Abstract:
The present invention provides a device for producing a composite fiber component. The device comprises a shaping tool having a shaping surface for shaping a resin-soaked fiber material, a filter panel that is arranged at the shaping surface and comprises a porous material, and a means for generating a negative pressure at the shaping surface at a side of the filter panel that faces away from the fiber material. In another aspect, the invention provides a method for producing a composite fiber component. First, a filter panel comprising a porous material is provided. In subsequent steps, a resin-soaked fiber material is arranged on the filter panel, the fiber material on the filter panel is covered and a negative pressure is generated at a side of the filter panel that faces away from the fiber material.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of and claims priority to PCT/EP2010/057124 filed May 25, 2010 which claims the benefit of and priority to U.S. Provisional Application No. 61/181,056, filed May 26, 2009 and German Patent Application No. 10 2009 026 456.6, filed May 25, 2009, the entire disclosures of which are herein incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a device for producing a fibre composite component, in particular for an aircraft or spacecraft. The invention also relates to a method for producing a fibre composite component. 
         [0003]    Although the present invention and the problem on which it is based can be applied to any fibre composite components, they will be described in detail with respect to fibre composite components for uses in aircraft construction. 
         [0004]    Such fibre composite components typically comprise fibres of, for example carbon, aramid and/or glass which in most cases are embedded in a thermosetting polymer matrix. In a conventional production process, fibres which are pre-impregnated with a resin, so-called prepregs, are introduced into a moulding tool shaped in accordance with the component, and the resin is cured under the effect of heat, for example. In other conventional methods, first of all, non-impregnated fibres are arranged in a moulding tool and are impregnated with the resin by feeding liquid resin into the moulding tool. The resin is then cured in the moulding tool. 
         [0005]    To prevent the inclusion of air and to prevent pores in the fibre composite component, the fibres are usually enclosed in an air-tight manner in the moulding tool with the uncured resin matrix before curing and are subjected to a vacuum. 
         [0006]    The quality of the vacuum through influencing the development of pores is one of the significant decisive factors for the later quality of the component. To produce the air-tight enclosure, vacuum films, silicone membranes or vacuum bags consisting thereof are used, for example. 
         [0007]    However, when the space enclosed under such films is evacuated from suitable suction points, the effect occurs, particularly in the case of planarly extended fibre composite components that the films are quickly drawn by suction onto the surface of the component and block further air flows from the component surface to the suction points. This restricts the quality of the vacuum which can be achieved on the component surface, so that the development of pores cannot be adequately prevented. 
         [0008]    To allow a flat suction, additional textile aids are usually arranged between the vacuum film and the fibre composite component and are evacuated by the vacuum film. The textile means have to be constructed such that they still allow a flow of air even under increasing vacuum pressure. Since a pure textile layer would greatly reduce the surface quality, perforated pressure sheets and perforated films, inter alia, are arranged in turn as a counter-measure between the textile layer and the fibre composite component. Overall, a complicated structure of numerous layers is thus created during each production of a fibre composite component, which has to be carried out carefully in keeping with the effects on the quality of the fibre composite component and entails high production costs. 
       SUMMARY OF THE INVENTION 
       [0009]    It is therefore the object of the present invention to allow the production of in particular planarly extended fibre composite components with a high quality and low production costs. 
         [0010]    The idea on which the present invention is based is to arrange a filter plate, which comprises a porous material, on a moulding surface of a moulding tool to mould a resin-impregnated fibre material. The device also comprises a means for producing a vacuum on a side of the filter plate remote from the fibre material. 
         [0011]    The fact that the material of the filter plate is porous allows the vacuum over the entire surface of the plate acting as a filter to also pass onto the side of the filter plate which faces the fibre material or allows air to be removed by suction in a planar manner in the opposite direction, so that a high-quality vacuum is produced over the entire surface of the fibre material facing the filter plate and pore formation is reliably prevented in the fibre composite component. In this respect, the low deformability inherent in the porous material configured as a plate prevents the material from being compressed under the effect of the vacuum, so that a high dimensional accuracy and surface quality of the fibre composite component are allowed even without perforated sheets, to be additionally inserted, or similar complex measures. 
         [0012]    During the use of the device, a resin-impregnated fibre material is arranged on the filter plate, the fibre material is covered in an air-tight manner above the filter plate and a vacuum is produced on the side of the filter plate remote from the fibre material. Since the low deformability of the material of the filter plate allows the filter plate to be arranged in the moulding tool without impairing the dimensional stability of the fibre composite component, it is unnecessary for the filter plate to be arranged anew for the production of each individual fibre composite component. The fact that the vacuum is produced on the side remote from the fibre material also allows the corresponding means to also be set up in a permanent manner, so that they do not have to be constructed anew for each production procedure, which is financially advantageous. 
         [0013]    According to a preferred development, the porous material comprises a sintered material. Such a material is characterised by a particularly high inherent stability, so that pores which have formed in the sintered material reliably remain open and a particularly high dimensional stability of the fibre composite component is achieved. The sintered material preferably has a grain size of from 0.2 to 2 mm, to allow on the one hand an unhindered air flow through the filter plate and on the other hand a sufficiently planar surface on the side of the fibre material. 
         [0014]    According to a preferred development, the filter plate comprises two layers of the sintered material with different grain sizes. The layer with the larger grain size is arranged on the side remote from the fibre material. As a result, due to a more finely-pored surface on the side of the fibre material, a particularly high surface quality of the fibre composite material is achieved, while larger pores in the layer remote from the fibre material ensure an optimum air permeability of the filter plate. 
         [0015]    According to a preferred development, the porous material comprises a metal material, which makes the device particularly robust. Preferred metal materials are, for example, bronze and/or steel due to their particular loading capacity. 
         [0016]    According to a preferred development, the filter plate has a thickness of from 1 to 5 mm. This allows a good inherent stability with good air permeability. 
         [0017]    According to a preferred development, a membrane is provided which is substantially impermeable to the resin and which covers a side of the filter plate facing the fibre material. This prevents resin from passing out of the resin-impregnated fibre material into pores in the filter plate. 
         [0018]    According to a preferred development, a vacuum film or a silicone membrane is also provided for covering the fibre material in an air-tight manner above the filter plate. This is particularly easy to position, because no suction connection pieces or the like have to be attached to the vacuum film or silicone membrane. 
         [0019]    According to a preferred development, the device comprises a first feed means for feeding resin into the fibre material at a first feed station and comprises a second feed means for feeding resin into the fibre material at a second feed station. The second feed station is spaced apart from the first feed station in a direction extending along the filter plate. Also provided are a resin detector at a detection station in the region of the second feed station which detects whether resin has reached the detection station, and a control means which activates the second feed station when resin has reached the detection station. This makes it possible to produce particularly large fibre composite components, because during infiltration, the resin only has to cover a path which approximately corresponds to the spacing of the feed stations, irrespective of the size of the component. The detection station is preferably arranged spaced apart from the second feed station in the direction of the first feed station. This ensures that the resin has already reached the second feed station when the control means activates it, so that air is prevented from being included between quantities of resin fed by the two feed stations. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    In the following, the invention will be described in more detail on the basis of embodiments with reference to the following figures of the drawings, in which: 
           [0021]      FIG. 1  is a schematic sectional view of a device for producing a composite component according to an embodiment; 
           [0022]      FIG. 2  is a detail sectional view of a filter plate of a device according to an embodiment; 
           [0023]      FIG. 3  is a sectional view of an example of a composite component; and 
           [0024]      FIG. 4  is a schematic representation of a method and device for producing an aircraft fuselage section according to an embodiment. 
       
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0025]    In the figures, the same reference numerals denote identical or functionally identical components, unless indicated otherwise. 
         [0026]      FIG. 1  is a schematic sectional view of a device  100  for producing a composite component  102 . A moulding tool  104  of the device  100  has a recess with a moulding surface  106 . Formed in the base of the recess, in the moulding surface  106  is a suction opening  111  which passes through the moulding tool  104  and ends in a suction connecting piece  112  configured on a rear side of the moulding tool  104  remote from the moulding surface  106 . The suction connecting piece  112  is connected to a vacuum pump  113  by a vacuum tube. 
         [0027]    Arranged in the recess in the moulding tool  104  is a filter plate  110  consisting of a porous material, for example a sintered material which is supported in a planar manner by the moulding surface  106  and completely fills the recess in the moulding tool  104 . The surface of the filter plate  102  remote from the moulding surface  106  is covered by a semi-permeable membrane  114  which is impermeable to resin but permeable to air, for example a correspondingly impregnated thin textile woven fabric. Arranged on an edge of the moulding tool  104 , surrounding the filter plate  110  is a seal  116  which seals a vacuum film  116  in an air-tight manner with the moulding tool  104 . A fibre composite component  102  is arranged by way of example between the vacuum film  118  and the filter plate  110  covered by the membrane  114 . 
         [0028]    During use of the device  100 , the fibre composite component  102  is arranged, for example in the form of prepregs over the filter plate  110  in the illustrated manner and covered with the vacuum film  118 . The vacuum pump  113  then evacuates the space surrounding the fibre composite component  102  and the fibre composite component  102  is cured, for example by the supply of heat by means of a heating device (not shown). In addition, external pressure can be applied, for example in an autoclave. 
         [0029]      FIG. 2  is a detail sectional view of a filter plate  110  of a device, for example of the filter plate  110  of  FIG. 1 . The filter plate  110  comprises two superimposed first and second layers  201 ,  202  of a sintered material  200 , for example bronze, steel or ceramics. In the first layer  201  which has a thickness h 1 , a grain size d 1  (diameter) is smaller than a grain size d 2  in the second layer  202  which has a thickness h 2 . The grain sizes d 1 , d 2  are, for example in a range of between 0.2 mm and 2 mm, with an overall thickness h of the filter plate  110  of approximately 1 mm to 5 mm. 
         [0030]    Grain sizes d 1 , d 2  and thicknesses h 1 , h 2 , h are coordinated with one another such that air-permeable pores  210  remain, the filter plate  110  is stable and it has a surface  230  facing the fibre composite component during the intended use. 
         [0031]      FIG. 3  is a sectional view of an example of a composite component  102  which can be produced by a device like the one shown in  FIG. 1 . The composite component  102  comprises a planarly extended core  408  consisting of a foam material, on the opposite, substantially parallel sides of which are configured a first cover layer  401  and a second cover layer  402  consisting of a fibre material. Extending between the first cover layer  401  and the second cover layer  402  are struts  403  consisting of fibre bundles through the core  408 , the ends  406  of which struts  403  rest against the cover layers  401 ,  402 . Cover layers  401 ,  402  and struts  403  are filled with a common polymer matrix which can be fed in the evacuated state, for example with an arrangement in the device from  FIG. 1 . 
         [0032]      FIG. 4  is a schematic representation of a method and a device for producing a fuselage shell  102  for an aircraft fuselage section in the form of a fibre composite component which has, for example, an internal structure like that shown in  FIG. 3 . 
         [0033]    The device comprises a moulding tool  104  which defines an outer surface of the aircraft fuselage. Attached to the inner moulding surface  106  is a filter plate  110  which is curved in the manner of a cylinder corresponding to the shape of the aircraft fuselage and is supported by the moulding surface  106 . Non-impregnated fibre material  102  having a structure as shown in  FIG. 3  is arranged on a membrane  114  covering the filter plate  110  and is sealed above the filter plate in an air-tight manner by a vacuum film  118 . 
         [0034]    Arranged at a first feed station  311  at the lowest point of the moulding tool  104  is a first feed means  301  for feeding resin into the fibre material  102  through the vacuum film  118 . Further feed means  302 - 306  are located upstream of the first feed station  311  along the curvature of the fuselage shell  102  to be produced in approximately regular intervals. 
         [0035]    Fitted in the filter plate  110 , in each case in the vicinity of one of the second  302  to sixth  306  feed means, are associated resin detectors  332 - 336  which are slightly offset in each case relative to the associated feed means in a direction away from the first feed station  311 . The resin detectors are configured to emit a detection signal via corresponding detector lines  392  if they detect the presence of resin. For example, the resin detectors  332 - 336  have a suitable recess with a light barrier which visually records penetrating resin. 
         [0036]    The detector lines lead to a detection unit  343  of a control means  342  of the device  100 , which detection unit  343  evaluates signals received during operation and instructs an activation unit  344  of the control means  342 , upon the response of a resin detector  332 - 336 , to activate the respectively associated feed unit  302 - 306  via corresponding activation lines  390 . The resin feed to the rest of the feed means  302 - 306  can expediently be interrupted at the same time. 
         [0037]    Although the present invention has been described above on the basis of preferred embodiments, it is not restricted thereto, but can be modified in many different ways. 
         [0038]    For example, the porous material can also consist of a single layer of a uniform grain size, or it can have a large number of different grain sizes mixed together. The porous material can be produced in a different manner to sintering, for example by chemical processes. 
         [0039]    In the following preferred embodiments of the device and the method are explained. 
         [0040]    1. Device for producing a fibre composite component, comprising: 
         [0041]    a moulding tool with a moulding surface for moulding a resin-impregnated fibre material; 
         [0042]    a filter plate which is arranged on the moulding surface and comprises a porous material; and 
         [0043]    a means for producing a vacuum on the moulding surface on a side of the filter plate remote from the fibre material. 
         [0044]    2. Device according to embodiment 1, characterised in that the porous material comprises a sintered material. 
         [0045]    3. Device according to embodiment 2, characterised in that the sintered material has a grain size of from 0.2 to 2 mm. 
         [0046]    4. Device according to embodiment 2 or 3, characterised in that the filter plate comprises two layers of the sintered material with different grain sizes, the layer with the larger grain size being arranged on the side remote from the fibre material. 
         [0047]    5. Device according to any one of the preceding embodiments, characterised in that the porous material comprises a metal material, in particular bronze and/or steel. 
         [0048]    6. Device according to any one of the preceding embodiments, characterised in that the filter plate has a thickness of from 1 to 5 mm. 
         [0049]    7. Device according to any one of the preceding embodiments, characterised by a membrane which is substantially impermeable to the resin and covers a side of the filter plate facing the fibre material. 
         [0050]    8. Device according to any one of the preceding embodiments, characterised by a vacuum film or silicone membrane for covering the fibre material in an airtight manner above the filter plate. 
         [0051]    9. Device according to any one of the preceding embodiments, characterised by 
         [0052]    a first feed means for feeding resin into the fibre material at a first feed station; 
         [0053]    a second feed means for feeding resin into the fibre material at a second feed station which is spaced apart from the first feed station along the filter plate; 
         [0054]    a resin detector at a detection station in the region of the second feed station, which detects whether resin has reached the detection station; and 
         [0055]    a control means which activates the second feed means when resin has reached the detection station. 
         [0056]    10. Device according to embodiment 9, characterised in that the detection station is arranged spaced apart from the second feed station in a direction of the first feed station. 
         [0057]    11. Method for producing a fibre composite component, comprising the following steps: 
         [0058]    providing a filter plate which comprises a porous material; 
         [0059]    arranging a fibre material impregnated with resin on the filter plate; 
         [0060]    covering the fibre material in an air-tight manner above the filter plate; and 
         [0061]    producing a vacuum on a side of the filter plate remote from the fibre material. 
         [0062]    12. Method according to embodiment 11, characterised by a step of covering the filter plate on a side facing the fibre material with a membrane which is substantially impermeable to the resin. 
         [0063]    13. Method according to embodiment 11 or 12, characterised by a step of supporting the filter plate, on the side remote from the fibre material, by a moulding tool. 
         [0064]    14. Method according to embodiment 13, characterised in that the vacuum is produced by a suction opening configured in the moulding tool. 
         [0065]    15. Method according to any one of embodiments 11 to 14, characterised in that the step of arranging the resin-impregnated fibre material comprises: 
         [0066]    arranging the fibre material on the filter plate; 
         [0067]    feeding the resin to the fibre material at a first feed station; 
         [0068]    detecting, at a detection station on the fibre material, whether the resin has reached the detection station; and 
         [0069]    feeding the resin to the fibre material at a second feed station when the resin has reached the detection station. 
       LIST OF REFERENCE NUMERALS 
       [0070]      100  production device 
         [0071]      102  fibre composite component 
         [0072]      104  moulding tool 
         [0073]      106  moulding surface 
         [0074]      110  filter plate 
         [0075]      111  suction opening 
         [0076]      112  suction connecting piece 
         [0077]      113  vacuum pump 
         [0078]      114  membrane 
         [0079]      116  seal 
         [0080]      118  vacuum film 
         [0081]      200  sintered material 
         [0082]      201 ,  202  layer 
         [0083]      210  air flow 
         [0084]      301 - 306  feed means 
         [0085]      311 ,  312  feed station 
         [0086]      322 - 326  resin detector 
         [0087]      332  detection station 
         [0088]      342  control means 
         [0089]      343  detection unit 
         [0090]      344  activation unit 
         [0091]      390  activation line 
         [0092]      392  detection line 
         [0093]      401 ,  402  cover layer 
         [0094]      403  strut 
         [0095]      406  bracing 
         [0096]      408  foam material 
         [0097]    d 1 , d 2  grain size 
         [0098]    h 1 , h 2  individual layer thickness 
         [0099]    h overall thickness