Design of a head-tape interface for ultra low flying

A novel tape head contour is proposed that allows very small head tape spacing at high velocities using three transverse bleed slots and a single radius cylindrical head. A finite element based numerical model is used to determine the head-tape spacing as a function of physical design parameters including tape roughness, tape speed and tape tension. The Greenwood-Williamson theory of contact between rough surfaces is applied to account for asperity contacts as the head-tape spacing decreases below the peak-to-valley surface roughness. The sensitivity of the new head design on geometrical parameters is studied and the variation of spacing and contact pressure is determined as a function of physical and geometrical design parameters. The numerical results are compared with interferometric measurements of the head-tape spacing using head contours based on our numerical design. Excellent agreement is found between numerical predictions and experimental measurements and it is concluded that the spacing at the head-tape interface is limited by surface roughness.