Abstract:
The present invention provides an apparatus and associated method for removing backing film from tape or tape during the fiber placement process. The present invention uses a passive (non-powered) take-up roller to wind up the backing film that has been separated from the tape.

Description:
BACKGROUND 
     1. Field of Invention 
     The present invention generally relates to a lamination device, and more particularly, to a system and method of fabricating a composite item. 
     2. Related Art 
     Composite items are typically constructed from layers of material that are laminated together. The categories of materials used to fabricate or “layup” composite items includes, for example: fiber; fabric; tape; film; and foil. When these items are arranged as woven sheets and unidirectional ribbons, for example they are referred to as fabric and tape respectively. 
     Fiber placement machines that apply tape require removal of a polyethylene backing film prior to lamination. Current systems depend on vacuum and/or compressed air to remove the backing film but are generally not reliable. Unreliable systems may cause excessive machine downtime and lower throughput. 
     What is needed an apparatus and associated method for removing backing film from tape during the fiber placement process that is reliable and may be passive. 
     SUMMARY OF THE INVENTION 
     The present invention provides an apparatus and associated method for removing backing film from tape or tape during the fiber placement process. The present invention uses a passive (non-powered) take-up roller to wind up the backing film that has been separated from the tape. 
     In one aspect of the present invention, a method is provided for removing backing film from a roll of tape, such as slit prepreg tape, used for tape laying or fiber placement. The method includes unwinding the tape from a roll using a first roller while the backing is attached partially removing the backing film from the tape and attaching the backing film to a second, take-up roller that is free to rotate; continuing to unwind the tape; partially wrapping it around the second, freely rotating take-up roller such that the tape drives the take-up roller as the tape laying or fiber placement proceeds. 
     In another aspect, the present invention provides an apparatus for removing backing film from a roll of tape used for tape laying or fiber placement. The invention includes a tape roller and backing film take-up roller, where the take-up roller has an axis which is parallel to a spool of tape. The take-up roller having the capacity to accept the entire length of backing film from the spool of tape as the tape unwinds from the spool, but before the tape enters a dispensing and compaction system. The take-up roller is driven by the tape as the tape is drawn by the tape roller from the spool on its way to the dispensing and compaction system 
     This brief summary has been provided so that the nature of the invention may be understood quickly. A more complete understanding of the invention can be obtained by reference to the following detailed description of the preferred embodiments thereof in connection with the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing features and other features of the present invention will now be described with reference to the drawings of various objects of the present invention. The illustrated embodiment is intended to illustrate, but not to limit the invention. The drawings include the following: 
         FIG. 1  is a simplified perspective view of an automated lamination device according to an embodiment of the invention; 
         FIG. 2  is a simplified perspective view of a front of an end effector that is suitable for use with the laminating device of  FIG. 1 ; and 
         FIG. 3  is a simplified top view of a backing removal system for use with the end effector of  FIG. 2  according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a perspective view of a laminating device  100  according to an embodiment of the invention. In one embodiment, laminating device  100  includes a positioning device  102  and an end effector  104 . Positioning device  102  is configured to position or otherwise control the movement of end effector  104 . In one embodiment, positioning device  102  may be a robotic armature or gantry-type positioning device configured to control three to ten or more axes of movement. 
     Laminating device  102  is configured to fabricate an item  106  by applying a course material  108  on a form  110 . Typically, item  106  is fabricated from multiple plies or layers of course material  108 . In one embodiment, end effector  104  includes a compaction roller  218  ( FIG. 2 ) and/or sweep to apply course material  108  to form  110 . Form  110  may be configured to provide a suitably stable and finished surface for ply placement. 
     As shown in  FIG. 1  form  110  is controlled to rotate about an axis. When controlled to rotate, form  110  is typically referred to as a mandrel In other embodiments, form  110  may be stationary or controlled to move in various axes. For example, form  110  may be secured to a sliding table or X-Y table. 
     Item  106  is shown in  FIG. 1  being constructed from a plurality of courses  114 . Each layer of courses  114  that is placed upon form  110  or a substrate  116  is described as a ply and item  106  is typically fabricated from a plurality of plies. Substrate  116  includes form  110  surface and/or a previously applied course  114 . 
     A laminating device is disclosed in U.S. Pat. No. 7,472,736, which is incorporated herein by reference for all purposes. 
       FIG. 2  is a perspective view of a front of end effector  104  that is suitable for use with laminating device  100 . As shown in  FIG. 2 , end effector  104  includes a set of spools  202 , a dancer roller  20 , a redirecting pulley  212 , a cutting assembly  214  a compaction roller  218  and a take-up roller  220 . 
     In one embodiment, tape  204  includes backing film or separator film  216 , which substantially prevents tape  204  from adhering to itself while it is on spool  202  or in roll film. Tape  204  may include any suitable course material for example, various fibers, films, foils, and/or the like. Particular examples of fibers include glass, aramid, carbon, and various other fibers. Tape  204  includes individual fibers, bundles, cords, plaits, ribbons in the form of unidirectional “tape,” woven fabric, biaxial cloth and the like. In addition, tape  204  may be pre-impregnated with a resin or other such binding substance. 
     Each of spools  202  is mounted on a respective spindle or tensioner  206 . Tensioner  206  detachably secures the respective spool  202  to end effector  104  and includes any suitable tensioning device such as, for example, a brake or motor to tension and otherwise modulate the rate at which tape  204  is dispensed. A specific example of a suitable tensioning device includes a belt that wraps around a portion of the circumference of tensioner  206  and generates friction that retards the rotation of tensioner  206 . 
     End effector  104  further includes a path  208  for tape  204  to follow as it travels from spool  202  to compaction roller  218 . As shown in  FIG. 2 , tape  204  with backing  216  traverses through path  208  from spool  202  around take-up roller  220  which takes up the separated backing film  216  around dancer roller  210 , which dampens rapid changes in tape feed rates, and through redirecting pulley  212 , used to guide tape  204  into cutting assembly  214 . According to an embodiment dancer roller  210  and redirecting pulley  212  may be fixed in angle relative to one another. Thus, the angle at which tape  204  is introduced to redirecting pulley  212  remains substantially constant even as the radius of spool  202  decreases due to removal of tape  204 . Dancer roller  210  further facilitates a smooth removal of tape  204  from spool  202  and facilitates removal of tape backing  216 . 
     In one embodiment, take-up roller  220 , may be a passive or non-powered, freely rotating take-up roll. The axis of take-up roller  220  is substantially parallel to the axis of spool  202 . Take-up roller  220  has the capacity to accept the entire length of backing film  216  from spool  202  as tape  204  unwinds from spool  202 . 
       FIG. 3  is a simplified top view of a backing removal system  300  according to an embodiment of the present invention. In one embodiments backing removal system  300  includes spool  202  dancer roller  210  and take-up roller  220 , which may be driven by tape  204  as tape  204  is drawn from spool  202  toward compaction roller  218  ( FIG. 2 ) 
     In one operational embodiment tape  204  is de-spooled with backing film  216  attached. Backing film  216  is attached to take-up roller  220 , which is free to rotate. As tape  204  continues to unwind from spool  202  and traverse around take-up roller  220 , backing film  216  is pulled away or separated from tape  204  and continues to wrap around take-up roller  220 . Tape  204  continues to traverse path  208  after traversing take-up roller  220  with backing film  216  having been removed. In this manner, tape  204  drives take-up roller  220  as the tape laving or fiber placement proceeds. 
     While the present invention is described above with respect to what is currently considered its preferred embodiments, it is to be understood that the invention is not limited to that described above. To the contrary, the invention is intended to cover various modifications and equivalent arrangements within the spirit and scope of the appended claims.