So the measurement uncertainty can be considered

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Unformatted text preview: chine table S PO 42 PO S 52 POS S 11 PO 51 S PO 41 POS 11 S PO 62 POS 11 S PO 1 6 S PO 2 3 S PO 31 POS S 11 PO 12 POS S 11 PO 11 S PO 22 S PO 1 2 Horizontalarm CMM Horizontal arm CMM Figure 3; Schematic representation of the sheet metal part distribution Since the feature specific deviations b are depended on the workpiece position in the measuring volume of the CMM, individual positions of the workpiece coordinate systems have to be stored, so that the deviations b can be traced back to the machine coordinate system. Figure 4; Shaft collet on a horizontal-arm CMM (courtesy Audi AG) The shaft collet is fixed at three points with a magnet fixture and repeatedly measured at each monitoring position (figure 4). The temperature is permanently recorded with calibrated platinum resistors Pt 100. The gradients have to be considered during the subsequent uncertainty calculation. Monitoring Coordinate Measuring Machines 133 4.3. Measurement strategy The selection of the geometrical features was restricted to circles and slotted holes of different dimensions. In each position all circles and slotted holes were measured 20 times. D...
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