Functional Requirement of Being Cost-Effective

An important requirement is being cost-effective. For this, the time-dependent costs, scrap rate, tool costs and auxiliary costs need to be low (Fig. 7.30). Time-dependent costs come from the processing time and dressing time (Figs. 7.3, 7.4 and 7.31). Processing time can be reduced by a high material removal rate either by more effective chip formation at given process parameters or increased material removal rate.

Low scrap rate is achieved by monitored and increased process stability and regarding outer disturbances from the environment, in particular heating (Fig. 7.32). HVAC, sunlight, friction in machine tool elements, hydraulics, pumps systems, etc. heat the process from outside. Process vibrations can be reduced by smaller tool vibrations, lower system stiffness, less mechanical impact on the workpiece, and a sharp tool (Fig. 7.32).

Tool costs summarize grinding tool costs and dressing tool costs (Fig. 7.33). Tool wear during the grinding process needs to be minimized as well as the dressing frequency.

Dressing tool wear is induced by thermal and mechanical load (Fig. 7.34). Thermal load can be explained by friction processes and the dressing grit collision

model [CINA95, LINK07]. Mechanical load arises from the single dressing grit forces, which is modeled through the dressing chip cross section [LINK07]. A dressing tool with higher wear resistance, e. g. by high quality diamond grits or a large diamond volume, withstands wear better (Fig. 7.34).

The most relevant auxiliary costs are the cooling lubricant costs (Fig. 7.35). They are impacted by the filtering system, exchange intervals, additives, mainte­nance, and cooling lubricant loss when fluid stays on the workpieces and chips.