Variation of roughness parameters onsome typical manufactured surfaces – T.R. Thomas and G. Charlton

Abstract

A number of specimen surfaces, including machined surfaces and calibration standards, are examined by a stylus instrument on-line to a microcomputer. For each measuement on each specimen 14 roughness parameters are computed for each of 10 profiles, and the mean and standard deviation of each parameter is calculated. Variations of up to 15% are found even on calibration standards, and 50% variations or larger are found on many machined surfaces. Increasing the range setting and decreasing the cut-off are both found to increase scatter. Using a skid has little effect. Measuring with the lay increases the scatter. Decreasing the sampling interval has no effect on R a and R q roughness but increase R z and similar roughness and makes texture parameters ‘shape’.