An increasingly popular approach to control thermal damage has been developed by Malkin [1989] with literature examples of its application in industry by General Motors on cast iron [Meyer 2001], with Bell Helicopter on hardened steel, and [Stephenson et al. 2001] on Inconel to impose a limit on grinding temperatures. Malkin [1989] provides the maximum allowable specific grinding energy for a given maximum temperature rise as
A and C are constants based on the thermal conductivity and diffusivity properties of the workpiece and wheel. A series of tests are made for different values of ae, vw, and de and the workpieces analyzed for burn. Plotting these on a graph of ec against d!/4a-3/4vw1/2 establishes the slope CTmax and intercept A.
The method is illustrated schematically in Figure 2.8. In an industrial situation, a power-meter is used to monitor specific energy values. If the specific energy values exceed the threshold level for burn, it is necessary to take corrective action to the process. This can mean redressing the wheel or making some other process change such as reducing the depth of cut, increasing the workspeed, or using a different grinding wheel.
