Load-unload slider dynamics in magnetic disk drives

The dynamics of a magnetic read/write slider as it is loaded onto and unloaded from a rotating magnetic medium disk was studied. A computer-controlled stepper-motor-actuated bar mechanism was used to load or unload the slider with a specified velocity at a desired circumferential location on the disk. A laser-Doppler vibrometer was used to detect the slider´s motion. Difficulties encountered with its use are discussed. The effects of load-unload velocity and location on the disk with respect to its runout profile were examined. Using a minimonolithic three-rail slider and a Whitney-type suspension, it was observed that during loading the slider aligns itself with the disk and begins to form the air bearing at a spacing of about 4 μm. The load is then transferred continuously from the load bar to the air bearing until the operational flying height is established where the slider is fully loaded. No contacts which lead to slider motions with frequencies below 100 kHz were observed