A flyability and durability dilemma in hard disk drives

Abstract

A magnetic hard disk drive lubrication dilemma was demonstrated through the touch down, wearability and burnish rate tests. It was found that attempts to improve durability and flyability through changes in lubricant film thicknesses, the addition of additives, changes in lubricant molecular weight and irradiating lubricant with deep UV rays (185 nm) have been futile with loss in either flyability or durability of magnetic hard disk. Three key types of head disk interface testing methods were introduced and the results from each parameter change were shown. The touch down test was used to check the fly height of the magnetic heads. The wearability test was used to check the wear resistance of the magnetic hard disks when in contact with the magnetic heads and the burnish rate test was employed to determine the amount of wear of the magnetic heads when in contact with magnetic hard disks. These three techniques may be used for the feasibility study for any newly designed lubricant or technique to reduce the spacing between the magnetic head and magnetic disk. We demonstrate the capability of the three techniques to discriminate different process treatments. The experiments were conducted in a class 100 cleanroom.