Punch grinding, a particular form of off-round grinding was investigated for the effect of contact length. The geometrical analysis of the contact length showed that the contact length in punch grinding is over three times that of an equivalent sized round component in cylindrical grinding. An increase in the punch grinding contact length leads to an increased threshold for onset of thermal damage. An increase in the contact length also leads to an increase in the normal force. An increase in material removal rate, as a consequence of the need for a lower process cycle time, is best achieved by an increase in the punch rotational speed, rather than by an increase in the depth of cut. Results showed that even though an increase in the contact length resulted in an increase in the process heat input into the workpiece, a larger proportion is dissipated over the larger contact area. ie, on balance, the effect of the contact length in off-round grinding is beneficial.
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