Output details

Measurement of influence function using swing arm profilometer and laser tracker

The “Influence Function” (IF) characterises the 3D morphology of the material-removal from a polishing tool acting on a single location. The global removal is simply the time-weighted super-position of moving IFs, and the stability, or prediction of variability of Ifs becomes the determining factor in overall process predictability (“convergence”). In order to provide a numerical optimisation of edge-control, or to verify numerical models of edge-polishing, it is necessary to measure the 3D geometry of representative Ifs. This is challenging, as slopes are usually beyond interferometry, profilometers are not well-suited to 3D measurement, and a CMM doesn’t provide the precision required. This paper describes a new hybrid method, combining a swing-arm profilometer with a laser-tracker to provide high-quality 3D data. This solution is expected to have much wider applications than measuring Ifs – being suitable to complex engineering surfaces with high slopes. The paper also points the way to other hybrid metrology solutions