Weights are moved electromechanically inside the balancing system to compensate for the original imbalance. The balancing systems can be mounted on the tool flange or inside the tool spindle [MPM12]. The position of the two masses inside the balancing system results in one angle between the masses and another angle between resulting force and tool spindle [WECK05, p. 247].
Wheel specification includes abrasive grit type, mean grit size or mesh size, bond type, structure, and effective hardness (see Sect. 6.1 “Abrasive Layer Composition”). However, the wheel specification does not give information about the topography of the abrasive tool [MARI04, p. 349]. Furthermore, the tool specification is only a rough guideline for the tool users [KLOM86, p. 14]. Unfortunately, often grinding tool specification and process results correlate only poorly. Grinding tools of different manufacturers perform differently despite similar specification, or even tools from one manufacturer from different charges [KLOM86, p. 11]. Several attempts to correlate the mechanical tool characteristics with technological performance characteristics rarely found significant correlations [KUEN98].
The properties of grinding tools show fluctuations, which may have unpredictable impacts on the grinding process. Therefore, quality control for grinding wheels is important [KLOM86, p. 11]. Fluctuations in the characteristics of grinding wheels can result in process instability and varying results. Testing the characteristics and quality of abrasive tools helps to predict process deviations [KLOC05c]. Companies apply abrasive tool testings to evaluate constant quality of self-produced products or to release newly or further developed products to market [STRA75].
Methods for tool qualification should be user-independent. Testing can be time and material intensive, in particular for testing of diamond tools [STRA75]. Consequently, tool testings have to be rigorously supported by statistical methods, not only to reduce costs but also to ensure reliability of the results [STRA75]. However, many methods are not user-independent or applicable to superabrasives because of destructive testing. Detailed material analysis of the grinding layer gives reliable information about tool performance, but is destructive and time intensive [KLOM86, LINE92].