DE102012108168B4 - Forming tool and method for the production of fiber composite components - Google Patents

Abstract

 Forming tool for producing fiber composite components, in particular for producing a preform, wherein the forming tool (1) has an upper tool (2) and a lower tool (3), wherein with closed upper tool (2) and lower tool (3) a mold cavity (5) for arranging a fiber material remains and on a mold surface (4) of the upper tool (2) and / or the lower tool (3) a plurality of needle-like extensions (6) are formed, characterized in that at least one clamping device (9) is provided, with the fiber strands or rovings comb-like over the needle-like extensions are windable and that the clamping device (9) during the closing operation of the forming tool (1) keeps the fiber strands or rovings fixed in position.

Description

The present invention relates to a forming tool for producing fiber composite components according to the features in the preamble of patent claim 1.

The present invention further relates to a method for the production of fiber composite components according to the features in claim 8.

From the prior art it is known to produce components from different materials. In particular, in the automotive industry has always been the outer skin of a motor vehicle made of metallic materials, for example, from a steel sheet or even from an aluminum sheet. For this purpose, components in forming tools are brought into the desired shape and at the same time have good, high-strength or even very high-strength strength properties, wherein these components can be produced in high volume with low production tolerances, especially in mass production.

Increasingly, however, the implementation of consistent lightweight construction has also drawn into the mass production of automobiles, which is why components made of fiber composite material combine high-strength or even very high-strength properties with particularly low component weight. The problem here was previously the production with only low production tolerances at the same time manageable production costs. For this purpose, methods have developed in recent years, with which an industrial mass production of fiber composite components can be realized, which then have a high production accuracy at the same time acceptable production costs, but low weight and high strength properties. For this purpose, fiber materials are provided with matrix resin and, similar to sheet metal forming in die tools, for example in forming tools with an upper tool and a lower tool, brought into the desired shape and cured there, so that then the component can be removed. If necessary, revisions in the form of surface treatments or edge trimming are required.

In particular, a preform, thus a preform, of the component itself is decisively produced and subsequently a matrix resin already contained within the fiber material is activated or a matrix resin is added. In particular, in fiber materials already provided with matrix resin, prepreg materials are used which activate an already contained matrix resin by the addition of temperature or else chemicals or pressure and subsequently cure the matrix resin with the fiber material to form a fiber composite material.

In an RTM process, a fiber material is first preformed and then injected into the mold a matrix resin, in which case in turn hardens the matrix resin with the fiber material to form a fiber composite component.

In particular, with this method, for example, roof skins or even hoods, thus large-scale components with low degrees of deformation in series can be produced inexpensively.

However, if at least locally high degrees of deformation are to be produced, the abovementioned preforming processes are only of limited suitability. This can lead to a shearing or tearing of at least individual fiber strands within the fiber material such that local thinning takes place, which then lead to rejects or goods with reduced production quality. However, this is disadvantageous, in particular, for the production of motor vehicle structural components with crash-relevant properties, which due to the weight optimization are said to have little excess material mass and, on the other hand, a particularly high production accuracy for the crash requirement.

For example, is from the DE 10 2010 015 199 A1 a device and a method are known, can be produced with the corresponding motor vehicle components, wherein a leg arm individual fiber strands or fiber rovings are placed on a mold. In this case, the respective ends of the fiber strands are fixed in position by means of edge fixing mechanisms, which are formed, for example, by way of negative pressure, freeze grippers or else via hooks on the edge. However, this does not yet solve the problem that when closing a forming tool in the region of locally high degrees of deformation sliding or shearing and even tearing of individual fiber strands can take place.

For this purpose, it is also known from the prior art to intertwine individual fiber strands or rovings deposited on a tool, to weave them together or else to sew them together. However, this means on the one hand an increased effort in the production of the component by the upstream braiding, weaving or sewing process, on the other wear the additional braid, woven or seams not or only slightly to an increase in strength and provide beyond for an increased cost of materials and increased component weight. Under certain circumstances, the resulting local thickening, in particular in a mold cavity, can even have a counterproductive effect on a matrix resin entry or also on the produced surface quality of the fiber composite component.

From the US 5,151,277 A is a forming tool for the production of fiber composite components is known, which has needle-shaped extensions which form in conjunction with a rubber-like compound layer itself the mold space of the forming device.

From the US 2008/0251975 A1 Also, an apparatus and a method for producing a fiber composite component is known, which has a plurality of needle-shaped extensions, which can be extended variably via a pressure supply and form in conjunction with a rubber-like film, the mold surface of the forming tool.

Other forming tools are from the DE 10 2007 037 680 A1 , of the DD 270 036 A1 , of the GB 2 239 835 A as well as the GB 2 353 246 A known.

The object of the present invention is therefore to provide a forming tool for producing a fiber composite component and a method for producing fiber composite components, with the cost and time efficient a preform with at least locally high degrees of deformation can be produced, at the same time high reproducibility and low production tolerances.

The above object is achieved with a forming tool for producing fiber composite components according to the features in claim 1.

The procedural part of the object is further achieved by a method for producing a fiber composite component according to the features in claim 8.

Advantageous embodiments of the present invention are part of the dependent claims.

The forming tool according to the invention for producing fiber composite components, in particular for producing a preform, wherein the forming tool has an upper tool and a lower tool, wherein a mold cavity for arranging a fiber material remains when the upper tool and lower tool are closed, wherein on a molding surface of the upper tool and / or the lower tool Variety of needle-like extensions is formed, is characterized in that at least one clamping device is provided, with which a fiber material on the lower tool is comb-like strippable and is fixed in position during the closing operation of the forming tool.

The needle-like extensions thus protrude into the mold cavity, whereby the possibility arises that a fiber material coming to rest on the respective mold surface is held in position by the needle-like extensions through the needle-like extensions. It thus does not come even with a draping to a slipping of fiber material, for example, an increase and not in the further closing of the forming tool, in which a retraction or retightening of the fiber material for the design of the three-dimensional shape of the component to be produced, to a sliding or Shearing the fiber material, since the individual fiber strands or rovings are held by the needle-like extensions in position.

The needle-like extensions are in particular coupled as needles with the mold surfaces of the upper tool and / or Unterwerkszeugs, in particular inserted into this. Most preferably, the needle-like extensions are arranged on the lower tool, since upon insertion or draping of the fiber material, first, due to the gravitational effect, a contact with or on the mold surface of the lower tool takes place.

In order that the fiber materials deposited on the forming tool are held fixed in position during the closing operation of the forming tool, a clamping device is furthermore provided with which the fiber material draped on the forming tool is fixed in position at least on one side. It is possible for the clamping device to deposit at least a part of the fiber material on the lower tool. In this case, a comb-like mounting of individual fiber strands or fiber rovings and in particular a fiber bundle such that the aforementioned materials are combed over the needle-like extensions comb-like and upon reaching the clamping tool on the side where they are to be fixed, there is a positive positional fixation.

So that the forming tool can perform a closing movement, so that the mold surfaces of the upper tool and lower tool are moved towards each other so that a mold cavity remains, the needle-like projections are relatively movable to the surface and / or on the opposite surface of the respective needle-like projection a recess is present so that the needle-like extension when performing the closing movement of upper tool and Sub-tool enters the recess. Thus, the closing movement is not hindered by the needle-like extensions, wherein the needle-like extensions may have a length which is greater than the distance between the two molding surfaces with closed forming tool.

In the context of the invention, in particular the needle-like extensions are oriented in the vertical direction, very particularly preferably they run parallel to the direction of the closing movement of upper tool and / or lower tool. As a result, in particular in the case of needle-like extensions which enter into recesses, it is ensured that the closing movement of the forming tool can be carried out. In the context of the invention, however, it is also possible with needle-like extensions which are spring-mounted, that they are not oriented parallel to the closing movement, being retracted by the positive contact with the plant contact with the opposite form surface of the needle-like extension in the tool opposite a spring force with which it is coupled.

Further preferably, the needle-like extensions can be actively extendable, in particular by means of a Stellaktuators, or the needle-like extensions are resiliently mounted. In particular, this spiral compression springs offer, as they have a high mechanical reliability and offer up to several dozen or even several hundred needle-like extensions on a forming tool cost-effective production possibility of the tool itself. In the context of the invention, it is possible that the needle-like extensions, in particular after completion of the closing movement, are drawn into the forming tool. In passive, spring-loaded needle-like projections, which are retracted by positive system contact of the opposite surface of the mold opposite the spring force in a Lageausnehmung, these still protrude at fully closed forming tool with a projection against the mold surface into the mold cavity. When removing the component thus produced, it may thus be a hindrance that the needle-like extensions are still at least partially in the mold cavity. In this case, it is particularly advantageous if the needle-like extensions are removed from the mold cavity during or after completion of a shaping process. In particular, the needle-like extensions are then pulled into the interior of the forming tool.

Thus, on the one hand, the retraction movement described above is possible without damaging the fiber strands of the fiber material, on the other hand, however, the possibility is given to drape fiber strands or rovings on the lower tool so that they are pulled like a comb through the needle-like extensions point the needle-shaped extensions in particular a non-stick surface. This non-stick surface may be formed, for example, in the form of an externally applied coating which on the one hand has a good sliding property with respect to the fiber material used, so that the fibers do not tear when passing or are pulled apart or are otherwise damaged, on the other hand, the non-stick surface can also be in one particularly smooth surface property of the needle-shaped extensions are formed. It is thus and also made possible by the features described above, with the forming tool according to the invention a variety of fiber material types, for example basalt fibers, carbon fibers, aramid fibers or even metallic fibers and in particular to process glass fibers or mixed forms of the aforementioned types of fibers.

Preferably, the needle-shaped extensions are arranged in a uniform pattern on the mold surface of the upper tool and / or lower tool, wherein in particular in areas of an outer curvature, an increased number of needle-like extensions can be arranged. In regions of an increase or outward curvature of the respective mold surface, there is an increased risk that shearing or slipping occurs when the forming tool is closed. Due to the increased density of needle-like extensions in this area, a particularly high shaping accuracy in the positioning and alignment of the individual fiber strands or fiber rovings is achieved here.

Furthermore, in particular the forming tool is further associated with a separating device such that upon closing of the forming tool or at the conclusion of the closing or shaping process, the protruding fiber materials are cut off.

Optionally, it is possible within the scope of the invention for the upper tool and / or the lower tool to be heated. For example, heating elements or even induction elements can be integrated in the upper tool and / or lower tool, so that heat can be exerted, in particular, on the fiber composite materials located in the mold cavity. In particular, a binder can be activated in the fiber material, so that the preform is produced.

In the context of the invention, furthermore, the needle-like extensions are particularly preferably formed from an elastic material. In particular, here comes a rubber material used and / or another flexible and / or elastic material through which the needle-like extensions in itself can be bent and / or compressed. Thus, should a malposition or contact with the opposite mold surface occur during the preforming operation, the needle-like extension does not break off, but merely becomes bent.

Further preferably, the needle-like extensions can be coupled via an elastic coupling in or on the mold surface. For example, here is a joint coupling or even a rubber-like root conceivable so that the needle-like extension can be either rigid and bendable over the elastic coupling or is bendable both via the elastic coupling, as well as by an elastic design of the needle-like extension itself is compressible or bendable.

• – Bereitstellen eines Fasermaterials,
• – Anordnen des Fasermaterials zwischen dem Oberwerkzeug und dem Unterwerkzeug durch kammartiges Abstreifen des Fasermaterials mittels einer Klemmvorrichtung über die nadelartigen Fortsätze auf dem Unterwerkzeug, wobei das Fasermaterial in die gewünschte Position gebracht wird und die nadelartigen Fortsätze ein Abgleiten des Faserwerkstoffs während des Abstreifvorgangs verhindern,
• – Schließen des Umformwerkzeugs.

Another component of the present invention is a method for producing a fiber composite component, in particular a preform, which is then used to the fiber composite component by adding or activating binder and / or matrix resin. The method according to the invention is produced on the forming tool described above and is characterized by the following method steps:

• Providing a fiber material,
• Arranging the fiber material between the upper tool and the lower tool by comb-like stripping of the fiber material by means of a clamping device on the needle-like projections on the lower tool, wherein the fiber material is brought into the desired position and the needle-like extensions prevent slipping of the fiber material during the stripping process,
• - Close the forming tool.

In the context of the invention, the fiber material can be provided, for example, flatly, wherein the fiber material is deposited in particular on the lower tool with the needle-like projections or even clamped in a clamping frame, which is then placed between the tools, the tools then a Execute closing movement.

However, in the context of the invention, fiber strands, rovings or else a fiber bundle which is formed from a plurality of unidirectional rovings are preferably draped on the lower tool in such a way that they are striped over the lower tool and the needle-like extensions in a comb-like manner into the interspaces of the rovings or fiber strands engage, but at the same time position fix them orthogonal to the grazing or pulling direction so that they can not slide off or shear off left side or on the right side during the Aufziehvorgangs. As a result, a large degree of freedom in the orientation or orientation of the fiber material is given. So they do not have previously been woven together or sewn or but a network of individual fiber strands or rovings are provided, the individual fiber strands, rovings or fiber bundles can then easily or even multi-layered, especially against each other crossing over the lower tool be stripped off.

For example, two fiber strands, rovings or even fiber bundles can be laid to each other at a 90 ° angle, for example, in relation to the forming a first fiber strand, roving or a fiber bundle is drawn at an angle of 45 ° to the forming tool and then a second Fiber strand, roving or a fiber share at an angle of -45 ° is raised on the forming tool. Both then have an angle of 90 ° to each other.

The needle-like extensions of the fiber strands, rovings or fiber bundles are then fixed in position-locking manner, especially during the forming process. A local thinning due to high degrees of deformation or a shearing or slipping of a survey or outer curvature of a mold surface is thereby avoided. An additional fixing within the mold cavity, for example by a panel or additional fixing means can also be omitted, with such additional fixing measure would also adversely affect the forming process itself, which is completely prevented by the needle-like extensions of the invention.

Another particular advantage of the present invention, however, is that during the forming process, first the individual fiber strands, rovings or fiber bundles are pulled over the forming tool substantially in two-dimensional form and are formed into a three-dimensional preform when the forming tool is closed. As a result, the fiber strands, rovings or fiber bundles undergo an additional change in length, wherein they are then drawn into the mold cavity. By the needle-like extensions such a pulling into the mold cavity is possible.

After completion of the forming process, it is then possible to cut off protruding fiber material and, for example, to activate binders already present in the fiber strands, rovings or fiber bundles, for example by thermal action as a result of heating. Especially in the latter operations for Production of the fiber composite component, it is possible to pull the needle-like extensions shortly before or after completion of the forming of the fiber composite material component or preform produced by drawing in the direction of the upper tool and / or lower tool, in which case the forming tool is optionally closed by another piece so that the fiber strands, rovings or fiber bundles located therein are pressed together and possibly remaining cavities are closed by the needle-like extensions. Thus, the fiber composite component or the preform produced in this way have no holes in their structure, which were produced by the needle-like extensions.

Further advantages, features and aspects of the present invention are part of the following description. Preferred embodiments are shown in the schematic figures. Show it:

1a to c an inventive forming tool as well as a production process carried out with needle-like extensions,

2a to c an inventive manufacturing method and an inventive forming tool with retracting needle-like extensions,

3a and b draping fiber material on a lower tool and

4 an inventive lower tool in a perspective view.

In the figures, the same reference numerals are used for the same or similar components, even if a repeated description is omitted for reasons of simplicity.

1a to c show an inventive forming tool 1 having an upper tool 2 and a lower tool 3 , The upper tool 2 and the lower tool 3 each have a mold surface 4 on, between those, in 1c shown a mold cavity 5 with closed forming tool 1 is trained. Further illustrated, the lower tool 3 opposite to its mold surface 4 projecting needle-like extensions 6 on, when performing the closing movement according to 1a to c in the closing direction S in in the upper tool 2 trained recesses 7 retract. This puncture the needle-like extensions 6 one between upper tool 2 and lower tool 3 arranged fiber material 8th and keep it fixed in such a way that it can not slide sideways or with respect to the image plane into the image plane or out of the image plane, but it does not 1b to 1c continue in the pulling direction Z in the forming tool 1 , thus into the mold cavity 5 , is confiscated.

This is the fiber material 8th on a clamping device 9 attached it to one side of the forming tool 1 fixed in position, wherein it is on the opposite side in the pulling direction Z in the forming tool 1 is retracted during the forming process. Shortly before completion or when reaching the desired shape according to 1c becomes the fiber material 8th then separated. So that the needle-like extensions 6 according to 1a to c in the respective recess 7 in the upper tool 2 can move in, they are aligned parallel to the closing direction S.

2a to c shows a substantially analogous arrangement of a forming tool 1 , here also a fiber material 8th via a clamping device 9 such between an upper tool 2 and a lower tool 3 that is arranged at 2c in a closed mold cavity 5 a three-dimensional shaping takes place. In contrast to 1 has the forming tool 1 spring-loaded needle-like extensions 6 on, with the needle-like extensions 6 over a spring 10 are stored so that they form-fit contact with the mold surface 4 of the upper tool 2 in a spring recess 11 of the lower tool 3 opposite to the spring force can be pressed. In the context of the invention, it is also possible, the needle-like extensions 6 according to 2c Position fixate in the position shown there or further withdraw, so that when subsequently opening the forming tool 1 the preform or the fiber composite material component produced in this way can be easily removed therefrom.

Further shown in FIG 3a and b is a lower tool according to the invention 3 in a plan view, wherein the lower tool 3 a variety of needle-like extensions 6 having. Shown is a border area 12 a form to be produced, on the example here a variety of fiber bundles 13 by means of the clamping device 9 was pulled in the pulling direction Z. The clamping device 9 is used as a draping tool. The clamping device 9 is then fixed in position on one side of the forming tool 1 , wherein on the opposite side of the clamping device 9 further retraction of the fiber bundles 13 in the pulling direction Z when carrying out the closing movement of the forming tool 1 is possible. In 3b shown is a comb-like mounting of fiber bundles 13 to an inventive forming tool 1 at an angle α, here also in the pulling direction Z, the comb-like mounting on the needle-shaped extensions 6 is done, in turn, further fiber bundles 13 in any orientation to the forming tool 1 can be raised.

In the context of the invention, it is possible here, first with the clamping device 9 a certain number of fiber bundles 13 in an orientation over the lower tool 3 to drape, then the upper tool 2 and the lower tool 3 drive together and close and preform the initially draped fiber bundles. After that, the top tool becomes 2 raised and, for example, according to 3b a new number of fiber bundles 13 at an angle to the first number of fiber bundles 13 on the lower tool 3 draped and then turn the upper tool 2 and the lower tool 3 moved together. This process can then be repeated as often as desired, so that different orientations or wall thicknesses at least spatially different from one another on the preform can be realized without problems with the method according to the invention.

In the context of the invention, it is also possible, thereby produce relatively thick preforms in their wall thickness, since the delay within the component due to the formation of each layer is kept individually low. Waves or wrinkles during the deformation of the multi-layer fiber material is thereby avoided.

Another particular advantage is in accordance with the invention 1c and 2c to be considered that a marginal trimming on the image plane based on the left side, only on one side and thus the trim or the fiber residue produced is reduced to a minimum. In the context of the invention, in particular, the supernatant of the fiber strand, which is related to the right side of the image, is in the clamping device 9 is trapped, kept to a minimum.

Furthermore, it is possible within the scope of the invention, the in 1c and 2c each to be reduced on the left side of the fiber strand in the area of the edge trimming to 0 to reduce. This means that the preform produced can be cut to the edge of the mold so that there is little or no waste in the form of production residues. Also on the right side of the picture in the clamping device 9 shown projecting fiber strand can be cut to the edge of the mold. Instead of a fiber strand and a fiber sheet can be inserted or draped and trimmed.

4 shows a lower tool according to the invention 3 with a mold surface 4 , being on the mold surface 4 a variety of needle-like extensions 6 is arranged. These have according to 3a and b a uniform surface pattern to each other, but can, for example, on the outside curvatures 14 be increased in their arrangement density.

LIST OF REFERENCE NUMBERS

1

forming tool

2

upper tool

3

lower tool

4

mold surface

5

mold cavity

6

needle-like extension

7

recess

8th

Fiber material

9

clamping device

10

 feather

11

 spring recess

12

 border area

13

 set of fibers

14

 outside vaulting

S

closing direction

Z

tensile direction

Claims (12)

Forming tool for producing fiber composite components, in particular for producing a preform, wherein the forming tool ( 1 ) an upper tool ( 2 ) and a lower tool ( 3 ), wherein when the upper tool is closed ( 2 ) and lower tool ( 3 ) a mold cavity ( 5 ) for placing a fiber material and on a mold surface ( 4 ) of the upper tool ( 2 ) and / or the lower tool ( 3 ) a plurality of needle-like extensions ( 6 ) are formed, characterized in that at least one clamping device ( 9 ) is provided with the fiber strands or rovings comb-like over the needle-like extensions are windable and that the clamping device ( 9 ) during the closing process of the forming tool ( 1 ) keeps the fiber strands or rovings fixed in position. Forming tool according to claim 1, characterized in that the needle-like projections ( 6 ) movable relative to the mold surface ( 4 ) are formed and / or that on the needle-like projections ( 6 ) opposite mold surface ( 4 ) Recesses ( 7 ) are present, wherein the needle-like extensions ( 6 ) when performing the closing movement of upper tool ( 2 ) and lower tool ( 3 ) into the recesses ( 7 ) and that the needle-like extensions ( 6 ) preferably in the direction of the closing movement of upper tool ( 2 ) and / or lower tool ( 3 ) are oriented. Forming tool according to claim 2, characterized in that the needle-like extensions ( 6 ) are actively extendable, in particular by means of a Stellaktuators and / or that the needle-like extensions ( 6 ) are spring-mounted and that the needle-like extensions ( 6 ) preferably in the direction of the closing movement of upper tool ( 2 ) and / or lower tool ( 3 ) are oriented. Forming tool according to one of claims 1 to 3, characterized in that the needle-like extensions ( 6 ), in particular with an anti-adhesion coating. Forming tool according to one of claims 1 to 3, characterized in that the needle-like extensions ( 6 ) in a uniform pattern on the mold surface ( 4 ) of the upper tool ( 2 ) and / or lower tool ( 3 ) are arranged, wherein in particular in areas of an outer curvature an increased number of needle-like extensions ( 6 ) is arranged. Forming tool according to one of claims 1 to 5, characterized in that the upper tool ( 2 ) and / or lower tool ( 3 ) are heated. Forming tool according to one of claims 1 to 6, characterized in that the needle-like extensions ( 6 ) are elastically formed and / or that the needle-like extensions ( 6 ) via an elastic coupling to and / or in the mold surface ( 4 ) are coupled. Method for producing a fiber composite component, in particular a preform, with a forming tool ( 1 ) according to the features of at least claim 1, characterized by the following method steps: - providing a fiber material in the form of fiber strands or rovings, - arranging the fiber material between the upper tool ( 2 ) and the lower tool ( 3 ) by comb-like mounting of the fiber material by means of a clamping device ( 9 ) over the needle-like extensions ( 6 ) on the lower tool ( 3 ), wherein the needle-like extensions ( 6 ) in the interstices of the rovings or fiber strands, wherein the fiber material is brought into the desired position and the needle-like extensions ( 6 ) prevent sliding of the fiber material during the Aufziehvorganges and on the lower tool ( 3 ) deposited fiber material ( 8th ) at least on one side by the clamping device ( 9 ), - closing the forming tool ( 1 ). A method according to claim 8, characterized in that the fiber material is provided on a clamping frame, wherein the clamping frame between the upper tool ( 2 ) and the lower tool ( 3 ) or that the fiber material on the lower tool ( 3 ) is stored. Method according to one of claims 8 or 9, characterized in that a plurality of fiber bundles ( 13 ) side by side and / or one above the other, particularly preferably oriented at an angle to one another on the lower tool ( 3 ) are stripped. Method according to one of claims 8 to 10, characterized in that the projecting on the opposite side of the fiber material ( 8th ) is cut off, especially after completion of the forming process. Method according to one of claims 8 to 11, characterized in that the needle-like extensions ( 6 ) after completion of the forming process of the produced fiber composite component by drawing in the direction of the upper tool ( 2 ) and / or lower tool ( 3 ) are pulled out.

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