Quick Guide to Precision Measuring Instruments
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PG63Quick Guide to MeasurementUndulations Per Revolution (UPR) data in the roundness graphsA 5 to 15 UPR condition often indicates unbalance factors in the machining methodor processes used to produce the workpiece.A 15 (or more) UPR condition is usually caused by tool chatter, machine vibration, coolant delivery effects, material non-homogeneity, etc., and is generally more important to the function than to the fit of a workpiece.009018027036090º270º0º180º AmplitudeAngle009018027036090º270º0º180º AmplitudeAngle009018027036090º270º0º180º AmplitudeAngle009018027036090º270º0º180º AmplitudeAngle009018027036090º270º0º180º AmplitudeAngle009018027036090º270º0º180º AmplitudeAngle009018027036090º270º0º180ºAmplitudeAngle009018027036090º270º0º180º AmplitudeAngle009018027036090º270º0º180º 振幅角度009018027036090º270º0º180º AmplitudeAngle15 upr15-150 uprΔZq=12.35μmΔZq=17.61μmΔZq=22.14μmΔZq=16.60μmΔZq=18.76μmΔZq=20.72μmΔZq=14.50μmΔZq=22.04μm50 upr15-500 upr150 upr50-500 upr500 uprUnlteredBand-pass lterMeasurement result graphsLow-pass lterEffect of Filter Settings on the Measured ProleProles can be ltered in various ways to reduce or eliminate unwanted detail, with a cut-off value set in terms of undulations per revolution (upr). The effect of different upr settings is shown in the diagrams below, which illustrate how the measured roundness value decreases as lower upr settings progressively smooth out the line.A 1 UPR condition indicates eccentricity of the workpiece relative to the rotational axis of the measuring instrument. The amplitude of undulation components depends on the leveling adjustment.A 2 UPR condition may indicate: (1) insufcient leveling adjustment on themeasuring instrument; (2) circular runout due to incorrect mounting of theworkpiece on the machine tool that created its shape; (3) the form of the work-piece is elliptical by design as in, for example, an IC-engine piston.A 3 to 5 UPR condition may indicate: (1) Deformation due to over-tightening of the holding chuck on the measuring instrument; (2) Relaxation deformation due to stress release after unloading from the holding chuck on the machine tool that cre-ated its shape.

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