Components with Microgeometries

Miniaturized components with increasingly smaller geometric features are manufactured for electronics, medical engineering, communications engineering, and the motor vehicle industries to enable complex functions requiring only a minimum amount of space. Inspections of bore diameters smaller than 0.1 mm and slot widths of less than 10 µm are now routine measuring tasks. One typical example of this is the measurement of the geometry of nozzles in fuel injection systems for diesel engines using image processing sensors and the Werth Fiber Probe. The component to be measured is positioned in the measuring volume to an accuracy of one micrometer on a two-axis articulating holder. The tiny (approximately 0.1 mm) bores are “captured” by the image processing system. The actual measurement of the bore is then performed by the fiber probe. This determines both the shape and the spatial position of the bore holes (Fig. 64).

Fig. 64: Six-axis multisensor coordinate measuring machine with image processing and Werth Fiber Probe for measuring the injection nozzles of turbodiesel engines.
Fig. 65: Accuracy comparison of a form measurement on a ring gage; a) PTB calibration; b) Measurement with the Werth Fiber Probe.

Other examples of the measurement of microcomponents include components for optical waveguide connectors with a diameter of approximately 120 µm and microgearwheels with modules measuring approximately 0.1 mm (see Fig. 23). Further measuring tasks of this type include the measurement of geometries of spinning nozzles used to manufacture ultramodern synthetic fibers and the measurement of stents used to expand damaged blood vessels in medical engineering.

The fiber probe is particularly suitable for measuring microthreads. The sensor must be tilted by a suitable swiveling device in order to measure the threads in the normal section. Alternatively, it is also possible to perform a measurement in the axial section and convert the result mathematically.

Form measurements are also required for many components with microgeometries. Conventional form measurement techniques are not suitable for this purpose due to the size of the required sensors. The smallest form deviations can be measured with sufficient accuracy by using maximum precision coordinate measuring machines in connection with a laser sensor, an image processing sensor and the Werth Fiber Probe (Fig. 65).