Mean flank temperature measurement in high speed dry cutting of magnesium alloy

Magnesium in the molten state is flammable when exposed to oxygen. The risk of fire is the main concern during cutting operation. High speed dry cutting is preferable in cutting magnesium alloys due to there being no extra part cleaning work required, the environmental benefits and the ecological concerns. However, fire ignition could happen when the cutting temperature is close to the melting point of magnesium during high speed cutting. An experimental study of the mean temperature on the flank face is presented in this paper. In high speed cutting, the mean flank temperature is not likely to be less than that on the rake face, that is, the cutting temperature, as the undeformed chip thickness is very thin and of the same order of cutting edge radius. To measure the flank mean temperature, it is critically important to mount the artificial thermocouple properly in the workpiece. A new thermocouple mounting arrangement is proposed in this paper. The mean flank temperatures in various cutting conditions were measured and the collected chips were examined under SEM to find the burn marks. It was found that below the mean flank temperature of 302 °C, there were no burn marks on the chips. This indicates that the mean flank temperature can reasonably be used to predict the occurrence of fire in high speed cutting of magnesium alloys.