In both UAMEG and CMEG, the normal grinding force decreases rapidly, and the tangential grinding force decreases smoothly when wheel speed increases from 8000r/min to 36000 r/min.
It is indicated from Table 4 that the variation percentages of tangential grinding forces with the increase of wheel speed, depth of cut, and feed rate in UAMEG are smaller than those in CMEG. The variation percentages of normal grinding forces with the increase of wheel speed and feed rate in UAMEG are larger than those in CMEG.
Considering the inhibiting effect of ultrasonic assistance on variation percentages of the tangential grinding force with increasing of grinding parameters, larger depth of cut and feed rate can be adopted in UAMEG compared with CMEG, which is helpful to improve removal rate and machining efficiency.
It points to the fact that cracks penetrated into the final machined surface lead to complex fracture in CMEG under high instantaneous abrasive cutting thickness and undeformed chip thickness.