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  Apparatus and method for modifying an edgeThe Patent Description & Claims data below is from USPTO Patent Application 20070298687. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD [0001]This disclosure pertains to edge modifying apparatuses. Specifically, the apparatuses include a mechanism for providing linear oscillation of an abrasive article relative to the edge of a work piece at a substantially constant velocity. Methods of modifying the edge of a work piece are also disclosed. BACKGROUND [0002]Rigid cylindrical discs are common intermediates in a variety of commercial enterprises. For example, in the manufacture of semiconductor devices, silicon wafers are obtained by slicing a solid cylindrical ingot. Other useful materials include glass, glass ceramics, ceramics, gallium arsenide, sapphire, and compound semiconductor substrates. [0003]Generally, the peripheral edges of the cylindrical discs may have defects including small sub-surface cracks or chips. These defects can create problems in subsequent processing steps, e.g., some defects can propagate from the peripheral edge to the interior of the disc. In addition, as initially produced, cylindrical discs may have sharp edges that are prone to chipping and can be hazardous to handle. Also, after one or more processing steps, undesirable debris may be present at or near the edge of the disc. [0004]Various types of grinding machines have been used to modify such peripheral edges both to minimize or eliminate defects and to round, bevel, or otherwise contour sharp edges. Grinding has been conducted using both grinding wheels comprising abrasive particles fixed in a metal or resin matrix, and fixed abrasive webs comprising abrasive particles fixed in a matrix and adhered to a flexible backing. In addition, polishing slurries have been used wherein the edge of the disc contacts a polishing pad in the presence of a slurry of abrasive particles in a liquid medium. SUMMARY [0005]In one aspect, the present disclosure provides an edge modifying apparatus comprising a disc chuck including a disc-mounting surface and an axis of rotation; a disc edge modifying unit comprising an abrasive article support having an axis of rotation and a support surface; and a uniform velocity linear oscillation driver coupled to at least one of the disc chuck and the abrasive article support. In some embodiments, the uniform velocity linear oscillation driver is mechanically coupled to the abrasive article support. In some embodiments, the uniform velocity linear oscillation driver comprises a cam having a peripheral edge defined by a curve resulting in a substantially constant linear oscillation velocity during at least 80% of each half-cycle of oscillation. In some embodiments, the uniform velocity linear oscillation driver further comprises a cam follower mechanically coupled to the peripheral edge of the cam, wherein the peripheral edge is defined by a curve resulting in a substantially constant oscillation velocity during at least 90% of each half-cycle of oscillation. In some embodiments, the disc chuck axis of rotation forms an angle of between about 30 degrees and about 75 degrees, inclusive, relative to the support axis of rotation. [0006]In another aspect, the present disclosure provides a method of modifying the edge of a disc. In some embodiments, the method comprises providing the edge modifying apparatus; centering a disc on the disc-mounting surface of the disc chuck; positioning an edge of the disc relative to a fixed abrasive article adjacent the support surface of the abrasive article support such that at least a portion of the edge of the disc contacts an abrasive surface of the fixed abrasive article; rotating the disc chuck; and providing an linear oscillation of the fixed abrasive support surface relative to the disc-mounting surface, wherein the linear oscillation has a substantially constant velocity for at least 80% of each half-cycle of oscillation. [0007]The details of one or more embodiments of the invention are set forth in the description below. Other features, objects, and advantages of the invention will be apparent from the description and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS [0008]FIG. 1 illustrates an exemplary edge modifying apparatus according to one embodiment of the present disclosure. [0009]FIG. 2 illustrates a cam according to one embodiment of the present disclosure. [0010]FIG. 3 illustrates the displacement provided by the cam of FIG. 2. DETAILED DESCRIPTION [0011]Referring to FIG. 1, an exemplary edge modifying apparatus according to one embodiment of the present disclosure is shown. Edge modifying apparatus 100 includes disc holding unit 200, and disc edge modifying unit 300. [0012]Generally disc-holding unit 200 includes disc chuck 210 having disc-mounting surface 215. In a typical operation, a disc is releasably held against the disc-mounting surface. In some embodiments, the disc chuck is a vacuum chuck. Generally, a vacuum chuck includes a vacuum source to create a vacuum at the disc-mounting surface sufficient to hold the disc in place during the edge modifying operation. In some embodiments, adhesives, e.g., pressure sensitive adhesives and non-pressure sensitive adhesives, may be used to hold the disc against the disc-mounting surface. Other known means of holding the disc against the disc-mounting surface, e.g., mechanical devices, may also be used. [0013]In some embodiments, disc-holding unit 200 includes positioning assembly 220. The positioning assembly is used to bring edge 255 of disc 250 in contact with, e.g., abrasive article 320. In some embodiments, the positioning assembly can be used to apply a contact force, e.g., a fixed contact force, between the edge of the disc and the surface of the abrasive article. In some embodiments, the positioning assembly can be used to retract the disc from the abrasive article during and/or following the edge modifying operation. [0014]In some embodiments, the positioning assembly comprises a piston connected to a pneumatic or hydraulic source. In some embodiments, the positioning assembly comprises a motor mechanically coupled to the disc holding unit. Other mechanisms for the controlled positioning of one element relative to another are well known in the art. [0015]Disc-holding unit 200 also includes drive shaft 225 mechanically coupled to motor 230. Motor 230 rotates drive shaft 225, and ultimately disc chuck 210 and disc 250 about disc chuck axis of rotation 205, as shown by arrow A. Generally, the disc may be rotated counterclockwise or clockwise about the disc chuck axis of rotation. [0016]In some embodiments, edge-modifying unit 300 includes abrasive article support 310 mechanically coupled to drive shaft 315, which is mechanically coupled to motor 330. Motor 330 rotates drive shaft 315 and ultimately abrasive article support 310 about support axis of rotation 305, as shown by arrow B. Generally, the abrasive article support may be rotated counterclockwise or clockwise about the support axis of rotation. [0017]In some embodiments, the abrasive article support and the disc are co-rotating, i.e., both are rotated clockwise or counterclockwise about their respective axis of rotation. In some embodiments, the abrasive article support and the disc are counter-rotating. [0018]In some embodiments, disc chuck axis of rotation 205 and support axis of rotation 305 are co-planar. In some embodiments, disc chuck axis of rotation 205 and support axis of rotation 305 are parallel. As shown in FIG. 1, in some embodiments, co-planar disc chuck axis of rotation 205 and support axis of rotation 305 intersect forming angle X. Generally, the angle between the axes of rotation can vary from 0 degrees (i.e., parallel) to 89 degrees. In some embodiments, the angle is between about 5 degrees and about 75 degrees. In some embodiments, the angle is at least about 5 degrees, in some embodiments, at least about 30 degrees, or even at least about 40 degrees. In some embodiments, the angle is no greater than about 75 degrees, in some embodiments, no greater than about 60 degrees, or even no greater than about 50 degrees. [0019]In some embodiments, the disc chuck axis of rotation and the support axis of rotation are not co-planar. For example, in some embodiments, the disc chuck axis of rotation also is tilted with respect to the plane initially formed by the disc chuck axis of rotation and the support axis of rotation by a further rotation about an axis, perpendicular to the disc chuck axis of rotation, which passes through the centroid of the area of contact between the disc and the abrasive article. Generally, the angle of tilt may range from about 15 degrees to about 50 degrees. In some embodiments, the tilt angle is at least about 30 degrees, and in some embodiments at least about 40 degrees. Continue reading... Full patent description for Apparatus and method for modifying an edge Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Apparatus and method for modifying an edge patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Apparatus and method for modifying an edge or other areas of interest. ### Previous Patent Application: Devices and methods for securing a clothing strap Next Patent Application: Method of eliminating surface stress of silicon wafer Industry Class: Abrading ### FreshPatents.com Support Thank you for viewing the Apparatus and method for modifying an edge patent info. 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