Abstract
We developed a new type of saw wire for slicing hard materials. Then we tried to slice 50.8mm diameter sapphire ingots into wafers by using this wire.
The surfaces of wires are composed of two layers. That is, in the first layer, electroless Ni-P alloy plated diamond abrasive grains were temporarily fixed on the brass coated piano wire by using solder. And in the second layer, Ni was electroplated for reinforcement of the first layer.
The curvature radii of filets formed between solder layer and diamond abrasive grains can be adjusted arbitrarily according to change the depth of solder layer. The stress concentration at finally Ni electroplated filets can be reduced according to the preliminary adjusted shapes of filets.
When cutting off sapphire ingots by using these saw wires, cutting surface properties, such as average thickness, maximum surface waviness (WT) and total thickness variation (TTV) of sapphire wafers were generally favorable. And when running velocities of saw wires were varied in the range from 600 m/min to 400 m/min, cutting surface properties of sapphire wafers at the lowest running velocity of 400 m/min was superior in these running velocities of saw wires.
