標準號：SIS SS-ISO 4292-1991
中文標準名稱：圓度誤差評定法．兩、三點法測量
英文標準名稱：Methods for the assessment of departure from roundness — Measurement by two- and three-point methods
發布日期：1991/6/5 12:00:00
實施日期：1999/12/31 12:00:00
適用范圍：This International Standard specifies methods of numerical assessment of out-of-roundness determined by the combi-nation of two- and three-point measurement:a) determination by means of two-point measurement (measurement of diameters);b) determination by means of three-point measurement, summit (symmetrical or asymmetrical setting);c) determination by means of three-point measurement, rider (symmetrical setting).Any statement regarding an out-of-round sectton is incomplete unless the extent and nature of the departures from roundness are given. Methods for making such descriptions and evaluating them are specified in ISO 4291.For routine or in-process inspection, the procedure specified in ISO 4291 may either be needlessly accurate or the items to be inspected may be too large to be accommodated.The methods specified give faster and cheaper ways of assess-ing departures from roundness. This assessed value will deviate from the true value. The difference between the measured value and the true value can be estimated with the help of tables 2 to 8, assuming that the undulation numbers are known and of sinusoidal nature. For non-sinusoidal undulations, a theory for estimating such deviations is not yet available.