Processing into Narrow Groove of Single Crystal Sapphire Using Wear with Glass Disk

Sapphire is difficult to process due to its high hardness. Generally, grooves are processed by grinding, cutting, laser processing or etching. However, grinding and cutting cause severe tool wear and increase processing costs. In addition, laser processing requires expensive equipment, and etching has problems such as low material removal per unit time and long processing time. Although sapphire is chemically stable, it is known that a chemical reaction occurs at the interface with SiO2 under high pressure and high temperature. The result of the reaction, double oxide composed of Al2O3 and SiO2 is produced. Therefore, in this paper, we devised a method for processing into a narrow groove of sapphire by processing the side surface of a glass disk into a convex shape and cutting this convex part with sapphire. As a result, narrow grooves were processed into the sapphire surface. The effects of processing conditions such as processing time, circumferential speed, feed rate, and rake angle on the processed height, processed depth, and processed width were investigated for the obtained narrow grooves. Processed surface became a mirror surface. Also, processed width became the width of the glass protrusion. The processed depth and groove length could be changed using the rake angle and processing time.