DE202013104091U1 - Draping device for producing a three-dimensional preform made of fiber material - Google Patents

Abstract

Draping device (13) for producing a three-dimensional preform (5) from fiber material with 1.1 a die (14), 1.2 depicting the three-dimensional shape of the preform (5), 1.2 one or more stamps (15) for draping and / or fixing, which work together with of the die (14), characterized in that 1.3 different punches (15) on their surface (16) facing the preform (5) and / or different areas of this surface (16) of at least one punch (15) have different surface roughnesses and / or have coefficients of friction; and / or 1.4 the surface (17) of the die (14) facing the preform (5) has areas with different surface roughness and / or coefficients of friction.

Description

The invention relates to a draping device for producing a three-dimensional preform made of fibrous material according to the preamble of claim 1.

In the production of fiber composite components, which are also referred to as fiber-reinforced plastic parts, a common method for industrial use, for example, the so-called RTM method (Resin Transfer Molding) is known. The applied manufacturing process, which ultimately leads to the usable plastic component, consists of several individual processes. First, near-net shape preforms or semi-finished fiber products are produced. These components, which are also referred to as a preform, are typically stacked and / or joined in a so-called preforming process from a plurality of individual layers of woven or fibrous layers, usually in two-dimensional form, for example by stapling, gluing or by methods known from textile technology are, for example, sewing or the like. The resulting stack of individual fabric layers or fiber layers essentially already has the necessary outer contour and typically also any special features with regard to the layer thickness, special fiber progressions and the like. In general, after the stack has been made from the fabric layers, a binder is applied to the fabric layers or is already present between the fibers, for example by the individual fiber bundles being impregnated with such a binder before they are further processed into the fabric or fiber layer.

Subsequently, in a drapery apparatus which images the desired three-dimensional shape of the preform in a die, the stack of fabric layers is preformed, typically by placing one or more draping and / or fixing dies adapted to cooperate with the die into the die stack Press to achieve the desired three-dimensional shape. The binder can then be activated, for example by heating and subsequent cooling of the die, so that an at least for the further manufacturing process manageable near net shape configuration of the three-dimensional preform is possible. Draping devices are for example from the DE 10 2010 027 466 A1 or from the DE 10 2010 043 666 A1 basically known. Decisive for the quality of the three-dimensional preform is that the individual layers of the stack come to rest in the matrix as possible without creases, unwanted draw, undesired stresses or the like, so as to obtain a three-dimensional preform that is as high-quality as possible and homogeneous with respect to the stack.

In the cited documents, therefore, the draping device is, for example, rotated so that the draping and / or fixing punches press the fabric stack into the die from below in order to achieve a lateral tension of the fiber material by means of gravity, so that wrinkles and creases can be easily avoided , However, this is associated with great expense, since on the one hand mold and structure must be rotated accordingly, so that the stamp can be actively raised. In the other cited document positioning pins are provided, which provide a similar effect without the die must be laboriously turned into an overhead position. However, while the die is extremely complex to manufacture, since the pins in their extended position must form an exact level as possible and because all the pins must go back into the die. The die is thus a very complex component, so that the resulting expense is worthwhile only for very large series and adversely allows no flexibility in the die. In addition, this very complex die is extremely susceptible to disturbances during the production process for the preform.

After the production of the three-dimensional preform this is inserted as near-net shape preformed intermediate product in a press for performing the RTM process. Depending on requirements, the three-dimensional preform can still be recut before, punched out at predetermined locations or provided with inserts or the like in order to achieve the most precise contour and functionality of the later fiber-reinforced plastic component. After inserting the three-dimensional preform into the tool, the tool halves are then closed in a manner known per se and the necessary resin is injected into the cavity of the tool in order to impregnate the fiber structure of the three-dimensional preform and to enclose the fibers. After curing of the resin matrix so the finished fiber-reinforced plastic component, which can be removed from the tool.

Since an important step in the production of such fiber-reinforced plastic components is already in the production of the three-dimensional preform, the draping device used has a decisive share in the quality of the later component. The above-described draping devices according to the prior art have the mentioned disadvantages.

The object of the present invention is now to provide an improved Specify Drapiervorrichtung, which avoids these disadvantages in particular. According to the invention this object is achieved by a draping device with the features in the characterizing part of claim 1. Further advantageous embodiments of the invention Drapiervorrichtung result from the dependent therefrom dependent claims.

In the case of the draping device according to the invention, it is the case that the draping and / or fixing punches have different surface roughness and / or friction values on their surface facing the preform and / or different regions of this surface of at least one draping and / or fixing die. Additionally or alternatively, the die may also have areas with different surface roughness and / or different coefficients of friction on their surface facing the preform. In the case of the draping device according to the invention, it is thus provided that either different punches with different surface roughness or friction coefficients are formed, or the one and the same punches, in particular if the stamper has a correspondingly complex shaping of its surface facing the preform, has different surface roughness or friction values. Alternatively or preferably in addition to this, the matrix can also be designed in different regions such that it has different surface roughness or friction coefficients. The surface roughness can be detected by metrology, for example by roughness depth, in particular in the form of an average roughness depth, and produced correspondingly in terms of manufacturing technology with regard to the desired values.

By means of such a variation of the surface roughness and / or friction values, it is possible to achieve different slip properties of the fiber material, that is to say the stack of fabric layers, which is optionally provided with a suitable binder. By the arranged in the center of the die stamp, parts of stamps or die surface have a correspondingly smooth surface or coated with a friction reducing material such as polytetrafluoroethylene, in this area a very good sliding of the fibers is achieved at the respective stamp, so that the then typically trained as Drapierstempel stamp the fibers with little friction can easily press into the counter-mold of the die. Other punches or other areas of the punch or die may accordingly be provided with a surface having high surface roughness and / or higher coefficients of friction for the fibrous material, for example a deliberately roughened surface having, for example, a mechanical corrugation or the like, or a corresponding coating for example, with polyurethane, which causes a much higher coefficient of friction for the fiber material than the already mentioned polytetrafluoroethylene.

By placing these punches or areas of punches or the surface of the die preferably in the outer region of the die, it is possible to ensure that the material of the preform is retained here more strongly than by the punches or surfaces with correspondingly smoother or with less friction Surface. The material can then be drawn from the areas in which the stamps are used with the larger surface roughness or the higher coefficients of friction, through the other stamp in the die. As a result, a very clean system is achieved without wrinkling or the like occurs. The structure is much simpler than the structure described in the prior art, for example, the construction with the positioning pins, since only a corresponding surface treatment of the draping and / or fixing punches and / or optionally the surface of the die is necessary to the desired Effect to achieve. The various properties of the surface with respect to surface roughness and / or coefficient of friction can be achieved very easily by a different processing of the individual surfaces or partial parts of the surface.

In a very favorable development of the draping device according to the invention, it is further provided that at least one of the draping and / or fixing punches is at least partially provided on its surface facing the preform with a resiliently deformable layer or is formed of resiliently deformable material. Such a resiliently deformable layer may for example be an elastomer layer or the like, which covers the surface of the Drapierstempels or which is particularly accurately inserted into a cutout so that it forms a flat surface with the remaining areas of the surface of the Drapierstempels in the deformed state. When draping, then, after an investment of the Drapierstempels has been achieved on the stack of tissues, another feed movement taking advantage of the elasticity of the resiliently deformable material. This allows a further movement of the stack out of the fabric layers, for example, to stretch the material and / or smooth individual wrinkles.

According to an advantageous development of the draping device according to the invention, it is provided that at least one of the drapery and / or Fixing punches and / or the die on the preform facing surface is at least partially coated. By such an at least partial coating, the surface properties can be easily changed, for example, by the surface is uniformly machined and then partially coated in a targeted area. The coating may, for example, take place such that the friction and / or the surface roughness is reduced, or, conversely, selective coating may take place in such a way that the friction or the surface roughness is increased, for example by applying a partial polyurethane layer.

In a further very favorable embodiment of the draping device according to the invention, it is now further provided that the surfaces of the at least one draping and / or fixing die facing the preform have different coatings. Different areas of the surface of a single stamp can thus be easily adapted to the different required properties, for example by removing parts of the surface with a friction-reducing coating, for example based on PTFE, and other parts of the surface with a friction-increasing coating, For example, based on polyurethane, are formed. In between, in principle uncoated areas of the surface may remain, which then lie in their properties between the properties of the two coated areas.

In order to minimize the effort with regard to the production of the individual draping and / or fixing punches, however, it can also be provided in a particularly advantageous development of the draping device according to the invention that the surface of each draping and / or fixing punch facing the preform is uniformly m substantially constant surface roughness and / or coefficient of friction is formed, wherein a plurality of draping and / or fixing punches are provided with different surfaces. This structure, in which each of the punches is formed with a uniform surface in itself, is particularly easy to produce the punches, because without masking and the like, the surface can be uniformly processed and / or coated. The fact that now several punches are used in the draping device, the desired property can still be achieved, for example, by the more outer punch have a rougher surface or have higher coefficients of friction than, for example, the centrally arranged stamp. As a result, the fiber material of the later preform is retained accordingly in the edge region of the die and must be drawn and pressed against the larger frictional force in the region of the outer die of the Drapierstempeln inside, which have a corresponding surface with low friction in the die. This results in a very clean preform, without the significant risk of wrinkling or the like.

In a particularly advantageous embodiment of the draping device according to the invention, it is now also provided that at least one of the draping and / or fixing has a direction of movement to the corresponding surface of the die, which from the vertical on the corresponding surface of the die or a deviates from this mediating plane. Such a construction in which at least one of the draping and / or fixing punches is thus moved obliquely, preferably at an angle of more than 5 ° with respect to the vertical to the die, can optimally tension the individual fibers in the stack of fabric layers. The oblique movement, in particular in combination with a resiliently deformable surface of the punch, generates when moving the punch a transverse movement of the fibers or fabric layers on the surface of the die, whereby wrinkles are smoothed and, optionally, alternatively or additionally, a reorientation of the fibers is achieved. This is especially true in combination with the already mentioned elastically deformable material, since then in particular by the residual stroke, which is achieved by utilizing the elasticity, such a transverse movement can be achieved with otherwise already fixed fiber material of the stack of fabric layers.

Further advantageous embodiments of the draping device according to the invention will become apparent from the remaining dependent subclaims and will be apparent from the embodiment, which will be described below with reference to the figures.

Showing:

1 a schematic representation of an industrial plant for the production of fiber-reinforced molded parts with a prior production of three-dimensional preforms;

2 a schematic representation of a section of a draping device according to the invention; and

3 a schematic representation of a section of a draping device in an alternative embodiment according to the invention.

In the presentation of the 1 is very heavily schematized an industrial plant 1 to recognize which ultimately for the production of a fiber-reinforced molding 2 by means of an RTM method in a tool 3 in a press 4 serves. The fiber reinforced molding 2 is made of a three-dimensional near net shape preformed preform 5 made previously generated in some schematically illustrated steps. As a starting point for the preform 5 serves a fiber material, for example in the form of a fabric layer, a fiber fabric or the like. This can, for example, as a roll over an indicated role 6 to provide.

In a cutting device 7 is then by means of a cutter 8th from the roll a single fabric layer or mat, which is not explicitly shown here, tailored. Subsequently, this fabric layer via a suitable transport device, which in the representation of 1 is indicated in principle only by curved arrows, an indicated device 9 fed, in which binder is applied to the fabric layer. This can be done for example by spraying, rolling, dipping or the like. Alternatively to this procedure with the device 9 for the application of binder, it would also be possible to preimpregnate the fiber material with a suitable binder, so that this step can be omitted. However, this is familiar to the person skilled in the art from the general state of the art, so that it need not be discussed further here.

After the order of the binder, or if this step is omitted and the binder is already present in the fiber material, immediately afterwards the fabric layer passes to a stacking device 10 , in which the individual fabric layers to a here indicated stack 11 be stacked from fabric layers. It can also be a stapling, sewing or otherwise connecting the individual layers of fabric at locations where this is useful and necessary for design reasons, can be provided. The fabric layers have after the cutting process in the cutting device 7 typically a near-net shape. Nevertheless, even after stacking the fabric layers to the stack 11 in the stacker 10 further trimming, punching or the like, if desired or required.

After the pile 11 is prepared so he gets in the embodiment shown here in a heater 12 in which, as indicated here, it is guided via a means of transport through an oven, a line with infrared radiation or the like. The stack 11 is preheated and the typically thermally activated binder is activated or liquefied so far that the stack 11 Although still has a high flexibility, but in the stack 11 However, processed fabric layers adhere to each other during cooling.

The core functionality in the production of the three-dimensionally preformed preform 5 Now comes the draping device shown in the next step 13 to. The draping device 13 has a die 14 on which the later form of the three-dimensionally preformed preform 5 maps. About stamp 15 for draping and / or fixing the stack 11 from fabric layers now in the form of this template 14 pressed and typically cools by the metallic material of the die 14 , which is very good heat-conducting and heat from the stack 11 the fabric layers dissipates, off. As a result, the binder hardens and there is the three-dimensionally preformed preform 5 , which in its shape is already shaped near net shape and the shape of the die 14 and the stamp 15 follows. The stamp can 15 be used as a fixing die, which hold the fiber material, and / or it will in particular stamp 15 used as Drapierstempel, which for moving the fiber material, for example, in the recesses of the die 14 serve.

The preform 5 is as far as dimensionally stable by the cured binder that this, without losing its shape, at least further transported and possibly stored. However, it has not yet reached its final shape and hardness, this will only be achieved in the subsequent RTM process. The so in the drapery device 13 preformed and ideally glued and hardened in her pile 11 then forms the preform 5 which, as already described above, the press 4 for the RTM process can be supplied.

Now it is so that in particular the Drapierstempeln 15 for pulling in the pile 11 On fabric layers of particular importance, since a very uniform feeding or pressing the stack 11 from fabric layers into the recesses of the matrix 14 must be done. Only so can wrinkles or unnecessary stresses in the material of the stack 11 be avoided. However, this is a basic requirement for a good quality of the molded part produced in the RTM process 2 and associated with a good quality of the fiber-reinforced molded parts thus produced 2 , To a high quality impressions or retraction of the stack 11 on fabric layers, so ultimately the fiber material in the die 14 or to reach their depressions, it is in the draping device 13 provided that the individual draping and / or Fixierstempel at her later preform 5 or the stack 11 from fabric layers facing surfaces which in the illustration of the 2 each with 16 have different surface roughness and / or friction coefficients. In principle, every single one of the stamps 15 on its surface 16 Have areas with specifically different surface roughness or friction. Ideally, however, are the surfaces 16 The Stamp 15 in itself largely homogeneous, while different stamp 15 have different surface roughness or friction values.

In particular, it makes sense when referring to the 2 the two smaller outer stamps 15 on their surfaces 16 have a higher surface roughness or higher coefficients of friction, so the material of the stack 11 to retain and tension from fabric layers. Accordingly, the surfaces with the larger surface roughness or the higher coefficients of friction with 16. * designated. The central stamp 15 pushes or pulls the material of the stack 11 into the recess of the matrix 14 one. The central stamp 15 has a correspondingly good surface quality with very low surface roughness or a very low coefficient of friction, so that the material slides on it particularly well. Its surface is with 16 ' denotes, for example, it could be polished. Basically, alternatively, but in particular, in addition to the in 2 With 17 designated surface of the die 14 which the material of the pile 11 facing regions having different surface roughness and / or different coefficients of friction. This also causes the material of the stack to be drawn in 11 facilitated in the wells, for example, when edges and radii around the material of the stack 11 must flow, are polished accordingly and, for example, with the two outer punches 15 interacting surfaces 17 the matrix 14 are also roughened to the material of the pile 11 when feeding through the central stamp 15 into the recesses of the matrix 14 to restrain and tension. The surface roughness or coefficient of friction must be the fiber material used, for example, the carbon fibers in a carbon fiber reinforced molding 2 to be adjusted accordingly. To produce a correspondingly large surface roughness or a high coefficient of friction, for example, a processing can be carried out in such a way that the surface has microscopic or even macroscopic corrugations, so as to adhere the fibers to the surface 16 . 17 to achieve. The fiber material is thereby retained and can through the central punch 15 be stretched accordingly. This will increase the risk of edges, wrinkles or wrinkles in the material of the stack 11 significantly reduced. In the case of the described, in the presentation of the 2 each outer stamp 15 , such a coating would have to produce a higher coefficient of friction with respect to the fibers of the fiber material than, for example, the surface of the central punch 15 or a coating applied thereto. Conceivable coatings would be in the area of the outer stamp 15 , For producing a higher coefficient of friction, for example coatings of polyurethane, which have a comparatively high coefficient of friction for the fibers. The central stamp 15 could accordingly have a friction-reducing coating, for example based on polytetrafluoroethylene.

The use of surfaces 16 . 17 with different surface roughness and / or friction values thus allows a targeted "flow" of the material of the stack 11 between the surface 17 the matrix 14 and the surface 16 of the respective stamp 15 , so very purposeful by a suitable coating or processing of the surfaces 16 . 17 the uniform and crease-free drawing of the fiber material into the recesses of the matrix 14 can be done.

This particularly good feeding of the material of the pile 11 between the surface 17 the matrix 14 and the surfaces 16 the respective stamp 15 can now also be supported by the fact that the surface 16 at least one stamp 15 is provided with a resiliently deformable layer or the entire stamp 15 is formed of resiliently deformable material. For example, a deformable elastomer in a cutout in a formed of metal or plastic stamp 15 are used, in particular so that in the deformed state, a flat surface of the punch 15 is achieved between the area with the elastomer and the adjacent areas. For example, when using rubber or rubbery materials then simultaneously a surface 16. * achieved with higher coefficient of friction. Due to the elastically deformable material can after the actual feed movement over a residual stroke of the punch 15 - Utilizing electricity - further tightening and possibly smoothing the material of the stack 11 and, optionally, biasing or reorienting the fibers therein.

In the presentation of the 3 is now an alternative embodiment of the draping device 13 to recognize. The single stamp 15 no longer all move perpendicular to the respective, their associated surface 17 the matrix 14 but partially oblique to a vertical S, on the corresponding surface 17 the matrix 14 or if this is uneven, a vertical S on an averaged plane to this. In the concrete embodiment in the representation of 3 becomes in particular the central stamp 15 which has a correspondingly smooth surface 16 ' has, temporally first in the direction of the die 14 emotional. Then come the neighboring obliquely outward stamp 15 , which in particular rougher surfaces 16. * and thus a clamping of the material of the stack 11 to cause the outside. Subsequently, the outer punches can 15 be delivered, which in the embodiment shown here also has a surface 16. * having higher surface roughness.

Now especially the two become the central stamp 15 neighboring stamp 15 in addition to their surface 16. * provided with greater roughness or a higher coefficient of friction for the fiber material with a resiliently deformable material, for example, as described above, then after the actual delivery on the achievable by the elastic residual stroke a transverse movement of the material of the stack 11 in the example of 3 achieved to the outside, so that wrinkles can be easily eliminated and if necessary, a tension or reorientation of the fibers can be achieved. Is this the surface 17 the matrix 14 as well as the surface 16 ' of the central stamp 15 designed to be smooth, then the material can easily refill, so an ideal attachment to the surface 17 the matrix 14 to ensure. The same applies to the two externally arranged stamp 15 corresponding. By this structure, possibly with a staggered setting of the individual stamp 15 successively, in particular from the inside to the outside, the draping device can be 13 So optimize again.

The skilled person is already known that the stamp 15 actuators 18 which are suitable, the punch in the direction of or from the die 14 to move away. Depending on the orientation of the actuators 18 and Drapiergeometrie thus results during draping also a corresponding component of movement of the stack 11 in or parallel to the surface of the die.

LIST OF REFERENCE NUMBERS

1

 industrial plant

2

 molding

3

 Tool

4

 Press

5

 preform

6

 role

7

 cutter

8th

 cutter

9

 Facility

10

 stacker

11

 stack

12

 heater

13

 draping

14

 die

15

 stamp

16

Surface of 15

16. *

 Surface (with higher coefficient of friction)

16 '

 Surface (with lower coefficient of friction)

17

Surface of 14

18

 actuators

S

 vertical

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010027466 A1 [0003]
• DE 102010043666 A1 [0003]

Claims (12)

Draping device ( 13 ) for producing a three-dimensional preform ( 5 ) made of fibrous material with 1.1 one of the three-dimensional shape of the preform ( 5 ) imaging matrix ( 14 ), 1.2 one or more stamps ( 15 ) for draping and / or fixing, which for cooperation with the matrix ( 14 ), characterized in that 1.3 different punches ( 15 ) on her preform ( 5 ) facing surface ( 16 ) and / or different areas of this surface ( 16 ) at least one stamp ( 15 ) have different surface roughness and / or friction coefficients; and / or 1.4 the preform ( 5 ) facing surface ( 17 ) of the die ( 14 ) Has areas with different surface roughness and / or friction coefficients. Draping device ( 13 ) according to claim 1, characterized in that at least one of the punches ( 15 ) at its preform ( 5 ) facing surface ( 16 ) is at least partially provided with a resiliently deformable layer or formed of resiliently deformable material. Draping device ( 13 ) according to claim 1 or 2, characterized in that at least one of the punches ( 15 ) at its preform ( 5 ) facing surface ( 16 ) or the preform ( 5 ) facing surface ( 17 ) of the die ( 14 ) is at least partially coated. Draping device ( 13 ) according to claim 1, 2 or 3, characterized in that the preform ( 5 ) facing surface ( 16 ) of the at least one stamp ( 15 ) has various coatings. Draping device ( 13 ) according to claim 1, 2 or 3, characterized in that the preform ( 5 ) facing surface ( 16 ) of each stamp ( 15 ) is formed uniformly with a substantially constant surface roughness and / or coefficient of friction, wherein a plurality of punches ( 15 ) with different surface roughness and / or friction coefficients on their surfaces ( 16 ) are provided. Draping device ( 13 ) according to claim 5, characterized in that in the outer region of the die ( 14 ) arranged stamps ( 15 ) have a rougher surface or higher coefficients of friction than centrally arranged draping and / or fixing punches. Draping device ( 13 ) according to one of claims 3 to 6, characterized in that coatings for surfaces ( 16 . 17 ) with low coefficients of friction polytetrafluoroethylene or are made of polytetrafluoroethylene. Draping device ( 13 ) according to one of claims 3 to 7, characterized in that coatings for surfaces ( 16 . 17 ) have a higher coefficient of friction polyurethane or polyurethane. Draping device ( 13 ) according to one of claims 1 to 8, characterized in that surfaces ( 16 . 17 ) have a microscopic or macroscopic corrugation with greater surface roughness. Draping device ( 13 ) according to one of claims 1 to 9, characterized in that surfaces ( 16 . 17 ), which have a low surface roughness, finely ground or polished. Draping device ( 13 ) according to one of claims 1 to 10, characterized in that at least one of the punches ( 15 ) a direction of movement to the corresponding surface ( 17 ) of the die ( 14 ), which of the vertical (S) or on the corresponding surface ( 17 ) of the die ( 14 ) or a middle plane of the optionally uneven surface ( 17 ) of the die ( 14 ) deviates. Draping device ( 13 ) according to claim 11, characterized in that the deviation of the direction of movement from the vertical (S) is at least 5 °.

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