Method and apparatus for producing off-axis composite prepreg material

Abstract

The invention is directed to a method and apparatus for preferably producing a two layer off-axis composite prepreg material in tape form that has fiber direction at angles such as plus or minus five degrees to the longitudinal direction of the backing paper. The use of such off-axis prepreg composite material tape is primarily for fabricating high length-to-width ration parts such as composite wing stringers or spars for aircraft.

1 . An apparatus for producing a two layer off-axis composite prepreg material in tape form comprising:
 a roll of backing paper mounted on a first roll stand;   at least one paper guide adapted to unroll the backing paper and wrap the backing paper around a cylindrical mandrel supported on at least two mandrel stands;   at least two application wheels supported independently of the mandrel and designed to rotate co-axially around the mandrel in opposite directions to one another, wherein within each wheel is mounted a paper stripping roll and at least one composite prepreg supply roll having prepreg material, where the paper stripping roll and the prepreg supply roll are on respective axes that are off-axis relative to a normal vector from a centerline of the mandrel, and further wherein each wheel is designed to synchronously lay from the prepreg supply roll a tape layer over the backing paper in a helix orientation around the mandrel;   a compacting component for compacting and pressing the prepreg material onto the backing paper to form a prepreg tube wrapped around the mandrel;   a cutting component for cutting the prepreg tube; and,   an opener component for opening and laying flat the cut prepreg tube to form a substantially flat two layer off-axis composite prepreg output material in tape form formed from the backing paper and the composite prepreg, wherein the tape is wrapped around to form an output roll mounted on a second roll stand.   
     
     
         2 . The apparatus of  claim 1  further comprising a heater component adjacent the prepreg supply roll for heating the prepreg supply roll in order to soften it. 
     
     
         3 . The apparatus of  claim 1  wherein the two layer off-axis composite prepreg material comprises uni-directional carbon fibers in an uncured resin matrix, wherein the carbon fibers are oriented at an angle of approximately plus five degrees for a first prepreg layer and minus five degrees for a second prepreg layer from a central axis of the backing paper. 
     
     
         4 . The apparatus of  claim 1  wherein the two layer off-axis composite prepreg material comprises uni-directional carbon fibers in an uncured resin matrix, wherein the carbon fibers are oriented at an angle of approximately plus less than thirty degrees for a first prepreg layer and minus less than thirty degrees for a second prepreg layer from a central axis of the backing paper. 
     
     
         5 . The apparatus of  claim 1  wherein the two layer off-axis composite prepreg material comprises uni-directional carbon fibers in an uncured resin matrix, wherein the carbon fibers are oriented at an angle of approximately plus less than eighty-five degrees for a first prepreg layer and minus less than eighty-five degrees for a second prepreg layer from a central axis of the backing paper. 
     
     
         6 . The apparatus of  claim 1  wherein only one prepreg supply roll within one application wheel is used in the apparatus. 
     
     
         7 . The apparatus of  claim 1  wherein each application wheel includes four prepreg supply rolls. 
     
     
         8 . The apparatus of  claim 1  wherein the number of application wheels is three or more. 
     
     
         9 . The apparatus of  claim 1  further comprising a second compacting component for compacting and pressing the composite prepreg tape before it is wrapped around the output roll. 
     
     
         10 . An apparatus for producing a three or more layer off-axis composite prepreg material in tape form comprising:
 a roll of backing paper mounted on a first roll stand;   at least one paper guide adapted to unroll the backing paper and wrap the backing paper around a cylindrical mandrel supported on at least two mandrel stands;   a plurality of application wheels equal in number to the number of layers of composite prepreg material to be formed, wherein each application wheel is supported independently of the mandrel and designed to rotate around the mandrel, wherein within the wheel is mounted a paper stripping roll and one composite prepreg supply roll having prepreg material, where the paper stripping roll and the supply roll are on respective axes that are off-axis relative to a normal vector from a centerline of the mandrel, and further wherein each wheel is designed to lay from the prepreg supply roll a tape layer over the backing paper in a helix orientation around the mandrel;   a compacting component for compacting and pressing the prepreg material onto the backing paper to form a prepreg tube wrapped around the mandrel;   a cutting component for cutting the prepreg tube; and,   an opener component for opening and laying flat the cut prepreg tube to form a substantially flat three or more layer off-axis composite prepreg material in tape form formed from the backing paper and the composite prepreg, wherein the tape is wrapped around to form an output roll mounted on a second roll stand.   
     
     
         11 . The apparatus of  claim 10  wherein the three or more layer off-axis composite prepreg material comprises uni-directional carbon fibers in an uncured resin matrix, wherein the carbon fibers are oriented at an angle of approximately plus between 5 degrees and eighty-five degrees for a first prepreg layer and minus between 5 degrees and eighty-five degrees for a second prepreg layer from a central axis of the backing paper. 
     
     
         12 . A method for producing a two layer off-axis composite prepreg material in tape form comprising the steps of:
 unrolling a roll of backing paper mounted on a first roll stand and wrapping the backing paper around a cylindrical mandrel supported on at least two mandrel stands;   rotating at least two application wheels co-axially around the mandrel in opposite directions to one another, wherein within each wheel is mounted a paper stripping roll and at least one composite prepreg supply roll having prepreg material, where the paper stripping roll and the supply roll are on respective axes that are off-axis relative to a normal vector from a centerline of the mandrel, and further wherein each wheel synchronously lays from the prepreg supply roll a tape layer over the backing paper in a helix orientation around the mandrel;   compacting and pressing with a compacting component the prepreg material onto the backing paper to form a prepreg tube wrapped around the mandrel;   cutting with a cutting component the prepreg tube;   opening and laying flat with an opener component the cut prepreg tube to form a substantially flat two layer off-axis composite prepreg material in tape form formed from the backing paper and the composite prepreg; and,   wrapping the composite prepreg tape around to form an output roll mounted on a second roll stand.   
     
     
         13 . The method of  claim 12  further comprising the step prior to the compacting step of heating with a first heater component the prepreg supply roll in order to soften it. 
     
     
         14 . The method of  claim 12  further comprising the step prior to the cutting step of heating with a second heater component the prepreg supply roll in order to soften it. 
     
     
         15 . The method of  claim 12  further comprising the step prior to the wrapping the composite prepreg tape step of compacting and pressing the composite prepreg. 
     
     
         16 . The method of  claim 12  wherein the two layer off-axis composite prepreg material comprises uni-directional carbon fibers in an uncured resin matrix, wherein the carbon fibers are oriented at an angle of approximately plus five degrees for a first prepreg layer and minus five degrees for a second prepreg layer from a central axis of the backing paper. 
     
     
         17 . The method of  claim 12  wherein the two layer off-axis composite prepreg material comprises uni-directional carbon fibers in an uncured resin matrix, wherein the carbon fibers are oriented at an angle of approximately plus less than thirty degrees for a first prepreg layer and minus less than thirty degrees for a second prepreg layer from a central axis of the backing paper. 
     
     
         18 . The apparatus of  claim 12  wherein the two layer off-axis composite prepreg material comprises uni-directional carbon fibers in an uncured resin matrix, wherein the carbon fibers are oriented at an angle of approximately plus less than eighty-five degrees for a first prepreg layer and minus less than eighty-five degrees for a second prepreg layer from a central axis of the backing paper. 
     
     
         19 . The method of  claim 12  wherein the number of application wheels is three or more. 
     
     
         20 . The method of  claim 12  wherein the number of application wheels is equal to the number of layers of off-axis composite prepreg material to be formed.