EP2637841A1

EP2637841A1 - Method and device for producing a three-dimensional preform during the production of fiber-reinforced molded parts

Info

Publication number: EP2637841A1
Application number: EP11779464.4A
Authority: EP
Inventors: Matthias Graf
Original assignee: Dieffenbacher GmbH Maschinen und Anlagenbau
Current assignee: Dieffenbacher GmbH Maschinen und Anlagenbau
Priority date: 2010-11-09
Filing date: 2011-11-09
Publication date: 2013-09-18
Also published as: WO2012062828A1; DE102010043666A1

Abstract

The invention relates to a method and a device for producing a three-dimensional perform during the production of fiber-reinforced molded parts. The method is carried out using a device (1) which comprises at least one draping device (2) for a fiber fabric staple (3) and a shell mold (5) for forming the preform (6) from the fiber fabric staple (3) by means of the draping device (2). The method is characterized by carrying out the following steps: a fiber fabric staple (3) is placed or formed between the draping device (2) and the shell mold (5); at least one draping tool (8) is then deployed from the draping device (2), thereby at least partly introducing the fiber fabric staple (3) into the shell mold (5) until the fiber fabric staple (3) is pressed against the shell mold (5) by means of the draping tool (8) and immobilized there; and then additional draping tools (8) are deployed in a predetermined order either individually or conjointly from the draping device (2) towards the shell mold (5), the order resulting from the flow properties of the fiber fabric staple (3).

Description

Method and device for producing a three-dimensional preform in the course of the production of fiber-reinforced molded parts

The invention relates to a method for producing a three-dimensional preform in the course of the production of fiber-reinforced molded parts according to the preamble of patent claim 1 and an apparatus for producing a three-dimensional preform in the course of the production of

fiber-reinforced molded parts according to the preamble of claim 15. In the course of the production of fiber-reinforced plastic components, too

Called fiber composite components, in particular as an industrial use, the resin transfer molding process (hereinafter abbreviated RTM method) common practice. The entire manufacturing process to obtain a usable plastic component consists of several

successive individual processes: In a first process step semi-finished fiber products are produced. In this preforming process, multi-layered fabrics or fiber fabrics are usually combined in 2D, ie substantially in one plane, so that the semifinished fiber product essentially already has the necessary outer contours and in some cases even special layers or layer thicknesses. Preferably, a binder is introduced into the parting lines of the scrim, which leads after its activation and curing to a fixation of the layers to each other and the draped 3D contour. For the preform process these are

Layers then transferred into a forming tool and usually under pressure by closing the forming tool so far approximated the contour of the subsequent molding and hardened by activating the binder (heating and cooling), so that the semi-finished fiber endkonturnah inserted into a tool of a press for performing the RTM process itself can be. Depending on requirements, the semifinished fiber product is still cut or punched at predetermined locations in order to obtain an even more precise contour. After inserting the semifinished fiber in the tool, the

Closed mold halves and injected the necessary resin into the cavity of the tool, wherein the resin impregnates the fiber structure of the semi-finished fiber, which includes fibers and binds firmly into the matrix. After curing of the resin, the fiber-reinforced plastic component can be removed from the mold.

In addition to the RTM process itself, already laying the production of a

Semi-finished fiber is the basis for success in the production of a plastic component. It has been found that the prior art describes a variety of ways to produce a preform, but usually exhausted in the manual or automated production of the most flat fiber fabric stack, which in a press finally from its 2D shape into a 3D shape is transferred. This can be done in a pre-fixed (eg sewn) or even in a flexible state. The aim is to obtain a preform after shaping that is rigid enough to be fully automated and reliable in the tool of an RTM press can be inserted or can be transported and stacked until further use. For the production, transformation and fixation of the preform, there are a variety of possibilities in the relevant prior art, such as

For example, EP 0 620 091 B1. The process disclosed in this patent has been proven, but shows a variety of process steps to produce a three-dimensional preform.

The object of the invention is to specify a method and a device with which three-dimensional preforms can be produced more quickly and more easily from two-dimensional fiber fabric stacks than in the prior art. Furthermore, it should be possible to produce highly complex preforms with significantly better precision to produce converted fiber fabric stack, which in particular the

Fiber orientation and the regularity of the used

Fibrous tissue stack concerns, so that wrinkling and distortion can be successfully prevented. Preferably, an originally substantially 2D shape to a three-dimensional preform to

Use in an RTM process can be reshaped.

The solution of the problem consists for the method according to the characterizing features of claim 1 in that a fiber fabric stack between a draping and a mold shell is placed or formed there, that then at least one Drapierwerkzeug is extended from the draping and thereby at least partially into the fiber fabric stack in the Mold shell brings in up to the fiber fabric pile by means of this

Draping tool is pressed to the shell mold and fixed there,

that then in a predetermined order other draping tools individually or together from the draping in the direction of

Form shell are moved, with the order of the

Flow behavior of the fiber fabric stack results. Preferably, the flow behavior is dimensioned so that wrinkles and / or cracks are avoided during the introduction of the fiber fabric stack in the mold shell.

In particular, after the first draping tool, the following draping tools are selected from the first draping tool in the direction of the outer or inner contour, in order to enable subsequent flow of these contours, that is, the sides. The solution of the task for the device is according to the features of claim 15 in that in the draping device at least two

independently controllable Drapierwerkzeuge are arranged. Next is a mold shell for heating and / or cooling of a

Fiber cloth stack proposed, wherein means for introducing hot and / or cold air are arranged in the fiber fabric stack in the shell mold. Alternatively or cumulatively, in the mold shell as

Temperature elements Peltier elements for heating and / or cooling of the fiber fabric stack and / or the supplied air to be arranged.

Advantageously, it is now possible with the invention

Method and a suitable but also independently usable device adapted to form a Vorform ling fiber fabric stack from a substantially planar state (2D) in a three-dimensional shape and fix. In particular, it is advantageous that the deformation can be carried out gently and kinks, wrinkles and compressions or distortions of the fiber fabric stack during the forming can be avoided. However, it is also possible to produce complex geometries that were feasible with the previous known from the prior art embodiments only by increased mechanical and plant engineering effort and this also required a higher amount of time.

The method and apparatus are used for 3D deformation of multilayer 2D blanks of fiber webs. Here are the following

Process steps are provided: fiber webs or webs are unwound from a roll and, as required, made up of a plurality of different webs or lay-ups, shapes and sizes to make a fiber web stack. It may be necessary to adjust the external and, if necessary,

Inner contour corresponding to a pattern of the preform respectively of the plastic molding to edit or cut. The pattern is generated from a development of the preform or the final component. Preferably, the created fiber fabric stack is then deposited on the support table of the draping device. Alternatively, it can also be provided to produce the fiber fabric stack from individual or pre-composed fiber fabrics directly on the support table.

If necessary, a binder material is sprinkled, applied or sprayed between the individual layers. Subsequently, the shell mold is pivoted or moved over the fiber fabric stack. It is obvious that the individual kinematics of components such as the shell mold is not the focus of the solution according to the invention, but rather the overall concept, which causes the upper shell mold to swing over the fiber fabric stack. Of course, the two main components Drapiervorrichtung and form shell could also be arranged to each other movable at a distance. Then the draping tools are moved from bottom to top around the

To move or push fiber fabric pile into the shell mold.

This is preferably carried out under NC control and has an order and speed of the draping tools matched to the fiber fabric stack or the shell mold.

To avoid soiling or distortion of the fiber fabric stack or to ensure an optimized molding of the fiber fabric stack in the shell mold, it would be advantageous to between the

Fiber fabric stack and the support table or the Drapierwerkzeugen provide an intermediate band. The intermediate band can be a drapable textile layer or a plastic band, which can preferably be held taut by means of a pulling device via deflection rollers, in particular during the introduction of the fiber tissue stack into the shell mold. By such an intermediate band larger distances between the Drape tools are enabled. In addition comes that possibly occurring relative movements between fiber fabric pile and

Drape tools when retracting the Drapierwerkzeuge held in the shell mold between the intermediate belt and the Drapierwerkzeugen so that the fiber fabric stack remains as stable as possible in itself.

Before, during or after the pivoting operation of the draping device with the mold shell, the mold shell can be heated to activate the binder or a resin layer for bonding within the fiber fabric stack. When using a thermoplastic binder material, for example, for heating (liquefaction of the binder) and then cooled (solidification of the binder). Already during partial hardening of the

Fiber cloth stack can retract the drapery tools back into the support table and the drapery device is returned to one

Pickup position pivoted so that the support table a new

Can accommodate fiber fabric pile. During the process, the intermediate belt can be relaxed depending on the requirement. After removal of the preform from the shell mold by a hand or an industrial robot, the mold shell is also pivoted again for the next forming process in the direction of the draping device. And the next one

Forming process can begin.

Of course, it would be conceivable to incorporate the shell into the overall concept of the plant and as a mold carrier and as an intermediate storage during the

Transports to use, preferably using several shells in the system use.

In an extension, for very complex fiber fabric stacks, these can be placed on a support table in a receiving position

Draping device are placed, followed by a mold shell is moved so in a receiving position that the fiber fabric stack is between the support table and the shell mold, then at least one Drapierwerkzeug is extended from the support table substantially against the weight and thereby the fiber fabric stack is at least partially introduced into the shell mold that after insertion into the mold shell the draping device

is pivoted together with the mold shell by a pivot angle α such

that the fiber fabric stack remains due to the weight in the mold shell, then that the draping back into the

Receiving position for receiving a further fiber fabric stack is pivoted and that the mold shell of the draping device is pivoted after removal or delivery of the at least partially cured preform in the receiving position.

In order to improve the transformation of the fiber fabric stack into a cavity-containing mold shell, the following points must be observed urgently:

- no undue tension should be allowed on the fiber pile, as otherwise the structure (fiber orientation and regularity) could warp or the fiber pile becomes cracked.

- There should be no wrinkling or jolts when draping the fiber fabric stack in component recesses.

- If desired, the fiber fabric stack can be fixed stress-relieved or with a specifically defined tension.

To achieve this, the fiber fabric stack is flat on the

Placed on the support table. Possibly. is an additional drape pad, e.g.

an intermediate foil or a tensioned textile between the Drapery tools and the fiber fabric stack necessary to create a slippery surface.

Preferably, one or more locating punches will extend and pinch the fibrous tissue stack at the location where no displacements are to take place, after which foam draping tools finally terminate

Press fibrous tissue stacks into the wells. The form tips off

Foam moldings are designed so that is not clamped on the side walls of the shell of the fiber fabric pile, but is free to move and can slide from the sides as desired. after the

Draping tools hit the ground, a contact pressure is built up and the sufficiently hard but flexible plastic deforms, causing it to dodge to the side and thus also the scrim respectively the

Fiber fabric pile against the wall sections or equivalent 3D contours presses. In this final state, the binder can now by means of

Temperature action activated and fixed the fiber fabric stack in the shell mold. After rotation or fixation, the

Draping tools withdrawn again. Possibly. can be further shrunk by applying vacuum or vacuum to avoid fiber shifts, before retraction, the foam. Of course, this requires a closed foam surface. In order to further improve the flow behavior of the fiber fabric stack during embedding in the shell mold, it is also conceivable that on the side of the shell mold at predetermined locations, preferably depressions, friction means or, for example, just foams are arranged. He comes

Fiber fabric stack in contact with this, it is clamped there and the flow or slip behavior is reduced or eliminated. About the pressure of the corresponding Fixierstempel or Drapierwerkzeuge can

Forming be controlled precisely. Depending on the complexity of the component can be described with the above

Basic concept individual draping steps with individually controllable

Draping tools and / or Fixierstempeln be carried out step by step. With an intermediate band made of film or textile, the resulting relative movements between Drapierwerkzeug and fiber fabric stack can be kept away from the fiber fabric stack and thereby undesirable

Fiber shifts are avoided. For this purpose, the intermediate band is specifically stretched and relaxed, for example, with traction devices. So can, for. B. when pulling back the Drapierwerkzeuge, the voltage can be reduced or switched off to avoid contact pressure at the deflection. The mold tips can finally over as foam form body

Vacuum or vacuum or oppositely executed by means of compressed air in their form changeable.

In terms of controllability, the following advantages result:

Adapted to the forming contour or the mold shell, the

Draping tools or fixing punches in advantageous and arbitrary

Order to be driven from the inside out (to the

Edge areas) to drape the fiber fabric pile and to avoid tension. This can be done using modern simulation programs

corresponding mode can be found, which allows an optimal shift or transformation of 2D layers to a three-dimensional contour. Preferably, the support table is in the form of a matrix with this

Drape tools provided, either as a draping tool or

Fixierstempel can act. In connection with flexible foam moldings as a shaping tip on the draping tools, preferably with undersize relative to the contour, which only after contact with the face

Deformation of the mold shell outward deform and the fiber fabric stack Press on the well walls, the possibility arises to approach almost any 3D contour.

It is also possible for the stiffening of the fiber fabric stack to fix these at least partially by means of seams to be introduced. This is particularly useful when individual layers, storage packages and / or the

Fiber fabric stack itself formed according to the outer and / or the inner contour of the preform and then cut. For fixing, it is also necessary that at least partially a curable binder is introduced between at least two layers of the fiber fabric stack during the folding, wherein accordingly the fiber fabric stack consists of at least two layers and

is merged. Preferably, at least one layer is cut from a roll.

In order to achieve a better result in the forming, it would be advantageous to use as an intermediate band, preferably slippery, plastic band or a, preferably slippery, textile cloth.

An optional intermediate band may be arranged between the fiber fabric stack and the shell mold and / or the draping device.

A mold shell preferably has means for the introduction of hot and / or cold air in the fiber fabric stack, for example, from at least one Peltier element for heating and / or for cooling the

Fiber tissue stack can exist.

Advantageously, in the method by the increasing contact surface of the fiber fabric stack at least partially more to the contour the mold shell are pressed, which is carried out gently and under possible Nachzieheffekten for the fiber fabric stack. In this case, the shape tip can essentially adapt to the contour of the mold shell present at the contact surface when expanding from the first to the second contact surface. Preferably, a mold tip is used, which is made larger in its cross section on the side of the fiber fabric stack than on the side of the draping device. Particularly preferably, the mold tip is designed as a fluid-changeable membrane.

Alternatively, if necessary, cumulatively, a mold tip proportionally of foam and a material harder with respect to the foam can be used.

Under the contact surfaces, the invention understands the following relationships: A first contact surface is formed when the shape of the tip

Fiber fabric pile touched. The second contact surface is formed when the fiber fabric stack is pushed by the shaping tip in the direction of the shell mold, wherein the contact surface may increase or remain constant during the displacement under certain circumstances. After contact of the mold tip with the shell mold and intervening fiber fabric stack resulting in greater contact pressure by the actuators, the consequence that the mold tip is deformed. It forms a third contact surface, which arises only by the deformation of the mold tip and must be greater than or equal to the second contact surface before entering the

Deformation phase. The shaping tip should therefore essentially assume the geometry of the component contour to be formed, wherein the undeformed shape of the molding tip, at least on the side surfaces (from the outer end in the direction

Draping device) is made smaller in cross-section, so that when driving in the direction of the shell shape of the fiber fabric stack is not clamped between the mold tip side and the shell mold. The shape tip should be at the for Mold shell corresponding surfaces smaller radii of curvature

As the mold shell itself increases, the mold tip will be partly or almost completely applied to the mold shell by elastic and reversible deformation and the fiber fabric stack will be pinched.

The shaping tip can be embodied as an inflatable membrane or be adjustable with respect to its elastic deformability with other fluids. Also can thus adjust the contact pressure and / or even the temperature entry in the fiber fabric stack. Finally, the shaping tip can also be made of foam only partially and the remaining region made of a material harder than the foam.

It would also be beneficial if after setting the first

Draping tool, the subsequent extending Drapierwerkzeuge from the fixing point in the direction of the outer or the inner contour

be used.

Preferably, the actuators for moving the draping tools can be designed as a pressure or travel-controllable linear drive

(Piston cylinder arrangements or spindle drives).

Further advantageous measures and embodiments of the subject matter of the invention will become apparent from the subclaims, which individually or in

Combination can be used together, and the following description with the drawing. The following representations are not directly as

To look at individual case solutions, but also contain in parts and general instructions and task solutions. They show schematically: Figure 1 shows a device for the production of preform lingen, consisting of a draping device with a support table and an associated shell mold in the receiving position, wherein the

Fiber fabric stack already finished formed on the support table for forming is ready;

Figure 2 shows the deformation of the fiber fabric stack through the

Draping tools of the draping device of Figure 1; Figure 3 shows the pivoting (by a pivoting angle a) of the entire

Device (Drape device with shell mold) to a frame from the receiving position in a curing and / or

Dispensing position;

Figure 4, the pivoting back (by a pivot angle a) of

Draping device in the receiving position for receiving a new fiber fabric stack, wherein an industrial robot for

Receiving the preform from the shell mold and the

Passing the preform to a stack or to a

Molding press is ready;

Figure 5 shows another embodiment with a rotation angle to the

Draping device respectively the shell mold;

Figure 6 is a plan view of a support table with the example

Drapierwerkzeugen;

Figure 7 is an enlarged schematic sectional view through the

Pad of the draping device with an additional

Fixing punches between two Drapierwerkzeugen with and a still original fiber fabric stack in a substantially planar basic form;

FIG. 8 shows the draping device according to FIG

Draping tools and engaging drapery tips at the lowest area of the shell; FIG. 9 the draping device according to FIG. 8 with extended one

Draping tools and deformed drapery tips for applying a contact pressure also laterally of the drape tips in a recess of the shell mold;

FIG. 10 shows, in a further exemplary embodiment, a draping device with drapery tips which can be changed in size by means of fluids;

Figure 1 1 is a further enlarged view of a Drapierwerkzeuges and a corresponding shape in a shell depression with a flexible abutment of the shell mold for fixing the fiber tissue stack in the middle of the recess during the

Introducing the fiber tissue stack into the shell mold;

FIG. 12 shows the exemplary result after introduction of the

Fiber tissue stack in the mold shell of Figure 1 1; and the

FIGS. 13 to 15 show an example of a varied drive

Draping tools with mold tips adapted to the mold shell.

The figures show a device which is also used to carry out the

Method is suitable, but can also be executed and operated independently. Here, the same reference numerals designate the same or similar components.

An exemplary apparatus 1 for the production of preforms 6 according to Figure 1 consists of a drapery device 2 with a support table 4 and an associated shell mold 5. In the present case, the fiber fabric stack 3 is already finished on the support table 4 ready for reshaping. The draping tools 8 are in a retracted state within respectively below the support table 4, on which the fiber fabric stack 3 comes to rest due to the weight N, shown. In a particularly advantageous variant is located between the

Fiber fabric stack 3 and the support table 4 an intermediate band 7. Das Intermediate belt 7 has the task here, between the Drapierwerkzeugen 8 as a connecting force introduction element for the transformation of

Fiber cloth stack 3 to serve and is for this reason also preferably via a traction device 9 tensioned and guided, for example via deflection rollers 13. The draping tools 8 in the draping device 2 usually consist of linear conveyors, in this case piston-cylinder arrangements 15, which make it possible to adjust the ends of the form-fitting 5 respectively corresponding to the contour of the preform 6

Drape tools 8 toward or away from the shell mold 5 away. On the side of the fiber fabric stack 3, the draping tools 8 can have flexible pressure elements, for example foams, which are preferably adapted in sections to the shape shell 5 or to the area of the shell 5 to which it is to be draped. In a form shown in later figures, the printing elements have special shapes which, when pressed by the piston-cylinder assemblies 15, take on their shape

Change application to the shell mold 5. The draping device 2 is preferably arranged movably on a frame 10 fixedly connected to the floor via a pivot axis 12. Also, the shell mold 5 has a connection to the pivot axis 12 via a holder 1 1, so that the shell mold 5 and the draping device 2 are arranged synchronously about the pivot axis 12 pivotally.

Now is the fiber fabric stack 3 placed on the support table 4 and the mold shell 5 in position, see illustration in Figure 2, the

Draping tools 8 by means of the piston cylinder assemblies 15, preferably against the weight N, extended from the support table 4 and press the fiber fabric stack 3 in the mold shell 5. The optional

Intermediate belt 7 bridges possibly existing distances between the individual Drapierwerkzeugen 8 and also ensures a backing of the smallest fiber fabric stack shares. At the same time, the intermediate band 7 useful due to the cleaning problem. However, the intermediate belt 7 can also be used in the sense of a conveyor belt for transporting the fiber fabric stack 3 out of and into the device 1 or onto the draping device 2.

If the fiber fabric stack 3 is substantially transformed and in the

Forming shell 5 is introduced, according to Figure 3, the pivoting about a pivot angle α of the entire device 1 (Drapiervorrichtung 2 with shell 5) to the frame 10, respectively the pivot axis 12, carried out from the receiving position to a curing and / or Auslegeposition. Advantageously, the fiber fabric stack 3 is still fixed in the mold shell 5 by the draping device 2, whereby during the

Pivoting process, the curing of the existing binder can be carried out partially or completely. Alternatively, it would also be conceivable for the draping device 2 to already start again after reaching a position of the form shell 5 in which the fiber fabric stack 3 is neatly draped and is held automatically in its position by the weight force N

Swing back towards the pickup position. The curing can then be carried out by external in the occupied shell mold 5 retracting heaters or welding respectively Vernäheinrichtungen (not shown). Also, only a partial curing in the shell mold 5 is conceivable.

By pivoting back, for example, only the support table 4, the drapery device 2 by a pivot angle α in the receiving position of Figure 4 for receiving a new fiber fabric stack 3 to carry out the previous process steps is free space on the preform 6, so that an industrial robot 14 for receiving the preform 6 can approach from the shell mold 5, which is ready for passing the preform 6 to a stack or to a molding press (not shown). Figure 5 shows a further embodiment in a before-after comparison, as with a rotation angle α rotation is performed so that after the draping (Figure 5 left) with the shell mold 5 above the shell mold 5 is rotated by 180 ° and now below the Supporting table 4 is located, wherein during the rotation, the draping tools 8 extended the

Keep fiber cloth stack 3 fixed in the mold shell 5 until it comes to lie alone by the weight force N (FIG. 5, right). This can be a possible variant, depending on space requirements or system requirements. It is also conceivable that not only a mold shell 5 is used for a draping device 2, but several, which also serve as a storage or transport trays. It has been shown that one

Pivoting or turning by 180 ° represents the most advantageous solution, and there may be applications which may also require a smaller swing angle α. It should be emphasized, of course, that after pivoting the weight N the fiber fabric stack 3 is no longer on the

Draping device 2, or the support table 4, presses, but in the mold shell. 5

Even if the variant envisaged in FIGS. 1 to 5 appears to be the simplest and most uncomplicated, it may be necessary, for example, at higher production speeds to use a plurality of shell molds 5, which alternate with the reception of a fiber fabric stack 3 for partial or complete curing. The shell molds 5 could also be provided as individually movable carrier shells, which drive in a separate curing device to complete the curing or even as a carrier to the transfer to a molding press for

Implementation of the RTM method. The fixation can be done not only by heating the shell molds 5 and possibly also by cooling the same, but there are also other common

Heating the fiber fabric stack 3 or stapling the Fiber tissue stack 3 at neuralgic points conceivable. If an intermediate band 7 is omitted, it is preferably provided that the to the

Auflagetisch 4 adjacent layer (a fabric or jelly) of the fiber fabric stack 3 is carried out substantially flat and continuous. Between at least two layers of the fiber fabric stack 3, at least partially, a curable binder can be introduced during the folding or already before.

With regard to Drapierens would be to mention that in several

Drapierwerkzeuge 8 these can be extended in a predetermined order from the support table 4 in order to avoid tearing or excessive distortion of the fiber fabric stack 3. This also unnecessary wrinkles or the like can be avoided. FIG. 6 shows a plan view of a support table 4 with a possible variant of draping tools 8 and the optional intermediate belt 7 shown by dashed lines.

FIG. 7 shows, independently of an optionally occurring rotation of the

Draping device Possibilities for improved forming of

This can be carried out preferably from bottom to top (against the weight N), but also from top to bottom (with the weight N), in the latter case, the optional intermediate band 7 for performing the draping highly recommended is, so that the fiber fabric stack 3 does not slip uncontrollably in the wells respectively in the contour of the shell mold 5 into it. In the present examples of the following FIGS. 7 to 15, the illustration of the optional intermediate belt 7 has been dispensed with. As already stated, during the draping process a, preferably carbon-comprising,

Fibrous pile 3 can be spent in a 3D contour. This should not get inadmissible train on the fiber fabric stack 3, otherwise the

Structure (fiber orientation and regularity) could be warped. Furthermore, wrinkling should be prevented. When draping the

Fiber fabric stack 3 in the shell mold 5, it is therefore important that parts of the fiber fabric stack 3 can flow almost free of tension.

In this case, it is preferable to start from a fixed point, which may for example lie on a plane which is closest to the support table 4 or, on the contrary, can first be started with a deeper contour of the mold shell 5, which possibly causes the most retraction effects in the fiber fabric stack 3 becomes. If the fiber fabric stack 3, as shown in FIG. 7, is fixed at one point, in the middle of FIG. 7 with a fixing punch 17, follow in a predetermined sequence, preferably adjacent,

Draping tools 8 after. The draping tools 8 may have mold tips 16 which have and preferably have flexible properties

Foam moldings exist.

According to Figure 8 now press the Drapierwerkzeuge 8 with the mold tips 16 a portion of the fiber fabric stack 3 in the recess of the mold shell 5. The mold tips 16 are preferably designed as foam moldings so that on the lateral walls of the shell mold 5 of the fiber fabric stack 3 during retraction into the Contour is not clamped, but can slide freely. Thus, parts of the fiber fabric stack 3 left and right (possibly also in front of and behind the plane) are drawn into the contour. The retracted areas of the fiber fabric stack 3 are visible on the edge of the support table 4 and are marked in their length with an E and in their feed direction with arrows.

FIG. 9 shows the advantage of flexible mold tips 16

Draping tools 8. When the drapery tools 8 are at the bottom of the contour the mold shell 5 impinge, a contact pressure on the

Piston cylinder assemblies 15 constructed and the mold tip 16 deforms, thereby avoiding the side and thus also pressed the fiber fabric stack 3 against the wall sections or other 3D contours of the shell mold 5. In this final state of the fiber fabric stack 3 is now held and activated, for example, a binder. For certain components, it may be sufficient, the resulting preform ling 6 easy to demold, the mold shell 5 to move up and remove the preform 6 from the drapery device 2. The Fixierstempel 17 could this serve as a lifting device or ejector. The rotation of the draping device 2 could for example take place without the shell mold 5 and used as "ejection" of the preform 6 lings.

These processes are partially illustrated in FIG. 10, with the mold tip 18 having a special quality in an extended advantageous embodiment. This can be shrunk, for example, by applying negative pressure in order not to damage the deformed fiber fabric stack 3 when it leaves the contour of the shell 5. Based on this possibility, it would also be conceivable to form undercuts with the fiber layer 3, wherein for this purpose the shell mold 5 would have to be designed in several parts accordingly.

Figures 1 1 and 12 show additional alternatives in the forming by means of a shell mold 5, in which a foam is embedded as an abutment 19 in a recess of the shell mold 5. This is useful if the fixed point should lie in the depression. This creates when retracting the mold tip 16 already has a back pressure, which prevents the

Fiber fabric stack 3 shifts uncontrollably at this point. The abutment 19 is considered as a kind of compliant element of the form 5 switching. It also arises here the circumstance that by fixing to the first entering in contact point of the fiber fabric stack 3, this is forced to flow into the contour of the shell mold 5 or the portion of the contour, as well as the contour edges of the shell mold 5 only at the end of the extension process of the Drapierwerkzeuges 8 come into contact with the mold tip 16 , The counter-bearing 19 'is designed so that it can muster in a relaxed form (when entering the Drapierwerkzeuges 8 in the shell 5) enough back pressure for fixing the fiber fabric stack 3 during retraction, but at the latest at the end of retraction not too much pressure on the Fibrous pile 3 applies so that it is not damaged.

Depending on the complexity of the component (shell 5, preform 6,

Fiber composite material 3) can be carried out step by step with the basic concept described above individual draping with individually controllable Drapierwerkzeugen 8. With an intermediate band 7 (foil and / or, textile), the resulting relative movements between

Draping tool 8 and fiber fabric stack 3 kept away from the fiber fabric stack 3 and thereby cracks or shifts within the

Fiber fabric stack 3 can be avoided. The intermediate belt 7 can be tensioned and relaxed with a pulling device 9 targeted. Thus, e.g. when pulling back the draping tools 8, the voltage is switched off in order to avoid contact pressure at the deflection points.

FIGS. 13 to 15 again show an exemplary sequence of an advantageous forming of a fiber fabric stack 3,

in particular with varying and subsequent activation of the

Draping tools 8. According to FIG. 13, the fiber fabric stack 3 is fixed in the center by extending the central fixing punch 17 and pressing the fiber cloth stack 3 against the shell 5. However, this can also be carried out, for example, with a depression in the contour. Subsequently, in FIG. 14 the left Drapierwerkzeug 8 in the contour of the shell mold 5, so that the fiber fabric stack 3 is pressed into the left contour. By the

asymmetrical configuration of the mold tip 16, the fiber fabric stack 3 can flow from left to right until the contact between the mold tip 16 (left tool, right side) and the mold shell 5 occurs. Subsequently, the same is done with the right Drapierwerkzeug 8 (Figure 15) and finally the pressure through the actuators so strong that deform the mold tips 16 and the fiber fabric stack 3 also to the

Press the edges against the shell 5.

Thus, after the end of the forming, the contour of the shell 5 is as strong as possible and also reshaped as much as necessary.

Figures 13ff. show that the Drapierwerkzeuge 8 in an advantageous

Order should be controlled, preferably from the inside out to drape the fiber fabric stack 3 and avoid tension. Use of foam moldings as Drapierwerkzeug 8, the

Use of foam moldings as mold tips 16 with undersize, which deform only after frontal contact with the shell mold 5 to the outside and press the fiber fabric stack 3, are to be used advantageously. DP1416.

List of Reference Numerals: DP 1416. contraption

2. Draping device

3. Fiber fabric pile

4th support table

5. Mold shell

6. preform

7. intermediate band

8. Draping tool

9. pulling device

10th frame

1 1. bracket

12. pivot axis

13. pulley

14. Industrial robot

15. Piston cylinder arrangement

16. Shape tip

17. Fixing punches

18. Shape tip evacuable

19 abutment in 5 α swivel angle

N weight

E Entry of 3

E 'total intake of 3

Claims

claims

Method of producing a three-dimensional preform in the course of the production of fiber-reinforced molded parts, the method being carried out with a device (1) comprising at least a drapery device (2) for a fiber fabric stack (3) and a shell mold (5) for forming the preform (6) from the fiber fabric stack (3) by means of the draping device (2),

characterized,

.1 that a fiber fabric stack (3) between the

Draping device (2) and the mold shell (5) is placed or formed there;

.2 that then at least one draping tool (8) from the draping device (2) is extended and thereby the

Fiber fabric stack (3) at least partially in the mold shell (5) introduces until the fiber fabric stack (3) is pressed by means of this Drapierwerkzeugs (8) to the mold shell (5) and fixed there; and

.3 that then in a predetermined order more

Draping tools (8) individually or together from the

Draping device (2) in the direction of the mold shell (5) are moved, wherein the order of the flow behavior of the fiber fabric stack (3) results.

A method according to claim 1, characterized in that the flow behavior is such that wrinkles and / or cracks during introduction of the fiber fabric stack (3) are avoided in the mold shell (5). A method according to claim 1 or 2, characterized

in that, after the first draping tool (8), the following draping tools (8) are separated from the first draping tool (8)

Draping tool (8) from in the direction of the outer or inner contour of the shell mold (5) can be selected.

Method according to one or more of the preceding claims, characterized in that for stiffening the fiber fabric stack (3) in the shell mold (5) a binder in the fiber fabric stack (3) at least partially cured and / or the fiber fabric stack (3) is fixed by means of seams to be introduced ,

Method according to one or more of the preceding claims, characterized in that the mold shell (5) and / or the fiber fabric stack (3) itself for curing the binder or when using a thermoplastic binder for melting heated and, if necessary, then cooled.

Method according to one or more of the preceding claims, characterized in that for heating or cooling hot air or cold air is passed through the fiber fabric stack (3).

Method according to one or more of the preceding claims, characterized in that the draping device (2) is pivoted together with the mold shell (5) by 180 °.

8. The method according to one or more of the preceding claims, characterized in that the fiber fabric stack (3) of individual layers on the support table (4) of the draping device (2) is merged.

9. The method according to one or more of the preceding claims, characterized in that the individual layers,

Bearing packages and / or the fiber fabric stack (3) itself according to the outer and / or the inner contour of the preform (6)

be tailored.

10. The method according to one or more of the preceding claims, characterized in that between at least two

Layers of the fiber fabric stack (3) during the folding at least partially a curable binder is introduced.

11. The method according to one or more of the preceding claims, characterized in that between the

Fiber fabric stack (3) and the support table (4) an intermediate belt (7) is arranged.

12. The method according to one or more of the preceding claims, characterized in that the intermediate band (7) is biased by means of a pulling device (9).

13. The method according to one or more of the preceding claims, characterized in that as an intermediate band (7) a, preferably slippery, plastic band and / or a,

preferably slippery, textile cloth is used.

14. The method according to one or more of the preceding claims, characterized in that the fiber fabric stack (3) is composed of at least two layers.

15. Device (1) for producing a three-dimensional preform (6) in the course of the production of fiber-reinforced molded parts, wherein the device (1) comprises at least one draping device (2) with a support table (4) for a fiber fabric stack (3) and a shell mold (3) 5) for forming the preform (6) from the fiber fabric stack

(3) by means of the draping device (2), characterized

in that at least two independently controllable draping tools (8) are arranged in the draping device (2).

16. Device (1) according to claim 15, characterized

in that an intermediate belt (7) is arranged between the fiber fabric stack (3) and the shell mold (5) and / or the draping device (2).

17. Device (1) according to one or more of the preceding

Claims 15 to 16, characterized in that the intermediate band (7) by means of a pulling device (9) is arranged tensioned.

18. Device (1) according to one or more of the preceding

Claims 15 to 17, characterized in that as an intermediate band (7) a, preferably slippery, plastic belt or a, preferably slippery, textile cloth is arranged.

19. Device (1) according to one or more of the preceding

Claims 15 to 18, characterized in that as actuators for moving the Drapierwerkzeuge (8) pressure or wegsteuerbare linear actuators are arranged. Device (1) according to claim 15, characterized by the use of the device (1) for carrying out the method according to at least one of claims 1 to 14.