DE202017101459U1 - Device for consolidating fiber composite structures - Google Patents

Abstract

Apparatus for consolidating fiber composite structures (10, 10 ') with at least one thermoplastic and / or thermoelastic polymer, comprising a plate-shaped base (20); a plate-shaped cover (30, 30'); a sealing element (15) for displaceably sealing the cover (30 At least one radiation source (14) for generating electromagnetic radiation for heating the fiber composite structure (10, 10 ') by means of electromagnetic radiation, preferably at least to the range of the melting temperature of the at least one thermoplastic and or thermoelastic polymer; anda vacuum pump for creating a negative pressure in the space between the base (20) and the cover (30, 30 ') so that the ambient pressure forces the cover (30, 30') against the base (20) and the fiber composite structure (10, 10). 10 ') between the cover (30, 30') and the base (20) is pressed, characterized in that the device further in the range of at least two opposite sides of the cover (30, 30 ') comprises provided support means, which are established , the cover (30, 30 ') relative to the support (20) supported in such a way to counteract caused by the negative pressure in the intermediate region, in the downward direction of the cover (30, 30') acting force and thus a bending of the cover ( 30, 30 ').

Description

The present invention relates to an apparatus for consolidating fiber composite structures according to claim 1, for example for automotive components.

Fiber composite applications have continued to increase over the past decades, especially when viewed as a cost-effective alternative to metallic materials, with the benefits of design freedom and application-specific formulation capabilities. Specifically, the material CFK (carbon fiber reinforced plastic) has an extremely high potential for lightweight construction, while being characterized by its high strength and very high structural rigidity. The latter is an important criterion in automotive engineering, for example.

The automatable production of the preform represents a key technology in the production process of continuous fiber reinforced fiber composite components to realize an efficient mass production with reproducible stable component quality. But also in so-called hybrid components, ie compression molded sheets, which are mainly pressed with carbon fiber semi-finished products to reinforce critical stress zones in addition All production units must be able to integrate plant and control technology if sufficient productivity is to be achieved.

For the production of continuous fiber reinforced components are now predominantly textile fiber semi-finished products such as with a binder (hot melt) wetted and / or partially impregnated with a matrix or fully impregnated fiber yarns and / or fabrics (so-called prepregs) such as fiber fabrics, fiber knits , Fiber scrims or fiber mats used. The matrix of fiber-reinforced plastics has the task of embedding the heavy-duty fibers (supporting function) and completely filling their intermediate space (blocking function).

In principle, materials from the groups of thermoplastics and optionally additional elasticizing components, such as elastomers, which differ in strength, maximum elongation, operating temperature, processing speed and chemical resistance, can be used on binder and / or matrix materials.

From these semi-finished products, which are available as rolls or sheets in standard formats, blanks are produced, for example, in a cutting process, which usually line the formed component over its entire surface.

Alternatively, continuous fiber-reinforced components can also be manufactured using fiber or tape-coating processes become much lower waste or waste and thus more resource efficient. Especially the use of tapes comprising preferably unidirectional continuous fibers in a thermoplastic matrix proves to be a very attractive process variant. By "tape" in the context is preferably meant any type of sheet material, in particular a prepreg material having, for example, a width of between 30 and 200 mm, which is suitable for being deposited by means of a tape laying device. In the present case, "prepreg material" means, in particular, fiber yarns (rovings), fiber scrims and / or fiber webs which are wetted with a binder and / or impregnated with a matrix, for example a thermoplastic matrix, partially or completely impregnated, in particular pre-impregnated , The "fibers" are in particular carbon fibers, but in the same way also for glass fibers or other, especially man-made fibers applicable. For the processing of tapes is known to deduct them by tape laying devices, in particular so-called fiber placement devices from a spool or roll to cut to length and place on a laying table or already laid on the laying table tapestry. When a tape strip is deposited, it is connected pointwise to the underlying tape layer via a number of ultrasonic welding heads. Exemplary tape-laying devices are, for example, from the documents WO 2014/083196 A1 and US 8,048,253 known.

After laying fiber composite structures with a desired shape by means of tapes of individual tapes or by arranging large-area blanks, it is necessary to compress the fiber composite structures in a subsequent process step under the action of pressure and temperature and thus consolidate them into a laminate.

An exemplary method for consolidating fiber composite structures with thermoplastic and / or thermoelastic polymers is disclosed in the document DE 10 2014 004 053 A1 known. In this document, as in 1 proposed to arrange a fiber composite structure 1 to be consolidated on a rigid base 2, as well as to place a rigid cover 3 on the fiber composite structure 1, so that the fiber composite structure 1 is located in a space between the base 2 and the cover 3. Laterally, the gap is sealed by a ring seal 5 of resilient material. Furthermore, radiation sources 4 are provided, which are arranged above or below the cover 3 and the base 2 are and generate the electromagnetic radiation, in particular infrared radiation. The cover 3 and the base 2 are permeable to the electromagnetic radiation generated by the radiation sources 4, so that the electromagnetic radiation can be coupled through the base 2 and the cover 3 into the fiber composite structure 1. In order to consolidate the fiber composite structure 1, the fiber composite structure 1 is irradiated with the electromagnetic radiation through the underlay 2 and the cover 3 to convert the impregnation polymer to a plasticized, molten state. In addition, the space between the pad 2 and the cover 3 by means of a connected to a gap in the pipe socket 6 connected vacuum pump (not shown), evacuated so that due to the top of the cover 3 (or at least partially from below the underlay 2) acting ambient pressure, the fiber composite structure 1 is compressed under compression of the ring seal 5 between the cover 3 and the pad 2.

An advantage of this method is the low required technical equipment effort, in particular the renunciation of pressing tools or the like, so that the process can be implemented easily and inexpensively. Moreover, the method allows direct heating of the fiber composite structure 1 without it being necessary, e.g. To heat large pressing tools, which makes the process very energy efficient and therefore cost-effective in operation.

However, this method has the possibility that when closing cover and pad to air pockets, or that form during the compression and consolidation within the fiber composite structure air pockets, such as the evaporation of adhering residual moisture, and thus to the formation of pores in arise from the consolidated laminate. Although a certain ventilation of the fiber composite structure is provided by the applied negative pressure, but since the fiber composite structure is pressed between the base and the cover, it may occur that extraction of air pockets or resulting vapor bubbles, especially in the middle of the fiber composite structure in some cases only insufficient. As a result, pores may form in the center of the fiber composite structure, which may lead to an optically inadequate impression of the surface of the consolidated laminate and / or to an inhomogeneous laminate.

Moreover, the method is poorly suited to consolidate fiber composite structures having localized reinforcements, for example, in component areas where hinges are later to be attached, or to be connected to other components.

It is therefore an object of the invention to provide an apparatus for consolidating a fiber composite structure which overcomes the foregoing disadvantages.

It is a further object of the invention to provide an apparatus for consolidating a fiber composite structure which makes it possible to consolidate a fiber composite structure into a laminate while largely avoiding the formation of air pockets and / or pores, thus enabling a laminate having a flawless, form homogeneous surface.

It is still a further object of the invention to provide an apparatus for consolidating a fiber composite structure which also enables the consolidation of fiber composite structures with high quality local reinforcements.

These and other objects of the invention are achieved with an apparatus for consolidating a fiber composite structure as recited in claim 1. Further preferred embodiments are set forth in the dependent claims.

As a solution, there is provided an apparatus for consolidating a fiber composite structure with at least one thermoplastic and / or thermoelastic polymer comprising a plate-shaped pad; a plate-shaped cover; a sealing member for displaceably sealing the cover with respect to the pad; at least one radiation source for generating electromagnetic radiation for heating the fiber composite structure by means of electromagnetic radiation, preferably at least up to the range of the melting temperature of the at least one thermoplastic and / or thermoelastic polymer; and a vacuum pump for creating a negative pressure in the space between the pad and the cover so that the ambient pressure presses the cover against the pad and the fiber composite structure is compressed between the cover and the pad, the device being further in the region of at least two opposite sides the cover provided supporting means, which are adapted to support the cover against the pad so as to counteract caused by the negative pressure in the intermediate region, acting in the downward direction of the cover force and thus to cause a bending of the cover.

According to the invention, therefore, the pressing and consolidation of the fiber composite structure does not occur simultaneously over the entire area, as this about when referring to 1 explained method happens. Rather, the fiber composite structure is pressed by means of the curved cover from a narrow portion successively and controlled to the outside, so that caused by the displacement of fiber and polymer material, which is caused by the local action of the force exerted by the curved cover compressive force in the fiber composite structure trapped air or pushed out by the heating vapors and reach after a relatively short distance in a range in which the cover due to the bend of the same or not so strong presses on the fiber composite structure, so that the trapped air or Vapors which form by heating can be more easily released from the fiber composite structure into the intermediate space and can be withdrawn via the connected vacuum pump. This makes it possible to consolidate the fiber composite structure largely without the formation of air pockets or with only a few and very small air pockets or pores and thus to form a high-quality laminate of high quality.

It is preferably provided that the cover has on at least two opposite sides in each case a support frame element, and / or the pad on at least two opposite sides each having a support frame element.

It can be provided that in each case a support device is arranged in the region of at least two opposite sides of the cover, which supports the cover relative to the base in order to counteract a force caused by the negative pressure in the intermediate region, acting downward in the direction of the cover and so to cause the bending of the cover.

The support devices can each be designed as one or more actuators, in particular as pneumatic actuators, hydraulic actuators or electromotive actuators. The use of actuators, which can be controlled in particular by a controller, allow a well-controlled and controlled positioning and / or bending of the cover. This can be advantageously supplemented by the fact that the vacuum pump is also controlled by the controller, so as to bring about a well-defined and desired pressure state, or a pressure course over time in the intermediate space. Particularly preferably, monitoring or measuring of the pressure in the intermediate space can also take place so that, if appropriate, the controller can readjust or readjust and / or initiate monitoring functions.

Alternatively, the support means may each be designed as spring elements. In this way, a very simple and inexpensive design can be realized, which also has very good properties. In particular, by selecting desired suitable spring characteristics, such as the use of degressive spring characteristics, it is possible to adjust the time course of the curvature of the cover and the consolidation to a desired course and thus to achieve a desired and tailored consolidation and compression. Even if the spring elements alone represent passive-acting elements, there is still the possibility of active intervention, in particular the control and / or regulation of the process sequence, for example by a controller correspondingly controls the operation of the vacuum pump for generating the negative pressure in the intermediate space and thus the prevailing ( Lower) pressure correspondingly raises or lowers, or instructs a desired temporal pressure curve, wherein the prevailing negative pressure in conjunction with the spring characteristics of the spring elements in turn leads to a corresponding expression of the bending of the cover.

As an alternative, the support devices can each be designed as spacer elements which have a height that is greater than a target thickness of the fiber composite structure after consolidation. With this embodiment, a simplest possible and thus structurally and cost-wise the least expensive solution is realized, which nevertheless achieves good results. The spacer elements may be arranged between the fiber composite structure and the sealing element, but are preferably arranged outside the sealing element, resulting in a better handling of the spacer elements and they can be exchanged to the particular requirements without problems.

The cover and / or the pad are preferably formed as a glass plate or include these.

The apparatus may preferably further comprise a sensor for detecting the pressure in the intermediate space and / or a thermal imaging camera for acquiring an image of the temperature distribution in the fiber composite structure, wherein the apparatus preferably further comprises a control unit which is set up upon detection of a sudden increase in pressure or a local cold spot recognizable in the thermal image relative to a hot environment to determine that there is a bubble, and in the presence of a bubble to instruct the vacuum pump and / or the support means designed as actuators to temporarily increase the pressure in the space and / or the cover in order to at least partially reduce the overlay of the cover, in particular to reduce the support of the section on the fiber composite structure and thus to enable a local venting path for withdrawing the air or vapor bubble.

As yet another solution, there is provided a plant for consolidating a fiber composite structure having a loading / unloading station, a pressing station, and a cooling station comprising a device as described above, and which is arranged in the loading / unloading station with a fiber composite structure in the press station, the fiber composite structure by means of the at least one radiation source preferably at least until at least until in the pressing station to take up the document or provide the pad for occupancy with a fiber composite structure, and to position the cover over the pad to move the pad and the cover with the interposed fiber composite structure to the pressing station to heat in the range of the melting temperature of the at least one thermoplastic and / or thermoelastic polymer, and by means of the vacuum pump, the negative pressure in the intermediate space for pressing the fiber composite structure between the cover and the pad to create; after compression, to move the backing and the cover with the compressed fiber composite structure placed therebetween to the cooling station, in the cooling station, to cool the assembly of backing, cover and fiber composite structure placed therebetween; after cooling, move the backing and the cover with the fiber composite structure placed therebetween to the loading / unloading station; and in the loading / unloading station, lifting the cover from the pad to remove the consolidated fiber composite structure from the pad or to remove the pad coated with the consolidated fiber composite structure.

Said device and said plant are preferably arranged to carry out the methods mentioned herein. The method for consolidating a fiber composite structure with at least one thermoplastic and / or thermoelastic polymer comprises placing the fiber composite structure between a plate-shaped base and a plate-shaped cover, wherein the cover is displaceably sealed against the base by a sealing element with respect to the base, creating a negative pressure in the space between the pad and the cover so that the ambient pressure presses the cover against the pad and the fiber composite structure is pressed between the cover and the pad, and heating the fiber composite structure by electromagnetic radiation preferably at least up to the range of the melting temperature of the at least one thermoplastic and / or thermoelastic polymer. The method is characterized in that it comprises the steps of: causing a bending of the cover so that the cover, optionally with additional lowering of the cover, contacts the surface of the fiber composite structure in a section; and further bending and / or lowering the cover until the cover contacts the entire surface of the fiber composite structure and the fiber composite structure is compressed between the cover and the backing.

Preferably, the cover is initially positioned at a distance above the fiber composite structure. More preferably, the cover only contacts the fiber composite structure after the fiber composite structure has already been fully heated to make the impregnation polymer molten.

In a preferred development, during the compression of the fiber composite structure, a detection of blistering can be performed, wherein in the case of blistering, the pressure in the space temporarily increased and / or the cover is raised to at least partially reduce the support of the cover, in particular the reduction of To achieve support of the section on the fiber composite structure and thus to allow a local venting path for removing the air or steam. In particular, bubble formation may be detected by monitoring the amount of negative pressure in the gap, and / or by detecting the temperature distribution in the fiber composite structure by means of a thermal imaging camera, wherein if there is a local cold junction detectable in the thermal image relative to a hot environment Presence of a bubble is closed.

By additionally performing bubble detection, the reliability of the consolidation can be further improved and the high quality and quality of a laminated and consolidated fiber composite structure can be ensured.

The seal can be effected by means of a sealing element, in particular an elastic ring seal.

It may be provided that the heating of the fiber composite structure takes place by means of electromagnetic radiation before, simultaneously or after the compression of the fiber composite structure between the cover and the base.

In a preferred embodiment, the fiber composite structure may comprise at least a portion of a survey, wherein for each area a Survey a cavity is provided in the cover to accommodate the corresponding area. In this case, it can further be provided in particular that each cavity surrounds the respectively associated elevation laterally with a gap, wherein the gap preferably has a width between 3 and 15 mm, particularly preferably between 5 and 10 mm. It can also be provided that each cavity has a depth that is between 0.7 times and 1.0 times the height of the respective associated elevation relative to the surface of the fiber composite structure in a non-raised region, and / or each cavity (FIG. K) has a depth sized to compensate for material shrinkage or compactification of the fiber composite material during consolidation.

This makes it possible to also crimp and consolidate high pitch fiber composite structures, which are increasingly in demand for various applications, by the methods described herein.

• 1 zeigt ein Verfahren zum Konsolidieren einer Faserverbundstruktur gemäß dem Stand der Technik:
• 2A bis 2E zeigen ein Verfahren zum Konsolidieren einer Faserverbundstruktur gemäß einer ersten bevorzugten Ausführungsform;
• 3A bis 3C zeigen ein Verfahren zum Konsolidieren einer Faserverbundstruktur gemäß einer zweiten bevorzugten Ausführungsform;
• 4A und 4B zeigen ein Verfahren zum Konsolidieren einer Faserverbundstruktur gemäß einer dritten bevorzugten Ausführungsform;
• 5A und 5B erläutern schematisch ein Verfahren zum Konsolidieren einer Faserverbundstruktur mit einer Erhebung, gemäß einer weiteren bevorzugten Ausführungsform; und
• 6 veranschaulicht den Aufbau einer Strahlungsquelle und das Erwärmen einer Faserverbundstruktur.

The invention will be described hereinafter with reference to the drawings:

• 1 shows a method for consolidating a fiber composite structure according to the prior art:
• 2A to 2E show a method for consolidating a fiber composite structure according to a first preferred embodiment;
• 3A to 3C show a method for consolidating a fiber composite structure according to a second preferred embodiment;
• 4A and 4B show a method for consolidating a fiber composite structure according to a third preferred embodiment;
• 5A and 5B schematically illustrate a method for consolidating a fiber composite structure with a bump, according to another preferred embodiment; and
• 6 illustrates the construction of a radiation source and the heating of a fiber composite structure.

With reference to the 2A to 2E First, a method for consolidating a fiber composite structure according to a first preferred embodiment will be described.

As in 2A is shown, with a thermoplastic or thermoelastic polymers preimpregnated or with such polymers in the solid state, dissolved or deposited or deposited state offset fiber composite structure 10 on a plate-shaped base 20 arranged. Providing a sealing element 15 , in particular an elastic ring seal, which the fiber composite structure 10 laterally and preferably at a distance surrounds, is further a plate-shaped cover 30 above that on the pad 20 positioned fiber composite structure positioned. The underlay 20 and the cover 30 are each formed of a for electromagnetic radiation, in particular infrared radiation, permeable and heat-resistant material. Particularly preferred are the pad 20 and the cover 30 each formed as glass plates. For example, the cover 30 and the pad 20 each formed as a rectangular glass plates with a width of 500 mm, 1000 mm, 1500 mm, 2000 mm or more, and a length of 1000 mm, 1500 mm, 2000 mm, 2500 mm or more. The thickness of the glass plate may be, for example, 2 mm, 3 mm, 5 mm or more.

To avoid getting the pad 20 Bends downwards due to its own weight, it is preferably provided that the pad 20 is supported from below, for example by being partially or completely applied to a table top or other support structure (not shown), which the pad 20 supported from below. It is also conceivable, the pad 20 to form with a greater thickness than the cover 30 , for example, for the pad 20 to use a glass plate with 5 mm or 8 mm while covering 30 a glass plate with 2 mm or 3 mm is used. In this case, the pad becomes 20 have an inherently greater rigidity and accordingly less prone to sag than the cover 30 ,

For easier handling of the cover 30 and the pad 20 to offer, they can each be attached to a support frame. The support frame may be made in one or more parts, and may cover 30 and the pad 20 completely or partially at their side edges. Accordingly, the shows 2A exemplified that on the cover 30 and the pad 20 two support frame elements each 21 respectively. 31 are arranged. An example of the cover 30 completely comprehensive or circumferential support frame of support frame elements 31 is in the 2E to see which is a top-down view of an exemplary cover 30 shows. For handling the cover 30 in particular for positioning the cover 30 over the pad 20 can be attached to the supporting frame elements 31 side projections, recesses or the like (not shown) may be provided, which allow corresponding hooks or other holding elements (not shown) the support frame 31 , and thus the cover 30 to be able to engage. Will for the cover 30 and / or the pad 20 each used a glass plate, the glass plate, for example, by gluing with the corresponding support frame elements 21 . 31 be firmly connected. Other types of attachment, such as bolting, or even clamps in a groove, in a support frame element 21 . 31 is provided, and which covers and clamps the glass plate on both sides are also conceivable.

Again with respect to 2A are at the on the cover 30 arranged support frame elements 31 actuators 32 , In particular arranged pneumatic actuators, which can be controlled with a preset pressure to a respective cylinder 33 extend to a predefined stroke limit. About the cylinders 33 , which are on the base 20 arranged support frame elements 21 can support the actuators 32 , in particular the pneumatic actuators so on the cover 30 arranged support frame elements 31 at a predetermined height above the on the pad 20 arranged support frame elements 21 position and hold. The actuators 32 with the cylinders 33 can therefore be considered as a support device, which the cover 30 opposite the pad 20 supported. The power of all actuators 32 , in particular pneumatic actuators is greater than the weight of the cover 30 and the support frame elements 31 applied weight. In this way, by pressurizing the pneumatic actuators with the preset pressure, the cover 30 in a predefined position above the base 20 and the on the pad 20 arranged fiber composite structure 10 held and / or positioned. In this position can be advantageously provided that the cover 30 is located at a height of 2 to 20 mm above a target thickness with consolidation completed, and / or the cover 30 at a height of at least 0.1 mm, preferably at least 1 mm, more preferably at least 3 mm, and most preferably at least 5 mm above the surface of the fiber composite structure 10 located. It should be noted that the cover 30 in this position due to its own weight and only lateral holding by the support frame elements 31 can experience a self-bending. The extent of this self-bending is essentially determined by the choice of the material of the cover 30 , in particular its rigidity and specific weight, as well as the thickness, the width and the length of the cover 30 , Particularly preferred are the material and the thickness of the cover 30 chosen so that the intrinsic deflection is in a range between 2 and 20 mm, preferably in a range between 3 and 15 mm, particularly preferably in a range between 5 and 10 mm. Correspondingly, in this case the height indications given are height indications with respect to the lowest point of the lower surface of the cover 30 to understand.

In the 2A are still radiation sources 14 shown above the cover 30 and below the pad 20 are arranged, and which are adapted to electromagnetic radiation for heating the fiber composite structure 10 leave. Alternatively, it is also possible to have only one radiation source 14 above the cover 30 or below the pad 20 to arrange. The radiation sources 14 are preferably designed as infrared light sources. The below the pad 20 arranged radiation source 14 Optionally also in the support structure (not shown) for the pad 20 be arranged. Preferably, the radiation sources 14 designed as a surface radiator, which the cover 30 and / or the pad 20 irradiate substantially over the entire surface and with substantially the same area-related radiation density. It should be noted that in the following 2 B to 2D the radiation sources 14 for clarity of illustration are not shown.

With the help of a pump or the like (not shown) is then from the cover 30 , the underlay 20 and the sealing element 15 sealed gap evacuated, so that sets a negative pressure in the intermediate space. Due to the cover 30 adjusting pressure difference between ambient pressure, on the one hand, and pressure in the space, on the other hand, puts a pressure force on the cover 30 a, as indicated by the arrow in 2 B shown. Because the cover 30 at the lateral edges (here, for example, the edges in the longitudinal direction of the cover 30 ) through the support frame elements 31 be held, and this by means of the actuator 32 and the cylinder 33 held in place in height, which leads to the cover 30 applied compressive force, together with the weight of the cover 30 , to a bend of the cover 30 so that the cover bulges downwards as in 2 B also shown schematically.

As the vacuum increases, it will be on the cover 30 applied force increasingly larger, so that the cover 30 increasingly stronger bend and in the middle first on the fiber composite structure 10 hang up. In other words, the cover touches 30 the fiber composite structure 10 only in a relatively small section A the surface of the fiber composite structure 10 , as in 2C shown schematically. With increasing negative pressure, the section increases A and its boundaries are gradually wandering outwards. The cover 30 thus pushes the fiber composite structure in an increasingly larger area 10 , which of the radiation sources 14 was preferably heated so far that the thermoplastic or thermoelastic polymers into the core of the fiber composite structure 10 have become molten.

Once the sum of the weight of the cover 30 and the support frame elements 31 (and possibly on the cover 30 further provided support frame elements 31 and / or other elements) and the weight due to the negative pressure on the cover 30 applied force, less that over the subsection A in the fiber composite structure 10 introduced pressure force exceeds a predetermined amount, in particular the amount of the maximum lifting force of the actuators 32 , in particular pneumatic actuators, open at the actuators 32 provided pressure limits. As a result, the support frame elements can 31 lower, as indicated by the arrows in the 2C emblematic, and the cover 30 completely closes against the surface 20 until complete coverage of the cover 30 on the fiber composite structure 10 , like in the 2D shown. The supporting frame elements 21 and 31 can be designed and dimensioned so that they define a stop which the distance of the pad 20 and the cover 30 defined to each other with complete closure, and thus the target thickness of the fiber composite structure to be consolidated 10 Are defined. However, it is preferred that the support frame elements 21 and 31 each with the corresponding surfaces of the cover 30 and the pad 20 are volatile, and that a compression limiting, the target thickness of the fiber composite structure 10 defining stop is provided in another way. For example, the minimum stroke limit of the actuators 32 , in particular pneumatic actuators, are used as a stop, wherein the actuators 32 arranged and relative to the support frame elements 31 be positioned that by the minimum stroke limit of the actuators 32 defined position of the desired target thickness of the fiber composite structure to be pressed 10 equivalent.

Alternatively, a separate stop may be provided, such as an abutment piece between the support frame elements 21 . 31 and / or between the pad 20 and the cover 30 is arranged, and which is dimensioned with a thickness, the target thickness of the fiber composite structure to be pressed 10 equivalent.

The pressing and consolidation of the fiber composite structure 10 Therefore, does not take place simultaneously over the entire area, as in the reference to 1 explained method happens. Rather, the fiber composite structure 10 by means of the curved cover 30 starting from a narrow section A successively and controlled compressed outwards, so that by the displacement of fiber and polymer material by the local action of the curved cover 30 applied compressive force is caused in the fiber composite structure 10 trapped air or be pushed out by the heating vapors and enter after a relatively short distance in an area in which the cover 30 due to the bending of the same or not yet so strong on the fiber composite structure 10 pushes so that the trapped air or vapors formed by the heating easier from the fiber composite structure 10 out into the space and can be deducted via the connected vacuum pump. This allows the fiber composite structure 10 to consolidate as far as possible without the formation of air bubbles or with only very small air inclusions or pores and thus to form a high-quality laminate of high quality.

It is also conceivable that during the compression of the fiber composite structure, a detection of blistering is performed. For example, the (sub) pressure prevailing in the interspace can be measured with a pressure sensor and evaluated by the control unit. If a rapid increase in pressure is measured, the control unit can evaluate this as the formation of a bubble, for example by evaporation of liquid. Alternatively or additionally, it is also possible to provide the surface of the fiber composite structure 10 with the help of a thermal camera in the form of a thermal image to capture and evaluate. The control unit can pay attention to the occurrence of local hot spots or local cold spots in the thermal image. A local hot spot, that is, a location at which the temperature of the fiber composite structure imaged in the thermal image 10 is significantly higher than the temperature in surrounding areas, for example, may indicate the presence of foreign bodies, which heat faster and higher under the influence of electromagnetic radiation, as the impregnating polymer. Conversely, a local cold spot, that is, a location where the thermal image indicates a significantly lower temperature than surrounding locations, may indicate an air or vapor bubble. This is because in the case of the presence of a bubble through the bladder, polymer and fiber material is displaced. Since hot polymer and fiber material emits more infrared radiation detected by the thermal imaging camera than a vapor or air bubble (even at the same temperature of the same), the thermal image at this point will therefore appear darker.

If the control unit detects bubbles in this way, the control unit can cause the vacuum pump to be throttled, so that the pressure in the intermediate space increases and there is less negative pressure. The cover 30 will be therefore less bending and the subsection A in which the cover 30 on the fiber composite structure 10 is supported by narrower. At the same time or alternatively, the control unit can also control the actuators 32 , in particular the pneumatic actuators, the cylinders 33 continue to extend and so the cover 30 to lift on the sides, which is also the subsection A in which the cover 30 on the fiber composite structure 10 supports, narrows. In this way, for improved ventilation of the fiber composite structure 10 , in particular a removal of the bubbles, be taken care of.

Having in this way the fiber composite structure 10 pressed and laminated to a laminate, also known as Tailored Blank, has been consolidated, and after the laminate is cooled, the cover can 30 be opened. This can be done easily by turning off the vacuum in the space and the cover 30 is lifted. However, it is preferred, in the reverse order to that in the 2A to 2D proceed as shown sequence. Thus, with continued negative pressure in the intermediate space, the actuators 32 , in particular the pneumatic actuators, pressurized with compressed air to the cover 30 to bend. The cover 30 Therefore, it bulges upwards at the lateral ends and dissolves locally from the consolidated laminate. Subsequently, the negative pressure in the intermediate space is successively reduced, so that the cover 30 gradually dissolves the laminate and the laminate in this way from the cover 30 peels. This has the advantage of making the laminate more reliable and non-destructive of the cover 30 can be separated.

While the use of pneumatic actuators as support means has been described above, this is not limiting, and other actuators may be used 32 or devices used to cover 30 opposite the pad 20 support. For example, hydraulic actuators, electromotive actuators or other actuators can also be used as support devices, in particular also servo actuators which, under the control of a control device, position the cover 30 in height and / or allow application of a predefined force.

The method may preferably be in a system (not shown) for consolidating a fiber composite structure 10 having a loading / unloading station, a pressing station and a cooling station.

In the loading / unloading station, the underlay can 20 for example, be made accessible to an operator so that the operator can apply a fiber composite structure, such as a taped structure, to the substrate 20 can place. About a provided in the system holder, for example, on the support frame or the support frame elements 31 the cover 30 can attack, the cover will 30 on or above the surface 20 placed so that the fiber composite structure 10 as above with reference to 2A described in the means of a sealing element 15 sealed space is arranged.

The underlay 20 can then, together with the fiber composite structure arranged thereon 10 as well as the cover also arranged above it 30 , are moved to the pressing station, in which the fiber composite structure 10 from the radiation sources 14 irradiated and heated, for example, to a temperature in the range between 200 and 400 ° C, depending on the impregnating polymer, to the core of the fiber composite structure 10 is molten. In the pressing station can be provided that a lifting table is arranged, which is preferably formed with a flat table surface to the pad 20 by a (not shown) conveyor, which provides for the transport in the plant to lift and so to spend in a well-defined position. Subsequently, the vacuum is built up in the space and the compression as further into the 2 B to 2D described executed.

After pressing is, preferably in a further applied vacuum, the entirety of pad 20 , Cover 30 and sandwiched fiber composite structure therebetween 10 moved to the cooling station.

In the cooling station, a cooling table may be provided, on which the pad 20 is dropped, or that can be raised to get in touch with the pad 20 to be brought. Also, a cooling device may be provided, which from above in contact with the cover 30 is brought. Alternatively, the cooling table, the pad 20 lift it up until the cover 30 is brought into contact with the cooling device. With the cooling table and the cooling device are the cover 30 and the pad 20 , as well as indirectly the fiber composite structure 10 cooled, for example, until the fiber composite structure 10 is cooled in the core to a temperature below 150 ° C, preferably below 100 ° C and the impregnating polymer solidified.

Subsequently, the whole of pad 20 , Cover 30 and sandwiched fiber composite structure therebetween 10 be moved to the loading / unloading station, in which the cover 30 be lifted and the operator ready to Laminate consolidated fiber composite structure can take.

Regarding 3A to 3C Now, a second embodiment of the invention will be described. The second embodiment differs from the first embodiment essentially in that spring elements 35 instead of the actuators used in the first embodiment 32 are provided. The spring elements 35 are preferred in the support frame elements 31 the cover 30 supported and support due to the inherent spring force the cover 30 opposite the pad 20 or the support frame elements 21 the underlay 20 from. The spring elements 35 can be executed as simple springs. However, it is preferred that the spring elements 35 be executed with a degressive spring characteristic. This can be achieved that at an initial load of the spring elements 35 , here due to the increasing negative pressure in the space, initially only a small compression of the spring elements 35 done so that as in 3B shown the cover 30 in turn undergoes a bend which the cover 30 in the narrow section A for supporting and supporting against the fiber composite structure 10 lets kick. With increasing negative pressure, and thus increasing load on the spring elements 35 , get the spring elements 35 in the range of flatter slope of the degressive spring characteristic, so that the spring elements 35 experience an increasingly greater compression and, accordingly, the lateral ends of the cover 30 increasingly lower. The subsection A in which the cover 30 on the fiber composite structure 10 is therefore increasingly expanding in width until the cover 30 finally over the entire surface in circulation on the fiber composite structure 10 comes and squeezes them as in 3C shown. Again, it may be provided again in a preferred manner that a control unit controls the vacuum pump so that a desired time profile of the (sub) pressure is set in the intermediate space, so as to take into account the spring characteristic of the spring elements 35 a desired course of the bending of the cover 30 , And thus to control a desired course of the pressing and / or to regulate.

To prevent excessive compression of the fiber composite structure 10 To avoid, as in the 3A to 3C further shown, preferably be provided, stop pieces 36 between the cover 30 and the pad 20 and / or between the respective support frame elements 31 . 21 provided. The stop pieces 36 are equal in height to the target thickness of the consolidated fiber composite structure 10 sized. The stop pieces 36 For example, they can be made of a metal. Preferably, the stop pieces 36 However, formed of a temperature-resistant plastic material, in particular with low specific heat capacity. This has the advantage that these stop pieces 36 during cooling of the fiber composite structure 10 also cool down quickly and it does not come to an effect that the stop pieces 36 Stay hot beyond the cooling process and next time you apply a fiber composite structure 10 These are heated prematurely and undesirably locally, which could lead to uneven compression and consolidation. The stop pieces 36 can be between the fiber composite structure 10 and the sealing element 15 be arranged. Alternatively and preferably, these stop pieces can also after or behind the sealing element 15 be arranged to respond flexibly and quickly to a changed target thickness of the fiber composite structure without this on the sealing element 15 to pay special attention, as this can remain in place.

A third embodiment of the invention is in the 4A and 4B described. As shown, spacers are in this embodiment 40 provided between the pad 20 and the cover 30 and / or optional corresponding support frame elements (in 4A and 4B not shown) are arranged. The spacers 40 For example, you can fix it with the pad 20 be connected. The spacers 40 have a height that is the target thickness of the fiber composite structure to be consolidated 10 corresponds, in addition to a small oversize, preferably in the range between 0.1 and 0.5 mm. The spacers 40 may also be formed of metal or preferably made of a temperature-resistant plastic material, in particular with low specific heat capacity. The spacers 40 are preferably at a distance between 20 and 200 mm from the outer edge of the fiber composite structure 10 arranged.

As in the 4A and 4B shown have the spacers 40 also the effect, the cover 30 support so that it under the influence of the negative pressure in the space in turn to a bend of the cover 30 comes.

The embodiments described above are particularly suitable for pressing and consolidating flat fiber composite structures 10, that is, fiber composite structures 10 which have a substantially uniform thickness. However, for many applications and applications of fiber-reinforced components, there is a requirement that these components should have local reinforcements, for example, in component areas where later hinges are to be applied, or at which a connection to other components should take place. For such applications are already the fiber composite structures 10 , for example, as Tapelegeverfahren trained Tailored Blanks, laid with appropriate locally reinforced sections. To such locally reinforced, raised fiber composite structures 10 To compress and consolidate into a laminate is, with a further preferred embodiment, as in 5A and 5B shown, provided a customized cover 30 ' to use.

The 5A shows schematically a fiber composite structure 10 ' , which here by way of example in a central region a locally reinforced section with a survey e having. Next is provided, the cover 30 ' with one of the survey e corresponding cavity K train. The cavity K in the cover 30 ' can be formed for example by milling. In the 5B giving a view of the cover 30 ' shows from below, it can be seen that the cavity K the assessment e with a circumferential gap S surrounds. The gap S in this case preferably has a width between 3 and 15 mm, particularly preferably between 5 and 10 mm. By having such a gap S is provided, a free flow channel is provided via the under the effect of the negative pressure and by means of the vacuum pump (not shown) in the fiber composite structure 10 ' especially in the area of the survey e , trapped air or sucked by the heating vapors and can be removed.

The free flow and removal of air and vapors is in particular the bending of the cover 30 supports, as described above, which can ensure that the gap S to one side of the cover 30 only late in contact with the surface of the fiber composite structure 10 ' comes and thus closed, at which time already a substantial extraction for the area of the survey e took place. Alternatively or additionally, an active ventilation of the gap S be provided, for example by the pressure in the space temporarily increased, or the vacuum is reduced, and / or the cover 30 ' is raised to at least partially reduce the overlay of the cover 30 ' on the fiber composite structure 10 ' to achieve and so a venting of the gap S to enable. It may also be contemplated to provide a vent passage, for example, as a narrow groove in the surface of the cover 30 ' is incorporated, or as a bore, extending through the cover 30 ' extends through and is also connected to the vacuum pump. Other types of ventilation of the gap S are also possible.

Like from the 5A and 5B to recognize form the fiber composite structure 10 ' and the cover 30 ' largely complementary geometries, so that the overall geometry of pad 20 , Fiber composite structure 10 ' and cover 30 ' overall has a substantially plate-shaped shape of constant thickness.

It is thereby taken advantage of the fact that in particular designed as a glass plate cover 30 ' has a largely similar heat capacity as that usually in fiber composite structures 10 ' used material. For this reason, with the same surface beam power of the radiation sources 14 the locally reinforced section of the survey e that is, the thicker portion of the fiber composite structure 10 ' , due to the thinner glass layer of the cover at this point 30 ' be heated in the same time as at the thinner thickness locations of the fiber composite structure 10 ' the case is.

The cavity K is preferably designed with undersize to compensate for the shrinkage of the material by the consolidation.

Like in the 5B can be seen further, the cavity K preferably with undercut corner radii H trained, so that surveys e can be processed with sharp edges suitable. This is particularly advantageous if the fiber composite structures to be pressed and consolidated are formed by a tape laying method, in which conventional rectangular tape sections are processed and laid to form a desired fiber composite structure.

The one with a cavity K provided cover 30 ' may be suitable as a cover 3 or 30 in the consolidation and / or reciting methods described herein and / or recited, the said methods are suitable for consolidating fiber composite structures 10 . 10 ' to be trained with height jumps.

Regarding 6 continues to be an exemplary embodiment of the radiation sources 14 explained. As in 6 shown include the radiation sources 14 preferably a plurality of infrared tubes 51 . 52 extending across the cover 30 or to the document 20 extend. The infrared tubes 51 . 52 are preferably designed and arranged to produce a uniform surface-related radiation power in order to heat the fiber composite structure as evenly as possible 10 to enable. Particularly preferred is provided that the infrared tubes 51 . 52 individually or in groups can be switched selectively, so that, depending on the size, shape and location of the fiber composite structure 10 only necessary areas are irradiated. In the example of 6 For example, the infrared tubes 52 which are over the fiber composite structure 10 extend, while the infrared tubes 51 which the fiber composite structure 10 do not overlap, remain off. This can be used to save energy and thus reduce costs. It can also be provided that in regions in which irradiation with infrared light is only partially required or desired, a shading element 55 is provided to prevent in this area in which no share of the fiber composite structure 10 is the cover 30 or the pad 20 irradiated and heated, or get the upper and lower radiation sources 14 in this area due to the non-existent fiber composite structure 10 through the cover 30 and the pad 20 alone heat each other and suspend each other thermal stress and possibly premature aging.

LIST OF REFERENCE NUMBERS

1, 10, 10 '

Fiber composite structure

2.20

document

3, 30, 30 '

cover

4, 14

radiation source

5, 15

sealing element

6

pipe socket

21

Supporting frame element

31

Supporting frame element

32

actuator

33

cylinder

35

spring element

36

stop piece

40

spacer

51, 52

infrared tubes

55

Abschattelement

A

part Of

e

survey

H

corner radius

K

cavity

S

gap

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

• WO 2014/083196 A1 [0007]
• US8048253 [0007]
• DE 102014004053 A1 [0009]

Claims (7)

Apparatus for consolidating fiber composite structures (10, 10 ') with at least one thermoplastic and / or thermoelastic polymer, comprising a plate-shaped base (20); a plate-shaped cover (30, 30 '); a sealing element (15) for displaceably sealing the cover (30, 30 ') with respect to the base (20); at least one radiation source (14) for generating electromagnetic radiation for heating the fiber composite structure (10, 10 ') by means of electromagnetic radiation, preferably at least up to the range of the melting temperature of the at least one thermoplastic and / or thermoelastic polymer; and a vacuum pump for creating a negative pressure in the space between the base (20) and the cover (30, 30 ') so that the ambient pressure presses the cover (30, 30') against the base (20) and the fiber composite structure (10 , 10 ') is pressed between the cover (30, 30') and the base (20), characterized in that the device further comprises support means provided in the region of at least two opposite sides of the cover (30, 30 ') are, the cover (30, 30 ') relative to the support (20) supported so as to counteract caused by the negative pressure in the intermediate region, in the downward direction of the cover (30, 30') acting force and thus a bending of the cover (30, 30 ') to effect. Device after Claim 1 , characterized in that the cover (30, 30 ') on at least two opposite sides in each case a support frame element (31), and / or the base (20) on at least two opposite sides in each case a support frame element (21). Device according to one of Claims 1 to 2 , characterized in that the support means are each formed as one or more actuators (32), in particular as pneumatic actuators, hydraulic actuators or electromotive actuators. Device according to one of Claims 1 to 3 , characterized in that the support means are each formed as spring elements (35). Device according to one of Claims 1 to 4 , characterized in that the cover (30, 30 ') and / or the base (20) is formed as a glass plate or comprises. Device according to one of Claims 1 to 5 characterized in that the apparatus comprises a sensor for detecting the pressure in the gap and / or a thermal imaging camera for acquiring an image of the temperature distribution in the fiber composite structure (10, 10 '), the apparatus further comprising a control unit which is arranged upon detecting a sudden increase in pressure or a local cold junction detectable in the thermal image relative to a hot environment, it is determined that a bubble is present and, in the presence of a bubble, instructing the vacuum pump and / or the support devices designed as actuators to temporarily increase the pressure in the intermediate space and / or to lift the cover (30, 30 ') in order to at least partially reduce the support of the cover (30, 30'), in particular the reduction of the support of the partial section (A) on the fiber composite structure (10, 10 ') and to allow a local venting path for evacuating the air or the vapor. Plant for consolidating a fiber composite structure (10, 10 '), comprising a loading / unloading station, a pressing station, and a cooling station, characterized in that the installation comprises a device according to one of the Claims 1 to 6 in the loading / unloading station, the substrate (20) occupied by a fiber composite structure (10, 10 ') or to provide the substrate (20) for occupation with a fiber composite structure (10, 10'), and positioning the cover (30, 30 ') over the base (20), moving the base (20) and the cover (30, 30') with the fiber composite structure (10, 10 ') placed therebetween to the pressing station in the pressing station to heat the fiber composite structure (10, 10 ') by means of the at least one radiation source (14) preferably at least to the melting temperature range of the at least one thermoplastic and / or thermoelastic polymer, and by means of the vacuum pump to reduce the negative pressure in the intermediate space for pressing the fiber composite structure ( 10, 10 ') between the cover (30, 30') and the base (20) to produce; after pressing, to move the base (20) and the cover (30, 30 ') with the compressed fiber composite structure (10, 10') placed therebetween to the cooling station, in the cooling station, the assembly (20), cover (30 , 30 ') and the inter-fiber composite structure (10, 10') to be cooled; after cooling, move the base (20) and the cover (30, 30 ') with the fiber composite structure (10, 10') placed therebetween to the loading / unloading station; and in the loading / unloading station, lifting the cover (30, 30 ') from the base (20) to remove the consolidated fiber composite structure (10, 10') from the base (20) or to Removal of the underlay (20) covered by the consolidated fiber composite structure (10, 10 ').

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