Abstract:
A system and method for wrapping fabric around a mandrel including providing a drum of fabric and a mandrel, removing a portion of the fabric from the drum and securing the fabric to the mandrel, rotating the mandrel such that the fabric wraps around the mandrel, and applying pressure to the fabric as the fabric is being wrapped around the mandrel to consolidate the fabric about the mandrel.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Embodiments of the present invention generally relate to a system and method for making fiber preforms by consolidating dry fiber fabric around a mandrel tool and, more particularly, to a system and method for applying an external force to dry fabric as it is consolidated in layers around a mandrel tool in order to prevent the fabric from sagging, distorting, and moving during the consolidation process. 
         [0002]    In the composite industry, cylindrical fiber preforms made of consolidated dry fiber fabric are used in numerous applications requiring a sturdy, hollow, generally cylindrical structure, such as a plane fuselage, a nacelle, the tail cone of a helicopter, and/or a case. The fiber preforms are made by tightly wrapping a sheet of dry fiber fabric, with the option of applying or pre-applying a light adhesive/resin, around a generally cylindrical mandrel in a series of layers—not unlike a long sheet of paper towels being wrapped around a tube—until the wrapped fabric forms a generally cylindrical structure having the desired thickness, dimensions, and outer diameter for the intended application of the fiber preform. Resin is then added to the bundle of fabric and the structure is heat treated to consolidate and strengthen the fabric into a structure. The fabric may be made of any number of fiber materials such as carbon, glass, or other man-made or other natural fibers, for example. 
         [0003]    The fabric is typically tightly wrapped about the mandrel so as to avoid any wrinkles or folds, which may compromise the overall strength of the final fiber-preform structure. This fabric may contain a small amount of resin applied thereto before or during the wrapping process. However, as the fabric is wrapped around the mandrel, and is overlapped around itself, the fabric can become loose and move, bulky in areas, and in general, not tightly wrapped around the mandrel. Therefore, periodically during the wrapping process, the wrapped fabric has to undergo a consolidation process, or a vacuum debulk process, where a solid sheet is placed over the wrapped fabric. A vacuum is then created within the solid sheet such that the fabric is pulled tight and consolidated. A heat treatment process may be applied to assist in the consolidation effort to bind and hold the structure intact. After the heat treatment process, the solid sheet is then removed and the wrapping process begins again. The vacuum debulk process is repeated several times throughout the wrapping process, typically once after about every five to seven layers are wrapped around the mandrel. Therefore, for a fiber preform requiring 42 layers of fabric wrapped around the mandrel, the process of wrapping the fabric will have to be interrupted six to seven times so that the wrapped fabric can undergo vacuum debulking and the consolidation process. 
         [0004]    The conventional method and system of consolidating dry fabric around a mandrel to make a fiber preform suffers from several drawbacks. The process of vacuum debulking the fabric is very time consuming and costly, especially when the process is performed numerous times while making a single fiber preform. Another drawback is the application of heat treatment option, which requires time to heat and cool the fabric before the solid film may be removed. For example, due to the time required to prepare for, and perform, the process of vacuum debulking plus the option of applying heat, 30 plus days may be required to finish a preform application having 42 layers of fabric. The additional cost of the tools, labor, and energy for performing the vacuum debulking process is also considerable. 
         [0005]    Thus, a need exists for an efficient system and method for effectively consolidating dry fabric, holding the fabric in place, preventing fabric movement and fabric distortion, and eliminating the need for the heat treatment process of the fabric wrapped around a mandrel. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    Certain embodiments of the present invention include a system for wrapping fabric around a mandrel. The system may include a sheet of fabric, a mandrel configured to receive the fabric, and at least one fiber and/or fabric tow line. The sheet of fabric is secured to the mandrel and the tow line is secured to one of the fabric and mandrel, and the mandrel rotates such that the fabric and the tow line are wrapped around the mandrel. The tow line is configured under specified tension to apply pressure to the fabric as the fabric is wrapped around the mandrel. 
         [0007]    Certain embodiments of the present invention provide a system that may include a sheet of fabric and a mandrel configured to receive the fabric, wherein the sheet of the fabric is secured to the mandrel and the mandrel rotates such that the fabric is wrapped around the mandrel. The system may further include a roller head that has at least one spring-loaded roller attached thereto, wherein the roller head is configured to be placed into position about the mandrel such that the roller rotatably engages the fabric on the mandrel and applies pressure to the fabric as the fabric is wrapped around the mandrel. 
         [0008]    Certain embodiments of the present invention provide a system that may include a roller assembly defining a gap configured to receive the mandrel. At least one roller support carrying at least one spring-loaded roller attached thereto is configured to be positioned about the mandrel such that the mandrel is received in the gap and such that the roller rotatably engages the fabric on the mandrel and applies pressure to the fabric as the fabric is wrapped around the mandrel. 
         [0009]    Certain embodiments of the present invention provide a method for wrapping fabric around a mandrel. The method includes providing a drum of fabric, providing a mandrel, removing a portion of the fabric from the drum and securing the fabric to the mandrel, rotating the mandrel such that the fabric wraps around the mandrel, and applying pressure to the fabric as the fabric is being wrapped around the mandrel to consolidate the fabric about the mandrel. 
     
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
         [0010]      FIG. 1  illustrates an isometric front view of a system for consolidating fabric to form a fiber preform according to an embodiment of the present invention. 
           [0011]      FIG. 2  illustrates an isometric front view of a system for consolidating fabric to form a fiber preform according to an embodiment of the present invention. 
           [0012]      FIG. 3  illustrates an isometric front view of a system for consolidating fabric to form a fiber preform according to an embodiment of the present invention. 
           [0013]      FIG. 4  illustrates an isometric front view of a system for consolidating fabric to form a fiber preform according to an embodiment of the present invention. 
           [0014]      FIG. 5  illustrates a bottom view of the roller head of  FIG. 4  according to an embodiment of the present invention. 
           [0015]      FIG. 6  illustrates an isometric front view of a system for consolidating fabric to form a fiber preform according to an embodiment of the present invention. 
           [0016]      FIG. 7  illustrates an isometric front view of a flange according to an embodiment of the present invention. 
       
    
    
       [0017]    The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings, certain embodiments. It should be understood, however, that the present invention is not limited to the arrangements and instrumentalities shown in the attached drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0018]      FIG. 1  illustrates an isometric front view of a system  10  for consolidating dry fiber fabric to form a fiber preform according to an embodiment of the present invention. The system  10  includes a roll  14  of dry fabric  18  wrapped around a drum or spool  22 . The drum  22  is mounted to a base  24  and is configured to rotate. The fabric  18  may be pulled off of the drum  22  as a continuous sheet  26  as the drum  22  rotates in the direction of arrow A. The fabric  18  may be made of any number of materials and the sheet  26  may have any width or length. By way of example only, the fabric  18  may be made from carbon glass, or other man made or other natural fibers and/or may be a woven, braided, unidirectional, crimped or non-crimped, or wool-stitched fabric. The drum  22  may come in a variety of sizes and shapes and the fabric  18  may be fabricated with any number of orientations or constructions that provide the mechanical properties required for a particular application. 
         [0019]    The system  10  further includes a mandrel  30  having a cylindrical body  34  formed with conical profiles  36  and rims  38 . The mandrel  30  may have any number of sizes, shapes, and configurations. By way of example only, the mandrel  30  may be significantly longer and have a greater diameter and circumference than the drum  22  and may be significantly longer than the width of the sheet  26  of fabric  18 . The mandrel  30  may be generally cylindrical, or may be barrel shaped, or have any number of other shapes that correspond to the desired shape of the end-product fiber preform. Optionally, the mandrel  30  may not have rims  38  such that the body  34  may taper off at its ends. The mandrel  30  may be made of any number of materials, for example, composite, plastic, or metal. The mandrel  30  is mounted to a base  42  such that the mandrel  30  is proximate the roll  14  of fabric  18  and is configured to rotate in the direction of arrow B. 
         [0020]    The system  10  also includes spools  46  mounted to a base  47  and positioned generally above the roll  14 . Each spool  46  carries wrapped thereon a tow line  50  or strand of material. The spools  46  are configured to rotate in the direction of arrow C as the tow lines  50  are pulled off of the spools  46  in the direction of arrow D. Each spool  46  may be any number of sizes in length and diameter. The tow lines  50  may be wrapped around the spools  46  in a spiral orientation like fishing line is wrapped about a fishing reel. By way of example only, the tow lines  50  may be made of fiber or fabric and may be a strand or a sheet. The tow lines  50  may be made from plastic, glass, carbon, or any other man made or other natural fibers and may have any number of different thicknesses or widths. Each spool  46  is mounted to a platform  54  having a circular tow guide  58  through which the tow line  50  extends from the spool  46 . The tow guide  58  guides the tow line  50  extending from the spool  46  such that, as the tow line  50  is pulled from the spool  46 , the tow line  50  extends from the tow guide  58  at a fixed angle with respect to the spool  46 . The tow lines  50  extend from the tow guides  58  through a tensioning bar  62  that is positioned between the spools  46  and the mandrel  30 . The tensioning bar  62  can be adjusted to control the amount of tension in each individual tow line  50  extending from a spool  46  to the mandrel  30  and fabric  18 . 
         [0021]    In operation, before the fabric  18  is first wrapped around the mandrel  30 , a resin is added to the exposed body  34  and/or conical profile  36  of the mandrel  30 . The fabric  18  is then pulled from the drum  22  and an end of the sheet  26  is placed on at least one of the body  34  and a conical profile  36  of the mandrel  30  over the adhesive. The tow lines  50  are then pulled from the spools  46  and ends of the tow lines  50  are placed on top of the fabric  18  on the mandrel  30  at the end of the fabric  18 . The tow lines  50  are then secured to the fabric  18  or the mandrel  30  by adhesive and/or tacks. Alternatively, the tow lines  50  can be tied to the fabric  18  or mandrel  30 . The tow lines  50  are positioned over the surface of the fabric  18  in such a way as to evenly distribute pressure across the fabric  18  as the fabric  18  and tow lines  50  are wrapped around the mandrel  30 . The mandrel  30  is then rotated in the direction of arrow B such that the sheet  26  of fabric  18  is pulled from the drum  22  and wrapped around the body  34  and/or the conical profile  36  of the mandrel  30 . Similarly, as the mandrel  30  rotates in the direction of arrow B, the tow lines  50  are pulled from the spools  46  in the direction of arrow D and wrap around the fabric  18  as the fabric  18  is wrapped around the mandrel  30 . The tow lines  50  are therefore positioned between each overlapped layer of fabric  18  as the fabric  18  wraps around the mandrel  30 . The spools  22  may be configured to move laterally as the tow lines  50  are wrapped around the fabric  18  and the mandrel  30  such that the tow lines  50  crisscross each other on the fabric  18  or are otherwise positioned along the fabric  18  in a manner that is not parallel to the edges of the sheet  26  of fabric  18 . 
         [0022]    As the fabric  18  and tow lines  50  are wrapped around the mandrel  30  together, the tow lines  50  are tightly pulled against the fabric  18  during the wrapping process to hold the layers of fabric  18  tightly against the mandrel  30  and each other, thereby preventing the fabric  18  from moving or forming folds. Fabrics made of different materials and having different weaves may require different amounts of pressure from the tow lines  50  to be kept in place on the mandrel  30 . Moreover, different fabrics  18  may require different amounts of consolidation. Therefore, as the tow lines  50  are pulled from the spools  46  and wrapped around the fabric  18  on the mandrel  30 , the tensioning bar  62  can be adjusted to increase or decrease the tension on the individual tow lines  50 . The tension on the tow lines  50  may be adjusted through the tensioning bar  62  such that the tow lines  50  apply the appropriate amount of pressure on the fabric  18  to keep the fabric  18  tightly in position about the mandrel  30  as it is wrapped thereabout. Alternatively, pressure may be applied to the tow lines  50  by any number of other ways, such as by mounting the spool  46  or the mandrel  30  to a tension device such that either one can be pulled away from the other to increase tension in the tow line  50  as needed. By way of example only, a pressure of anywhere from 10 to 100 pounds may be applied by the tensioning bar  62  to the tow lines  50 , and thus to the fabric  18  on the mandrel  30 . The mandrel  30  is structured to withstand the pressure applied onto the fabric  18  wrapping thereabout. 
         [0023]    During the wrapping process, resin or some other tacky substance may be added to the fabric  18  as the fabric  18  is wrapped around the mandrel  30 . The fabric  18  and the resin may be heated during the wrapping process such that the overlapping layers of fabric  18  better adhere to each other and are better consolidated by the pressure applied by the tow lines  50 . 
         [0024]    After the fabric  18  has been tightly wrapped into a bundle around the mandrel  30  in enough layers so that the fiber preform has the proper thickness for the given application, the fabric  18  and tow line  50  are cut and tied to the bundle. Resin is then applied to the fiber preform bundle by any number of different methods, such as injection or infusion. The fiber preform is then further treated and pressurized in an oven or autoclave until it is appropriately consolidated and hardened. The mandrel  30  is then removed from the preform and an end-user can use the finished fiber preform for the appropriate application. 
         [0025]    The spools  46  and tow lines  50  of  FIG. 1  can have any number of different orientations to distribute the tow lines  50  across the fabric. By way of example only, the spools  46  may all be positioned along the same plane, or may be positioned with respect to each other such that the tow lines overlap and criss-cross each other on the fabric  18  and thus are more evenly and uniformly distributed across the fabric. Alternatively, instead of being stationary, the spools  46  may oscillate such that the tow lines  50  crisscross each other on the fabric  18 . Alternatively, the system  10  may include any number of different spools  46  distributing tow lines  50  across the fabric  18 . By way of example only, the system  10  may include anywhere from 1 to 10 spools  46  that distribute tow lines  50  that either criss-cross, or are parallel to, each other. The number and arrangement of the spools  46  may be chosen to best apply and distribute the appropriate amount of pressure on a particular kind of fabric for a particular kind of application. 
         [0026]      FIG. 2  illustrates a front isometric view of a system  70  for consolidating dry fabric to form a fiber preform according to an embodiment of the present invention. The system  70  includes fabric  18  being fed from a drum  22  to a mandrel  30 . The fabric  18  may have a weave and pattern such that the surface of the sheet  26  of fabric  18  is uneven and not generally smooth. Overlapped layers of such a pattern may be more likely to form folds or wrinkles therebetween. The system  70  includes a single spool  74  positioned above the drum  22  that includes numerous strands or tow lines  58  extending therefrom to the fabric  18  around the mandrel  30 . The tow lines  58  operate in the same fashion as the tow lines  50  of the system  10  shown in  FIG. 1 . As the fabric  18  is wrapped around the mandrel  30 , the tow lines  50  apply pressure to the fabric  18  as needed to consolidate the fabric  18  about the mandrel  30 . Because the tow lines  50  all extend from the same spool  74 , the pressure applied by the tow lines  50  is centralized and distributed along the fabric  18  to tightly hold uneven fabric layers down on each other and prevent folds. Alternatively, the tow lines  50  may extend from more than one spool or each tow line  50  may extend from its own spool. 
         [0027]      FIG. 3  illustrates a front isometric view of a system  80  for consolidating dry fabric to form a fiber preform according to an embodiment of the present invention. The system  70  includes fabric  18  being fed from a drum  22  to a mandrel  30  like the embodiments of  FIGS. 1 and 2 . Again, the fabric  18  may have a weave and pattern such that the surface of the sheet  26  of fabric  18  is uneven and not generally smooth. The system  80  includes a single spool  84  positioned above the drum  22  that includes a single wide sheet or tow line  58  extending therefrom to the fabric  18  around the mandrel  30 . The tow line  58  may be as wide as the fabric  18  and operates in the same fashion as the tow lines  50  of the systems  10  and  70  shown in  FIGS. 1 and 2 , respectively. By way of example only, the tow line  58  may be any type of fabric. The pressure applied by the tow line  50  as the tow line  50  and fabric  18  are wrapped around the mandrel  30  is distributed across the fabric  18  to tightly hold the uneven fabric layers down on each other and prevent folds. Alternatively, the tow line  58  may be a single netting or mesh and not a sheet of material. Alternatively, the system  80  may include multiple tow lines  50  that are thinner than the tow line  50  shown in  FIG. 3  that each extend from a separate spool and are distributed across the fabric  18 . 
         [0028]    Alternatively, each embodiment shown in  FIGS. 1-3  may include tow lines  50  of varying thickness. By way of example only, a tow line  50  may have a width ranging from ⅛ of an inch to 1 foot depending on factors such as the fabric and the application for the fiber preform. By way of example only, a tow line  50  may have a thickness ranging from 0.001 of an inch to 0.125 depending on factors such as the fabric, application for the fiber perform and/or the force needed to consolidate the fiber perform. 
         [0029]      FIG. 4  illustrates an isometric front view of a system  100  for consolidating dry fabric to form a fiber preform according to an embodiment of the present invention. The system  100  includes a roll  14  of fabric  18  and a mandrel  30  with the fabric  18  partially wrapped around the mandrel  30 . The system  100  also includes a roller head  104  that is mounted on a piston  108  such that the roller head  104  is positioned above the mandrel  30 . Alternatively, the roller head  104  may be mounted to any number of other spring-loaded, or actuated structures. The roller head  104  includes a base  116  having a top surface  120  which is connected to the piston  108  and a bottom surface  124  from which extends roller assemblies  128 . Each roller assembly  128  includes a cylindrical roller  140  rotatably mounted to a roller frame  136  that is connected to the base  116  by a spring  132 . The roller assemblies  128  extend generally perpendicularly from the bottom surface  124  of the roller head  104 . Two end roller assemblies  130  extend from the bottom surface  124  of the roller head  104  at a non-perpendicular angle. Alternatively, each roller assembly  128  and  130  may extend from the bottom surface  124  of the roller head  104  at any number of different angles as needed for a particular application. 
         [0030]      FIG. 5  illustrates a bottom view of the roller head  104  of  FIG. 4 . The roller assemblies  128  and  130  are aligned along the bottom surface  124  of the roller head  104  in two parallel rows  144  with each roller assembly  128  in a row overlapping a gap  148  between adjacent roller assemblies  128  in the other row. Alternatively, any number of roller assemblies  128  and  130  may be aligned along the bottom surface  124  of the roller head  104  in any number of different alignments, arrays, rows, or orientations as needed for a particular application. Alternatively, the size of rollers  140  may vary. By way of example only, the roller head  104  may include at least one roller  140  that extends across the length of the bottom surface  124  from side wall  152  to side wall  152 . By way of example only, the roller head  104  may include at least two rollers  140  of different sizes. 
         [0031]    Returning to  FIG. 4 , in operation, the fabric  18  is attached to the mandrel  30  by a resin and then the roller head  104  is lowered in the direction of arrow E on top of the fabric  18  on the mandrel  30  such that the rollers  140  on the roller assemblies  140  engage the fabric  18  at a generally perpendicular angle and press the fabric  18  against the mandrel  30 . The mandrel  30  is then rotated in the direction of arrow B such that the fabric  18  begins to wrap around the mandrel  30 . As the fabric  18  passes between the mandrel  30  and the roller head  104 , the rollers  140  are pushed against the fabric  18  by the springs  132  and/or the piston  108  such that the rollers  140  apply pressure to the fabric  18 . The rollers  140  of the end roller assemblies  130  apply angular pressure to the fabric  18 . The rollers  140  also rotate in the direction of arrow F as the fabric  18  passes under the rollers  140 . Therefore, the spring-loaded rollers  140  apply a compressive force on the fabric  18  as it is wrapped around the mandrel  30  without resisting the progress of the fabric  18  in such a manner as to damage the fabric  18 . The pressure applied by the rollers  140  consolidates the fabric to prevent folds or wrinkles from forming in the fabric  18  and to keep the fabric  18  tightly wrapped around the mandrel  30 . 
         [0032]    When the fabric  18  is wrapped around the mandrel  30  to the desired thickness, the fabric  18  is cut and the loose end of the fabric  18  is secured to the bundle of wrapped fabric  18  by resin and is pressurized by the rollers  140 . The roller head  104  is then pulled away from the bundle of fabric  18  in the direction of arrow G. The bundle of fabric  18  may be treated with resin and heat treated to complete the fiber preform product. 
         [0033]    The rollers  140  can be used to apply pressure to the fabric  18  regardless of the contours or textures of the fabric  18 . By way of example only, the fabric  18  of  FIG. 4  may have an uneven texture due to a criss-cross weave. The rollers  140  can be sized and orientated to roll along the contours of a particular fabric and apply pressure along both the “peaks” and “valleys” along the surface of the fabric. For each kind of fabric having a specific contour, a different assembly of rollers  140  having different sizes and orientations may be used to apply the appropriate amount of pressure along the surface of the particular fabric to properly consolidate the fabric. Furthermore, the pressure applied by the rollers  140  through the springs  132  and/or the piston  108  may be adjusted depending on how tight and consolidated a fabric has to be for a particular application. 
         [0034]    Again, during the wrapping process, resin or some other tacky substance may be added to the fabric  18  as the fabric  18  is wrapped around the mandrel  30 . The pressure applied by the rollers  140  helps the adhesive hold adjacent layers of fabric  18  tightly together. Additionally, the fabric  18  and the resin may be heated during the wrapping process such that overlapping layers of fabric  18  better adhere to each other and are better consolidated by the pressure applied by the rollers  140 . By way of example only, the roller head  104  may include a heating unit that applies heat to the fabric  18  as the fabric  18  passes under the rollers  140 . 
         [0035]    Additionally, the system  100  of  FIG. 4  may include more than one roller head  104  positioned around the mandrel  30  to apply pressure to the wrapped fabric  18  at different points along the mandrel  30 . By using multiple roller heads  104 , more pressure is applied to the fabric  18  for a longer period of time as the fabric  18  is wrapped around the mandrel  30  to further consolidate the fabric  18 . 
         [0036]      FIG. 6  illustrates an isometric front view of a system  200  for consolidating dry fabric to form a fiber preform according to an embodiment of the present invention. The system  200  includes a roll  14  of fabric  18  and a mandrel  30 , with the fabric  18  partially wrapped around the mandrel  30 . The system  200  also includes a roller assembly  204 . The roller assembly  204  includes a main roller housing  208  having a semi-circular gap  212  defining a perimeter or inner contour  214  along curved side walls  216 . The gap  212  is generally sized to receive a portion of the mandrel  30  within the main roller housing  208 . The main roller housing  208  is mounted on rails  220  proximate the mandrel  30  such that the main roller housing  208  may be slid, or otherwise moved in relation to the mandrel  30 , such that the mandrel  30  may be positioned within the gap  212 . Alternatively, the main roller housing  208  may be mounted on any number of other mechanisms that can be used to move the main roller housing  208  in position about the mandrel  30 . 
         [0037]    The main roller housing  208  of the roller assembly  204  includes a series of roller supports or roller rails  222  mounted therein along the inner contour  214  of the side walls  216 . Each roller rail  222  includes row of cylindrical rollers  224  rotatably mounted to roller frames  228  that are connected to the roller rail  222  by springs  232 . The rollers  224  are positioned within the main roller housing  208  generally along the inner contour  214  of the side walls  216  and may extend past the side wall  216  and into the gap  212 . The main roller housing  208  may include any number of roller rails  224  along the inner contour  214  of the gap  212  from a top end  236  of the main roller housing  208  to a bottom end  240 . The roller rails  222  may have any number of rollers  224  of different sizes and shapes extending therefrom and positioned along the inner contour  214  of the side walls  216 . The rollers  224  extend generally perpendicularly from the roller rails  222 . Alternatively, each roller  224  may extend from a roller rail  222  at any number of different angles as needed for a particular application. Alternatively, any number of rollers  224  may be aligned along a roller rail  222  in any number of different alignments, arrays, rows, or orientations as needed for a particular application. Alternatively, the size of the rollers  224  may vary. By way of example only, a roller rail  222  may include at least one roller  224  that extends across the length of the roller rail  222 . By way of example only, a roller rail  222  may include at least two rollers  224  of different sizes. 
         [0038]    In operation, the fabric  18  is attached to the mandrel  30  by an adhesive and then the roller assembly  204  is slid along the rails  220  in the direction of Arrow H until the mandrel  30  is received within the gap  212  and the rollers  224  engage the mandrel  30  and the fabric  18  at a generally perpendicular angle. The mandrel  30  is then rotated in the direction of arrow B such that the fabric  18  begins to wrap around the mandrel  30  in layers. As the fabric  18  passes between the mandrel  30  and the rollers  224  on the series of roller rails  222 , the rollers  224  are pushed against the fabric  18  by the springs  232  such that the rollers  224  apply pressure to the fabric  18 . The rollers  224  also rotate in the direction of arrow F as the fabric  18  passes under the rollers  224 . Therefore, the spring-loaded rollers  224  apply a compressive force on the fabric  18  as it is wrapped around the mandrel  30  without resisting the progress of the fabric  18  in such a manner as to damage the fabric  18 . By using multiple rails  222  of rollers  224  along the gap  212  from the top end  236  to the bottom end  240  of the main roller housing  208 , the fabric  18  is repeatedly pressurized as it passes on the mandrel  30  through the roller assembly  204 . Such repeated pressurization consolidates the fabric tightly around the mandrel  30 . 
         [0039]    The force applied by the rollers  224  to the fabric  18  may be adjusted by moving the main roller housing  208  closer to, or further from, the mandrel  30  along the rails  220 . Alternatively, the main roller housing  208  may be adjusted in other ways so as to adjust the pressure applied by the rollers  224  to the fabric  18 . Alternatively, different springs  232  may be used to apply different amounts of force on the fabric  18  through the rollers  224  depending on the consolidation required for a particular fabric  18 . 
         [0040]    The pressure applied by the rollers  224  consolidates the fabric  18  to prevent folds or wrinkles from forming in the fabric  18  and to keep the fabric  18  tightly wrapped around the mandrel  30 . When the fabric  18  is wrapped around the mandrel  30  to the desired thickness, the fabric  18  is cut and the loose end of the fabric  18  is secured to the bundle of wrapped fabric  18  by adhesive and is pressurized by the rollers  224 . The roller assembly  204  is then slid away from the bundle of fabric  18  on the rails  220 . The bundle of fabric  18  is then treated with resin and treated in the oven to complete the fiber preform product. 
         [0041]    In an alternative embodiment, the roller assembly  204  may be configured to receive most of the mandrel  30  within a gap lined with the roller rails  222 . By way of example only, the roller assembly  204  may be configured to receive generally about three-fourths of the mandrel  30  (such as by engaging generally 270 degrees of the cylindrical mandrel) at any given time. The more of the mandrel  30  that is received in the gap, the more rollers  224  that can engage the fabric  18  and consolidate the fabric  18  as it is wrapped around the mandrel  30 . 
         [0042]      FIG. 7  illustrates an isometric front view of a flange  250  according to an embodiment of the present invention. Referring to  FIG. 1 , in some applications, creases or contours may be added to the fabric  18  such that the fabric  18  is pre-shaped for wrapping around a particular mandrel  30 . For example, where the mandrel  30  has rims  38  extending out from the body  34  and the fabric  18  is wider than the body  34 , the fabric  18  may be shaped to wrap around the body  34  and along the sides of the inner rims  38  of the mandrel  30 . Returning to  FIG. 7 , the flange  250  has a generally flat base  254  formed with side walls  258  extending therefrom. Each side walls  258  extends upward from the base  254  at an angle. In operation, the flange  250  may be used with any of the systems  10 ,  100 , or  200  of  FIGS. 1-6  to form the fabric  18  prior to the fabric  18  being fed onto the mandrel  30 . That is, the flange  250  is positioned between the mandrel  30  and the roll  14  such that, as fabric  18  is fed from the drum  22  to the mandrel  30 , the fabric  18  is pulled over the flange  250 . The side walls  258  engage the fabric  18  to form creases along the fabric  18  such that the fabric  18  is formed to fit along the body  34  and rims  38  of a mandrel  30  as the fabric  18  is wrapped around the mandrel  30 . 
         [0043]    The embodiments of the present invention provide many benefits over conventional methods and systems for wrapping dry fabric around a mandrel to make a fiber preform. The embodiments apply pressure to, and consolidate, the fabric as the fabric is wrapped around the mandrel without a need to stop the wrapping process to vacuum debulk the bundle of fabric. Thus, the embodiments save considerable amounts of time, money, materials, energy, and labor in preparing cylindrical fiber preforms. For example, using the embodiments of the present invention, a fiber preform that would ordinarily take up to 30 days to prepare using the vacuum debulk method may only take roughly 2-3 days to prepare. 
         [0044]    While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.