Interactions of different parameters

Strong interactions between different parameters have been observed by several researchers. Figures 10-11 show some results from a set of factorial design of experiments (Prabhakar, 1992; Prabhakar et al. 1992). As shown in Figure 10(a) and Figure 11(a), at the high level of the rotational speed, the effects of the static pressure are more significant that those at the low level of the rotational speed. In other words, rotational speed tends to enhance the effects of static pressure.

The interaction between the rotational speed and the static pressure was also reported by Kubota et al. (1977). They observed that each rotational speed has its own optimum pressure, which yields maximum MRR, and that higher rotational speed results in smaller optimum pressure.