WO2013107850A2

WO2013107850A2 - Method and device for producing a three-dimensional preform from a laid scrim in the course of production of fiber reinforced molded parts

Info

Publication number: WO2013107850A2
Application number: PCT/EP2013/050914
Authority: WO
Inventors: Steffen Maertiens
Original assignee: Dieffenbacher Gmbh
Priority date: 2012-01-18
Filing date: 2013-01-18
Publication date: 2013-07-25
Also published as: AT515808A5; AT515808B1; WO2013107850A3; DE102012200700A1

Abstract

The invention relates to a method and a device for producing a three-dimensional preform (19) from a laid scrim (1) in the course of the production of fiber-reinforced molded parts, comprising a draping device (3) and a transport device (21) for the laid scrim (1), the draping device (3) comprising at least one draping mold (18) for a laid scrim (3) and means for shaping the laid scrim (3) in accordance with the contour of the draping mold (18), the means being movable relative to the draping mold (18). The aim of the invention is to ensure an expeditious and yet high-quality shaping, especially of large-surface-area and/or complex geometries of a preform. A belt tray (8) is used in the method as the transport device (21), said belt tray (8) draping the laid scrim (1) in a targeted manner onto the draping mold (18) by way of a movement of its belt (9) and a corresponding superimposed relative movement of the belt tray (8) itself.

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 10.

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 fabric 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 hardened by activating the binder (heating and cooling), the final shape of the semi-finished fiber in a tool of a press for 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 subsequent 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 heavily heated fiber fabric can not manipulate 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 at least one tape tray is used as a transport device, wherein the tape tray drapes the fiber fabric itself by means of a movement of its band and a corresponding superimposed relative movement of the tape tray itself on the draping form.

The solution of the problem for a device is that

Transport device at least one tape tray is arranged, wherein the tape tray is suitable by means of a movable belt and means for superimposing a relative movement of the tape tray for draping the fiber fabric into the Drapierform.

The device is particularly suitable for carrying out the method, but can also be operated independently. Advantageously, it is now possible a gentle removal with or without tension on to ensure the fiber fabric in the drape shape. Preferably, the fiber fabric is heated on the belt tray. In this case, the temperature of an already tempered fiber fabric can be set and / or maintained on the belt tray to a predetermined minimum temperature. Preferably, the minimum temperature will substantially correspond to the melting point of the binder within the fiber scrim. It can be provided, after the first contact of the fiber fabric with the Drapierform means of at least one fixing die and / or a Drapierstempel the fiber fabric on the

To fix drape shape. It may be provided in complex geometries, with the Drapierstempeln the drained from the belt tray areas of the fiber fabric gradually drape into the drape form.

In particular, it may be provided by the Drapierstempel or

Fixing punches and the ribbon tray to keep the fiber fabric under tension. To establish the tension, a restraining device may be used on or associated with the tape tray. In particular, it is also conceivable that the entire transport device consists of a combination of one or more tape trays (8) and / or trays (7).

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 match the contour of the preform 17 or the molding 19, but may also be 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 provided there 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 can be designed here as a two-part tray 7. For reasons of clarity, a special representation of the optional tempering device was dispensed with. If now 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 tempering device. 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. The tape tray 8 may be divided into two or have another supporting element which extends at the beginning of the draping operation. Again, the temperature control device is not shown, but can be effectively present to the resting on the tape tray 8

Fabric lay 1 according to its temperature set or hold. By the rolling tape 9 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 described tray 7 is heated to a corresponding temperature which is sufficient to by means of radiating from the tray 7 Radiant heat to heat the fiber fabric accordingly or keep its possibly 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. (1431)

List of Reference Numerals: DP1431

1 . fiber fabrics

2nd heating device

3. Draping device

4. Fixing stamp

5. Drape stamp

6. Retention device

7. Tray

8. Tape tray

9th volume

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 layer (3) and for the drape shape (18) movable means for reshaping the fiber fabric (3) corresponding to the contour of the drape form (18), characterized in that as a transport device (21) at least one tape tray (8) is used, wherein the tape tray (8) the Fasergelege (1) by means of a movement of its belt (9) and a corresponding superimposed relative movement of the tape tray (8) itself targeted to the

Draped drape (18).

2. The method according to claim 1, characterized in that the fiber fabric (1) on the belt tray (8) 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) on the tape tray (8) is set to a predetermined minimum temperature and / or held.

4. The 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).

5. The method according to one or more of the preceding claims, characterized in that after the first contact of the fiber fabric (1) with the Drapierform (18) at least one

Fixing punch (4) or a Drapierstempel (5) the fiber fabric (1) on the Drapierform (18) fixed.

6. The method according to one or more of the preceding claims, characterized in that the Drapierstempel (5) drape the output from the tape tray areas of the fiber fabric (1) successively in the Drapierform (18).

7. The method according to one or more of the preceding claims, characterized in that by the Drapierstempel (5) or the Fixierstempel (4) and the tape tray (8) the

Fiber layer (1) is kept under tension.

8. The method according to one or more of the preceding claims, characterized in that for establishing the Voltage a restraint device (6) is used.

9. The method according to one or more of the preceding claims, characterized in that as a transport device (21) a combination of one or more tape trays (8) and trays (7) is used.

10. An 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 Forming the fiber fabric (3) according to the contour of the draping mold (18), characterized in that at least one tape tray (8) is arranged as a transport device (21), wherein the tape tray (8) by means of a movable belt (9) and means for superposition a relative movement of the belt tray (8) for draping the fiber fabric (1) in the Drapierform (18) is suitable.

11. The device according to claim 10, characterized in that the tempering device at least for Temperature maintenance of a preheated fiber scrim (1) and / or for heating the fiber scrim (1) on the melting point of the binder within the fiber scrim (1) is suitable.

12. Device according to claims 10 or 11, d a d u r c h

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

13. The device according to one or more of claims 10 to 12, characterized in that for introducing a tension in the fiber fabric (1) the tape tray (8) a

Retaining device (6) for the fiber fabric (1) to or arranged on it.