Patent Publication Number: US-2021170637-A1

Title: Mold for prepreg lamination and prepreg lamination method

Description:
TECHNICAL FIELD 
     The present invention relates to a mold for prepreg lamination and a prepreg lamination method. 
     BACKGROUND ART 
     As a method of manufacturing a composite material, there is a technique of laminating a tape-shaped prepreg tape with a predetermined width multiple times on a mold using an automated fiber laminating device (AFP) or an automated tape laminating device (ATL). At this time, the tape fed from a head of the laminating device is compressed onto the mold by a compaction roller. 
     PTL 1 discloses a technique of manufacturing a mold based on a mold model, in which, as a result of the press molding, the shape of the mold model is modified such that wrinkles or cracks do not occur in a prepreg laminated product. PTL 2 discloses a technique relating to a composite spar for an aircraft wing including a web, an upper flange, and a lower flange, in which a region where there is too little or too much material is reduced in a final product by twisting a web surface so that a decrease in strength is suppressed. 
     CITATION LIST 
     Patent Literature 
     [PTL 1] Japanese Patent No. 5260593 
     [PTL 2] Japanese Patent No. 5686286 
     SUMMARY OF INVENTION 
     Technical Problem 
     As illustrated in  FIG. 10 , when a composite material molded article  60  has a shape in which two plate materials are combined at a predetermined angle (for example, 90°), a mold  50  for forming a molded article has an upper surface  51  and a side surface  52 . As illustrated in  FIG. 11 , in a case where a prepreg tape  61  is compressed from the upper surface  51  toward the side surface  52  (or from the side surface  52  to the upper surface  51 ) of the mold  50  by the laminating device such as AFP, a plurality of tapes  61  can be compressed without generating a gap or a wrap (overlapping), on a portion where there is no bent part in a length direction on both the side surface  52  and the upper surface  51 . In the example illustrated in  FIG. 11 , the plurality of tapes  61  are attached in parallel with a vertical direction on surfaces  52 A and  52 C. 
     On the other hand, in a case of providing a part where the plate thickness is changed along the length direction to the composite material molded article or a case where providing a stepped part along the length direction (plate thicknesses t 1  and t 2  in  FIG. 10 ), the bent part is formed on the surface (side surface) of the mold. In the mold  50  illustrated in  FIGS. 10 and 11 , bent parts  53  and  54  are formed. In the mold  50 , the side surfaces  52 A and  52 C on one side are inclined with respect to the other surface  52 B with the bent parts  53  and  54  as boundaries. In this case, in a case where the prepreg tape  61  is compressed from the upper surface  51  toward the side surface  52  (or from the side surface  52  to the upper surface  51 ) of the mold  50  by the laminating device, a direction deviation is caused due to the inclination of an attachment direction of the tape  61 , as illustrated in  FIG. 11 . As a result, a gap is generated between the plurality of tapes  61  or the plurality of tapes  61  overlap each other. 
     As a result, the strength of the molded article may be decreased or the surface of the molded article may have irregularities as compared with a case where the prepreg is uniformly laminated. There is a method of reducing the gap or overlapping generated between the tapes by steering a feed direction of the lamination tape or adding the lamination tape to the generated gap. However, in this method, it is necessary to narrow the width of the tape fed from the head of the laminating device or to reduce the number of tapes to be fed, the width and the number of tapes which can be compressed at the same time are reduced, and thus repetition of a compression process is increased. Accordingly, there is a problem that the time required for lamination is increased. 
     As illustrated in  FIGS. 12 and 13 , in a case where the bent parts  53  and  54  are formed on the surface of the mold  50 , in the bent parts  53  and  54 , an opening occurs between a compaction roller  70  and the mold  50 , and thus the compression of the tape by the compaction roller  70  tends to be insufficient. 
     The invention is made in view of such circumstances, and an object of the invention is to provide a mold for prepreg lamination and a prepreg lamination method which can reduce the gap generated between the plurality of tapes or the overlapping of the plurality of tapes by reducing the direction deviation of the attachment direction of the tape in a case where the prepreg tape is compressed on the surface of the mold having a bent part. 
     Solution to Problem 
     In order to solve the problem, a mold for prepreg lamination and a prepreg lamination method of the invention adopt the following means. 
     That is, a mold for prepreg lamination according to a first aspect of the invention includes a first surface having only a flat surface along one direction; a second surface which has a flat surface along the one direction and is disposed at a predetermined angle with respect to the first surface; and a third surface in which a cross-sectional shape of a surface cut in a direction orthogonal to the one direction is an arc, and which has one end side connected to the first surface and the other end side connected to the second surface, in which, in the second surface and the third surface, a protruding first bent part is formed, and one surface is inclined with respect to the other surface with the first bent part as a boundary, and a diameter of the arc of the other surface of the third surface is gradually reduced as a distance from the first bent part is increased along the one direction. 
     With this configuration, the third surface has one end side connected to the first surface having only a flat surface along the one direction, and the other end side connected to the second surface having only a flat surface along the one direction. Further, in the third surface, the cross-sectional shape of the surface cut in a direction orthogonal to the one direction is an arc, and in the second surface and the third surface, the protruding first bent part is formed, and the one surface is inclined with respect to the other surface with the first bent part as a boundary. The diameter of the arc of the other surface of the third surface is gradually reduced as the distance from the first bent part is increased along the one direction. As a result, in a case where the prepreg tape is compressed from the first surface toward the second surface (or from the second surface toward the first surface) of the mold by the laminating device, the attachment direction of the tape in the second surface is less likely to be inclined with respect to the vertical direction. Therefore, overlapping (wrap) of a plurality of tapes is reduced. 
     A mold for prepreg lamination according to a second aspect of the invention includes a first surface having only a flat surface along one direction; a second surface which has a flat surface along the one direction and is disposed at a predetermined angle with respect to the first surface; and a third surface in which a cross-sectional shape of a surface cut in a direction orthogonal to the one direction is an arc, and which has one end side connected to the first surface and the other end side connected to the second surface, in which, in the second surface and the third surface, a recessed second bent part is formed, and one surface is inclined with respect to the other surface with the second bent part as a boundary, and a diameter of the arc of the other surface of the third surface is gradually increased as a distance from the second bent part is increased along the one direction. 
     With this configuration, the third surface has one end side connected to the first surface having only a flat surface along the one direction, and the other end side connected to the second surface having only a flat surface along the one direction. Further, in the third surface, the cross-sectional shape of the surface cut in a direction orthogonal to the one direction is an arc, and in the second surface and the third surface, the recessed second bent part is formed, and the one surface is inclined with respect to the other surface with the second bent part as a boundary. The diameter of the arc of the other surface of the third surface is gradually increased as the distance from the second bent part is increased along the one direction. As a result, in a case where the prepreg tape is compressed from the first surface toward the second surface (or from the second surface toward the first surface) of the mold by the laminating device, the attachment direction of the tape in the second surface is less likely to be inclined with respect to the vertical direction. Therefore, the gap generated between a plurality of tapes is reduced. 
     In the first and second aspects, the first bent part or the second bent part may have a curved portion having a curved shape, and may be connected to the one surface and the other surface through the curved portion. 
     With this configuration, in a case of compressing the prepreg tape by the compaction roller, the contact surface of the roller is elastically deformed, and the contact surface comes into contact with flat portions on both sides with the bent part interposed therebetween, so that the tape can be compressed more. 
     A mold for prepreg lamination according to a third aspect of the invention includes a first surface having only a flat surface along one direction; a second surface which has a flat surface along the one direction and is disposed at a predetermined angle with respect to the first surface; and a third surface in which a cross-sectional shape of a surface cut in a direction orthogonal to the one direction is an arc, and which has one end side connected to the first surface and the other end side connected to the second surface, in which, in the second surface and the third surface, a protruding or recessed bent part is formed, and one surface is inclined with respect to the other surface with the bent part as a boundary, and the bent part has a curved portion having a curved shape, and is connected to the one surface and the other surface through the curved portion. 
     With this configuration, the third surface has one end side connected to the first surface having only a flat surface along the one direction, and the other end side connected to the second surface having only a flat surface along the one direction. Further, in the third surface, the cross-sectional shape of the surface cut in a direction orthogonal to the one direction is an arc, and in the second surface and the third surface, the protruding or recessed bent part is formed, and the one surface is inclined with respect to the other surface with the bent part as a boundary. 
     A prepreg lamination method according to a fourth aspect of the invention includes a step of attaching a tape-shaped prepreg tape to the first surface or the second surface of the above-described mold for prepreg lamination, and then attaching the prepreg tape to the third surface; and a step of attaching the prepreg tape to the second surface or the first surface after attaching the prepreg tape to the third surface. 
     A prepreg lamination method according to a fifth aspect of the invention includes a step of attaching a tape-shaped prepreg tape to the curved portion and the one surface or the other surface of the above-described mold for prepreg lamination, and compressing the prepreg tape using a compaction roller. 
     Advantageous Effects of Invention 
     It is possible to reduce a gap generated between a plurality of tapes or overlapping of the plurality of tapes by reducing the direction deviation of an attachment direction of the tape in a case where a prepreg tape is compressed on a surface of a mold having a bent part. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating a mold for prepreg lamination according to a first embodiment of the invention. 
         FIG. 2  is a perspective view illustrating the mold for prepreg lamination according to the first embodiment of the invention, and illustrates a state where prepreg tapes are compressed on a surface. 
         FIG. 3  is a perspective view illustrating a mold for prepreg lamination according to a second embodiment of the invention. 
         FIG. 4  is a perspective view illustrating the mold for prepreg lamination according to the second embodiment of the invention, and illustrates a state where the prepreg tapes are compressed on the surface. 
         FIG. 5  is a perspective view illustrating a mold for prepreg lamination according to a third embodiment of the invention. 
         FIG. 6  is a perspective view illustrating the mold for prepreg lamination according to the third embodiment of the invention, and illustrates a state where the prepreg tapes are compressed on the surface. 
         FIG. 7  is a perspective view illustrating a first example of a mold for prepreg lamination according to a fourth embodiment of the invention. 
         FIG. 8  is a perspective view illustrating a second example of the mold for prepreg lamination according to the fourth embodiment of the invention. 
         FIG. 9  is a plan view illustrating the second example of the mold for prepreg lamination according to the fourth embodiment of the invention. 
         FIG. 10  is a perspective view illustrating a mold for prepreg lamination in the related art. 
         FIG. 11  is a perspective view illustrating the mold for prepreg lamination in the related art, and illustrates a state where the prepreg tapes are compressed on the surface. 
         FIG. 12  is a perspective view illustrating the mold for prepreg lamination in the related art. 
         FIG. 13  is a plan view illustrating the mold for prepreg lamination in the related art. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the invention will be described with reference to the drawings. 
     First Embodiment 
     Hereinafter, a mold for prepreg lamination  1  according to a first embodiment of the invention will be described using  FIGS. 1 and 2 . 
     The mold for prepreg lamination  1  (hereinafter, referred to as a “mold  1 ”) according to the embodiment is used in a case of laminating the prepreg, by a laminating device such as an automated fiber laminating device (AFP) or an automated tape laminating device (ATL). The laminating device such as the AFP feeds tape-shaped prepreg (hereinafter, referred to as “prepreg tape”)  61  having a predetermined width to the surface of the mold for lamination. At this time, the prepreg tape  61  is continuously attached in one direction on the surface of the mold  1 . The prepreg laminated in a plurality of layers is cured to be formed as a molded article. 
     When a composite material molded article has a shape in which two plate materials are combined at a predetermined angle (for example, 90°) (for example, when a part of the cross section has an L shape), the mold  1  for forming a molded article has a first surface  6  and a second surface  7 . In a case where the prepreg tape  61  is attached to such a mold  1 , the prepreg tape  61  is attached from the first surface  6  toward the second surface  7  (or from the second surface  7  toward the first surface  6 ) of the mold  1  as illustrated in  FIG. 2 . Further, the prepreg tape  61  fed from the laminating device is attached while being compressed by the compaction roller. A plurality of prepreg tapes  61  are disposed side by side along a length direction of the mold  1 . 
     The mold  1  includes the first surface  6  having only a flat surface along the length direction, the second surface  7  which has a flat surface along the length direction and is disposed at a predetermined angle with respect to the first surface  6 , and a third surface  8  formed between the first surface  6  and the second surface  7 . Here, the molded article formed by the mold  1  is a long material that is long in one direction. Further, in a case where the first surface  6  is dispose to face an upward direction and the second surface  7  is disposed to face a lateral direction, the first surface  6  becomes an upper surface and the second surface  7  becomes a side surface. 
     The third surface  8  is a fillet surface, and is a curved surface in which the cross-sectional shape of the surface cut in a direction orthogonal to the length direction is an arc. The third surface  8  has one end side continuously connected to the first surface  6  and the other end side continuously connected to the second surface  7 . The arc as the cross-sectional shape of the third surface  8  may be a part of a perfect circle or may be a part of an ellipse. 
     In a range of the length direction in which the first surface  6  only has the flat surface along the length direction, protruding first bent parts  9  and  10  are respectively formed on the second surface  7  and the third surface  8 . In the second surface  7 , one surface  7 B is inclined with respect to the other surface  7 A with the protruding first bent part  9  as a boundary, and in the third surface  8 , one surface  8 B is inclined with respect to the other surface  8 A with the protruding first bent part  10  as a boundary. For example, the angle formed by the one surface  7 B and the other surface  7 A and the angle formed by the one surface  8 B and the other surface  8 A are greater than 180° and smaller than 270°. 
     The first bent part  9  is a part where the surface  7 A and the surface  7 B are combined, and has a linear shape. The first bent part  10  is a part where the surface  8 A and the surface  8 B are combined, and has a curved shape. 
     The diameter of the arc of the cross-sectional shape of the surface  8 B of the third surface  8  is gradually reduced as the distance from the protruding first bent part  10  is increased along the length direction. As illustrated in  FIG. 2 , in a case where the prepreg tape  61  is compressed from the first surface  6  toward the second surface  7  (or from the second surface  7  toward the first surface  6 ) of the mold  1  by the laminating device, the length of the side end portion of the tape  61  attached on the surface  8 B of the third surface  8  is shorter on a side far from the first bent part  10  than a side close to the first bent part  10 . Therefore, as illustrated in  FIG. 2 , the attachment direction of the tape  61  in the surfaces  7 A and  7 B of the second surface  7  is less likely to be inclined with respect to the vertical direction as compared with a case where the arc of the cross-sectional shape of a surface  55 B of a fillet surface  55  has the same diameter along the length direction as illustrated in  FIG. 10 . Therefore, the direction deviation is reduced, and the overlapping (wrap) of the plurality of tapes  61  is reduced. 
     According to the embodiment, since the overlapping (wrap) of the plurality of tapes  61  is reduced, after the prepregs are laminated, the unevenness of the lamination thickness is reduced. As a result, the strength of the cured molded article is less likely to be decreased, and irregularities occurring on the surface of the molded article are reduced. Further, unlike a case of using the mold  50  in which the direction deviation of the tape  61  is large as illustrated in  FIG. 10 , it is not necessary to narrow the width of the tape  61  fed from the head of the laminating device or to reduce the number of tapes  61  to be fed. Therefore, since it is not necessary to reduce the width or the number of tapes  61  which can be compressed at the same time, the repetition of the compression process is not increased, and the time required for lamination can be prevented from being increased. 
     Second Embodiment 
     Hereinafter, a mold for prepreg lamination  2  according to a second embodiment of the invention will be described using  FIGS. 3 and 4 . The detailed description of the configurations overlapping with those of the first embodiment is omitted. 
     As with the mold  1  of the first embodiment, the mold for prepreg lamination  2  (hereinafter, referred as a “mold  2 ”) according to the embodiment is used when a composite material molded article has a shape in which two plate materials are combined at a predetermined angle (for example, 90°) (for example, when a part of the cross section has an L shape), the mold  2  for forming a molded article has the first surface  6 , the second surface  7 , and the third surface  8 . 
     In a range of the length direction in which the first surface  6  only has the flat surface along the length direction, recessed second bent parts  11  and  12  are respectively formed on the second surface  7  and the third surface  8 . In the second surface  7 , one surface  7 B is inclined with respect to the other surface  7 C with the recessed second bent part  11  as a boundary, and in the third surface  8 , one surface  8 B is inclined with respect to the other surface  8 C with the recessed second bent part  12  as a boundary. For example, the angle formed by the one surface  7 B and the other surface  7 C and the angle formed by the one surface  8 B and the other surface  8 C are greater than 90° and smaller than 180°. 
     The second bent part  11  is a part where the surface  7 B and the surface  7 C are combined, and has a linear shape. The second bent part  12  is a part where the surface  8 B and the surface  8 C are combined, and has a curved shape. 
     The diameter of the arc of the cross-sectional shape of the surface  8 B of the third surface  8  is gradually increased as the distance from the recessed second bent part  12  is increased along the length direction. As illustrated in  FIG. 4 , in a case where the prepreg tape  61  is compressed from the first surface  6  toward the second surface  7  (or from the second surface  7  toward the first surface  6 ) of the mold  2  by the laminating device, the length of the side end portion of the tape  61  attached on the surface  8 B of the third surface  8  is longer on a side far from the second bent part  12  than a side close to the second bent part  12 . Therefore, as illustrated in  FIG. 4 , the attachment direction of the tape  61  in the surface  7 B of the second surface  7  is less likely to be inclined with respect to the vertical direction as compared with a case where the arc of the cross-sectional shape of the surface  55 B of the fillet surface  55  has the same diameter along the length direction as illustrated in  FIG. 10 . Therefore, the direction deviation is reduced, and the gap generated between the plurality of tapes  61  is reduced. 
     According to the embodiment, since the gap generated between the plurality of tapes  61  is reduced, after the prepregs are laminated, the strength of the cured molded article is less likely to be decreased and the irregularities occurring on the surface of the molded article are reduced. Further, unlike a case of using the mold  50  in which the direction deviation of the tape  61  is large, it is not necessary to narrow the width of the tape  61  fed from the head of the laminating device or to reduce the number of tapes  61  to be fed. Therefore, since it is not necessary to reduce the width or the number of tapes  61  which can be compressed at the same time, the repetition of the compression process is not increased, and the time required for lamination can be prevented from being increased. 
     Third Embodiment 
     Hereinafter, a mold for prepreg lamination  3  according to a third embodiment of the invention will be described using  FIGS. 5 and 6 . The detailed description of the configurations overlapping with those of the first and second embodiments is omitted. 
     As with the molds  1  and  2  of the first and second embodiments, the mold for prepreg lamination  3  (hereinafter, referred as a “mold  3 ”) according to the embodiment is used when a composite material molded article has a shape in which two plate materials are combined at a predetermined angle (for example, 90°) (for example, when a part of the cross section has an L shape), the mold  3  for forming a molded article has the first surface  6 , the second surface  7 , and the third surface  8 . 
     In the molds  1  and  2  according to the first and second embodiments described above, a case where the protruding first bent parts  9  and  10  or the recessed second bent parts  11  and  12  are formed on the second surface  7  and the third surface  8  has been described, but in this embodiment, both the protruding first bent parts  9  and  10  and the recessed second bent parts  11  and  12  are formed on one mold  3 . 
     In the mold  3  according to the embodiment, in a range of the length direction in which the first surface  6  only has the flat surface along the length direction, the protruding first bent parts  9  and  10  are respectively formed on the second surface  7  and the third surface  8 , and the recessed second bent parts  11  and  12  are respectively formed on the second surface  7  and the third surface  8 . In a case where the prepreg is laminated on the mold  3  having the first bent parts  9  and  10  and the second bent parts  11  and  12  and the outer surface of the laminated prepreg is flush along the length direction, the outer surface of the molded article is flat, the plate thickness of the side surface of the molded article formed to correspond to the second surface  7  is gradually changed (becomes thick or thin) along the length direction. Further, in a case where the prepreg is laminated on the mold  3  having the first bent parts  9  and  10  and the second bent parts  11  and  12  and the plate thickness of the outer surface of the laminated prepreg is constant along the length direction, a stepped part is formed on the outer surface of the molded article. 
     The diameter of the arc of the cross-sectional shape of the surface  8 B of the third surface  8  is gradually reduced as the distance from the protruding first bent part  10  is increased along the length direction, and is gradually increased as the distance from the recessed second bent part  12  is increased along the length direction. As illustrated in  FIG. 6 , in a case where the prepreg tape  61  is compressed from the first surface  6  toward the second surface  7  (or from the second surface  7  toward the first surface  6 ) of the mold  3  by the laminating device, the length of the side end portion of the tape  61  attached on the surface  8 B of the third surface  8  is shorter on a side far from the first bent part  10  than a side close to the first bent part  10 , and the length of the side end portion of the tape  61  attached on the surface  8 B of the third surface  8  is longer on a side far from the second bent part  12  than a side close to the second bent part  12 . On the other hand, as illustrated in  FIG. 10 , when the arc of the cross-sectional shape of the surface  55 B of the fillet surface  55  has the same diameter along the length direction, the length of the side end portion of the tape  61  attached on the surface  55 B of the fillet surface  55  is substantially the same on a side close to the first bent part  10  and a side far from the first bent part  10 . Therefore, the deviation of the attachment direction of the tape  61  is large in the side surface  52 . 
     In contrast, in this embodiment, as illustrated in FIG.  6 , the attachment direction of the tape  61  in the surfaces  7 A and  7 B of the second surface  7  is less likely to be inclined with respect to the vertical direction as compared with a case where the arc of the cross-sectional shape of the surface  55 B of the fillet surface  55  has the same diameter along the length direction as illustrated in  FIG. 10 . Therefore, the direction deviation is reduced, the overlapping (wrap) of the plurality of tapes  61  is reduced, and the gap generated between the plurality of tapes  61  is reduced. 
     According to the embodiment, since the overlapping (wrap) of the plurality of tapes  61  is reduced and the gap generated between the plurality of tapes  61  is reduced, after the prepregs are laminated, the unevenness of the lamination thickness is reduced. As a result, the strength of the cured molded article is less likely to be decreased, and irregularities occurring on the surface of the molded article are reduced. Further, unlike the case of using the mold  50  in which the direction deviation of the tape  61  is large, it is not necessary to narrow the width of the tape  61  fed from the head of the laminating device or to reduce the number of tapes  61  to be fed. Therefore, since it is not necessary to reduce the tapes  61  which can be compressed at the same time, the repetition of the compression process is not increased, and the time required for lamination can be prevented from being increased. 
     Fourth Embodiment 
     Hereinafter, a mold for prepreg lamination  4  and a mold for prepreg lamination  5  according to a fourth embodiment of the invention will be described using  FIGS. 7 to 9 . 
     In the first to third embodiments described above, the first bent part  9  or the second bent part  11  is a portion where both the flat surfaces  7 A and  7 B are combined or a portion where both the flat surfaces  7 B and  7 C are combined, and a straight line is formed in a ridge shape or a valley shape at the top of the protruding portion or the bottom of the recessed portion. In the first to third embodiments described above, the first bent part  10  or the second bent part  12  is a portion where both the curved surfaces  8 A and  8 B are combined or a portion where both the curved surfaces  8 B and  8 C are combined, and a curved line is formed in a ridge shape or a valley shape at the top of the protruding portion or the bottom of the recessed portion. 
     In contrast, in this embodiment, as illustrated in  FIGS. 7 to 9 , in the first bent part  9  or the second bent part  11 , a protruding curved portion  13  or a recessed curved portion  15  is formed such that a straight line is not formed at the top of the protruding portion or the bottom of the recessed portion. Further, in the first bent part  10  or the second bent part  12 , a protruding curved portion  14  or a recessed curved portion  16  is formed such that a curved line is not formed at the top of the protruding portion or the bottom of the recessed portion. 
     The first bent part  9  is connected to the one surface  7 A and the other surface  7 B through the protruding curved portion  13 , and the first bent part  10  is connected to the one surface  8 A and the other surface  8 B through the protruding curved portion  14 . The second bent part  11  is connected to the one surface  7 C and the other surface  7 B through the recessed curved portion  15 , and the second bent part  12  is connected to the one surface  8 C and the other surface  8 B through the recessed curved portion  16 . 
     The protruding curved portions  13  and  14  or the recessed curved portions  15  and  16  are fillet surfaces, and are curved surfaces in which the cross-sectional shape of the surface cut in a direction in parallel with the length direction is an arc. The one surface  7 A and the other surface  7 B are smoothly connected through the protruding curved portion  13 , and the one surface  8 A and the other surface  8 B are smoothly connected through the protruding curved portion  14 . The one surface  7 C and the other surface  7 B are smoothly connected through the recessed curved portion  15 , and the one surface  8 C and the other surface  8 B are smoothly connected through the recessed curved portion  16 . The arc as the cross-sectional shape of the protruding curved portions  13  and  14  or the recessed curved portions  15  and  16  may be a part of a perfect circle or may be a part of an ellipse. 
     As in the first to third embodiments, in a case where the top of the first bent parts  9  and  10  or the bottom of the second bent parts  11  and  12  is formed in a straight line or a curved line on the surface of the mold  1 ,  2 , or  3 , it is difficult for the contact surface of the compaction roller  70  to come into contact with the surface of the mold  1 ,  2 , or  3  on both sides of the first bent parts  9  and  10  or both sides of the second bent parts  11  and  12 . As a result, the compression of the tape  61  by the compaction roller  70  tends to be insufficient. 
     On the other hand, according to this embodiment, an angle formed by the tangent planes of the curved portions  13  and  14  and the one surfaces  7 A and  8 A of the first bent parts  9  and  10  is smaller than an angle formed by the one surfaces  7 A and  8 A and the other surfaces  7 B and  7 C of the first bent parts  9  and  10  in a case where the curved portions  13  and  14  are not provided. The same applies to an angle formed by the tangent planes of the curved portions  13  and  14  and the other surfaces  7 B and  8 B of the first bent parts  9  and  10 , and an angle formed by the tangent planes of the curved portions  15  and  16  and the one surfaces  7 C and  8 C or the other surfaces  7 B and  8 B of the second bent parts  11  and  12 . The direction of the tangent line of the protruding curved portions  13  and  14  or the recessed curved portions  15  and  16  is gradually changed along the length direction. It is easy for the contact surface of the compaction roller  70  to come into contact with the surface of the mold  4  or  5  on both sides of the first bent parts  9  and  10  or both sides of the second bent parts  11  and  12 . Accordingly, it is possible reliably perform the compression of the tape  61  by the compaction roller  70  on both sides of the first bent parts  9  and  10  or both sides of the second bent parts  11  and  12 . 
     REFERENCE SIGNS LIST 
     
         
         
           
               1 ,  2 ,  3 ,  4 ,  5 : mold for prepreg lamination 
               6 : first surface 
               7 : second surface 
               8 : third surface 
               9 ,  10 : first bent part 
               11 ,  12 : second bent part 
               13 ,  14 ,  15 ,  16 : curved portion 
               50 : mold 
               51 : upper surface 
               52 : side surface 
               53 ,  54 : bent part 
               55 : fillet surface 
               60 : molded article 
               61 : prepreg tape 
               70 : compaction roller