TABLE OF CONTENTS Creep-feed grinding is characterized by the use of slow (creep) workpiece velocities and extremely large depths of cut which are hundreds or even thousands of times greater than those in regular grinding applications. With this process, it may be possible to grind complex profiles or deep slots in only a few or even a single pass. Applications of creep-feed grinding include the machining of drill flutes and the profiling of turbine blade roots for jet engines [55 57].
Because of the heavy wheel depths of cut in creep-feed grinding, which typically range from 1 to 10 mm, the wheel-work contact lengths and grinding zone areas are also very big. Therefore, we should expect much bigger specific energies than in regular grinding owing to much bigger sliding forces (Eq. (5-11)). An example of this behavior in Figure 5-19 illustrates the sensitivity of the specific grinding energy to the wear-flat area for straight creep-feed grinding of a nickel-base alloy with a high-porosity aluminum oxide wheel [58,59]. Whereas our grinding model predicts a linear relationship between specific energy and wear-flat area, these results suggests a discontinuous curve with two slopes. This discontinuity at a specific energy approaching 200 J/mm 3 may be associated with burn-out of the grinding fluid (see Chapter 7). The intercept at about 25 J/mm 3 in Figure 5-19 is comparable to that expected for the combined chip-formation and plowing energy components, and the very large specific grinding energies can be attributed to sliding of the...
