Contributions of scanning metrology uncertainty to milling force prediction

This paper describes an uncertainty evaluation for axial location-dependent cutting edge radius and angle values extracted from structured light scans of a variable pitch endmill. Two cases are evaluated: 1) a single scan of the endmill is performed and that scan is manually fit five times to record the cutting edge geometry for all teeth on the endmill; and 2) five scans of the endmill are performed and each scan is manually fit a single time. Both cases therefore include five manual fits. The standard deviations in radius and angle values are used to represent the statistical uncertainty and the two cases are compared. The mean standard deviations in radius are 0.005 mm and 0.007 mm; the mean standard deviations in angle are 0.066 deg and 0.092 deg. As expected, the uncertainties are higher with additional scans. The scan results are then used in a time-domain simulation to predict the cutting force profiles for the variable pitch endmill. It is shown that the two cases provide similar agreement between prediction and measurement due to the small measurement uncertainties.