WO2013107848A2

WO2013107848A2 - Method and device for producing a three-dimensional preform from a laid fiber fabric in the course of the production of fiber-reinforced molded parts

Info

Publication number: WO2013107848A2
Application number: PCT/EP2013/050910
Authority: WO
Inventors: Matthias Graf
Original assignee: Dieffenbacher GmbH Maschinen- und Anlagenbau
Priority date: 2012-01-18
Filing date: 2013-01-18
Publication date: 2013-07-25
Also published as: WO2013107848A3; DE102012200698A1

Abstract

The invention relates to a method and to a device for producing a three-dimensional preform (19) from a laid fiber fabric (1) in the course of the production of fiber-reinforced molded parts, said device comprising a draping device (3) and a transport device (21) for the laid fiber fabric (1), wherein the draping device (3) at least comprises a draping mold (18) for a laid fiber fabric (3) and elements that can be moved relative to the draping mold (18) for shaping the laid fiber fabric (3) according to the contour of the draping mold (18). The aim of the invention is to ensure quick yet high-quality shaping, in particular of extensive and/or complex geometries, of a preform. To achieve said aim in the method, the temperature of the laid fiber fabric (1) is controlled by means of a temperature-control device that is effectively connected to the transport device (21) during the transport and/or transfer of the laid fiber fabric into the draping device (3). For this purpose, in a device for controlling the temperature of the laid fiber fabric (1) during the transport and/or transfer into the draping device (3), a temperature-control device is arranged in such a way that the temperature-control device is effectively connected to the transport device (21).

Description

Method and device for producing a three-dimensional

Preform of a fiber fabric in the course of the production of

fiber-reinforced molded parts

The invention relates to a method for producing a three-dimensional preform from a fiber fabric in the course of the production of

Fiber-reinforced molded parts according to the preamble of claim 1 and an apparatus for producing a three-dimensional preform from a fiber fabric in the course of the production of fiber-reinforced molded parts according to the preamble of claim 5.

In the course of the production of fiber-reinforced plastic components, too

Fiber composite components mentioned, is in particular as industrial use the RTM process, resin transfer molding process, common practice. The entire manufacturing process up to a usable one

Plastic components consists of several consecutive expiring

Individual processes. In a first process step, near-net shape preforms / semi-finished fiber products are produced. In this preform process are usually several layers of fabric or fiber fabric, usually in two-dimensional form, stacked or possibly joined (sewing, welding, gluing), so that the fiber fabric stack substantially already the necessary outer contours and sometimes already special

Has layers or layer thicknesses. Preferably, a binder in the Dividing planes of the scrim introduced that after reaching a reshaped three-dimensional shape and its activation and curing leads to a fixation of the layers to each other and the draped 3D contour. For the preform process, the tissue stacks are then transferred to a forming tool and usually under pressure by closing the forming tool as far as the contour of the subsequent molding approximated and cured by activating the binder (heating and cooling), the final fiber in a tool press a Implementation of the RTM method itself can be inserted. As needed, that will

Semi-finished fiber still recut or at predetermined locations

punched out to achieve an even more precise contour. After inserting the semi-finished fiber into the tool, the tool halves

closed and injected the necessary resin into the cavity of the tool, wherein the resin impregnates the fiber structure of the semifinished fiber, which includes fibers and firmly binds in the resin matrix. After curing of the resin, the fiber-reinforced plastic component can be removed from the mold. In addition to the RTM process itself, the production of a semifinished fiber product already lays the foundation for success in the production of a plastic component. It has been found that the state of the art describes a large number of possibilities for producing a preform, which, however, as a rule results in manual or automated production of as level as possible

Fiber cloth stack exhausted, which is finally transferred in a press from its 2D form into a 3D shape. This can be done in a prefixed (eg. sewn) or still be performed in a flexible state. The goal is to obtain a preform after shaping, which has sufficient inherent rigidity to be fully automated and process-safe in the tool of a RTM press can be inserted or can be transported and stacked until further use. to

Production, deformation and fixation of the preform, there are a variety of possibilities in the relevant prior art.

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

Semifinished fiber is the foundation for the success of the production of a

Plastic component. The aim is to obtain a preform that is rigid enough to be fully automated and process-safe in the tool of a RTM press after forming the preform from a pliable material or to the other

Use can be transported and stacked. For the production, transformation and fixation of the preform, there are a variety

Possibilities in the relevant state of the art.

For the 3D forming of multi-layered two-dimensional blanks from fiber fabrics, the following process steps are known: fiber webs or webs are unwound from a roll and made into a fiber stack as required from a plurality of different fabrics or plies, shapes and sizes. It may be necessary, the outer and possibly inner contour corresponding to a pattern of the Preform or the plastic molding to edit or

tailor. The pattern is generated from a development of the preform, or the final component. Preferably, the created, essentially flat fiber stack is then draped by means of a draping device, respectively converted into a three-dimensional preform. In order to obtain a substantially rigid preform from a limp fiber fabric, it is usually necessary that a binder is introduced between the individual layers and then cured. It is state of the art that the fiber fabric respectively the

Fiber stack is heated by means of suitable heating devices and placed in a relatively cool or cold Drapierform. Subsequently, the draping form is quickly closed or draped appropriately to cure the binder. It has now been found that, especially in the case of complex geometries or large-area fiber layers, pre-solidification of the binder in the fiber layer may occur if this partially results in good heat transfer for cooling. Closing the mold now causes problems during forming, since stiff or hardened areas serve as brakes and so unwanted stress on the individual layers of the

Fiber fabric. It comes to shifts, creases or the like

Problems in the careful construction of the fiber fabric, which endangers the consistency and the value of the future component. To avoid this, it is generally well above the melting or activation temperature of the Binder heated, which can lead to unwanted distortions in the fiber fabric and also brings an unnecessary energy consumption. Also, a strongly heated fiber fabric can not be manipulated so well. The object of the invention is to provide a method and a device in which despite a rapid forming, in particular of

large and / or complex geometries, a high quality deformation of the preform can be ensured. The solution of the task for the method consists in that during transport and / or the transfer of the fiber fabric in the

Draping device with an operatively connected to the transport device tempering the fiber fabric is tempered.

The solution of the problem for a device is that the

Temperature control of the fiber fabric during transport to and / or for transfer to the draping a temperature control device with the transport device is operatively connected.

The device is particularly suitable for carrying out the method, but can also be operated independently. Advantageously, it is now possible to keep a fiber fabric during deposition in a Drapierform at a preheated temperature or even during transport to temper, preferably to heat. This makes it possible, for example, even in lengthy Drapierprozessen not yet draped and still not laid on the Drapierform fiber fabric to a sufficient

Temperature to bring or hold. This can be especially true

multilevel draping processes that are complex geometries ,. For example, you have to drape first in the border area before you can drape other areas with a central area.

Preferably, the temperature of an already tempered fiber fabric is set and / or maintained at a predetermined minimum temperature. The minimum temperature corresponds essentially to the melting point of the binder within the fiber fabric.

A selected tempering should at least for

Temperature maintenance of the preheated fiber fabric and / or be suitable for heating the fiber fabric over the melting point of the binder within the fiber fabric. As a transport device can

be arranged at least two-piece tray or a tape tray.

Further advantageous measures and embodiments of the subject matter of the invention will become apparent from the dependent claims and the following description with the drawing.

The combination options shown in the figure description are all individually and independently and in any combination usable. In particular, individual sentences are also to be evaluated as independent characteristics.

Show it:

1 shows a plant for the production of fiber-reinforced molded parts in one

Press using preformed preforms as a large industrial application in a schematic side view, Figure 2-7 a split tray as a transport device for the

Fabric covering in a draping device showing a possible gradual or continuous deposition of the

Fasergeleges in the drapery form and with

8 to 13, the use of a belt tray as a transport device according to the example of Figures 2 to 7.

Figure 1 shows a plant for the production of fiber-reinforced molded parts 19 in a RTM press 15 using preformed preforms 17 as a large industrial application in a schematic side view. To produce the preforms 17, one or more different fiber mats 10, preferably as roll goods, are first provided and cut on a cutting device 12 with a cutting device 1 1 into individual fiber mat blanks (not shown). The contour of the fiber mat blanks may substantially coincide with the contour of the preform 17 or the molding 19, but it may also predetermined Partial geometries are made of it. The fiber mat blanks are then moved by means of a suitable transport device (which are shown in Figure 1 by curved directional arrows) through a glue applicator 13 and there provided with binder before they to a

Fibrous scrims 1 are joined together. Depending on the system, the ready-made fiber fabric 1 is subsequently tempered by a heating device 2 and preferably raised to a temperature which at least the

Melting temperature of the binder corresponds. Subsequently, the

Fiber web 1 spent in a drapery device 3 and there by means

suitable means along the contour of Drapierform 18 converted. Through the Drapierform 18 of the draping device 3, the fiber fabric 1 undergoes a

Cooling and solidifies to a preform 16, which can usually be stacked without problems on a stack 17 before it is pressed in a RTM press 15 to a reinforced molding 19.

In the figures 2 to 7 while a possible transport device 21 is described, which is designed here as a two-part tray 7. For the sake of clarity, a special presentation of the

Temperierungsvorrichtung omitted. Now, if a fiber fabric 1 preheated or stored cold on the transport device 21, the

Transport device, the fiber fabric 1 with the tempering, for example, in the tray 7 or also moving along the tray. 7 is arranged, heat up or keep its already existing temperature at least above the melting point of the binder.

Now, if the transport device 21 is retracted into the draping device 3, in a two-part tray 7, the first part of the tray can be moved out of engagement with a part of the fiber fabric 1. There are

various possibilities conceivable, such as folding, retracting or the like in the second part of the tray 7 itself or even selective extension of the first part of the tray 7 from the draping device 3 out. It is possible that the necessary number of parts of the tray 7 is a multiple and that at least one of these parts, preferably all, have the option for temperature control or contain a Tmperierungsvorrichtung. Preferably, but not absolutely necessary, a first Fixierstempel 4 or a Drapierstempel 5 fix the vacant area of the fiber fabric 1 on the Drapierform 18 accordingly and if necessary. Reshape. Depending on the frictional resistance of the individual

Machine elements, the second part of the tray 7 can now start to move out of the draping device 3, stepwise or continuously as needed. As shown in FIGS. 3 to 7, the draping punches 5 now entering in the draping direction 20 become corresponding to the areas which have become "vacant" (the areas no longer resting on the transport device)

Fasergeleges 1 the fiber fabric according to the contour of Drapierform 18 transform. In the present example, this is done by the subsequent process of four Drapierstempeln 5 in Drapierrichtung 20. Thus, it is now possible in all areas of Drapierform 18 a uniformly preheated respectively tempered fiber fabric 1 to form a preform 17.

In the figures 8 to 13 instead of a tray 7 as a transport device 21, a tape tray 8 is arranged. Again, the tempering is not shown, but effectively available to adjust the resting on the belt tray 8 fiber fabric 1 according to its temperature or to keep. By the rolling tape of the tape tray 8 and a simultaneous

Relative movement of the belt tray 8, the fiber fabric 1 can be gently stored in the Drapierform 18. The fixation of the first part of the

Fasergeleges means of a Fixierstempel 4 can be provided as a precaution, especially in complex geometries, but is not necessary with simple geometries of Drapierform 18. Instead of the Drapierstempel 5, it may also be possible to provide other suitable means for draping.

The temperature control device can be designed as a convection radiator or as a (resistance) heating device for the transport device 21. Preferably, the tray described 7 is heated to a corresponding temperature sufficient to heat by means of radiating from the tray 7 radiant heat the fiber fabric accordingly or the possibly to maintain sufficient temperature at least above the melting point of the binder.

Depending on the application, the transport device 21 can be subdivided several times by single extension or a combination of the possibilities described lay the fiber fabric according to the requirements.

In particular, it may be conceivable that, for example, in the middle or in an edge region or at two or more points simultaneously with the filing of the fiber fabric 1 must be started. Nevertheless, for example, in the case of lengthy draping processes, the fabric layer not yet draped and laid down on the draping form 18 remains at a sufficient level

Temperature warmed up. (1429)

List of Reference Numerals: DP 1429

1 . fiber fabrics

2nd heating device

3. Draping device

4. Fixing stamp

5. Drape stamp

6th

7. Tray

8. Tape tray

9th

10. Fiber mat

1 1. cutter

12. Cutting table

13. Glue applicator

14. preform

15th RTM press

16. Stack

17. preform

18. Drape form

19. Moldings

20. Drape direction

21. transport device

Claims

claims

1. A process for producing a three-dimensional preform (19) from a fiber fabric (1) in the course of the production of

fiber-reinforced molded parts, with a draping device (3) and a transport device (21) for the fiber web (1), wherein the

Draping device (3) at least comprises a draping form (18) for a fiber fabric (3) and for the drape form (18) movable means for forming the fiber fabric (3) corresponding to the contour of the drape form (18), characterized in that during transport and / or the transfer of the fiber scrim into the draping device (3) with a temperature control device operatively connected to the transport device (21), the fiber scrim (1) is tempered.

2. The method according to claim 1, characterized in that the fiber fabric (1) is heated.

3. The method according to one or more of the preceding claims, characterized in that the temperature of an already tempered fiber fabric (1) is set and / or maintained at a predetermined minimum temperature. Method according to one or more of the preceding claims, characterized in that the minimum temperature substantially corresponds to the melting point of the binder within the fiber fabric (1).

Apparatus for producing a three-dimensional preform (19) from a fiber fabric (1) in the course of the production of

fiber-reinforced molded parts, comprising a draping device (3) and a transport device (21) for the fiber web (1), wherein the draping device (3) comprises at least a draping mold (18) for a fiber web (3) and for the draping mold (18) movable means for Conversion of the fiber fabric (3) according to the contour of Drapierform (18), characterized in that for the temperature control of the fiber fabric (1) during transport to and / or transfer to the draping device (3) a

Tempering device with the transport device (21)

is arranged operatively connected.

Apparatus according to claim 5, characterized in that the tempering device at least for

Temperature maintenance of a preheated fiber fabric (1) and / or for heating the fiber fabric (1) above the melting point of the Binder within the fiber fabric (1) is suitable.

Device according to claims 5 or 6, characterized

in that an at least two-part tray (7) or at least one belt tray (8) is arranged as the transport device (21).