Quick Guide to Precision Measuring Instruments

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PG59Quick Guide to MeasurementAspheric lens contourFemale thread formInner/outer ring contour of a bearingMale thread formInternal gear teethGage contourContour analysis methodsYou can analyze the contour with one of the following two methods after completing the measurement operation.Data processing section and analysis programThe measured contour is input into the data processing section in real time and a dedicated program performs the analysis using the mouse and/or keyboard. The angle, radius, step, pitch and other data are directly displayed as numerical values. Analysis combining coordinate systems can be easily performed. The graph that goes through stylus radius correction is output to the printer as the recorded prole.Data CombinationConventionally, if tracing a complete contour is prevented by stylus traceable-angle restrictions then it has to be divided into several sections that are then measured and evaluated separately. This function avoids this undesirable situation by combining the separate sections into one contour by overlaying common elements (lines, points) onto each other. With this function the complete contour can be displayed and various analyses performed in the usual way.Tolerancing with Design DataMeasured workpiece contour data can be compared with design data in terms of actual and designed shapes rather than just analysis of individual dimensions. In this technique each deviation of the measured contour from the intended contour is displayed and recorded. Also, data from one workpiece example can be processed so as to become the master design data to which other workpieces are compared. This function is particularly useful when the shape of a section greatly affects product performance, or when its shape has an inuence on the relationship between mating or assembled parts.Best-ttingIf there is a standard for surface prole data, tolerancing with design data is performed according to the standard. If there is no standard, or if tolerancing only with shape is desired, best-tting between design data and measurement data can be performed.Measurement ExamplesThe best-t processing algorithm searches for deviations between both sets of data and derives a coordinate system in which the sum of squares of the deviations is a minimum when the measured data is overlaid on the design data.Measured dataData 1Data 2Data combinationMeasured dataDesign dataDesign data

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