Time-frequency methods are effective tools in identifying the frequency content of a signal and revealing its time-variant features. This paper presents the use of instantaneous features (i.e. instantaneous energy and signal phase) of acoustic emission (AE) in the detection of thermal damage to the workpiece in grinding. Both the instantaneous energy and mean frequency are obtained using the low-order frequency moments of a scalogram. While the zero-order frequency moment yields the instantaneous energy, the first-order frequency moment gives the instantaneous frequency by which the signal phase is recovered. The grinding process is monitored using acoustic emission for various operating conditions, including the regular grinding, grinding at a higher cutting speed and larger infeed, and small dressing depth of cut. It has been found that both the instantaneous energy and phase deviation indicate the presence of burn damage and serve as robust and reliable indicators, providing a basis for detecting the grinding burn.

Time-frequency methods are effective tools in identifying the frequency content of a signal and revealing its time-variant features. This paper presents the use of instantaneous features (i.e. instantaneous energy and signal phase) of acoustic emission (AE) in the detection of thermal damage to the workpiece in grinding. Both the instantaneous energy and mean frequency are obtained using the low-order frequency moments of a scalogram. While the zero-order frequency moment yields the instantaneous energy, the first-order frequency moment gives the instantaneous frequency by which the signal phase is recovered. The grinding process is monitored using acoustic emission for various operating conditions, including the regular grinding, grinding at a higher cutting speed and larger infeed, and small dressing depth of cut. It has been found that both the instantaneous energy and phase deviation indicate the presence of burn damage and serve as robust and reliable indicators, providing a basis for detecting the grinding burn.

This experimental study consists of two main steps. In the first step, the effects of cutting conditions and tool geometry on cutting forces, roundness error and surface integrity (surface roughness, residual stresses, and subsurface phase transformations) were studied on 6208-type deep groove ball bearings. In the second step, performances of grinding (GR), hard turning (HT) and hard turning + deep rolling (DR) applied to the inner ring raceways are compared to each other in terms of surface roughness, roundness error, residual stresses, noise level and fatigue life. Experimental results in the first step showed that lower surface roughness, roundness error and higher compressive stresses are achieved by V-35 cutting insert. A remarkable result in the second step is that although DR process produces higher compressive stresses in deeper layers of work surface, the bearings possess lower fatigue life than HT and GR bearings due to their higher roundness error values.

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