Already in 1936, Goedecke emphasized that the process performance of a grinding tool depends strongly on the spacial distribution of the cutting edges [GOED36, EVER06, p. 383]. Several methods to measure, replicate and model the tool topography exist. Karpuschewski summarizes sensors and methods for measuring the grinding tool microtopography [KARP01, p. 131 ff].
6.2.2.1 Tactile Measurement
The statical cutting edge number can easily obtained by tactile measurement of the grinding wheel topography [DAUD60, p. 47 ff, PAHL68, LORT75]. However, the tactile measurement does not differentiate between grits, bonding, or chips [DAUD60, p. 48]. Stylus tip geometry affects resolution. Furthermore, the tip will be abraded by the abrasive grits. Compared to optical measurements, tactile methods are rather time consuming.
6.2.2.2 Optical and Electron Measurement Methds
Several optical measurement methods exist to analyze the actual wheel topography or topography replica. Goedecke charted replicated cutting edges with a light microscope [GOED36, EVER06, p. 383]. Stereoscopy enables obtaining three dimensional surfaces and grit shapes [DEPE05]. White stripe projection can also be used for 3D measurements. Although light scattering methods work best on a small measuring range and homogeneuous surfaces, they can be used for abrasive tools when self-shadowing phenomena are analyzed [LUKI05].
Scanning Electron Microscopy has a better resolution than light microscopical methods. Stereoscopic SEM pictures even give detailed information about abrasive layer profile and potential cutting edges [MATS75]. The disadvantage is, however, that the abrasive layer has to fit into the SEM chamber, be cleaned for the chamber vacuum, and potentially be coated with conductive gold or graphite coatings.