Slider Pitch Moment Associated With Dimple Friction

In the design of a magnetic recording disk file, pitch moment exerted by the flexure on the slider is usually treated as a product of flexure pitch static attitude and pitch-stiffness $(kp)$⁠, both measured in the absence of preload (gram-load). However, a slider operates in the presence of preload, which permits a large dimple friction to exist. We shall show by elementary beam theory that the pitch moment due to dimple friction is appreciable. The lever-arm of dimple friction is proportional to the bow height, and is independent of the slope of the flexure. To minimize the pitch moment associated with dimple friction, hence improving fly-height distribution, the flexure must bow toward the disk. These results are confirmed by optical fly-height tests.