Ceramographic material analysis helps to understand and qualify the grinding wheel structure by picture analysis [KLOM86, LINE92]. However, samples from the abrasive layer have to be cut and prepared by embedding and polishing. Additional element analyses unveil material composition and chemical reactions during the tool production process [LINE92, p. 39 f.]. Back pressure is a pneumatic measurement method which allows to define the smallest cross-section of a flow channel [LINE92, p. 74]. In the case of an abrasive layer, the back pressure difference indicates porosity and grit distance [LINE92, p. 74 f.].
5.3.1.3 Conclusion on Hardness and Elasticity Tests
Today, the Zeiss-Mackensen and Grindo-Sonic test methods are industrial practice for qualifying conventional grinding tools [KLOC05c]. However, they are not applicable for superabrasive tools (Table 5.4).
Rammerstorfer and Hastik [RAMM74] state that the hardness definition via E-Modulus is more reliable than via penetration methods. Ktinanz et al. [KUEN98] critize that Young’s modulus and sand blasting depth show no technological useful relation to the grinding ratio, i. e. the ratio between removed workpiece volume and worn grinding tool volume.
|
Table 5.4 Comparison of different tool qualification methods after [MERB03]
|