Patent Publication Number: US-2021170617-A1

Title: Visual indication of composite fiber orientation

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This is a U.S. non-provisional patent application claiming the benefit of priority from U.S. Provisional Patent Application Ser. No. 62/944,684, filed on December 6, 2019, the entire contents of which are hereby incorporated by reference. 
    
    
     FIELD 
     This application relates generally to the fabrication of parts from composite material. 
     DESCRIPTION OF RELATED ART INCLUDING INFORMATION DISCLOSED UNDER 37 CFR 1.97 AND 1.98 
     The orientation of fibers in a composite article may result in wide variation in the article&#39;s ability to withstand forces applied at a given angle relative to the article and/or at different locations on the article. For this reason, it&#39;s important to be able to ascertain the direction of fiber orientation before forming such an article from a workpiece, and/or after removing that workpiece from a larger stock composite panel. 
     Fiber orientation in a composite workpiece, or an article fabricated from such a workpiece, can be difficult to determine for various reasons. The composite may, for example, have an opaque layer of resin or paint that obscures the fibers, the fibers may be too fine for their orientation to be easily detectable, and other types of references (such as the rectilinear shape of an unmodified stock panel) may be removed or destroyed during cutting of a stock panel into a workpiece or finished article, or may be unavailable for reference after a workpiece or finished article has been removed from the stock panel. Where the fiber orientation is not readily visible, it may still be detected by known means such as ultrasonic or laser imaging, but such solutions require time and specialized equipment. 
     SUMMARY 
     A method for indicating the orientation of fibers in a selected portion to be removed from a composite stock panel comprises the steps of determining the orientation of fibers in a composite stock panel based on a pre-existing indicator carried by the stock panel; applying a fiber orientation indicating mark to at least part of a selected stock panel portion that is to be separated from the stock panel and from the pre-existing indicator, the fiber orientation indicating mark corresponding to the orientation of the pre-existing indicator. 
    
    
     
       DRAWING DESCRIPTIONS 
         FIG. 1  is a flow chart showing a method for indicating the orientation of fibers in a selected portion to be removed from a composite stock panel; 
         FIG. 2  is a flow chart showing an alternative method for indicating the orientation of fibers in a selected portion to be removed from a composite stock panel; 
         FIG. 3  is a flow chart showing a further alternative method for indicating the orientation of fibers in a selected portion to be removed from a composite stock panel; 
         FIG. 4  is a plan view of a composite stock panel showing locations of marks indicating fiber orientation in the composite stock panel and marks showing where selected portions are to be separated from the panel to serve as workpieces that will subsequently be machined into finished articles; 
         FIG. 5  is a plan view of a workpiece after removal from the panel of  FIG. 4  and after the addition of a mark showing fiber orientation; 
         FIG. 6  is a side view of the workpiece of  FIG. 5 ; and 
         FIG. 7  is a perspective view showing an alternate embodiment of the workpiece of  FIGS. 5 and 6 , in which the mark indicating fiber orientation comprises a pair of notches. 
     
    
    
     DETAILED DESCRIPTION 
     The orientation of fibers in a composite material is important to know during various stages of the composite material&#39;s fabrication and commercial lifespan. Knowledge of fiber orientation may be useful well after the composite material is formed into commonly-sold units such as stock panels, shown at  10  in  FIG. 4 , especially during the operations of cutting selected portions  12  such as workpieces  14  from those stock panels  10 , transforming those workpieces  14  into finished products or components of such products, installing those products, and end use of the products. 
     These composite stock panels  10  may be formed from any common composite material combination. For example, a resin or epoxy may be filled with fibers comprising fiberglass or carbon. These fibers need not be precisely aligned to one another; even a general alignment is sufficient to have a significant effect on a composite stock panel&#39;s structural qualities. 
     A method for indicating the orientation of fibers in selected portions  12  (such as workpieces  14 ) to be separated from a composite stock panel  10  may include the steps of determining the orientation of fibers in the panel  10  via a pre-existing indicator  16 , applying one or more fiber orientation marks  18  to one or more selected portions  12  of the panel  10 , and then separating the selected portions  12  of the panel from the panel  10  and, consequently, from the pre-existing indicator  16 . These steps need not be performed in this order. For example, in one embodiment the application and separation steps may be performed as part of the same process. 
     In practice, the step of identifying the orientation of fibers in a composite stock panel  10  may be performed by referencing a pre-existing indicator  16  carried by the composite stock panel  10 , as shown in action step  20  of  FIGS. 1-3 . This pre-existing indicator  16  need not be a mark intentionally left during the composite stock panel&#39;s manufacturing process. An indirect clue, such as the shape of the composite stock panel  10 , is also suitable. For example: a particular brand of composite stock panels  10  may be known to reliably have a fiber orientation  22  that is, for example, parallel, and/or at right angles to, one or more of the panels&#39; edges  24  (as shown in  FIG. 4 ), allowing one or more of these composite stock panel edges  24  to be used as a pre-existing indicator  16  to identify the orientation  22  of the fibers. 
     The step of applying one or more fiber orientation indicating marks  18  may comprise applying marks  18  that correspond to the orientation of the pre-existing indicator  16 , and that are located at least partially on at least one or more selected portions  12  of the composite stock panel  10 . These orientation marks  18  may be applied via one or more additive processes (such as printing or painting new visible material onto the panel  10  as shown in action step  26  of  FIG. 1 ), one or more subtractive processes (such as engraving, as shown in action step  28  of  FIG. 2 ) that visibly remove material from the panel  10 , or one or more processes that involve otherwise visibly altering the material of the panel  10  (such as burning or stamping as shown in action step  30  of  FIG. 3 ). The marks  18  may comprise anything from a repeating pattern (such as a grid, dot matrix, or the series of lines shown in  FIG. 4 ), to a single symbol (such as an arrow or crosshair), so long as the marks  18  correspond to the pre-existing indicator  16 , and are thus indicative of fiber orientation in the composite stock panel  10 . In the example shown in  FIGS. 5 and 6 , the mark  18  comprises a groove running through a generally disk-shaped workpiece  14  that has been cut from a stock panel  10 .  FIG. 7  shows an alternate exemplary embodiment in which the marks (indicated at  18 ′) comprise two notches made at diametrically opposite ends of a generally disk-shaped workpiece  14 ′ that has been cut from a stock panel  10 . The diametrical alignment of the line marks  18  of  FIGS. 4-6 , and of  FIG. 7 &#39;s notch marks  18 ′, corresponds to the orientation of a pre-existing indicator  16  that has been removed.  FIG. 7 &#39;s use of prime marks with previously defined numbers (for example workpiece  14 ′ in  FIG. 7  vs. workpiece  14  in the other figures) indicates that a particular feature is comparable or analogous to a similarly-numbered feature shown in embodiments shown in the other figures. For example, descriptions of workpiece  14  may generally be assumed to apply to workpiece  14 ′, except where precluded elsewhere in the description or figures. 
     The selected portions  12  of the composite stock panel  10  are eventually separated from the composite stock panel  10  and from the pre-existing indicator  16 , as shown in action step  32  of  FIGS. 1 and 3 , preventing the use of the pre-existing indicator  16  to determine fiber orientation  22  in the separated selected portions  12 . Separation of the selected potions  12  from the stock composite stock panel  10  may comprise discarding the part of the panel  10  that includes the pre-existing indicator  16  after the selected portions  12  of the composite stock panel  10  have been cut out from the composite stock panel  10  to serve as workpieces  14  to be formed into finished articles. However, this separating step may be performed by any operation that prevents the pre-existing indicator  16  from being easily or reliably used to determine the orientation of fibers in the selected portions  12  of the composite stock panel  10 . 
     The step of applying one or more fiber orientation indicating marks  18  may comprise applying the marks  18  to the selected portions  12  of the composite stock panel  10  while cutting or otherwise separating the selected portions  12  from the composite stock panel  10  to serve as workpieces  14 . According to action step  34  of  FIG. 2 , this may be accomplished by adding some representation of the marks and their desired locations on a composite stock panel  10 , to a blueprint, computer assisted design (CAD) file, or any other cutting pattern suitable for guiding tools or technicians in creating such marks  18  in or on a composite stock panel  10  and/or in cutting or otherwise separating selected portions  12  from the composite stock panel  10  to serve as workpieces  14 . This blueprint, file, or pattern may then be used to guide a milling machine to, for example, cut the selected portions  12  from the composite stock panel  10  and/or to cut the marks  18  into the selected portions  12  of the composite stock panel  10 . As shown in action step  28  of  FIG. 2 , the cutting of the selected portions  12  and marks  18  may be performed in a single manufacturing operation. In the course of such an operation, the marks  18  may be cut or otherwise formed while the selected portions  12  are cut or otherwise separated from the composite stock panel  10  and from portions  12  of the composite stock panel  10  that include or comprise the pre-existing indicator  16 . In some embodiments the marks  18  may expand across, or be repeated across an entire surface, or even all surfaces of, the composite stock panel  10 . In other embodiments, the mark or marks  18  may only be applied to one or more selected portions  12  of the composite stock panel  10 . Where multiple fiber orientations are present (for example, if a workpiece  14  comprises a composite of several fiber layers having different fiber orientations  22 ), multiple sets or types of marks  18  may be used to depict each fiber orientation  22  of each fiber layer within a workpiece  14 . 
     As shown in  FIG. 4 , a plan view or “blue print” used in forming the marks  18  and cutting-out the selected portions  12  may include straight lines  36  showing where the marks  18  indicating fiber orientation are to be cut into selected portions  12  of the stock panel  10 . In this example, the blue print may also include circular lines  38  showing where the selected portions  12  are to be cut from the stock panel  10  in the form of disk or puck-shaped workpieces  14 . As is also shown in  FIG. 4 , the lines  36  indicating fiber orientation may run through each of the circular lines  38  indicating where the selected portions  12  are to be cut from the panel  10 . Before each workpiece  14  is machined via computer aided machining (CAM) into a final product, the CAM device references the marks  18  that visually indicate fiber orientation (in this case, the straight lines) on each puck-shaped workpiece  14 , to ensure that the workpiece  14  is in the optimum orientation to be cut and/or milled into a finished article, as shown in action step  40 . Beyond this example, the same method may be followed in a similar fashion using other types of marks  18  and/or workpiece shapes. 
     Once the marks  18  are applied, the fiber orientation  22  in the selected portions  12  may be determined by referencing the marks  18  as shown in action step  40  of  FIGS. 1-3 . And where the selected portions  12  are to serve as workpieces  14  and are thus subject to further operations such as cutting, bending, or assembly, as shown by action step  42  of  FIGS. 1-3 , these further operations may be modified via reference to the marks for various purposes. For example, the marks  18  may be referenced in a cutting operation to orient the workpieces  14  in such a way that the direction of cuts will not threaten the structural integrity of the workpieces  14 . In other words, the marks  18  allow for optimal positioning of each workpiece  14  in a milling machine for fabrication of a finished article. As another example, an assembly operation may comprise using the marks  18  as a guide to ensure that each of the finished articles fashioned from the workpieces  14 , is installed in an assembly such that its fibers are aligned in a direction that will optimize the assembly&#39;s ability to handle anticipated loads to be applied to the finished article. 
     According to these methods, pre-existing fiber orientation indications on stock panels may be used as references to provide corresponding orientation marks on workpieces and components, which are better suited for the idiosyncratic placement and shape of the workpieces and components that a user may wish to produce from the stock panel. This description, rather than describing limitations of an invention, only illustrates embodiments of the invention recited in the claims. The language of this description is therefore exclusively descriptive and is non-limiting. Obviously, it&#39;s possible to modify this invention from what the description teaches. Within the scope of the claims, one may practice the invention other than as described above.