DE10105976A1 - Large area fiber-reinforced composite component manufacture, involves distribution of resin to a molding chamber via a flexible cover with channels whose cross-section varies during injection - Google Patents

Abstract

Large area fiber-reinforced composite component manufacture, involves distribution of resin to a molding chamber via a flexible cover with channels whose cross-section varies during injection. A fiber preform (7) is located on a rigid tool part (8) and a flexible cover with injection channels (5) placed on top to form a chamber (14) between them. When the chamber is evacuated resin mixture is drawn into the channels which enable it to flow quickly over the main surface area of the chamber to outlets entering the chamber. When the resin is introduced the cross-section of the channels increases and when the resin is transferred from the channels to the chamber the cross-section reduces again. An independent claim is made for the process equipment whose flexible cover for introducing resin to a fiber preform(7) in a molding chamber(14) has resin flow channels(5) with an expandable cross-section.

Description

The invention relates to a method for producing large areas ger components made of fiber composite materials, with a fiber fabric applied to a dimensionally stable molded part and with a deformable molded part is covered on the injection channels are formed, with an intermediate space between the dimensionally stable len and the deformable molded part is evacuated and wherein a Resin mixture is introduced into the injection channels from where it is through over a main area of the gap distributed injection openings in the space.

Furthermore, the invention relates to a device for Manufacture of large-area components from fiber composite materials, with a dimensionally stable component and with a deformable one Molding on which injection channels are formed, with a  Space between the dimensionally stable and the deformable Molding can be evacuated and the injection channels to one Source for a resin mixture can be connected and via a Main extension area of the space distributed injection have openings towards the gap. This device is in particular to carry out the aforementioned method intended.

A method and an apparatus of the one described in the introduction Kind are known from WO 97/12754. The one described Possibility of making the two molded parts large to introduce flat components into an autoclave with which additionally an overprint on the back of the deformable Molding can be applied to the resin mixture in the fiber fabric and to stabilize the shape of the future components lizing turns out to be advantageous, but not mandatory necessary. These additional measures can therefore also be used the invention are provided, but are not in the foreground here reason. Rather, the invention is about the way how the resin mixture is brought into the space in which the fiber fabric is arranged. According to WO 97/12754 Injection channels with a fixed free cross section are provided be connected to a source for the resin mixture. The Resin mixture is injected into the injection channels from the source presses and gets from there through the injection openings into the Space with the fiber fabric. It must be done throughout Operation of introducing the resin mixture into the compound the source of the resin mixture can be maintained. The Resin mixture can only slowly enter the injection channels be pressed as it passes through this into the space entry. That means it is a very lengthy one and because of the binding of the device used in the process costly process. In addition, the resin mixture in the Injection channels, which no longer towards the end of the process enters the gap, lost. The corresponding one Amounts of resin mixture are not insignificant because of the free Cross section of the injection channels a certain minimum size  must have in order to flow safely through the resin mixture his. In addition, the structure of the deformable molded part is in the area the injection channels comparatively complex, what the total cost of the known method additionally increased.

The invention has for its object a new method and a new device of the type described above to demonstrate the significant compared to the prior art Show cost advantages.

According to the invention, this is the case with a method of the beginning described type in that the resin mixture under Widening their free cross-section into the injection channels is introduced and that the free cross section with the Injection channels filled with resin mixture to discharge the Resin mixture in the space is reduced again.

The new process varies the free cross-section of the Injek tion channels over the period required for the transfer of the Resin mixture needed in the space with the scrim becomes. First, the free cross section through the insertion of the resin mixture greatly expanded. Then decreased the free cross section again while the resin mixture is passing through the injection ports actually in the space with the Fiber scrim passes. In the end the free cross section of the Injection channels towards zero. Accordingly, only a minimal one is possible Share of the resin mixture lost.

In addition, all of the resin mixture used to manufacture a component is needed, initially in the injection channels be introduced. It then becomes a source of the resin mixture no longer needed and can be removed from the injection channels be separated. It is then sufficient to place the injection channels in front of the Reduce their cross-section to seal the inlet side to prevent this To continue proceedings. Accordingly, with the source for that Resin mixture to be worked on elsewhere, although the resin mixture from the injection channels only to one  lower proportion already in the space with the fiber occasionally.

The free cross-section of the injection channels can be affected a differential pressure between the evacuated space and the outside of the deformable molding can be reduced. In addition, it is conceivable to mechanically check the free cross section the injection channels to act in the sense of a reduction, for example by spreading rollers, press bars or like. But is preferred over the main extension area of the interspace particularly uniformly acting groove a differential pressure that is generated solely by evacuating the Space or by adding an over pressure generated on the outside of the deformable molded part can be.

The injection channels are preferably within one the deformable molded part that closes the vacuum film on the outside arranged so that the differential pressure immediately on the Cross-section of the injection channels acts.

Additional forces to reduce the free cross section of the Injection channels can be built up in that the Vacuum film or the material of the injection channels elas is table. The elastic forces then also result in one for emptying the injection channels through the injection openings acting pressure.

It is preferred if the injection openings are perpendicular to the Main area of extension of the space with the fiber fabric be aligned. With one not perpendicular to the main one Extension area of the space-oriented injection opening there is a risk that the emerging resin mixture is not pressed directly into the fiber fabric, but at least first the deformable molded part of the fiber fabric takes off, which destabili the position of the deformable molded part can be settled. In this context, it is particularly preferred  the injection openings within a perpendicular to the main extension surface of the space Arrange the median longitudinal plane of the injection channels.

The injection channels can be inserted before the resin mixture is introduced parallel to the main extension surface of the intermediate space be merged so that they have virtually no free volume exhibit. When the resin mixture completely comes out of the Injection channels are removed, they can be the same again take a flat shape.

However, it is not necessarily preferred to actually have one Zero volume of the injection channels before the introduction of the Resin mixture and after the resin mixture has passed into the To aim for space with the fiber fabric. Rather it is for an easy introduction of the resin mixture into the injection channels and their even emptying is an advantage before Introducing the resin mixture into the drainage mat Insert injection channels.

The device of the type described is fiction characterized in that the injection channels through a Introducing the resin mixture expandable and to discharge the Resin mixture in the space reducible free Has cross section. The injection channels are preferred as separable from the source of the resin mixture and sealable on the inlet side.

Further preferred embodiments of the new device are already above in the description of the preferred embodiment of the new process has been indicated.

In addition, the deformable molded part of the new device is preferably designed as a disposable item. This one way Article comprises at least one film or another two-dimensional sional structure on which the injection channels preferably through Hoses or elongated pockets with deformable free  Cross-section are formed so that they define each other te have relative positions. This item can already comprise a vacuum film. Such a vacuum film can, however also be added and then does not belong necessarily to the parts of the deformable molding that can only be used once. The rest of the resin mixture contained in the injection channels of the moldable molded part remain, after their free cross-section has been reduced again only slight.

In principle, just like the injection channels can with the deformable molded part also vacuum lines for evacuating the Intermediate space can be provided with the fiber fabric. Here it is but in any case required a drainage mat in the Arrange vacuum lines to provide a free suction cross section to be kept open for evacuation.

In a specific embodiment, the deformable molded part two welded together using linear welds Have films, the lower film with the injection openings is provided and wherein the welds between the injection channels formed laterally on the two foils limit. Such a deformable molded part is producible that first the injection openings in the lower Foil can be introduced. Then preferably in the area the striped drainage of the planned injection channels arranged mats. Then the second, top slide applied, and ultimately the welds become the limit injection channels between the two foils attached. In addition, connections for the injection channels can be provided become. Furthermore, the suction channels can be in exactly the same Be formed between the two welded foils. Drainage mats are mandatory for the suction channels.

Another alternative to perforated hoses for training The formation of the injection channels is the formation of the injection channels channels through elongated, in the area of the injection openings  open pockets in multiple folded foil strips. On such a film strip shows that the respective pocket symme trained above the respective injection port can be an even number of refoldings. At least and typically there are four. It turns out to be favorable if the side edges of the film strips over the Area of the pocket formed above, also in its flat collapsed condition, survive. This will make the location the film strip and the injection you have trained channels stabilized below a vacuum film. Even in the Pockets of the folded foil strips can be used for drainage mats to be ordered. You are also training for Suction channels suitable.

For the injection channels based on folded-over foils The injection openings are slit-shaped with a longitudinal stripe run in the main direction of extension of the film strips. If the injection ports are in a closed position Foil or a tube are formed, they can also be perforated, d. H. Rows of holes from individual have limited and successive holes.

The invention will be explained in more detail below by means of exemplary embodiments explained and described. It shows

Fig. 1 shows a schematic arrangement of injection channels and vacuum lines wherein the deformable mold part of a first embodiment of the present invention Vorrich tung,

Fig. 2 shows a cross section through an injection channel of the deformable mold part of FIG. 1 with an adjacent batt,

Fig. 3 shows the cross-section of FIG. 2 after introduction of a resin mixture into the injection channel,

Fig. 4 shows the cross section of a vacuum line of the deformable mold part of FIG. 1 with an adjacent batt,

Fig. 5 injection openings at the bottom of a channel of the deformable Injek tion molding according to Fig. 1,

Fig. 6 shows the arrangement of injection channels and vacuum lines wherein the deformable mold part of a second embodiment of the device according to the invention,

Fig. 7 shows a first step for producing the deformable mold part according to Fig. 6,

Fig. 8 shows a second step for manufacturing the deformable mold part according to Fig. 6,

9 shows a cross section through an injection channel of the deformable form part of a further embodiment of the device. According to the invention

Fig. 10 shows the injection channel of FIG. 9 adjoining after introduction of a drainage mat, covering with a bagging film and fiber fabric,

Fig. 11 the injection channel of FIG. 10 after introduction of a resin mixture,

Fig. 12 shows the arrangement of injection channels shown in FIGS. 10 and 11 with respect to a large-area component to be produced.

The illustrated in Fig. 1 deformable mold part 1 is part of a mold which is also formed of a dimensionally stable molded part as a counter-form. A fiber fabric is applied to this dimensionally stable molded part, not shown here. Then the deformable molded part 1 is placed. A seal is made in the edge area. A space between the two molded parts, in which the fiber fabric is located, is then evacuated. For this purpose, vacuum lines 2 are provided with the suction openings, which are not visible here, and which can be connected in the direction of an arrow 3 to a vacuum source. A resin mixture is then introduced into the space. This comes in the direction of an arrow 4 from a source for the resin mixture and first enters injection channels 5 on the molded part 1 . From there it passes through injection openings into the space with the fiber lay. The injection openings are again not recognizable in FIG. 1. From the injection openings of the injection channels 5 , the resin mixture flows in the direction of arrows 6 through the intermediate space or the fiber fabric arranged therein to the vacuum lines 3 until the entire fiber fabric is saturated with the resin mixture to the desired extent. In this case and subsequently, the resin mixture can be cured, which is excited, for example, by an elevated temperature of the stable molded part.

Fig. 2 shows, using an injection channel 5 shown in cross section, the detailed structure of the deformable molded part 1 as it rests on the fiber fabric 7 shown here above the dimensionally stable molded part 8 indicated here. The injection channel is formed by an initially flat folded tube 9 , on the underside of which the injection openings 10 are formed. The hose 9 is covered by a vacuum film 11 , which seals the fiber fabric 7 also outside the injection channel 5 on the back of the molded part 1 . If the resin mixture 12 according to FIG. 3 is now introduced into the injection channel 5 , its free cross section, which was initially zero, widens considerably. The entire resin mixture, which is required for impregnating the fiber fabric 7 , can be introduced into the injection channels 5 at once. The resin mixture via the injection openings 10 in the direction of arrow 13 and then the arrows 6 is pressed into the space 14 from the injection channels 5 which receives the fiber fabric. 7 The forces acting thereby, which again reduce the free cross section of the injection channel 5 , are based on the differential pressure inside and outside the vacuum film 11 and also on elastic forces which are caused by the expansion of the vacuum film 11 . When the resin mixture 12 has completely passed into the intermediate space 14 , the free cross section of the injection channel 5 returns to its shape according to FIG. 2.

Fig. 4 shows the cross section of a vacuum line 2 of the deformable molded part 1st The vacuum line 2 also builds on a hose 9 , in which, however, a drainage mat 16 is arranged here in order to always keep a free suction cross section free. So can be sucked through the vacuum lines 2 always in the direction of arrows 6 , through the suction openings 15 and the drainage mat 16 through, even if a high differential pressure of the vacuum film 11 tries to squeeze the cross section of the vacuum line 2 together.

The simple construction of both the vacuum lines 2 and the injection channels 5 makes it possible to produce the entire deformable molded part inexpensively as a disposable item. Further cost advantages of the invention result from the fact that the injection channels 5, after being filled, can be suspended from the source for the resin mixture and sealed on the inlet side, because the individual introduction of the resin mixture 12 from the injection channels 5 into the intermediate space 14 with the fiber fabric 7 independently of the Source for the resin mixture 12 takes place.

FIG. 5 shows the underside of a hose 9 , which here forms an injection channel 5 , but could also form a vacuum line 2 . The injection openings 10 can be seen, which are arranged in close succession in the middle of the underside of the hose 9 , ie in its longitudinal center plane 17 , which runs perpendicular to the main extension plane of the deformable molded part 1 . The injection openings 10 are in turn also aligned perpendicular to the main extension plane of the adjacent intermediate space 14 or the fiber fabric 7 arranged therein.

The embodiment of the deformable molded part 1 according to FIG. 6, which can also be supplemented by an additional vacuum film placed on top, is a construction based on two films 18 and 19 welded together in the area of linear weld seams 20 . In this case, 18 slots 21 are provided in the lower film for forming both the injection openings 10 and the suction openings 15 . The slots 21 run parallel to one another and alternately form a suction opening and an injection opening. Drainage mats 16 are arranged above the slots 21 . To the side of the drainage mats 16 , the two foils 18 and 19 are welded to one another by the weld seams 20 . So both the vacuum lines 2 and the injection channels 5 are formed over the slots 21 between the welds 20 . The injection channels 5 and the vacuum lines 2 also continue beyond the area of the slots 15 until they are combined on a resin connection 23 on the one hand or a suction connection 21 on the other hand. The deformable molded part 1 according to FIG. 6 can be produced inexpensively as a disposable item in adaptation to the component to be manufactured in each case. The deformable molded part 1 according to FIG. 6 is preferred, in particular in the case of large-area, less structured components.

In Figs. 7 and 8, the first steps of manufacturing the elastic mold part 6 are shown in FIG. Sketched. According to FIG. 7, the film 18 , which is later located below, is first provided with the slots 15 . Fig then the drainage mats 16 are in accordance. Ver 8 applies, on the one hand via the slots 15 and on the other hand to the attached also in this step, terminals 22 and 23. With the laying of the drainage mats 16 , the slots 15 are already assigned on the one hand to the later vacuum lines 2 and on the other hand to the later injection channels 5 . Then, the upper film 19 is placed up as shown in FIG. 6, and the welds 20 are made as shown in FIG. 6.

Fig. 9 shows an alternative possibility for forming an injection channel 5 or a vacuum line 2. The starting point here is a film strip 24 which is folded over several times. A first folding 25 limits the cross-sectional view according to FIG. 9 to the injection opening 10 to the left. A second folding 26 forms the left edge of the folded injection channel 5 ; a third fold 27 the right edge. A fourth fold 28 limits the injection opening 10 to the right. The edges 29 of the film strip 30 protrude laterally over the folds 26 and 27 . That is to say, the injection channel 5 is only provided in the central region of the folded film strip 24 in the manner of an open pocket. The projecting edges 29 stabilize the position of the injection channel 5, in particular after it has been filled with a resin mixture (not shown here).

A drainage mat 16 is preferably arranged in the injection channel 5 designed according to FIG. 9. After placing it on a fiber fabric 7 to form a component, it is then covered with a vacuum film 11 . This is shown in Fig. 10, which also identically reproduces the formation of a vacuum line.

Fig. 11 shows a contrast in FIG. 10 formed Injek tion channel 5 after loading with a resin mixture 12 to the fiber ply 7 to soak via injection opening 10 with the resin mixture. The drainage mat 16 ensures a uniform opening of the injection channel 5 when it is filled with the resin mixture 12 . With the appropriate design of a suction line 2 , the drainage mat 16 ensures a free residual cross section.

Fig. 12 shows the arrangement of injection channels 5 , which start from a resin connection 23 , and of vacuum lines 2 , which lead to a suction connection 22 , in relation to a large-area component 30 with ribs 31 projecting therefrom. A vacuum line 2 or an injection channel 5 is provided between the individual ribs 31 . The resin mixture must therefore pass through the area of the ribs 31 in order to pass from an injection channel 5 to the closest vacuum line 2 . All injection channels 5 and all vacuum lines 2 up to the connections 22 and 23 according to FIG. 12 are formed on the basis of the film strips 24 and have the cross section shown in FIG. 10.

LIST OF REFERENCE NUMBERS

1

molding

2

vacuum line

3

arrow

4

arrow

5

injection channel

6

arrow

7

fiber fabrics

8th

molding

9

tube

10

injection port

11

vacuum film

12

resin mixture

13

arrow

14

gap

15

suction

16

drainage mat

17

Longitudinal center plane

18

foil

19

foil

20

Weld

21

slot

22

suction connection

23

resin connection

24

film strips

25

refolding

26

refolding

27

refolding

28

refolding

29

edge

30

component

31

rib

Claims (20)

1. Process for the production of large-area components made of fiber composite materials, wherein a fiber fabric is applied to a dimensionally stable molded part and covered with a deformable molded part, on which injection channels are formed, with an intermediate space between the dimensionally stable and the deformable molded part being evacuated and a resin mixture is introduced into the injection channels, from where it passes through injection openings distributed over a main extension surface of the intermediate space into the intermediate space, characterized in that the resin mixture ( 12 ) is introduced into the injection channels ( 5 ) while widening their free cross section and that the free one Cross section of the injection channels filled with the resin mixture for discharging the resin mixture into the intermediate space ( 14 ) is reduced again. 2. The method according to claim 1, characterized in that the injection channels ( 5 ) are sealed on the input side before reducing their cross section. 3. The method according to claim 1 or 2, characterized in that the free cross section of the injection channels ( 5 ) is reduced by the action of a differential pressure between the evacuated space ( 14 ) and the outside of the deformable molded part ( 1 ). 4. The method according to claim 1, 2 or 3, characterized in that the injection channels ( 5 ) within a the deformable molded part ( 1 ) to the outside, elastic vacuum film ( 11 ) are arranged. 5. The method according to any one of claims 1 to 4, characterized in that the injection openings ( 10 ) are aligned perpendicular to the main extension surface of the intermediate space ( 14 ). 6. The method according to any one of claims 1 to 5, characterized in that the injection openings ( 10 ) in a perpendicular to the main extension surface of the intermediate space ( 14 ) extending longitudinal center planes ( 17 ) of the injection channels ( 5 ) are arranged. 7. The method according to any one of claims 1 to 6, characterized in that the injection channels ( 5 ) before the introduction of the resin mixture ( 12 ) parallel to the main extension surface of the intermediate space ( 14 ) are folded flat. 8. The method according to any one of claims 1 to 9, characterized in that a drainage mat is introduced into the injection channels ( 5 ) before introducing the resin mixture ( 12 ). 9. Apparatus for producing large-area components made of fiber composite materials, with a dimensionally stable molded part and with a deformable molded part on which injection channels are formed, an intermediate space between the dimensionally stable and the deformable molded part being evacuable and wherein the injection channels can be connected to a source for a resin mixture and have injection openings distributed towards the intermediate space over a main extension surface of the intermediate space, characterized in that the injection channels ( 5 ) have a free cross-section which can be expanded by introducing the resin mixture ( 12 ) and reduced again in order to discharge the resin mixture into the intermediate space ( 14 ). 10. The device according to claim 9, characterized in that the injection channels ( 5 ) from the source for the resin mixture ( 12 ) can be separated and sealed on the inlet side. 11. The device according to claim 9 or 10, characterized in that the injection channels ( 5 ) are arranged inside a deformable molded part ( 1 ) to the outside, elastic vacuum film ( 11 ). 12. The device according to one of claims 9 to 11, characterized in that the injection openings ( 10 ) are aligned perpendicular to the main extension surface of the intermediate space ( 14 ). 13. The device according to one of claims 9 to 12, characterized in that the injection openings ( 10 ) are arranged in a perpendicular to the main extension surface of the intermediate space ( 14 ) extending longitudinal center planes ( 17 ) of the injection channels ( 5 ). 14. Device according to one of claims 9 to 13, characterized in that the injection channels ( 5 ) are folded flat parallel to the main extension surface of the intermediate space ( 14 ) before the introduction of the resin mixture ( 12 ). 15. Device according to one of claims 9 to 14, characterized in that a drainage mat is arranged in the injection channels ( 5 ). 16. The device according to one of claims 9 to 15, characterized in that the deformable molded part ( 1 ) is a disposable item. 17. Device according to one of claims 9 to 16, characterized in that the deformable molded part ( 1 ) has two films ( 18 , 19 ) welded to one another via linear weld seams ( 20 ), the lower film ( 18 ) with the injection openings ( 10 ) is provided and the weld seams ( 20 ) laterally limit the injection channels ( 5 ) formed between the two foils ( 18 , 19 ). 18. Device according to one of claims 9 to 16, characterized in that the injection channels ( 5 ) are formed by elongated te, in the region of the injection openings ( 10 ) open pockets in multiple folded foil strips ( 24 ). 19. Device according to one of claims 9 to 18, characterized in that the injection openings ( 10 ) are slit-shaped. 20. Device according to one of claims 9 to 18, characterized in that the injection openings ( 10 ) are perforations-shaped.