Abstract:
Techniques for manufacturing sheet product of varying surface profile and products thus manufactured are disclosed herein. In some embodiments, the disclosed invention provides a method for profiling a surface of a sheet product having a first profile on first surface. In one embodiment, the method includes creating a profiling template or contoured support surface. A profiled surface may be formed by arranging the profiling template and the sheet product such that the profiling template is located between the sheet product and a support surface, conforming the arrangement of the sheet product and the profiling template to the support surface such that conformance causes the sheet product to have a second surface profile on the first surface, and processing the sheet product to form a third surface profile on the first surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/156,350 which was filed on Feb. 27, 2009, the entirety of which is incorporated by reference as if fully set forth in this specification. 
    
    
     BACKGROUND OF THE INVENTION 
     I. Technical Field 
     The present invention relates generally to systems and methods for profiling a surface of a sheet product such as a sheet of metal or a metallic alloy. 
     II. Background of the Related Art 
     Thin gauge sheet product having tight tolerance (such as, for example, ±0.05 mm) can be manufactured by grinding and polishing the sheet product using a belt-grinding machine. The belt-grinding machine generally includes an abrasive grinding head and a vacuum bed which holds the sheet product flat in position and acts as a datum face to a grinding head. The grinding head itself is typically comprised of a fixed cylinder, around which a grinding belt passes. The vacuum bed, alternatively known as a vacuum chuck, generally has an o-ring groove machined into it such that a vacuum may be applied to hold the sheet product in position on the vacuum bed during grinding. 
     A conventional process to grind and polish flat thin gauge sheet product includes placing the sheet on the vacuum bed, holding the sheet product flat in position by applying a vacuum followed by passing the vacuum bed under a fixed grinding head numerous times. After each pass, the bed is raised to decrease the gap between the vacuum bed and the grinding head, thus grinding off and thinning the sheet product uniformly across the entire width of the sheet product. 
     Alternatively, the process to grind and polish tapered thin gauge sheet product can include passing the bed under the grinding head while gradually raising or lowering the bed between two set positions during each pass to gradually change the thickness of the sheet product between the set positions. This technique creates a tapered change in thickness which is uniform across the entire width of the sheet product. 
     In either of the above cases, the resultant sheet product is of substantially uniform thickness across the full width (i.e., the direction perpendicular to the grinding direction) of the sheet product, with a given surface roughness which itself depends on the grade of abrasive belt utilized and the number of passes performed. 
     A sheet product with uniform thickness across the full width of the sheet can, in some instances, have an impact on its performance. For example, where increased rigidity or additional material is required in certain regions, an as-formed sheet product must have the additional thickness across its full width. This additional material increases the final component weight and can potentially hinder performance. Both of these results can create additional costs which is undesirable to users of sheet product. 
     Accordingly, there exists a need in the art for a cost effective technique for producing a sheet product of controlled, variable thickness, which is both sufficiently controllable and repeatable to be utilized as a commercial manufacturing process. 
     SUMMARY OF THE INVENTION 
     In view of the above-describe problems, needs, and goals, the present invention provides techniques for manufacturing sheet product of varying surface profile and products thus manufactured. 
     In one embodiment, a method for profiling a surface of a sheet product having a first profile on first surface is provided. The method includes creating a profiling template, arranging the profiling template and the sheet product such that the profiling template is located between the sheet product and a support surface, conforming the arrangement of the sheet product and the profiling template to the support surface such that the conformance causes the sheet product to have a second surface profile on the first surface, and processing the sheet product to form a third surface profile on the first surface. 
     In another embodiment, the sheet product can be released from conformance with the profiling template such that the sheet product has a fourth surface profile on the first surface. The support surface can be a vacuum bed, and conforming the sheet product to the profiling template can further include applying a vacuum force to the arrangement of the profiling template and the sheet product. In still another embodiment the first surface may be processed by repeated passes of a grinding head. The separation between the grinding head and the arrangement of the profiling template and sheet product may also be reduced between passes of the grinding head. 
     In another embodiment, the present invention provides a system for profiling a surface of a sheet product. The system includes (1) a profiling template for creating a surface profile of the sheet product, (2) a support surface for holding the sheet product and the profiling template during processing, and (3) a processing head to process a first surface of the sheet product. 
     In some embodiments, the support surface can be a vacuum bed. In some embodiments the processing head and the support surface can be movable in one or more directions. In a preferred embodiment the processing head is a grinding head and the sheet product comprises a metal or alloy. 
     In yet another embodiment, the present invention provides a sheet product having a profiled surface. The surface is profiled by a method which includes creating a profiling template, arranging the profiling template and the sheet product such that the profiling template is located between the sheet product and a support surface, conforming the arrangement of the sheet product and the profiling template to the support surface, where the conformance causes the sheet product to have a second surface profile on a first surface, and processing the sheet product to form a third surface profile on the first surface. 
     In still another embodiment, techniques for profiling a surface of a sheet product including creating a profiling support surface, arranging the sheet product on the support surface, conforming the sheet product to the support surface, where the conformance causes the sheet product to have a second surface profile on the first surface, and processing the sheet product to form a third surface profile on the first surface. Systems for carrying out the exemplary method and products manufactured using the method are also disclosed. 
     The accompanying drawings, which are incorporated and constitute part of this disclosure, illustrate exemplary embodiments of the disclosed invention and serve to explain the principles of the disclosed invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a flowchart illustrating a method in accordance with an exemplary embodiment of the present invention. 
         FIG. 2A  is a perspective view of a sheet product, profiling template, and vacuum bed in accordance with an embodiment of the present invention. 
         FIG. 2B  is a perspective view of a profiling template and sheet product, where the profiling template has been machined to create a gradient and to remove portions thereof in accordance with an embodiment of the present invention. 
         FIG. 3A  is a cross-sectional side view of the sheet product, profiling template, and vacuum bed shown in  FIG. 2A  in accordance with an embodiment of the present invention. 
         FIG. 3B  is a side view of a state of the sheet product, profiling template, and vacuum bed shown in  FIG. 2A , where a vacuum is applied to the sheet product and the vacuum bed is passed under a grinding head in accordance with an embodiment of the present invention. 
         FIG. 3C  is a side view of a state of the sheet product, profiling template, and vacuum bed shown in  FIG. 2A , where a vacuum is applied to the sheet product and the vacuum bed has been passed under a grinding head to reduce overall thickness of the sheet product in accordance with an embodiment of the present invention. 
         FIG. 3D  is a side view of a state of the sheet product, profiling template, and vacuum bed shown in  FIG. 2A , where the vacuum is released and the sheet product regains its original shape in accordance with an embodiment of the present invention. 
         FIG. 4  is a flowchart illustrating a method in accordance with an exemplary embodiment of the present invention. 
         FIG. 5  is a perspective view of a contoured vacuum bed in accordance with an exemplary embodiment of the present invention. 
         FIG. 6  is a perspective view of a grinding head and another contoured vacuum bed in accordance with an exemplary embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of a grinding head, sheet product, and profiling vacuum bed in accordance with an exemplary embodiment of the present invention. 
         FIG. 8A  is a photograph of a resulting sheet product in accordance with an exemplary embodiment of the present invention. 
         FIG. 8B  is a photograph of a profiling template in accordance with an exemplary embodiment of the present invention. 
         FIG. 9  is a photograph of a resulting sheet product in accordance with another exemplary embodiment of the present invention. 
         FIG. 10  is a perspective view of a resulting sheet product formed in accordance with an exemplary embodiment of the present invention. 
     
    
    
     Throughout the drawings, the same reference numerals and characters, unless otherwise stated, are used to denote like features, elements, components or portions of the illustrated embodiments. Moreover, while the disclosed invention will now be described in detail with reference to the figures, it is done so in connection with the illustrative embodiments. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention provides techniques for the manufacture of sheet product having a varying surface profile that reduces or prevents increase of the overall weight of the sheet product and is well suited for any application where varying surface profile may be required of the final product and where repeatability of tight tolerances is desired. Thus, the disclosed techniques enable the resulting sheet product to have varying surface profile changes both along the length and across the width of the sheet. Such changes can be varied in terms of starting and ending points of the surface profile changes, and can occur along curved or straight lines. 
       FIG. 1  illustrates an exemplary method  100  for the manufacture of sheet product of varying surface profile in accordance with the disclosed invention. As shown in  FIG. 1 , the process begins in step  110  with the creation of a profiling template. The profiling template can be formed of any suitable material, for example steel or aluminum. 
     The profiling template should be sized such that it fits securely onto a suitable support surface, thus forming an air tight seal between the profiling template and the support surface, for example sized such that it fits inside an o-ring groove. In one embodiment, the profiling template can be ground or machined as in step  114  to create a gradient or taper along any portion of the template. In the same or another embodiment, the template can be laser cut or machined in step  112  to remove any number of portions of the template in any size or shape. As an example circles with 50 mm diameters may be formed. 
       FIG. 2A  illustrates an exemplary system for the manufacture of sheet products having a varying surface profile in accordance with one embodiment of the disclosed invention. While the profiling template  220  illustrated in  FIG. 2A , which is made of thin steel, has been laser cut to remove circular portions  222  of the profiling template  220 , the disclosed invention envisions that the portions  222  could be of any shape or size such as, for example, circles with 50 mm diameters. 
       FIG. 2B  illustrates an exemplary profiling template  220  for the manufacture of sheet product  200  of varying surface profile in accordance with the disclosed invention. The profiling template  220  has been ground or machined to create a gradient or taper  227  and laser cut or machined to remove an oval portion  223  and a polygonal portion  224 . Although the portions illustrated in profiling template  220  in  FIGS. 2A-B  are shown as circular  222 , oval  223 , and polygonal  224 , it is to be understood that the portions can take on any desired shape depending upon the final surface profile desired. 
     Returning to  FIG. 1  and  FIGS. 2A-B , following the creation of the template in step  110 , the profiling template  220  is placed on the support surface of the grinding machine in step  120 , which acts as a datum surface. In an exemplary embodiment, the support surface can be a vacuum bed  240  and the profiling template  220  is placed inside an o-ring groove  250 . In step  130 , the sheet product  200  to be processed is then placed on top of the profiling template  220 , extending outside the o-ring  250 , and is conformed to the profiling template  220  in any suitable way. The disclosed invention envisions that the sheet product  200  could be of any length, width, and thickness. For example, a sheet product that measures 500 mm×1000 mm and has thickness between 0.5 mm and 2.0 mm may be used. 
     In an exemplary embodiment, in step  140  a vacuum can be applied at any point in this process by the vacuum bed  240 . This can be accomplished by the utilization of any suitable means for applying a suction to the vacuum bed  240 , e.g., by use of a vacuum pump. In the same or another embodiment, the support surface can be any suitable surface for permitting and enabling the sheet product to be pressed against the profiling template. Examples include the use of adhesive methods or by use of mechanical methods, e.g., by applying pneumatic pressure. 
       FIG. 3A  illustrates a cross-sectional view of an exemplary profiling template  220  placed between the sheet product  200  and vacuum bed  240 . The vacuum bed  240  will require an evacuation channel  328  and can be of any suitable type, e.g., a custom made vacuum bed  240  with an o-ring groove  250  (not shown in  FIGS. 3A-D ). 
       FIG. 3B  illustrates a cross-sectional side view of an exemplary sheet product  200 , profiling template  220 , and vacuum bed  240  while a vacuum is applied though evacuation channel  328 . Where parts of the sheet product  200  can lay above cavities created by removed portions  222  of the template  220 , the applied vacuum draws the sheet product  200  down into the cavities  222 , and away from a grinding plane  300 . Those portions of the sheet product  200  that lie above the grinding plane  300  can be removed by grinding head  260 . 
     The grinding head  260  can be any suitable device for removing material from the sheet product  200 , and will vary depending on the constitution of the sheet product  200 . For example, if the sheet product  200  is a titanium or titanium alloy sheet, an appropriate grinding head can be either fixed or belt, with belts between 60 grit and 240 grit SiC or Al 2 O 3  grinding media. In addition, the grinding head  260  can be a stationary head, or it can move along one or more axes, e.g., the vertical axis relative to the sheet product, or along rotational axes. Similarly, the vacuum bed  240  can also be stationary (in which case the grinding head  260  would move in at least one horizontal direction) or the vacuum bed  240  can have the capacity to move in one or more axes, including rotational axes. 
     Returning to  FIG. 1  and  FIGS. 3A-B , after the vacuum is applied, in step  150  the vacuum bed  240  is passed under the grinding head  260  to grind and/or polish the sheet product  200 . The vacuum bed  240  can be passed under the grinding head  260  in step  152  in multiple directions, one or more times. After each pass, the vacuum bed  240  can be raised in step  154  to decrease the gap between the vacuum bed  240  and the grinding head  260 . The vacuum bed  240  is repeatedly passed under the grinding head  260  in step  150  until the desired surface profile of the sheet product  200  is achieved. 
       FIG. 3C  illustrates a cross-sectional side view of an exemplary sheet product  200 , profiling template  220 , and vacuum bed  240  after the vacuum bed  240  has been passed under the grinding head  260  along grinding plane  300  to reduce the overall surface profile (varying thicknesses across the surface on one or both sides) of sheet product  200 . 
     Returning to  FIG. 1 , after the desired surface profile of the sheet product  200  is achieved, the vacuum can be released in step  160 . By releasing the vacuum, the parts of sheet product  200  that were drawn into the cavities in the template can return to the grinding plane. The resulting sheet product has a new surface profile. The resulting sheet product  200  will also have given surface roughness depending on the type of grinding head  260  utilized and amount of processing performed. 
       FIG. 3D  illustrates an exemplary sheet product  200 , template  220 , and vacuum bed  240  after the vacuum has been released. The resulting sheet product  200  has a new surface profile with reduced thickness overall, for example a thickness of 0.5 mm at the thinnest point, but can have the original, or another desired thickness, where the sheet product  200  was drawn down into the cavities created by removed portions  222  of the profiling template  220 . This is indicated by the surface protrusion  230  shown in  FIG. 3D . The sheet product  200  would have the original thickness, for example, where the portions of the sheet product  200  were drawn down into the cavities  222  at a depth below the grinding plane  300 . 
       FIG. 8A  is a photo of an exemplary sheet product  200  profiled using the method shown in  FIG. 1 , wherein the sheet product  200  has been drawn down into the cavities created by removed portions  222 , and is part way through the grinding process. A number of circular-shaped surface indentations  230  are visible in  FIG. 8A  and it can be seen that these surface indentations  230  have retained the original surface finish.  FIG. 8B  is a photo of the exemplary profiling template  220 , used to create the sheet product shown in  FIG. 8A . As shown in  FIG. 8B , profiling template  220  is made of 0.5 mm sheet steel, and has been laser cut to remove circular portions  222  of approximately 25 mm to 200 mm diameter. The vacuum bed  240  shown in  FIG. 8B  is an aluminum custom-made bed approximately 1.5 m×1 m.  FIG. 8B  is also illustrated in  FIG. 2A  as template  220 . 
       FIG. 9  is a photo of an exemplary sheet product of Ti 6-4 alloy measuring 685 mm×1195 mm, which has been profiled using the method shown in  FIG. 1 . The sheet product shown in  FIG. 9  has been drawn down into the cavities created by oval portion  223  and polygonal portion  224 , thereby producing the oval protrusion  225 , and polygonal protrusion  226 , respectively, as shown in  FIG. 9 . The profiled sheet product has also been ground to create a gradient or taper (not visible). The profiling template used to create the exemplary sheet product shown in  FIG. 9  is illustrated as profiling template  220  in  FIG. 2B . As illustrated by the surface markings provided on the sheet product  200  in  FIG. 9 , the resulting surface profile of the sheet product  200  varies in thickness from 0.60 to 1.40 mm. 
       FIG. 4  illustrates an exemplary method  400  for the manufacture of sheet product  200  of varying surface profile in accordance with the disclosed invention. As shown in  FIG. 4 , the process begins at step  410  with the creation of the contoured support surface of the grinding machine, which acts as a datum surface. The contoured support surface can be formed of any suitable material, for example aluminum. In an exemplary embodiment, the contoured support surface can be a contoured vacuum bed. In the same or another embodiment, the support surface can by any surface suitable to permit and enable the sheet product to be conformed thereto. 
     As shown in  FIG. 4 , an exemplary contoured vacuum bed may be formed by machining the material of a vacuum bed in step  410 . In one embodiment, the contoured vacuum bed may be machined in step  412  to remove any number of portions of the vacuum bed in any size, shape, or angle, and depth. In one exemplary embodiment, the vacuum bed may be machined to remove portions up to 0.5 mm deep. In the same or another embodiment, the contoured vacuum bed may be machined as in step  414  to create high spots on the contoured vacuum bed in any size, shape, angle, or height. 
       FIG. 5  illustrates an exemplary contoured vacuum bed  540 , which can be machined to remove cavities  542  of any shape such as, for example, a circular shape from the contoured vacuum bed  540 . In the same or another embodiment, the exemplary contoured vacuum bed  540  can be machined to create high spots  546  in the contoured vacuum bed  540 . 
     Returning to  FIG. 4 , following the creation of the contoured vacuum bed  540 , in step  420  the sheet product is placed onto the contoured vacuum bed  540  and is conformed to the contoured vacuum bed  540  in any suitable way. In an exemplary embodiment, in step  430  a vacuum can be applied at any point in this process by the contoured vacuum bed  540 . This can be accomplished by the utilization of any suitable means for applying a suction to the contoured vacuum bed. In an exemplary embodiment, the contoured vacuum bed  540  can be machined with an o-ring groove  250 . A plurality of evacuation channels (not shown) are provided across the surface of the contoured vacuum bed  540  to ensure conformance of the sheet product  200  to its surface. The number of evacuation channels required generally depends on the complexity of the surface profile provided on the contoured vacuum bed  540 . In the same or another embodiment, the sheet product  200  can be conformed to the support surface by any other suitable means such as, for example, by use of adhesive methods or by use of mechanical methods, e.g., by applying pneumatic pressure. 
       FIG. 6  illustrates an exemplary grinding head  260  and contoured vacuum bed  540 , which can be machined to remove cavities  542  of any shape, for example a circular shape. In one embodiment, the grinding head  260  may be a cylinder with a 300 mm diameter and length of 850 mm. 
       FIG. 7  illustrates a cross-sectional side view of an exemplary sheet product  200  that has been conformed into cavities  542  and over high spots  546  in the contoured vacuum bed  540 . 
     Returning to  FIG. 4 , after the vacuum is applied in step  430 , the contoured vacuum bed  540  is passed under the grinding head  260  to grind and/or polish the sheet product in step  440 . In step  442 , the contoured vacuum bed  540  can be passed under the grinding head  260  in multiple directions, one or more times. After each pass, in step  444  the contoured vacuum bed  540  can be raised to decrease the gap between the contoured vacuum bed  540  and the grinding head  260 . The contoured vacuum bed may be passed under the grinding head  260  the desired number of times as in step  442  until the desired overall surface profile of the sheet product  200  is achieved. 
     The cross-sectional side view of the exemplary grinding head  260 , sheet product  200 , and contoured vacuum bed  540  shown in  FIG. 7  also provides an illustrative grinding plane  300 . After the vacuum bed has been passed under the grinding head  260  along grinding plane  300  the desired number of times, the overall surface profile (varying thickness across one or both sides) of sheet product  200  is reduced. 
     Returning to  FIG. 4 , after the desired surface profile of the sheet product  200  is achieved, the vacuum is released in step  450 . The resulting sheet product has a new surface profile. The resulting sheet product  200  will have given surface roughness depending on the utilized grinding head. 
       FIG. 10  is a perspective view of a resulting sheet product  200  profiled using the method shown in  FIG. 4  and the contoured vacuum bed  540  provided in  FIG. 5 . The presence of a high spot  546  creates a surface cavity on the profiled sheet product (shown at left in  FIG. 10 ) whereas a cavity  542  creates a surface protrusion on the resulting sheet product (at right in  FIG. 10 ). 
     It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described in this specification. Rather, the scope of the present invention is defined by the claims which follow. It should further be understood that the above description is only representative of illustrative examples of embodiments. For the reader&#39;s convenience, the above description has focused on a representative sample of possible embodiments, a sample that teaches the principles of the present invention. Other embodiments may result from a different combination of portions of different embodiments. 
     The description has not attempted to exhaustively enumerate all possible variations. The alternate embodiments may not have been presented for a specific portion of the invention, and may result from a different combination of described portions, or that other undescribed alternate embodiments may be available for a portion, is not to be considered a disclaimer of those alternate embodiments. It will be appreciated that many of those undescribed embodiments are within the literal scope of the following claims, and others are equivalent. Furthermore, all references, publications, U.S. patents, and U.S. patent application Publications cited throughout this specification are incorporated by reference as if fully set forth in this specification.