In some embodiments an abrading tool is provided having a desired surface texture for a lapping surface of the tool. The abrading tool has a platen defining an external surface and a cavity intersecting the external surface. An adhesive is disposed in the cavity. An abrasive member is adhered at a proximal end thereof to the platen in the cavity by the adhesive so that the abrasive member extends beyond the external surface at a distal end thereof to define the lapping surface.
In some embodiments a method is provided for manufacturing an abrading tool to have a desired surface texture for a lapping surface of the tool. The method includes the steps of obtaining a platen defining an external surface and a cavity intersecting the external surface; applying an adhesive to the platen in the cavity; adhering an abrasive member to the platen by the adhesive at a proximal end of the abrasive member so that a distal end of the abrasive member extends beyond the external surface to define the lapping surface.
In some embodiments an abrading tool is provided for lapping a workpiece. The abrading tool has a platen that is selectively moveable in relation to the workpiece, and means for supporting abrasive members from the platen to define a desired surface texture for a lapping surface of the tool.
The present embodiments relate most generally to the manufacture of abrading tools. For purposes of this description, although not so limited, reference is made to the use of an abrading tool in high precision lapping of magnetic transducing heads (referred to as “heads”) used in data storage devices. The heads, operably used to store and retrieve data on rotatable magnetic recording discs, require extremely precise manufacturing tolerances. The heads are typically formed by applying layers of an electrically conductive material and a magnetic flux conducting core along one side of a comparatively large support member, referred to as a slider. An air bearing surface (“ABS”) is precisely machined into the slider that aerodynamically supports the slider upon a thin film of air generated by the spinning recording disc. This maintains a desired spatial separation between the slider and the recording disc suitable for reliable data transfer operations between the head and the disc. Although generally referred to as an “air” bearing surface, the skilled artisan understands that in some instances the term is used universally even when the slider is similarly aerodynamically supported upon a fluid (likewise generated by the spinning disc) that is other than air, such as but not limited to an inert gas environment.
The abrading action that removes material from the sliders also causes a constant and rapid diminishment of the lapping surface texture, rendering it less effective over time and ultimately ineffective. This is particularly true during the initial lapping passes across the slider bar 106, the part of the lapping process referred to as “rough lapping,” where the dimensional part-to-part variance of the slider bars 106 is the greatest.
The adhesive 122 can be constructed of a multi-part epoxy, wherein a first part 126 of the multi-part epoxy is applied to the platen 116 in the cavity 120 as shown in
During reduction to practice of the claimed embodiments, a low viscosity epoxy was successfully used in a ratio of ten parts resin (such as first part 126) to one part hardener (such as second part 128). Various diamond powder sizes were successfully used, such as but not limited to 0.1, 0.25, 0.5, 1.0, 2.0, 3.0, and 6.0 microns. Thinning the epoxy is preferred as smaller diamond power sizes are used, such as by heating the epoxy or cutting it with a thinning agent such as isopropanol. The use of thermal set epoxies require baking time and temperature that tends to advantageously reduce the epoxy coating thickness, facilitating more robust and uniform abrasive particle exposure.
Generally, the embodiments described in the foregoing are directed to an apparatus and method associated with an abrading tool for lapping a workpiece, involving a platen that is selectively moveable in relation to the workpiece and means for supporting abrasive members from the platen to define a desired surface texture for a lapping surface of the tool. For purposes of this description and meaning of the claims, “means for supporting” the abrasive members encompasses the disclosed structure and structural equivalents thereof in which the abrasive members are rooted and adhered to the platen in a cavity intersecting the platen's external surface. The “means for supporting” expressly does not include previously attempted solutions in which the abrasive members are merely adhered to the external surface and thereby maintained in place by the sheer strength of that adhesion, and does not include other previously attempted solutions in which the abrasive members are merely embedded in the platen without also being adhered to the platen by an adhesion member.
It is to be understood that even though numerous characteristics and advantages of various embodiments of the invention have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts and values for the described variables, within the principles of the present embodiments to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
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Number | Date | Country | |
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20120009856 A1 | Jan 2012 | US |