object. To date, flatpanel and line detectors have been used for indus- trial testing. Now researchers at the Development Center for X-ray Technology have found a way to combine the advantages of these two detector types in a single hybrid detector. This allows even processes taking place inside materials to be precisely traced and observed almost live. The ambitious technology is called MULIX (multiline CMOS Xray detector).
The detector is based on multi-line detector technology – a concept that has been limited to medical applications until now. Multi-line detectors work according to the same principles as line detectors, but they can cover greater areas simultaneously, which significantly reduces imaging times. Because MULIX is capable of imaging 256 object layers simultaneously, it can quickly and efficiently scan even large objects such as car body parts. What makes the detector so special is that it supplies high-quality images very quickly. Unlike commercially available detectors, the radius of curvature can also be changed. This maintains the flexibility required for industrial computed tomography in order to adapt the system to the size and material characteristics of the test object.
MULIX opens up a whole range of new possible applications in materials research and quality assurance, such as in the automotive and aerospace sectors and for research institutions, because it allows processes taking place inside materials to be observed. “When we test mechanical characteristics – let’s say tensile strength for example – we can use the images to track how a failurerelevant defect arises,” explains Thomas Hofmann, researcher at the De- velopment Center for X-ray Technology. The scientists already have concrete plans for their project: “We’re looking for industrial partners to further develop MULIX into a prototype,” explains the head of the department involved, Dr. Norman Uhlmann.
The Development Center Xray Technology (EZRT) is a division of Fraunhofer IIS, Erlangen, in cooperation with Fraunhofer IZFP, Saarbrücken. It carries out research in the fields of system development, Xray sensors and simulation, computed tomo graphy, imaging, CT-assisted measurement engineering, applications, and training. The center is a leading international research and development facility for industrial Xray technology. It defines and expands the state of the art in the area of non destructive testing, particularly with regard to optical and X-ray testing technologies. In addition, it positions itself between a focus on basic research in the field of nondestructive imaging (Xray and optical techniques) and industrial applications with end customers (in the form of prototypes) and with system integrators (via licensing). The EZRT possesses core competencies in the area of nondestructive testing along the entire product life cycle, all the way from raw materials to recycling. To strengthen the competitive position of regional, national, and international industry and to open up new markets and application possibilities, the Development Center for Xray Technology devises applicationoriented solutions that extend to the manufacturing of prototypes and small-scale series.