Alignment of sliders in head gimbal assemblies

Metal working – Method of mechanical manufacture – Electrical device making

Reexamination Certificate

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Details

C029S407040, C029S407100, C029S603100, C360S245100

Reexamination Certificate

active

06212760

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to manufacture of head gimbal assemblies, known as HGAs. More particularly, the invention relates to manufactures and manufacturing steps that simplify and make more accurate and less time-consuming the juxtaposing of the slider with the dimple when mounting the slider to the flexure tongue. The invention substitutes added optically readable indicia for the outlines of the dimple as the locating criteria for the slider, thus ensuring accurate placement of the slider every time.
2. Related Art
In the manufacture of suspensions comprising a load beam, a flexure attached to the load beam and having a tongue, and a slider, mounted for gimbaling movement around a dimple defined by the flexure tongue or the load beam rigid portion, the positioning of the slider by automatic equipment is essential to efficient manufacture. A misplaced slider, that is a slider that is not properly aligned with reference to the dimple, will not gimbal properly or predictably and are a costly defect that reduces manufacturing yield. Taking additional time to properly place the slider increases costs in a very cost conscious industry.
SUMMARY OF THE INVENTION
This application refers to sliders as the mounted element. The term slider herein is used to encompass not only the slider itself, a typically ceramic body designed to fly over the rotating disk in a disk drive, but also to include the read-write head carried within the slider body and connected to the device electronics.
The need for increased accuracy in positioning of sliders must be met at no greater expenditure of manufacturing time. This can be achieved by the use of automatic positioning apparatus using optical reading to locate the correct position. Presently available optical readers, known per se, cannot, however, read with certainty the location of the dimple because the dimple, being an upset or etch formed boss, lacks clear delineation at its junction with the surrounding wall of the flexure tongue or load beam rigid portion. That is, there is not a sufficiently sharp, or uniformly distributed, target for the optical reader to use as a marker for positioning the slider relative to the dimple.
It is an object, therefore, of the present invention to provide markers of such sharpness and uniformity of distribution that positioning equipment can read and position the slider with reference to them, as opposed to the dimple, with increased accuracy, better speed and fewer defects. It is a further object to provide a system of optically readable indicia, typically geometric shapes, arranged in a pattern useful in the invention method. It is a further object to provide a series of such indicia arranged in such proximity and uniformity of pattern relative to the dimple as to be useful as a proxy for the dimple in locating the slider properly on the flexure tongue.
These and other objects of the invention, to become apparent hereinafter, are realized in a head gimbal assembly of a load beam, a flexure attached to the load beam and having a tongue, and a slider attached to the flexure tongue, the load beam and flexure tongue defining between them a dimple positioned, sized and shaped to allow gimballing movement of the slider, where the head gimbal assembly has optically readable indicia centered on the dimple for precisely locating the slider opposite the dimple by reference to the optically readable indicia rather than the dimple.
In this and like embodiments, typically, the load beam defines the dimple, the flexure tongue is shaped to expose at least portions of the dimple and optically readable indicia from the side of the flexure tongue remote to the dimple, the dimple has a circular periphery, the optically readable indicia are uniformly distributed a given distance from the dimple periphery, and the flexure tongue is relieved along its longitudinal extent to expose the indicia, and the optically readable indicia are uniformly distributed about the periphery of the dimple, and the flexure tongue has a dog-bone shape to expose the optically readable indicia, the optically readable indicia being sharper edged than the dimple edge with the load beam.
In a further embodiment, the flexure tongue defines the dimple. In this and like embodiments, typically, the optically readable indicia comprise a series of circular holes uniformly distributed about the periphery of the dimple, or the optically readable indicia comprise a series of polygonal holes uniformly distributed about the periphery of the dimple, e.g. the polygonal hole optically readable indicia are diamond shaped in longitudinal cross-section, or the optically readable indicia comprise a series of arcuate holes uniformly distributed about the periphery of the dimple, the optically readable indicia are semi-circular in longitudinal cross-section, the optical indicia comprise a series of annular slots uniformly distributed over the surface of the dimple, or, the optically readable indicia comprise a series of arcuate slots uniformly distributed over the surface, the arcuate slots, or any combination of such shapes or other optical indicia noted above or used being distributed both within and/or without the periphery of the dimple in a generally uniform pattern.
In its method aspects, the invention provides a method of mounting sliders onto load beams or flexure tongues in position opposite the dimple in a head gimbal assembly comprising a load beam, a flexure having a tongue and a slider, including marking the situs of the dimple with optically readable indicia, and guiding placement of the slider on the flexure tongue with reference to the optically readable indicia rather than the dimple.
In this and like embodiments, typically, the invention method includes also forming the dimple on the load beam, and shaping the flexure tongue to expose the optically readable indicia for reading, or forming the dimple on the flexure tongue.
In this and like embodiments, typically, the method also includes forming a series of circular holes uniformly distributed about the periphery of the dimple as the optical indicia, forming a series of polygonal holes uniformly distributed about the periphery of the dimple as the optical indicia, e.g. the polygonal holes that are diamond shaped in longitudinal cross-section, forming a series of arcuate holes uniformly distributed about the periphery of the dimple, e.g. to be semi-circular in longitudinal cross-section, forming a series of annular slots uniformly distributed over the surface of the dimple, or any combination of such shapes, forming a series of arcuate slots uniformly distributed over the surface, and distributing the series of arcuate slots both within and/or without the periphery of the dimple in a generally uniform.


REFERENCES:
patent: 4866836 (1989-09-01), Von Brandt et al.
patent: 5758406 (1998-06-01), Hunsaker et al.

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