Method for producing a fiber preform for a fiber composite component

Abstract

Method for producing a fiber preform for a fiber composite component, in which a fiber arrangement is arranged on a support material (11) and the support material (11) is held by a clamping device (24) during a forming process, comprising the following steps: - Providing at least one cut piece (15) of a fibrous material, - Aligning the cut (15) according to the direction of the load on the cut (15) in the fiber composite component by means of an automated handling device (14), - Fixing the cut piece (15) to the substrate (11), - Providing the carrier material (11) with a fixed blank (15) for a subsequent process, characterized in that a two-dimensional reinforcement structure is arranged by means of direct placement of a carbon fiber roving on a structure made of carrier material (11) and at least one blank (15) and the reinforcement structure is arranged on the structure in the direction of the main load direction of the fiber composite component.

Description

[0001] The present invention relates to a method for producing a fiber preform for a fiber composite component, in which a fiber arrangement is arranged on a carrier material and the carrier material is held by a clamping device during a forming process, according to the preamble of claim 1.

[0002] For the industrialized production of fiber composite components, it is necessary to form a multi-layer structure in a single forming process. To prepare for the forming process, a two-dimensional fiber preform consisting of several individual layers must be created. To produce the fiber preform, layers of fiber materials were previously assembled into a stack or layer structure and chemically or mechanically fixed at specific points. This stack was then further processed by cutting all individual layers at once to form the preform to be formed. Finally, the fiber composite component was manufactured in a single forming process with the addition of heat.

[0003] To ensure that the preform deforms in the tool cavity during the forming process in a controlled manner with a defined change in fiber orientation without the formation of undesired wrinkles or warping, the preform must be held with a clamping frame or hold-down device that allows controlled relative movement and flow of areas of the individual layers to one another, but prevents uncontrolled slipping of the individual layers relative to one another. For this purpose, the starting material of the fiber composite component was previously cut over a large area to ensure that sufficient material was available to secure the material in the clamping frame. It is in the nature of things that this procedure results in high material consumption of fiber material, which only needs to be added to ensure that sufficient material is available for clamping in the clamping frame.

[0004] DE 10 2010 023 044 A1 discloses a method for producing a fiber preform for a fiber composite component, in which a fiber bundle of carbon fibers is laid down on a carrier material along a predetermined spatial curve by means of a laying device and is fixed to the carrier material by thermal activation of a thermoplastic binder material.

[0005] Furthermore, a device for securing a fiber arrangement to a conveyor belt using a sewing station is known from the prior art. The fiber arrangement can be arranged on the fiber base structure using a laying device.

[0006] In order to reduce the material consumption of starting material for the fiber composite component, it is already known in the prior art to arrange the fiber arrangement to be formed in a sheath made of a flexible material that simplifies the handling of a multilayer fiber arrangement. The sheath is dimensioned larger than the fiber arrangement and can be held by the clamping frame. It is also possible to connect the sheath, at least in sections, to the fiber arrangement in a force-fitting and / or material-fitting manner to enable force transmission between the sheath and the fiber arrangement.

[0007] Various methods for producing fiber preforms, some of which also disclose providing and fixing a blank from a carrier material, or aspects of such a method are also known from the documents DE 10 2010 040 970 A1, CH 704 406 A1, US 8 349 105 B2, WO 2013 / 056 789 A1, US 7 137 182 B2 and in particular DE 10 2014 100 882 A1.

[0008] Based on this, the present invention is based on the object of providing a method with which, on the one hand, the material consumption of fiber starting material can be reduced, the costs of manufacturing the fiber composite component can be reduced and a fiber composite component can be manufactured which has a complex outer contour and a complex integrated structure.

[0009] To achieve this object, the invention has the features specified in claim 1. Advantageous embodiments thereof are described in the further claims.

[0010] The invention provides a method for producing a fiber preform for a fiber composite component, in which a fiber arrangement is arranged on a carrier material and the carrier material is held by a clamping device during a forming process, comprising the following steps: - Providing at least one blank made of a fiber material - Alignment of the blank according to the direction of the load on the blank in the fiber composite component using an automated handling device - Fixing the cut to the carrier material - Providing the carrier material with fixed cutting for a subsequent process.

[0011] In contrast to the known method, in the method according to the invention, at least one blank made of a fiber material is initially provided, and the at least one blank is arranged on the carrier material by means of an automated handling device according to the direction of the load on the blank in the fiber composite component. The alignment process can involve positioning and rotating the at least one blank by the automated handling device, which can, for example, detect a directed fiber path in the blank using a sensor device and then position the blank on the carrier material in accordance with the load path.

[0012] For a three-dimensional fiber composite component, differently shaped blanks made from different starting fiber materials can be arranged on the carrier material using the automated handling device, for example along the longitudinal and transverse direction of the fiber preform in different layer thicknesses and different position orientations of the individual blanks to optimize the strength and stiffness of the finished fiber composite component.

[0013] Depending on the multi-dimensional stress distribution prevailing in the fiber composite component during later use, blanks made of different fiber base materials and fiber base orientations can be applied layer by layer to the carrier material and the at least one blank already arranged thereon by means of the automated handling device, whereby the area required for fiber starting material can be significantly reduced and can be adapted to the required dimensions of the blank in the finished fiber composite component and thus significantly less fiber base material is required than is the case with the known method in which a stack with equally sized layers of starting fiber materials stacked on top of one another is provided, through all of which a cutting process then takes place at once.

[0014] The fiber arrangement produced in this way is then fixed to the carrier material at least in sections in a next step of the method according to the invention, wherein, for example, a sewing process can be used here to fix individual areas of the fiber arrangement to the carrier material or to integrate reinforcement structures into the fiber arrangement, which positively influence the subsequent forming process in the subsequent process.

[0015] The resulting fiber assembly with carrier material is then prepared for a subsequent process in a next step, for example, it is fed directly into a thermal forming process or temporarily stored in a stacking area upstream of a forming station. The carrier material, which can be a cost-effective glass fiber mat or similar material, facilitates handling of the fiber preform in clamps, clamping frames, hold-down devices, and the like. It can remain in the fiber preform for the subsequent forming process. It can support subsequent processes during the further processing of the fiber preform into a fiber composite component, improving the strength, rigidity, and corrosion protection of the component.

[0016] According to a further development of the invention, the provision of the blank comprises the step of cutting the blank out of a fiber material and the immediately subsequent arrangement of the blank on the carrier material and the step of intermediate storage of the cut-out blank in a template area before the arrangement of the blank on the carrier material.

[0017] According to the method according to the invention, for example, the carrier material can be provided in the form of a web on a roll, from which a blank of the carrier material is then formed by a cutting gantry, which is then fed to a transfer gantry arranged downstream of the cutting gantry. It is also possible for prefabricated blanks of the carrier material to be kept ready in a supply area of ​​the transfer gantry and then placed on the transfer gantry by an automated handling device.In a similar manner, at least one blank of a fiber material can be formed by the cutting gantry from a semi-finished product storage device assigned to the cutting gantry. The semi-finished product is fed from the storage device to the cutting gantry. The cutting gantry produces a blank from the material web originating from the semi-finished product storage device according to shape specifications determined, for example, using a nesting program or a finite element calculation. The cutting gantry then places it directly on the carrier material without an intermediate storage step. Several devices for storing fiber material semi-finished products can also be located upstream of the single or multiple cutting device of the cutting gantry, from which the semi-finished product is removed and fed to the cutting gantry for cutting.These blanks can then be applied immediately by the automated handling device in the form of a robot or the like to the carrier material blank and / or blanks already arranged thereon or can be temporarily stored before being arranged by the automated handling device.

[0018] The angular orientation of the fiber orientation of the blank or blanks made of fiber material after their production by the cutting portal is not relevant, since the load-path-appropriate alignment of the blank before application to the carrier material and / or a blank already applied to it is carried out by the automated handling device according to, for example, the finite element calculation, i.e., quite generally in a predetermined manner. In this way, blanks from different semi-finished product storage devices upstream of the cutting portal, containing fiber materials with different material properties in the form of, for example, knitted fabrics, stitched fabrics, non-crimp fabrics, woven fabrics, or warp-knitted fabrics, can also be integrated into the automated process for producing a fiber preform.

[0019] According to a further development, the method according to the invention also provides that at least one further blank is arranged on a blank arranged on the carrier material, bringing about an at least partial overlap of the further blank on the arranged blank, and the further blank is aligned, i.e. positioned and rotated in accordance with the load path, by means of the automated handling device prior to the arrangement according to the direction of the load on the blank in the fiber composite component.

[0020] In this way, at least one blank with unidirectional fiber orientation and / or multidirectional fiber orientation can be arranged on a blank already attached to the carrier material, thus also a multi-layer fiber preform with differently dimensioned blanks can be provided in an automated manner, so that in contrast to the known method, a fiber preform is created in an automated manner which is multi-layered, i.e. reinforced, only in areas relevant to the load, so that the total mass of the resulting fiber preform and thus the total mass of the fiber composite component can be reduced and a significant material saving in fiber semi-finished product and a gain in lightweight construction potential can be achieved in the subsequent component.

[0021] According to a further development, the invention also provides for the integration of inserts in the form of patches, inserts, or TFP structures or the like and / or shaping structures in the form of, for example, resin films or thermoplastic films or the like, or blanks thereof, into the fiber preform. Thus, in addition to the fiber base materials, special materials can also be integrated into the layer structure, which are positioned in a predetermined manner and inserted into the layer structure in a rotated manner by the automated handling device. In this way, blanks with overlapping areas can be arranged next to one another, and intended cavities or areas with beveled overlapping areas of the blanks can be formed with scarfs, in which the layers overlap in sections and / or angular changes of the load-bearing fiber structures can be brought about in accordance with the load path.

[0022] According to a further development of the invention, it is also provided that predetermined regions of a structure comprising carrier material and at least one blank are fixed to one another in regions, for example in a fixing station arranged downstream of the automated handling device and upstream of an intermediate storage area for preforms arranged upstream of the forming station, by sewing the regions together, for example using a fiber. This also allows targeted reinforcement structures to be integrated into the layer structure during the sewing process. These reinforcing structures specifically support the subsequent thermal forming process and prevent the formation of folds or warping. The sewing can also locally mechanically reinforce the subsequent finished component, fix its structure in the forming process, and specifically fix the directly deposited structures for the injection process, achieving better infiltration in the thickness direction and in-plane direction.

[0023] According to the invention, a two-dimensional reinforcement structure is arranged in the layered structure by directly depositing a carbon fiber roving onto a structure consisting of a carrier material and at least one blank. The reinforcement structure is applied in a load-path-oriented manner in the direction of the main load direction of the fiber composite component.

[0024] Finally, the invention also provides that the carrier material, via which tensile forces stabilizing the shape are introduced into the fiber preform, remains on the preform during the subsequent process following the production of the fiber preform, for example the entire handling up to the thermal forming and during the thermal forming process.

[0025] The method according to the invention makes it possible to integrate different surface grammages into the layer structure of the preform. To form the preform, the textile semi-finished product does not need to be in the correct layer orientation with regard to its fiber flow for integration into the preform, since the automated handling device aligns the blank in accordance with the load path according to the functional specifications of the stack. This also allows for the intermixing of blanks from fiber material semi-finished products in the layer structure, since the automated handling device picks up the separated individual layer blanks and applies them to the carrier material and / or individual layer blanks already present on it in accordance with the functional specifications, while also being able to integrate special materials into the layer structure.Defined overlap areas can be created between individual layer cuts, and cavities can be formed within the layer structure, as well as predetermined layer seams and angle changes in the fiber orientation. Shaping structures in the form of resin films, thermoplastic films, or similar materials can also be integrated into the layer structure.

[0026] A preform produced in this way can be fed directly to a downstream thermal forming process or, for example, can be temporarily stored before the forming process in order to wait for the dwell times required for the thermal process sequence.

[0027] The invention is explained in more detail below with reference to the drawing, which shows: Fig. 1 a schematic representation of a manufacturing device with a supply area with several different fiber material semi-finished products for producing a fiber preform; Fig. 2 shows a schematic structure of a production line for carrying out the method according to the invention; Fig. 3 a representation similar Fig. 2 to explain the integration of a reinforcement structure by direct fiber deposition; Fig. 4 is a plan view of a fiber preform arranged on a portion of a carrier material in the form of a preform from the upper region of an A-pillar and the roof frame; Fig. 5 a top view similar Fig. 4, which shows the application of UD fibers as a reinforcement structure; Fig. 6 a top view similar Fig. 4, which shows the application of blanks with 45° fibers as a reinforcement structure; and Fig. 7 a top view similar Fig. 6, which shows the application of blanks with 0° fibers as a reinforcement structure.

[0028] Fig. Figure 1 of the drawing shows a schematic overview sketch of a manufacturing device or forming system for producing a fiber preform according to the method according to the invention.

[0029] In the example shown, three different fiber material semi-finished products 2, 3, and 4, each with different surface grammages, are arranged in a template area 1. Although only three semi-finished products are shown in the example shown, the number of semi-finished products can be expanded depending on the application requirements.

[0030] The semi-finished products 2, 3 and 4 are fed to a common cutting portal 5, from which specific cutting shapes are generated in advance, for example by means of a nesting program and a finite element calculation, which are optimized for the corresponding application.

[0031] The angle of the textile semi-finished product is not relevant here, since in the downstream transfer portal 6 each fiber angle can be produced in accordance with the load path by positioning and rotating the respective blank accordingly by an automated handling device arranged in the transfer portal.

[0032] The transfer portal 6 is also capable of removing special materials in the form of, for example, patches or inserts from storage devices 7, 8 and feeding them into the layered structure. This creates a layered structure of a fiber arrangement, as shown in more detail in the following figures. This structure is then fixed to the carrier material 11 in a fixing section 9 downstream of the transfer portal 6 and, after trimming, is fed to a downstream stacking area 10.

[0033] Instead of feeding the fiber preforms to the stacking area 10, which is located upstream of a thermal forming station (not shown in detail), it is also possible to immediately feed the fiber preforms produced in this way to the forming station for thermal forming; this depends, for example, on the processing capacity of the forming station or the necessary residence time of the fiber preform before thermal forming.

[0034] In Fig. 2 and Fig. 3 of the drawing shows a schematic representation of production lines for carrying out the method according to the invention.

[0035] In a first section, a carrier material 11 is provided in the form of glass fiber carrier material on a roll 12, which is conveyed by means of a conveyor belt 13 towards an automated handling device in the form of a robot 14. In the illustrated embodiment, the robot 14 removes a blank 15 from a supply area (not shown in detail) containing already manufactured blanks made of fiber materials and positions it on the carrier material 11 in such a way that the fiber path of the blank 15 is aligned with the load path to absorb forces from the loading of the fiber composite component to be produced.

[0036] In the case of a first layer of the layer structure, this can be a cut in 0° angle orientation; even in the first layer, several cuts 15 with different surface grammages of textile semi-finished products can be processed.

[0037] Although in Fig. 2 of the drawing only one blank 15 is shown, the robot 14 can arrange a plurality of blanks 15 with different angular arrangements of the fiber path of the individual blanks 15 to one another on the carrier material 11, so that with a plurality of blanks arranged at least in sections one above the other, regions of the fiber preform are produced which have different material thicknesses in accordance with the load path, so that fiber material is only present with different material thicknesses at the load-relevant points, but not, for example, in regions of the subsequently finished fiber composite component which lie outside the main load direction, so that unnecessary accumulations of fiber material can be avoided and thus, on the one hand, material savings are achieved and, on the other hand, a weight reduction of the finished fiber composite component can be achieved.

[0038] After a closer look at Fig. 4 to Fig. 7 has been created by the robot 14, the layer structure 16 with carrier material 11 is fed to a next section of the production line by means of the conveyor belt 13, in which a CNC gantry sewing machine 17 produces two-dimensional fixing seams by means of a sewing head 18 and fixes the layer structure 16 or the cuts 15 to the carrier material 11.

[0039] The carrier material 11 with the blanks 15 fixed thereto then leaves the section of the production line with the gantry sewing machine 17 and is fed via the conveyor belt 13 to a traversing separation system in the form of, for example, a laser-operated cutting device, which cuts off a section 20 shown in the drawing from the web-shaped glass fiber carrier material 11 and a resulting fiber preform with carrier material 11 is produced for stacking on a schematically shown storage device 20.

[0040] Fig. 3 of the drawing shows a schematic representation of a production line, which basically corresponds to the Fig. 2 of the drawing, and in which additional functionality has been integrated. This additional functionality is evident in the area where the robot 14 is located for the automated positioning and rotation of the blanks 15.

[0041] In addition to the automated load-path-aligned positioning and rotation of the blanks 15 on the carrier material 11, the robot 14 performs the additional function of forming a reinforcement structure by direct fiber deposition on the blanks 15. For this purpose, fiber material in the form of fiber cables is fed to a multiple laying head 22 of the robot 14 via a roving feeder 23, which is then applied by the multiple laying head 22 to the layer structure to form a reinforcement structure.

[0042] The further steps of the Fig. 3 shown production line then corresponds again to that according to Fig. 2.

[0043] Fig. 4 of the drawing shows a plan view of a fiber preform arranged on a section of a carrier material 11 in the form of a preform from the upper region of an A-pillar and the roof frame of a vehicle not shown in detail.

[0044] The drawing also serves to explain that, according to the method according to the invention, it is also possible to provide in advance a section of a carrier material 11 made of, for example, glass fiber material, onto which blanks 15 made of fiber materials can then be applied by means of the automated handling device 14, in such a way that the blanks 15 are positioned and rotated in the respective section of the preform in accordance with the load path. The drawing also shows that the carrier material 11 can be held laterally by clamping means in the form of collets 24 and kept under tension. Instead of the collets 24, it is also possible to fix the carrier material 11 at least on the short end faces of the carrier material 11 by means of a clamping frame (not shown in detail).

[0045] An integration preform corresponding to the desired shape of the fiber composite component can be provided in the manner described above by applying several blanks 15 made of fiber materials to the carrier material 11.

[0046] In addition, a reinforcement structure can also be applied to the integration preform by applying UD fibers running in the direction of force flow, which are applied by means of a corresponding laying head of the robot 14 in the form of a strand 25 to at least one already laid blank 15.

[0047] Fig. 6 of the drawing also shows the possibility of increasing the torsional rigidity of the integration preform by means of the method according to the invention, in that patches 28 made of 45° fiber material, which can be present in the overlap area 26 between different blanks 15 with straight or beveled cut edges, are applied by means of the automated handling device 14.

[0048] Finally, Fig. 7 of the drawing also shows the formation of reinforcement structures on the integration preform by means of the method according to the invention at local overlapping areas 27, which are applied by applying blanks 15 with 0° fiber material to blanks already placed to form the fiber arrangement.

[0049] The fiber preform produced in this way can then be transferred directly to a forming station for thermal treatment or can be placed in an intermediate storage area, as already explained above.

[0050] The method according to the invention makes it possible to automatically apply carbon fiber reinforcement structures to the substrate material with a near-net-shape, relative to the component geometry of the fiber composite component. Wastage of expensive carbon fiber material is reduced.

[0051] The carrier material participates in the process steps following the production of the fiber preform and facilitates the handling and storage of the fiber preform.

[0052] The carrier material allows the retention forces required for the forming process to be transferred to the seam and the reinforcement structure. This prevents the formation of wrinkles and warping during the forming process and increases the quality of the preform.

[0053] In addition to incorporating reinforcement structures into the fiber preform by applying cut pieces and / or patches, it is also possible to spread a carbon fiber roving into a fiber ribbon and apply it directly to the structure to be reinforced. This results in significant material savings and reduced waste compared to forming a stack, in which reinforcement structures are formed over the entire surface.

[0054] The reinforcement structures can be integrated into the fiber arrangement in a load-path-oriented manner, resulting in material savings and the finished fiber composite component being able to absorb higher loads while simultaneously reducing weight.

[0055] In the course of fixing the blanks to each other and to the carrier material, reinforcing structures can also be integrated into the fiber arrangement, which prevent the formation of wrinkles during the forming process, thus achieving a better forming result.

[0056] The fixation in the form of stitching also increases the load-bearing capacity of the laminate in the thickness direction, which means that higher loads can be absorbed locally, especially at bonding points.

[0057] The method according to the invention also ensures that the layer structure is not limited with regard to the number of individual layers, since no trimming takes place through all full-surface individual layers at once, as is the case when forming a stack according to the known method.

[0058] The method according to the invention also enables the supply of special materials in the form of inserts or the like; the angular orientation of the blank is not dependent on the angular orientation of the starting material, i.e. the semi-finished product, since the individual blanks are each produced separately.

[0059] With regard to features of the invention not explained in detail above, reference is expressly made to the claims and the drawings. List of reference symbols 1 template area 2 Fiber material semi-finished products 3 Fiber material semi-finished products 4 Fiber material semi-finished products 5 Cutting portal 6 Transfer portal 7 storage 8 storage 9 Fixing section 10 Stacking area 11 Carrier material 12 rolls 13 Conveyor belt 14 robots 15 Cutting 16 layer structure 17 Gantry sewing machine 18 sewing head 19 Cutting device Section 20 21 Storage device 22 laying head 23 Roving feed 24 clamping device 25 strands 26 Overlap area 27 Overlap area 28 patches

Claims

[1] Method for producing a fiber preform for a fiber composite component, in which a fiber arrangement is arranged on a carrier material (11) and the carrier material (11) is held by a clamping device (24) during a forming process, comprising the following steps: - Providing at least one blank (15) made of a fiber material, - aligning the blank (15) according to the direction of the load on the blank (15) in the fiber composite component by means of an automated handling device (14), - Fixing the blank (15) to the carrier material (11), - Providing the carrier material (11) with fixed blank (15) for a subsequent process, characterized bythat a two-dimensional reinforcement structure is arranged by means of direct deposition of a carbon fiber roving on a structure made of carrier material (11) and at least one blank (15), and the reinforcement structure is arranged on the structure in the direction of the main load direction of the fiber composite component. [2] Method according to claim 1, characterized by that the provision of the blank (15) comprises the step of cutting the blank (15) out of a fiber material and the immediately subsequent arrangement of the blank (15) on the carrier material (11) and the step of intermediate storage of the cut-out blank (15) in a template area (1) before the arrangement of the blank (15) on the carrier material (11). [3] Method according to claim 1 or 2, characterized bythat at least one further blank (15) is arranged on a blank (11) arranged on the carrier material (11), bringing about an at least partial overlap of the further blank (15) on the arranged blank (15), and the further blank (15) is aligned before the arrangement according to the direction of the load on the blank (15) in the fiber composite component. [4] Method according to one of the preceding claims, characterized by that at least one blank (15) with unidirectional fiber orientation and / or multidirectional fiber orientation is arranged on a blank already attached to the carrier material (11). [5] Method according to one of the preceding claims, characterized by the integration of inserts and / or shaping structures into the fiber preform. [6] Method according to one of the preceding claims, characterized bythat predetermined regions of a structure made of carrier material (11) and at least one blank (15) are sewn together. [7] Method according to one of the preceding claims, characterized by that the carrier material (11) remains on the fiber preform in a shaping process following the production of the fiber preform.

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