Abrading – Precision device or process - or with condition responsive... – By optical sensor
Reexamination Certificate
2000-06-30
2003-08-26
Morgan, Eileen P. (Department: 3723)
Abrading
Precision device or process - or with condition responsive...
By optical sensor
C451S008000, C451S539000, C264S153000, C264S160000
Reexamination Certificate
active
06609951
ABSTRACT:
TECHNICAL FIELD
The present invention relates to generally to a method of making a surface treating article and such surface treating article, and more particularly to a method of sensing the location of a fastener on a surface treating web and thereafter cutting the surface treating web around the fastener to provide a surface treating article, and such a surface treating article.
BACKGROUND OF THE INVENTION
Machine vision and methods of employing machine vision are known in the art. For example, U.S. Pat. No. 6,005,978 (Garakani) describes an apparatus and method for a two-dimensional search for a model image using edge-based and area-based matching. U.S. Pat. No. 5,978,521 (Wallack and Michael) describes improved methods for determining a calibration relationship among the imaging reference frames of multiple cameras that acquire images of a common moveable object. U.S. Pat. No. 6,064,759 (Buckley et al.) teaches an automatic inspection method and apparatus using machine vision cameras to inspect a three-dimensional object.
Adaptive operations enabled by machine vision systems are also known in the art. For example, U.S. Pat. No. 5,777,880 provides a method and apparatus for correctively guiding an item on a desired path along a material. U.S. Pat. No. 5,380,978 (Pryor) describes the use of datums on three-dimensional objects for the purpose of optically guided positioning. U.S. Pat. No. 5,886,319 (Preston et al.) discloses a method and apparatus for guiding a laser cutter along a path on a patterned material using machine vision.
Various articles and methods for attaching fasteners to articles are known in the art. For example, U.S. Pat. No. 4,551,189 to Peterson discloses a friction welding fastener system for fusing a thermoplastic material fastener to a substrate by heat of friction induced through the application of rotative and axial forces applied to the fastener. A cavity is formed inwardly of the bottom surface of the thermoplastic base member and a heat activated adhesive material having a bonding affinity for both the base material and the substrate material is inserted into the cavity to form a layer having a thickness equal or greater than the thickness of the base member. The base member is rotated with sufficient rotative and axial forces to cause the heat activated adhesive layer to adhere to the substrate.
European Patent Application 0 937 544 A2 to Smith discloses a method of producing an abrasive treatment disc, whereby the disc is formed from an abrasive material ultrasonically welded to a mounting member.
U.S. Pat. No. 5,931,729 to Penttila et al. discloses a method of spin welding a fastener to an article and such an article. The fastener is melt-bonded to the back of the surface conditioning disc. The surface treating article comprises a working surface adapted to treat a workpiece surface, and a back surface, the back surface comprising an open woven scrim. In a preferred embodiment, the surface treating article has a nonwoven abrasive surface conditioning disc. The Penttila et al. reference states it is also possible for the surface treating article to be a coated abrasive disc, a polishing pad, a brush, or a similar surface treating element.
Applicant's copending U.S. patent application Ser. No. 09/551477, filed on Apr. 18, 2000, teaches a method of attaching a fastener to an abrasive article via spin welding and employing an intermediate thermoplastic adhesive layer.
U.S. Pat. No. 3,561,938 to Block et al. discloses an abrasive disk and a method of making an abrasive disk, which includes impregnating a compressible porous backing sheet matrix having a plurality of segments defining voids with a bonding material, which coats the segments to form a backing sheet. The backing sheet is then placed next to a hub and the two are heated and squeezed to compress the backing sheet and cause the bonding material to flow to bond the hub to the backing sheet. The large lamination may then be cut to form a number of abrasive disks.
Surface conditioning discs having a threaded button bonded to the back side of the disc by an adhesive are available commercially as Roloc™ surface conditioning discs from Minnesota Mining and Manufacturing Company, St. Paul, Minn. These surface conditioning discs have an abrasive member and a fastener attached to the abrasive member by a layer of thermosetting adhesive. The fastener has a base and a threaded portion for attaching to a suitable back-up pad. These surface conditioning discs are assembled by first loading the fastener into heated fixture (typically 200-260° C.), such that the threaded portion of the fastener is held by the heated fixture and the base is exposed. The heated fixture heats the fastener. Next, a layer of thermosetting adhesive is applied to the fastener base, typically by spraying. After spraying the thermosetting adhesive, a circular or disc-shaped abrasive member is centered relative to the fastener held by the heated fixture and then makes contact with the layer of thermosetting adhesive on the fastener. The abrasive member and fastener are held in a compressive force until the layer of thermosetting adhesive has cured. Then, the surface conditioning disc is removed from the heated fixture.
Threaded fasteners for surface treating articles are taught in U.S. Pat. No. 3,562,968, “Surface Treating Tool,” Johnson et al.
It has been known to cut coated abrasive webs with lasers to form coated abrasive discs.
SUMMARY OF THE INVENTION
One aspect of the present invention provides a method of making a surface treating article. The method comprises the steps of: a) providing a surface treating web with a fastener attached thereto; b) sensing the position of the fastener on the surface treating web; and c) cutting the surface treating web around the fastener to provide a surface treating article including the fastener.
In one preferred embodiment of the above method, step b) further comprises sensing the position of the center of the fastener and step c) comprises cutting the surface treating web around the center of the fastener to provide a surface treating article including the fastener centered thereon. In another aspect of this embodiment, step c) further comprises cutting the surface treating web around the fastener in the shape of a disc. In another preferred embodiment of the above method, step b) is performed using machine vision. In another aspect of this embodiment, the fastener includes a fiducial, and step b) further comprises using the machine vision to determine the position of the fiducial to thereby determine the position of the fastener on the surface treating web.
In another preferred embodiment of the above method, step c) further comprises laser cutting the surface treating web around the fastener to provide a surface treating article with the fastener thereon. In another preferred embodiment of the above method, the method further comprises: d) advancing the web forward to bring a second fastener attached to the surface treating web to within a desired region; and e) repeating steps b) and c) with regard to the second fastener to provide a second surface treating article. In another aspect of this embodiment, the method is a continuous method in which a plurality of fasteners are sequentially brought into the desired region, and steps b) and c) are then repeated with respect to each of the plurality of the fasteners.
In yet another preferred embodiment of the above method, step c) further comprises partially cutting the surface treating web around the fastener to provide a partially-cut surface treating article with the fastener thereon, and subsequently separating the surface treating article from the surface conditioning web. In another preferred embodiment of the above method, the method further comprises the step of attaching the fastener to the surface treating web prior to step a). In another aspect of this embodiment, the step of attaching the fastener to the surface treating web comprises spin welding. In another aspect of this embodiment, the fastener comprises a thermoplastic
Bates Michael S.
Conwell Stanley L.
Devaney Douglas E.
Elgin Darla A.
Fritz Peter J.
3M Innovative Properties Company
Buss Melissa E.
Morgan Eileen P.
Shakeri Hadi
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