A modified version of the capacitance probe technique is used to investigate the head-tape interface in a rotating head configuration. The relationship between air-bearing spacing and contour design is studied as a function oftape tension, head protrusion, and velocity; in addition, the effect of wave dynamics on flying height is examined.
IntroductionThe measure of capacitance between adjacent surfaces has been used extensively to study the spacing of bearing surfaces separated by thin lubricant films. Crook [ 1,2] used the technique to measure the spacing in the contact zone between oil-lubricated disks. Archard and Kirk [3] applied the method to study elastohydrodynamic lubrication of crossed cylinders and derived a simple empirical expression for the oil film thickness of the contact zone. In an application involving air-lubricated bearings, Ma [4] and Licht [5] studied the dynamics ofse1f-acting foil bearings on a rotating circular drum using aluminized Mylar tape. Dynamic spacing variations were likewise investigated with the capacitance technique by Lin and Beye [6] and by Briggs and Herkart [7] in the study of the magnetic head-disk interface of magnetic recording disk files,In the work reported in [4] through [7] the capacitance method was found especially useful because it furnished dynamic spacing information. This latter information is desirable in the design of magnetic recording devices, since a recording head has to maintain a stable and uniform transducer/medium spacing.In this communication we use the capacitance probe technique to investigate the behavior of the magnetic head-medium interface in a rotating head configuration [8]. In particular, we have incorporated the capacitance probe in the magnetic head and have studied the headtape flying behavior as a function of contour design, tape tension, and head velocity.