DE102012015374A1 - Multilayered fiber composite plastic component manufacturing method, involves applying partial layers with pressure, and removing manufactured fiber composite plastic component after hardening hardenable matrix material - Google Patents

Abstract

The method involves inserting partial layers (5a, 5b) in form of press tools (8) such that a semipermeable membrane (6) completely lies at the press tools. A low pressure is produced at the semipermeable membrane by vent holes (10) in the press tools. Air is sucked from the partial layers. Resin is not discharged from the partial layers. The partial layers are applied with a pressure such that no separate resin injection into the press tools takes place. A manufactured fiber composite plastic component is removed after hardening a hardenable matrix material (7) i.e. resin. Independent claims are also included for the following: (1) a multilayered fiber composite plastic component (2) a press tool.

Description

The invention relates to a method for producing a fiber composite plastic component with a plurality of reinforcing layers and a corresponding fiber composite plastic component. Furthermore, the invention relates to a pressing tool, with which the method for producing the fiber composite plastic component can be performed.

Several methods are known for fabricating such three-dimensionally shaped fiber composite plastic components having multiple reinforcement layers; such as the SMC and the RTM method.

The production of a stiffened three-dimensional FRP component with several layers is from the DE 10 2008 054 540 A1 known; the FRP component described therein has a hollow bracing member made of fiber composite material and a shell component, wherein the hollow reinforcing member which generates the shaping is produced by the mandrel technique. However, the semi-finished products required for this technique are expensive and the materials used hitherto require long curing times.

The EP 2 145 751 A1 describes the production of a hollow body made of FRP by means of an arrangement with a braiding woven braid of reinforcing fibers on a soluble core. This mold core is made of a molding material which is dispersible in liquid. The preparation comprises impregnating the reinforcing fibers with matrix material in the vacuum RTM injection method, ie the matrix material is sucked by the action of negative pressure into a space bounded by a vacuum film without solid molds. After curing or curing of the matrix material, the soluble core is removed by dissolving it with a liquid. This technique is very complex; Furthermore, for the textile structures and any uses in the tool injection under high pressure, however, is problematic because the structures can be moved by the resin. The impregnation itself, from the sprue to the vent, which is vented in the longitudinal or width direction of the tool, takes a long time. In addition, especially in RTM process, the problem occurs that the resin enters fine columns of composite tools or slide, where it hardens and the tool is only to be cleaned again with great effort.

Starting from this prior art, it is an object of the present invention to provide an improved method for producing a multilayer FRP component, which allows fast cycle times and is also inexpensive.

This object is achieved by a method for producing a FRP component having the features of claim 1.

The object of providing a multilayer FRP component improved with regard to its homogeneous composition and its fiber content is achieved with the component having the features of claim 8.

It results in the further object of providing a pressing tool for the application of a correspondingly improved method for producing a FRP component, which has a simple construction and allows a faster cycle time.

This object is achieved by a pressing tool for the application of the method for producing a fiber composite plastic component having the features of claim 9.

Further developments of the method and the objects are set forth in the subclaims.

• – Herstellen eines mehrlagigen Preformlings durch Aufeinanderlegen von mehreren Gewebelagen unter Zwischenlage einer Trennschicht und Vorpressen der Lagen in Form des herzustellenden Bauteils;
• – Teilen des Preformlings entlang der Trennschicht, so dass wenigstens eine erste und eine zweite Teillage gebildet wird;
• – Ablegen wenigstens einer der Teillagen auf einer semipermeablen Membran;
• – Aufbringen von Matrixmaterial auf wenigstens eine der Teillagen;
• – Einlegen der Teillagen in eine Form eines Presswerkzeug, wobei die semipermeable Membran vollflächig am Presswerkzeug anliegt;
• – Erzeugen eines Unterdrucks an der semipermeablen Membran durch Entlüftungskanäle im Presswerkzeug, dabei wird Luft aus den Lagen abgesaugt, aber kein Harzaustritt aus den Lagen erfolgt, und gleichzeitiges Beaufschlagen der Teillagen mit Druck, wobei keine separate Harzinjektion in das Presswerkzeug erfolgt; und
• – Entnehmen des fertigen Faserverbundkunststoffbauteils nach dem Aushärten des Matrixmaterials.

The method according to the invention for producing a multilayer fiber composite plastic component comprises the following steps in a first embodiment:

• - Producing a multi-layer preform by stacking several layers of fabric with the interposition of a release layer and pre-pressing the layers in the form of the component to be produced;
• - Parting of the preform along the release layer, so that at least a first and a second partial position is formed;
• - depositing at least one of the partial layers on a semipermeable membrane;
• - Applying matrix material on at least one of the partial layers;
• - Inserting the partial layers in a mold of a pressing tool, wherein the semi-permeable membrane over the entire surface of the pressing tool is applied;
• - Generating a negative pressure on the semipermeable membrane by venting channels in the pressing tool, while air is sucked from the layers, but no resin leakage from the layers, and simultaneously applying the partial layers with pressure, with no separate resin injection into the pressing tool; and
• - Remove the finished fiber composite plastic component after curing of the matrix material.

The preform can be made dry, whereby the fabric layers can be pressed into shape simply by laying them on one another. The contact pressure used is adapted to the particular condition of the fabric layers. At the interposed separating layer of the Preformling then be divided into at least two corresponding partial layers. Alternatively, more than two partial layers can be produced in this way. Advantageously, by dividing the preform into several partial layers, the depth of impregnation of the matrix material to be applied later can be reduced. This results in an optimized and more uniform distribution of the matrix material.

The release layer may have a paper-like structure occupying little space, whereby a coated paper may be used which additionally has the advantage of being easily peelable. The separation of the layers takes place by levering the layers on the separating layer, vacuum-supported lifting or simply lifting the respective upper layer, depending on which material the separating layer is made or at what pressure was pre-pressed.

After the division of the preform, in each case one of the partial layers can be inserted into the semipermeable membrane, wherein the semipermeable membrane consists of an adhesion-repellent material, in particular silicone, and is microperforated. In another embodiment, a membrane of polytetrafluoroethylene may also be used. Particularly preferably, the semipermeable membrane can be flexible or have an already prefabricated shape into which the partial layers can be inserted. Alternatively, with more than two partial layers only a lower and an upper partial layers can be inserted into the mold. The semipermeable membrane advantageously adapts to the shape of the preform and can readily adapt to the shape of the tool to be used hereafter. As a result, wrinkles and inaccuracies in the final product to be produced are avoided. The semi-permeable membrane can project beyond the partial layers at the side edges, so that it can also serve as a seal when used in the tool.

A preferred embodiment of the semipermeable membrane has the advantage that the material used has separating properties with respect to the adhesion of the resin systems used. The micro-perforation can penetrate air, but no resin. The thickness of the mold is chosen according to the heat transfer properties of the tempered tool surface and the reactivity of the resin systems used so as to ensure a chronological sequence (first complete impregnation and then curing). This results in a good component strength despite temporal temperature shifts during impregnation due to the wall thickness of the mold. Also, a tool cleaning can be omitted, since the semi-permeable membrane seals the partial layers to the tool.

On both partial layers, it is preferable to apply the matrix material by spraying. Alternatively, the matrix material may be poured or applied as a fusible resin film on one of the partial layer. A preferred matrix material is a resin which preferably hardens upon heating. If more than two partial layers are provided, a coating by means of resin can take place between all adjacent partial layers.

Furthermore, a multi-layer application of the matrix material can be provided, wherein a first layer is applied compactly and a second layer is applied foaming. The compact material is intended to penetrate the textile layers and the foamable layer to support the impregnation into the tissue, since the foaming creates an internal pressure that pushes the compact material through the tissue. Another aspect is the emergence of sandwich structures with the ability to achieve locally different component thicknesses.

After resin application, the two partial layers are again stacked as in the original manner and inserted into the pressing tool. Depending on the requirements, the partial layers can also be inserted individually into the moldings of the tool and assembled by closing them.

The closing of the tool and the application of the pressing pressure of preferably 40 bar provide for the impregnation from the middle of the layer structure by hydrostatic pressure. Furthermore, the invention preferably provides that the pressing tool during the pressing operation to a temperature between 60 ° C to 180 ° C is heated. This allows a fast curing reaction as well as faster cycle times due to high isothermal mold temperatures. In addition, no further resin injection during the pressing process is necessary due to the previously applied resin.

At the same time by applying a negative pressure to the semipermeable membrane during pressing constantly air from the interior of the layer package sucked through the ventilation channels in the tool surface, whereby a uniform impregnation of the fabric layers is achieved. It is thus possible to impregnate tissue with a higher fiber volume content than with conventional methods of the prior art.

For carrying out the method according to the invention, the invention provides a pressing tool which has shaped parts corresponding to the shaping of components, of which at least one shaped part can be heated. In the moldings a plurality of ventilation channels is inserted, which is for generating a negative pressure on the semipermeable membrane, which rests on the pressing tool, are suitable, so that remaining air can be sucked out of the layers. This tool, in conjunction with the method used, allows easy integration of ejectors and gate valves, allowing for highly complex part geometries. The component is sealed during manufacture solely by this membrane, whereby. simpler tools without seals and dipping edges are possible.

A multilayer FRP component is manufactured according to the method described above and is characterized by a high degree of robustness.

The invention has the particular advantages of low investment costs for the system technology, since the method can be used in existing systems, or can be rebuilt quickly and easily by replacing the tool. Also, a parallelization of the processes can be made possible by a preimpregnation can take place in a separate vacuum tool, whereby the process can proceed even faster.

These and other advantages are set forth by the following description with reference to the accompanying figures. The reference to the figures in the description is to facilitate understanding of the subject matter. Articles or parts of objects which are substantially the same or similar may be given the same reference numerals. The figures are merely a schematic representation of an embodiment of the invention.

Showing:

1 a perspective view of a structure of a preform;

2 a longitudinal section through the preform,

3 . 4 in each case longitudinal sections through two partial layers of the preform;

5 a longitudinal section through a populated pressing tool; and

6 a longitudinal section through an inventive FRP component.

The method according to the invention relates to a method for producing a multilayer FRP component 1 ,

Such a FRP component 1 is exemplary in 6 shown. The 1 to 5 give the individual process steps again. In 5 is also a pressing tool 8th for the use of the method, the structure of which is explained in more detail below in the description of the method.

In 1 and 2 is the production of a preform 2 shown, consisting of several layers of fabric 3 is composed, in this embodiment, four layers of fabric 3 , Between these is a separation layer 4 arranged, which preferably consists of a coated paper-like material. For the production of the preform 2 Depending on the requirements of the component to be manufactured 1 two or more layers of fabric 3 superposed, being between two middle layers 3 ' the separation layer 4 is inserted. The layers are dry pre-pressed together in the form.

A next step of the procedure is in 3 shown, wherein the preform 2 along the separation layer 4 in two corresponding partial layers, a lower partial layer 5a and an upper part position 5b is shared. This results in an optimized and more uniform distribution of the matrix material to be applied later, since the impregnation depth is reduced, ie the flow path of the matrix material is shorter than in the otherwise known production.

The partial days 5a . 5b after that, how 3 points to a semipermeable membrane 6 , such as B. a microporous silicone mold. In the embodiment shown are the partial layers 5a . 5b each with its underside on the semipermeable membrane 6 , wherein the semipermeable membrane 6 the shape of the partial layers 5a . 5b adapts. The membrane 6 can be at the margins of the partial layers 5a . 5b protrude to continue within the tool 8th to serve as a seal.

At least one of the partial layers 5a . 5b becomes a hardenable matrix material 7 , such as As a resin applied, that in the partial layers 5a . 5b is to be impregnated (see 4 ). An application can be done by spraying, pouring etc. Also, the resin may be applied as a fusible resin film.

In the next step in 5 become the now prepared partial layers 5a . 5b in the pressing tool 8th used, which is installed in a commonly used pressing device. The pressing tool 8th has in this embodiment two corresponding moldings 9a . 9b on, as negative forms for the produced FRP component 1 serve. The moldings can be configured arbitrarily complicated and have slide or ejector. Also tools with multiple moldings are possible. The moldings 9a . 9b have a variety of ventilation channels 10 on, along the pressing direction (arrows in 5 ) and which serve to generate a vacuum or a vacuum. The pressing tool 8th is used to cure the Resin heated to temperatures of preferably 60 ° C to 180 ° C.

An insertion of the partial layers 5a . 5b in the tool 8th Now takes place such that the two surfaces corresponding to each other as in the preform 2 reassembled, giving it the shape of the finished FRP component 1 receive. Alternatively, the partial layers 5a . 5b also individually in the appropriate moldings 9a . 9b are inserted and the partial layers 5a . 5b are assembled by closing the tool.

The tool 8th is closed and the composite partial layers 5a . 5b are pressed under a pressure of about 40 bar, wherein the matrix material 7 evenly in the partial layers 5a . 5b is distributed and the remaining air from the fabric layers 3 is squeezed out. At the same time is via the venting channels 10 constantly sucked air, allowing a uniform impregnation of the fabric layers 3 he follows. The semipermeable membrane 6 forms inside the tool 8th a kind of seal against leakage of the matrix material 7 , thus by the semipermeable membrane 6 retained and thus neither the venting channels 10 still clog in columns or slider of the tool 8th can penetrate.

For curing the matrix material 7 becomes the tool 8th additionally heated during the pressing process. The FRP component 1 is in a last step from the pressing tool 8th removed (see 6 ) and of the semipermeable membrane 6 freed and possibly reworked (deburred, ground, etc.). Finally, the finished FRP component is available 1 ready for further processing.

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 102008054540 A1 [0003]
• EP 2145751 A1 [0004]

Claims (10)

Method for producing a multilayer fiber composite plastic component ( 1 ), comprising the steps: - producing a multilayer preform ( 2 ) by stacking several layers of fabric ( 3 ) interposing a separating layer ( 4 ) and pre-pressing the layers in the form of the component to be produced ( 1 ); - dividing the preform ( 2 ) along the separation layer ( 4 ), so that at least a first and a second partial position ( 5a . 5b ) is formed; - removal of at least one of the partial placements ( 5a . 5b ) on a semipermeable membrane ( 6 ); - application of matrix material ( 7 ) on at least one of the partial layers ( 5a . 5b ); - submission of partial contracts ( 5a . 5b ) into a mold of a pressing tool ( 8th ), the semipermeable membrane ( 6 ) over the entire surface of the pressing tool ( 8th ) is present; Generating a negative pressure on the semipermeable membrane ( 6 ) through ventilation channels ( 10 ) in the pressing tool ( 8th ), while air is sucked out of the layers, but no resin leakage from the layers ( 5a . 5b ), and simultaneous loading of the partial layers ( 5a . 5b ) with pressure, wherein no separate resin injection takes place in the pressing tool; and - removing the finished fiber composite plastic component ( 1 ) after curing of the matrix material ( 7 ). Method according to claim 1, comprising the step of placing the partial layers ( 5a . 5b ) after application of the matrix material ( 7 ) and in the form of the pressing tool ( 8th ). Method according to claim 1 or 2, characterized in that the separating layer ( 4 ) has a paper-like structure. Method according to at least one of claims 1 to 3, comprising the step of depositing at least one of the partial layers ( 5a . 5b ) on a flexible semipermeable membrane ( 6 ). Method according to at least one of claims 1 to 4, characterized in that the semipermeable membrane ( 6 ) consists of an adhesion-repellent material, in particular silicone, and is microperforated. Method according to at least one of claims 1 to 5, comprising the step of applying the matrix material ( 7 ) by spraying and / or pouring and / or as a meltable resin film on the at least one partial layer ( 5a . 5b ). Method according to claim 6, comprising the step of applying the matrix material in multiple layers ( 7 ), wherein a first layer is applied compact and a second layer is applied foaming. Multilayer fiber composite plastic component ( 1 ), characterized in that the component ( 1 ) is produced by a method according to at least one of claims 1 to 7. Pressing tool for use of the method according to at least one of claims 1 to 8, wherein the pressing tool ( 8th ) corresponding moldings ( 9a . 9b ), of which at least one molded part ( 9a . 9b ) is heated, characterized in that in the moldings ( 9a . 9b ) a plurality of ventilation channels ( 10 ), which are used to generate a negative pressure on the semipermeable membrane ( 6 ) on the pressing tool ( 8th ), are suitable, so that remaining air from the layers ( 5a . 5b ) is sucked. Press tool according to claim 9, characterized in that the pressing tool ( 8th ) is heated to a temperature between 60 ° C, 180 ° C during the pressing process.

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