Head suspensions for supporting a head slider over a rotating disk in a magnetic data storage device are in widespread use and are well known. Such head suspensions typically comprise a load beam having a flexure or gimbal at its distal end. A head slider having a read/write transducer is mounted to the flexure. In operation, the rotating disk creates an air bearing on which the head slider floats. The head suspension provides a spring force to counteract the force generated by the air bearing to position the slider at the "fly height." The flexure is sufficiently compliant to allow the head slider to pitch and roll in response to fluctuations in the air bearing created by variations in the surface of the rotating disk. In this manner, the head slider is supported and can be positioned over the disk by an actuator assembly in the drive to access or create information on the disk.
The use of a dimple formed in a surface of a head suspension is also well known. Dimples are frequently used to transfer the spring force generated by the head suspension to the slider, and are used to provide a point about which the slider can gimbal in pitch and roll directions at the fly height. Such dimples are commonly referred to as "load point dimples," and can be formed in a loading region at the distal end of the load beam. A load point dimple formed in the loading region extends from the distal end of the load beam and contacts either a top surface of the slider or a cantilever beam of the flexure to which the slider is mounted. Alternatively, a load point dimple can be formed in the cantilever beam to extend toward and contact the distal end of the load beam.
Load point dimples are typically formed in one of two ways, and the physical structure of the dimple is determined by the method used to form the dimple. A load point dimple can be formed by engaging a shaped punch with a first surface of the component of the head suspension in which the dimple is to be formed. The punch plastically deforms the component to create a dimple having a concave side on the first surface of the component and a convex side on a second surface opposite the first surface of the component. The use of an open through-hole socket or a shaped socket on the second surface of the head suspension component during the punching operation is also known. Alternatively, a load point dimple can be formed by masking and partial etching the surface in which the dimple is to be formed, thus reducing the surface to a uniform thickness and leaving a full-thickness protuberance. In this manner, a solid, generally cylindrical dimple having a planar top surface is formed. Such an etched dimple is shown in the Hagen Patent, U.S. Pat. No. 5,428,490. As stated in the Hagen patent, the edges of the planar surface can be radiused by "spanking" the dimple with a die.
Another type of dimple used in head suspensions is a static attitude compensation dimple. Static attitude compensation dimples are generally formed in the cantilever beam of the flexure. The dimple extends toward the slider mounted to the cantilever beam and contacts the top surface of the slider. The static attitude compensation dimple provides a point about which the slider pivots prior to being permanently mounted to the flexure to compensate for any static attitude misalignments in the head suspension. When properly positioned, the slider is then secured to the flexure, typically by adhesive. Static attitude compensation dimples are generally partial etched in the cantilever beam of the flexure in a manner similar to that described above, and thus have a solid, cylindrical shape. An example of a partial etched static attitude compensation dimple along with a load point dimple formed in a distal end of a load beam is shown in the Jurgenson et al. patent, U.S. Pat. No. 5,636,089.
Dimples such as those described above, however, have certain disadvantages. A head suspension having a dimple formed with a punch and a socket generally has high stress in the transition area between the planar surface of the head suspension and the dimple due to the plastic deformation of the head suspension material. Because such a dimple is "stretched" from the head suspension material during the forming process, high stress regions are created in the structure surrounding the dimple, which in turn can create a bias in the static attitude of the head suspension. Moreover, it is often difficult to accurately form a punched dimple at a desired location due to positioning errors in the dimple punch, thus introducing manufacturing tolerances into the head suspension. Additionally, the convex surface of a punched dimple formed using an open through-hole socket generally "peels" to create a rough outer surface having a series of small plateaus or flat surfaces, which in turn affects the gimballing of the head slider. Partial etched dimples, on the other hand, generally have a more accurate position due to the precise nature of the etching process, but can negatively affect the gimballing of the head slider as the slider rocks back and forth on the planar top surface of the etched dimple. This, in turn, can lead to off track alignment errors in the positioning of the head slider. Finally, whether formed using a punch or by partial etching, conventional tend to wear over time, which decreases the useful life of the head suspension.
There is therefore a continuing need for improved dimples in a head suspension. Specifically, there is a need for a dimple having increased accuracy in the position of the dimple, having a smoother outer surface, and that creates lower overall stress in the head suspension component in which the dimple is formed. A dimple having increased hardness would also be desirable.
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USPTO Backgrounds