Multisensor Coordinate Measuring Machines with X-ray Tomography
The base of the machine frame is of solid granite design. Other system components, such as scales, linear and rotary axes, drives, and guide components come from the family of coordinate measuring machines described above. Using this construction, calibration data such as magnification, rotary axis position and geometric corrections are stable over long periods.
The basic machine construction is shown in Figure 37. The linear axes serve to adjust the magnification of the X-ray sensors for rasterizing during tomography and for classic measurement with tactile and optical sensors. For the latter task, the various sensors and associated probe changer already described can be used. In order to ensure crash-free operation, the X-ray sensors and the other sensors are mounted on separate Z-axes.
The Werth TomoScope® (Fig. 38) is the first implementation of the above principle in the world. The mechanical components, and thus the device precision, are based on the ScopeCheck® concept. By selecting the appropriate X-ray components (voltage range of Xray tube, detector type), the device can be configured optimally for a variety of different materials. Low voltages, for example, are required for measuring plastic parts that have low density. High voltages are needed for measuring high-density metal parts.
The TomoCheck® shown in Figure 39 can be configured to suit the applications. Its mechanical base components come from the VideoCheck® product line. In order to obtain significantly lower measurement uncertainty, air bearings and other high-precision components are used. For the X-ray sensors, tubes with particularly small focal points (“nanofocus”) are utilized. This increases precision and allows measurement of the smallest features.
Operation of the measuring device is done by the measurement software which is also used for optical-tactile coordinate measuring machines. The software modules needed for tomography measurements are also integrated in WinWerth® (Fig. 40). The entire measurement process using computer tomography and other sensors is controlled within this one measurement software. Operation is as simple as measurements using an image processor in backlight mode.