Adjustable Burnish Slider Using Thermal Expansion for HDD Applications
Original Publication Date: 2001-Sep-13
Included in the Prior Art Database: 2003-Jun-18
Current burnish technology uses a single head designed to fly at a particular height. That height is the "burnish height". Any disk asperities higher than the burnish height will be worn or cut off by the burnish head, thus producing a smoother disk. Currently, a change in burnish height requirements necessitates a change in the design of the burnish slider or burnish slider preload in order to change the fly height. These are costly and imprecise modifications. This invention consists of a slider incorporating a hard "burnish pad" of slider material (currently N58) on the trailing end with inductive coils or a resistive element (hereafter referred to as the "heating element") deposited on the rear. The coils or resistive element produce heat, which expands the burnish pad toward the disk. This invention allows an adjustable burnish height which is controlled simply by the current being input to the coils. The burnish pad incorporates a heating element (several deposited coils, similar to an inductive write head, or a resistive element) which produces heat. The heat is conducted to the burnish pad, which moves toward the disk due to the thermal expansion. Thus, new burnish height requirements only necessitate a change in the current supplied to the heating element (and hence the amount of heat conducted to the burnish pad), and not an entirely new slider design. Figure 1 shows a schematic (not to scale) of the new adjustable burnish slider. There are several heating elements on the rear of the burnish pad in order to apply heat over the entire pad and thus provide a large contact area to burnish off disk asperities. The slider air-bearing surface (ABS) and the burnish pad can be a different size, geometry, and/or location, depending on the needs.