Abstract
The processing of herringbone grooves is required in the small hydrodynamic bearings used for hard disk drive units that are used in cellular phones and other portable information devices, which involves a complex shape, microdimensions, and a high degree of accuracy. In this study, we developed a coining process for herringbone grooves, which is effective in improving accuracy, productivity, and cost performance. We investigated the fabrication of micro-end mills for cutting of a coining punch for herringbone grooves, which is made of hardened die steel (60HRC). We fabricated a cBN micro-end mill with a diameter of 100μm, and clarified its effectiveness in cutting hardened die steel.
