Methods for the Assessment of Departure from Roundness - Measurement of Variations in Radius
|Publication Date:||1 January 1985|
|ICS Code (Properties of surfaces):||17.040.20|
Scope and field of application
This International Standard specifies a method for determining departures from roundness by measuring variations in radius by means of contact (stylus) instruments.
a) types of instruments and general requirements;
b) recommendations for the use of instruments;
c) procedures for calibration of instruments and verification of their characteristics.
This International Standard applies to the assessment of the departures from ideal roundness of a workpiece through the medium of a profile transformation, obtained under reference conditions, expressed with respect to any one of the following' centres
a) centre of the least squares circle;
b) centre of the minimum zone circle;
c) centre of the minimum circumscribed circle;
d) centre of the maximum inscribed circle. Each of these centres may have its own particular application. The position of the least squares centre can be calculated from a simple explicit equation given in annex F.
Departures from roundness of the measured profile, procedure, calibration and determination of systematic errors of rofation are dealt with in annexes A to D, respectively. Annex E gives rules for plotting and reading polar graphs.
1 Profile transformation is defined in IS0 6318.
2 Reference conditions include the stylus, frequency limitations of an electric wave filter (if used), permissible eccentricity of the graphical or
digital representation of the profile (generally 7 % to 15 % of its mean radius, see annex E), the position of the measured section or sections relative to some feature of the workpiece.