| The diameter of cylindrical objects, such as pins, bolts, thin tubes, calibration standards, needles, filaments, fine and finest wires must be measured accurately, yet without contact between measurement system and object. In particular, for diameters ranging between 0.005 and 0.5mm, the principle of Fraunhofer slit diffraction (the Babinet theory), has become the established method for measurement. The main advantage is that the measurement accuracy increases with decreasing object diameters. In addition, since vibrations of the sample have no effect on the measurement accuracy, this method is ideally suited for integration in production lines, especially for wire extruders.
Klaus Jakob Messtechnik AG, Germany, offers measurement systems for diameters up to 5mm that are based on the Fraunhofer diffraction principle, whereby also relatively large diameters of cylindrical objects can be measured precisely in-line or off-line. At a sample rate of 40 measurements per second, for instance, a repeatability of better than 0.00005mm can be achieved. Besides the demonstrated advantage of measurement accuracy, a fundamental consideration is the design of the apparatus without moving parts, which allows the system to be practically maintenance-free. The company supplies the following types of systems:
- Single-axis systems for determination of diameter, either for in-line or off-line use;
- Oscillating systems for determination of object form, either for in-line or off-line use.
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