Initial Wear of Fixed Diamond Wire Tool –Effect of Slurry Assisted Slicing on Machining Mechanism—

In this study, we investigated the effect of adding cerium oxide (CeO2) particles to the cutting fluid on the machining mechanism when slicing sapphire wafers using an electrodeposited diamond wire tool. The results showed that the added CeO2 acted to suppress wire tool deflection and promote initial wear of the nickel plating to rapidly expose the abrasive grains. In addition, elemental analysis of the shed wear particles suggested that they were adsorbed particles of nickel plating and sapphire. It was statistically confirmed that the CeO2 slurry reduced the size of the wear particles. In addition, the machining force was measured, and it was found that the CeO2 slurry reduced the machining force. Based on these results, it is the CeO2 slurry likely changed the wear mode from severe to mild and suppressed the lifting of the tool because smaller wear particle were formed. This suppressed wire tool deflection and stabilized the machining pressure to make the abrasive grains uniformly contact and remove material from the workpiece. Therefore, the number of cutting grains increased and the depth of cut per grain was kept small, which likely resulted in a transition to the crack-free ductile mode.