WO2012069123A1 - Preform and production device for fiber composite components made from preforms - Google Patents

Abstract

The invention relates to a preform (1) for producing fiber composite components, wherein a plurality of additional fibers (2) are arranged in the preform (1) in addition to the fibers (2') that constitute the preform. The additional fibers comprise a paramagnetic or ferromagnetic material. The invention further relates to a preform processing device for preforms (1), comprising at least one forming tool having a die (10) for accommodating the preform (1). A plurality of electromagnets (12) is arranged in the die (10) near a surface of the die (10) that forms a forming contour (11), and the magnetic fields produced by the electromagnets (12) can be developed according to the arrangement of the magnetic additional fibers (2) of the preform (1) in the forming contour (11). The preform processing device comprises a control device, which is coupled to the electromagnets (12) in order to control the electromagnets. The invention further relates to a method that is suitable for the large-scale production of fiber composite components from the preforms (1).

Description

 Daimler AG

Preform and manufacturing device for fiber composite components from preforms

The present invention relates to a preform with additional fibers which are para or ferromagnetic for the manufacture of fiber composite components. Next, a preform processing device for such preforms and a method which is suitable for large-scale production of fiber composite components from the preforms, the subject of the invention.

To date, in the conventional production of fiber composite plastic components, the components must be brought by a variety of finishing steps to final dimensions, because in the implementation of particular forming and impregnation often an inaccurate arrangement of the preforms in the appropriate tool, resulting in a reshaped preform, respectively Semi-finished leads, which does not have the desired final dimension with the required precision. This is caused, inter alia, by the fact that especially dry fiber arrangements or moist or semi-moist preforms are very difficult to transport and can result in distortion of the fibers. It must be performed steps such as cutting, drilling, milling, grinding or deburring, which are therefore time consuming and costly. As a result, the high-production suitability of fiber composite plastic components is adversely affected, especially with more complex geometries.

In order to optimize the production of plastic components accordingly and to provide mass production capability, a device and a method for producing a plastic component is already known from DE 10 2007 002 309 A1. There, the quality of at least one of the sides of the plastic component should already be optimized from the outset in such a way that this side can be regarded as almost finished. For this purpose, DE 10 2007 002 309 A1 provides an apparatus for producing a plastic component which has a fabric layer and which has at least one high and one low quality side, in front of which the nozzle through which the plastic is introduced into the cavity of a molding tool , is arranged on the side of the plastic component, which is of lower quality, so that the plastic from just this side into the cavity the mold is introduced so that either only one side must be processed or, if it does not depend on high quality on this page, a post-processing can be omitted. There, it is provided to fix the fabric layer in the mold by magnetically acting means, which is why the fabric layer can be made ferromagnetic. This is to prevent the fabric layer from slipping during injection in the mold.

The magnetic properties of the fabric layers should also be able to be provided afterwards by adhering the fabric layers with iron-containing pads. The method thus requires separate coating steps to coat the tissue, or it requires the placement of the pads.

If the fabric-containing component produced in the casting mold is removed from the mold before it has finally hardened, there is still a risk of deformation or distortion, in particular in edge areas, so that reworking steps may become necessary.

On the basis of this state of the art, the object is to provide on the one hand a preform which can be deformed in a secure manner without the fibers, which are explicitly stored in the flow of force, being displaced in the preform.

This object is achieved by a preform with the features of claim 1.

Furthermore, the object of providing a manufacturing device, which makes it possible to reshape the preforms according to the invention in a suitable manner, while ensuring that the fiber orientation and positioning in the tool does not change during the forming. The preform processing device with the features of claim 5 solves this problem.

Next, the task of providing the method, which is suitable to produce fiber composite components from preforms mass production technology while avoiding post-processing steps. This object is achieved by the method having the features of claim 10.

Further developments of the devices and the method are carried out in the corresponding subclaims. In a first embodiment of a preform according to the invention, from which fiber composite components can be produced, a plurality of additional fibers is advantageously arranged in addition to the preform constituent fibers, wherein the additional fibers have a para or ferromagnetic material.

The additional fibers may themselves be made of the para or ferromagnetic material, or they are merely coated with it. According to the invention, such additional fibers are advantageously provided at areas of the preform which form the component contour or break-through lines of the fiber composite component.

This advantageously achieves that in the positioning and forming of the preform in a forming tool of a preform processing device according to the invention or during transport of the preforms with a gripping device, both, forming tool and gripping device, the arrangement of additional fibers in the preforms correspondingly arranged electromagnets, none Deformation, or no change in the fiber orientation and positioning of the preform occurs, so that the preform once shaped with retained therein flow oriented fibers with the desired quality is maintained, even if it must be handled in further process steps.

This allows in particular, fiber mats, which are particularly difficult to transport due to their limp state, safely and maintain quality and continue to process.

An embodiment of a processing device for preforms suitable for this purpose according to the invention provides for this purpose at least one forming tool with a die, which receives the preform for forming. In the die, a plurality of electromagnets are arranged near a surface which forms the forming contour of the die. The magnetic fields generated by these electromagnets can be advantageously formed so that they correspond to the arrangement of the additional magnetic fibers in the preform.

Furthermore, the processing device has a control device which is coupled to the electromagnets for their control, so that the magnet can be switched on, switched off or reversed; also the magnetic strength can be adjustable. This embodiment of the forming tool according to the invention makes it possible for the additional magnetic fibers present in the preform, and thus the entire preform, to remain exactly in position due to the corresponding arrangement of the electromagnets in the die once they have been arranged in the die. Thus, the preform is held at many points temporarily in the die, so that slipping and shifting of fibers does not result even if pressure is exerted on the preform in later steps or the casting material, in particular resin, is injected into the tool ,

It is particularly advantageous if the edges of the preform and the subsequent component contours are contoured with additional fibers; Also, the break-through lines of the later fiber composite component are advantageously reinforced with additional fibers, so that slipping and shifting of fibers or warping of the edge regions is excluded precisely at these positions by the electromagnets in the die of the forming tool just at this the component contours, etc. forming Arranged areas. This ensures that post-processing to achieve the desired final dimension can be omitted.

Furthermore, in a further embodiment, the processing device according to the invention has a transfer robot with a corresponding robot arm, on which a gripping device for picking up and transporting the preform is arranged. The inventive gripping device disclosed herein has a plurality of electromagnets disposed in the gripping device near a receiving surface provided on the underside of the gripping device facing the preform, such that the magnetic fields formed by the electromagnets correspond to the additional magnetic fibers disposed in the preform , Further, the receiving surface of the gripping device has a size and shape corresponding to the size and shape of the male preform. The processing device, which comprises the transfer robot in addition to the forming tool, has a control device with which the electromagnets of the gripping device can also be controlled. Of course, a separate control device for the electromagnets of the gripping device could be provided. Again, taxes means at least turning on and off and reverse polarity. Further, control in all cases of the invention disclosed herein is also to be understood to mean adjustment of the magnetic field strength.

Thus, the gripping device can advantageously transport the preform over long distances or machining processes with arranged on the receiving surface preform run, without causing the slipping of the preform or to move the fibers of the preform.

Particularly advantageously, the receiving surface of the gripping device may have a shape that corresponds to the counter-shape of the forming contour of the die. As a result, the preform, when picked up by the gripping device, adopts the exact three-dimensional contour that it will acquire later during the forming, and it can be positioned particularly precisely in the die.

In addition, it is also advantageous that it also assists, after the removal of the preform from the die, in that the preform, which may be not only reshaped fibers but also fibers already impregnated with resin and thus a component blank, maintains its shape when removed from the die. Especially with dry textiles, it is hardly or not at all possible in the prior art to merely reshape fibers and to continue to transport the limp, deformed fibers while retaining their exact shape. This is easily and readily possible with the device according to the invention.

The removal of reshaped impregnated fibers or the removal of fibers that were soaked in resin only in the forming tool and are still wet when removed from the mold or from the die, designed with the help of designed as a counter-mold gripper problem and while ensuring the Form preserving the deformed preform and the position retention of the fibers in the preform or in the component blank.

The method according to the invention, which is suitable for mass production of fiber composite components from preforms, since special finishing steps such as the final dimensioning of the final form are superfluous because of the precise handling of the preforms, requires the use of a preform forming apparatus according to one embodiment of the invention described herein. as well as the use of the disclosed preforms according to the invention.

The method comprises the steps:

 Providing the preform and arranging the plurality of additional fibers in addition to the preform constituent fibers in the preform, wherein the additional fibers comprise a para or ferromagnetic material,

Transferring and positioning the preform in a die of the forming tool Preform machining device, wherein in the die near the forming the forming contour surface of the die, the plurality is arranged on electromagnets,

- By means of the control device of the preform processing device, driving the electromagnets in the die and forming the magnetic fields by the electromagnets according to the arrangement of the additional magnetic fibers of the preform in the forming contour, and

 - Perform a deformation of the preform.

Furthermore, the method can also provide that before carrying out the deformation of the preform, this was impregnated with resin. Again, there are various ways to make the impregnation of the preform. Thus, on the one hand, the preform can be impregnated with the resin in an impregnating device before the preform is transferred into the die and positioned there. However, it is also possible to impregnate the preform in the die with the resin by injecting the resin into the die. With the forming apparatus according to the invention in which the die having these electromagnets, the preform equipped with the magnetic fibers is securely held in the die by the attraction force even if resin is injected into it under pressure.

Even after carrying out the forming of the preform, the impregnation - exclusively or additionally - of the preform with resin can be carried out by feeding resin into the matrix. In the die, the positioned preform is held by magnetic attraction as described.

It is particularly advantageous if the transferring and positioning of the preform into the die takes place by means of the gripping device of the invention. This is not mandatory, other devices could be used for transfer and positioning. Since the gripping device has the described electromagnets, which can be set in motion by means of the control device of the preform forming device, the preform can be picked up by the gripping device at the desired time and transported safely and positioned in the die, without causing any displacement of fibers comes.

Furthermore, impregnation of the preform with resin in a separate impregnating device can advantageously also be carried out by using the gripping device according to the invention: this step requires switching on the transfer robot, respectively actuating the same, generating the magnetic fields, picking up the preform at the gripper Receiving surface and transferring the preform in the impregnating device; penetrate the resin into the preform and finally transfer the preform into the matrix and position it there.

After the forming in the preform has been carried out, the transfer robot can be restarted to remove the preform from the die by means of the gripping device. This is preceded by the fact that the electromagnets in the die have been switched off by the control device of the preform forming device or have been correspondingly reversed in order to release the preform for demolding.

These and other advantages are set forth by the following description with reference to the accompanying drawings.

The reference to the figures in the description is to aid in the description and understanding of the subject matter. The figures are merely a schematic representation of an embodiment of the invention.

Showing:

 Fig. 1 is a perspective view of the gripping device of the invention

 Preform forming device when positioning over a preform according to the invention,

 Fig. 2 is a perspective view of the gripping device according to the invention

 Preform forming device in the positioning of the gripping device on the die, in which a deformed preform according to the invention is arranged.

The present invention generally relates to the manufacture of fiber composite component parts for the automotive industry, explicitly in mass production scale.

Essential steps in the large-scale production of fiber composite component parts is the transfer of dry textiles, so-called preforms in a press shop, in which the deformation of the preform to the desired Bauteilrohteil takes place. In the known forming processes, which are formed with common transfer and forming tools, the preform, which may be a fiber mat in the simplest case, brought into the forming tool and held there, which by a clamping between the two tool components according to the thermoforming process takes place. This can result in the disadvantage that subsequently the reshaped textile or the component close to the endform has to be reworked, for example by trimming. Disadvantageously, this can lead to delamination and breaking due to the fiber structure in the preform. Furthermore, it is difficult to transport fiber mats due to their limp state. Even in the deformed state of the dry textile or the impregnated textile, which is still wet and must be spent for curing in other tools, may result in the transport changes in the fiber orientation or positioning, which is to avoid the flow of power appropriate arrangement of the To obtain fibers in the component.

Therefore, in the present invention, a preform is disclosed, see Fig. 1, which in addition to the fibers 2 'forming the preform comprises additional fibers 2 comprising a para or ferromagnetic material. The para or ferromagnetic material may either be the fiber material itself or a base fiber is coated with a para or ferromagnetic substance. As can also be seen in FIG. 1, the additional fibers 2 are expediently provided, in particular in the region, which form the component contour or break-through lines of the fiber composite component. This is clearly shown in FIG. 2, in which the preform can be seen in an already formed state.

In particular, the fibers which form the preform may already be preimpregnated with resin, so that the final shape of the component can already be produced in the forming tool by heating and pressure application without supplying further material. This is not absolutely necessary, of course, even more resin can be supplied in or immediately before the forming process in the tool, even if the fibers are pre-impregnated.

Such a preform according to the invention can be advantageously further processed and, in particular, reshaped while avoiding the aforementioned disadvantages of the reorientation of fibers, since the preform processing device has a forming tool with a die 10, see FIG. 2, into which the preform 1 is introduced.

In the die 10 near the surface, which forms the Umformkontur 11, many electromagnets 12, indicated by the coil-shaped strands 12, arranged. The arrangement of the electromagnets 12 is designed such that the magnetic fields generated by the electromagnets 12 are formed according to the arrangement of the ferromagnetic or paramagnetic additional fibers 2 of the preform 1 in the Umformkontur 11 when the generation of the magnetic field is generated by turning on the electromagnet 12 , This is done via a control device, which is also associated with the preform processing device, and which serves to drive the electromagnets 12 in the die 10. Once the field is applied, the inserted preform 1 is held precisely in the die 10, so that the fiber orientation is maintained in the subsequent forming processing. In particular, it is prevented that a shift of the fibers 2,2 'results in the edge region during processing.

As can be seen, the density of the additional fibers 2 is particularly great in areas which are to result in complex component contours. Thus, by the magnetic fixation of the fiber mat, respectively the preform 1 and the fibers forming this 2,2 ', in particular in the edge region, a rework and cutting-free production of a fiber composite component component blank possible. Thus, the production of such components with the device according to the invention is also suitable for large scale technology.

In order to transport the preform according to the invention, either before the forming, when the fiber mat 1 is to be transferred into the die 10 and positioned precisely on the forming contour 11, or after the forming, when the dry formed textile or even one moist, or uncured, deformed preform can be seen from the die 10, the preform processing device further comprises a on a robot arm 6 of a transfer robot 5, see Fig. 1, arranged gripping device 3. This is adapted to receive the preform 1 and then to transport because it is near its receiving surface 7, which is on the underside of the gripping mold 3, which faces the preform 1 during the transport process, has many electromagnets 4. The electromagnets 4 are also arranged such that the magnetic fields generated by them correspond to the arrangement of the magnetizable additional fibers 2 of the preform.

It is important that the receiving surface 7 of the gripping device has a size and shape that corresponds to the size and shape of the male preform 1, so that it can be completely and appropriately accommodated and positioned in a further processing device. It is to be prevented that just in the edge regions of the preform 1 fibers of the limp part hang down or reposition themselves.

The control device of the preform processing device is set up so that it also actuates the electromagnets 4 of the gripping device 3 to turn them on or off, umzupolen or to adjust the corresponding field strength. The receiving surface 7 of the gripping device 3 shown in FIGS. 1 and 2 advantageously even has a shape which corresponds to the counter-shape to the forming contour 11 of the die 10, which is advantageous in particular because the gripping device 3, after the forming process has been carried out, forms the reshaped, but not stiffened preform 1 can be removed from the die 10 and safely transport on.

The process shown in Fig. 2 indicates the gripper 3 immediately before receiving the die 10 to transfer the preform 1 approximately in a Aushärtwerkzeug. In this case, however, the electromagnetic device of the forming tool must be turned off, that is, the magnetic fields of the electromagnets 12 must be degraded to release the preform 1 undamaged. Correspondingly, the procedure is reversed with the gripper 3 when the gripper 3 deposits a preform 1: Even then, it is necessary for the electromagnets present in the gripper to be switched off or reversed in order to allow the preform 1 to be detached from the gripper 3.

Impregnation of the preform 1 with resin may be accomplished prior to performing the forming of the preform 1 and, thus, prior to transferring and positioning the preform into the die 10, but it is also possible to alternatively feed resin into the die 10 in which advantageous is held by generating the magnetic fields and fixed preform 1 is held. This advantageous fixing a change in the fiber orientation of the preform is prevented even during injection of the resin in the forming tool.

Of course, resin can also be supplied if the preforms 1 are already preimpregnated with resin. During forming, the additional fibers 2 are firmly taken up in the resin matrix of the preform 1 or of the expectant component blank. Alternatively, the impregnation of the preform 1 may also be carried out after carrying out the deformation of the preform 1 or in addition to a pre-impregnation after carrying out the deformation of the preform, in such a way that the resin is filled into the die 10, in which the positioned preform 1 held by attraction.

If the deformed and resin-added preform 1 is also allowed to cure in the forming device, which is quite possible if this device has the appropriate devices necessary for curing, such as a heater, the component blank is already produced in a finished state; Reworking for the purpose of a precise final Maßerzielung are no longer required by using the preform 1 according to the invention with the forming tool according to the invention. This allows tion steps are eliminated and the manufacturing process becomes cheaper. In addition, the quality of the component blanks can be increased.

By using the gripper according to the invention, the impregnation of the preform can also be carried out in or with an external impregnating device without difficulty: precisely when it is necessary to immerse the preform in an impregnating bath, this can be done in a suitable manner with the gripper which holds the preform by magnetic attraction precisely positioned and fixed. Other impregnation operations may provide for the impregnator to have spray nozzles and to spray the preform; It will usually happen before the transfer into the die 10 and therefore does not necessarily have to be done with the use of a gripper. However, the gripper 3 according to the invention is particularly suitable in the form designed as a counter-mold to the component blank, since the transfer can take place at any time, in a damp state or in a cured state, without the deformed preform or the component blank being damaged.

Thus, the device according to the invention, with which the presently described preforming processing steps can be carried out, offers the advantage that both the preform, if it is present as a dry textile, and the still moist preform or even the hardened component blank, in each processing step held securely and the fiber assembly can be maintained. This ensures the proper flow positioning of the fiber composite component constituting fibers and increases the quality of the component; Furthermore, in particular post-processing steps that serve a final dimension generation are unnecessary.

Claims

Daimler AG claims 1. preform (1) for the production of fiber composite components,  characterized in that  a plurality of additional fibers (2) in addition to the preform (1) constituent fibers (2 ') in the preform (1) is arranged, and wherein the additional fibers (2) comprise a para- or ferromagnetic material. 2. preform (1) according to claim 1,  characterized in that  the additional fibers (2) are obtained from the para or ferromagnetic material or are coated with the para or ferromagnetic material. 3. preform (1) according to claim 1 or 2,  characterized in that  the additional fibers (2) are provided at areas that form component contour or break-through lines of the fiber composite component. 4. preform (1) according to at least one of claims 1 to 3,  characterized in that  the preforms (1) constituting fibers (2 ') are pre-impregnated with resin. 5. Preform processing device for preforms (1) according to at least one of claims 1 to 4, wherein the preform processing device has at least one forming tool with a die (10) for receiving the preform (1), characterized in that in the die (10) near a forming contour (11) forming surface of the die (10) a plurality of electromagnets (12) is arranged, wherein the magnetic fields generated by the electromagnets (12) corresponding to the arrangement of the additional magnetic fibers (2) of the preform (1) can be formed in the forming contour (11), and wherein the preform processing apparatus comprises a control device coupled to the solenoid (2) for control. 6. The preform processing apparatus according to claim 5, wherein the preform processing apparatus further comprises a gripper device (3) arranged on a robot arm (6) of a transfer robot (5) for receiving and transporting the preform (1),  characterized in that  in the gripping device (3) near a receiving surface (7), which is present on one of the preform (1) facing bottom, a plurality of electromagnets (4) is arranged, wherein the magnetic fields generated by the electromagnets (4) corresponding to the arrangement of the magnetic Additional fibers (2) of the preform (1) can be formed on the receiving surface (7),  and wherein the receiving surface (7) of the gripping device (3) has a size and shape that corresponds to the size and shape of the male preform (1), and that  the preform processing device comprises a control device which is coupled for control with the electromagnets (4). 7. preform machining apparatus according to claim 6,  characterized in that  the receiving surface (7) of the gripping device (3) has a shape which is a counter-shape to the forming contour (11) of the die (10). 8. A method suitable for large-scale production of fiber composite components from preforms (1) according to at least one of claims 1 to 4, and using a preform machining apparatus according to at least one of claims 5 to 7,  comprising the steps  - Providing the preform (1) and arranging the plurality of additional fibers (2) in addition to the preform (1) constituent fibers (2 ') in the preform (1), wherein the additional fibers (2) comprise a para- or ferromagnetic material . Transferring and positioning the preform (1) in a die (10) of the Forming tool of the preform processing device, wherein in the die (10) near the forming of the forming contour (11) surface of the die (10) A plurality of electromagnets (12) is arranged,  - By means of the control device of the preform processing device driving the electromagnet (12) in the die (10) and forming the magnetic fields by the electromagnets (12) corresponding to the arrangement of the additional magnetic fibers (2) of the preform (1) in the forming contour (1 ), and  - Performing a deformation of the preform (1). 9. The method according to claim 8,  comprising the steps  before carrying out the forming of the preform (1) impregnating the preform (1) with resin, wherein the impregnation of the preform (1) by  Impregnating the preform (1) with the resin in an impregnating device before transferring and positioning the preform (1) in the die (10),  - Impregnating the preform (1) with the resin by supplying resin into the die (10), in which the positioned preform (1) is held by magnetic attraction, takes place. 10. The method according to claim 8,  comprising the steps  after performing the forming of the preform (1), impregnating the preform (1) with resin by feeding resin into the die (10) in which the positioned preform (1) is held by magnetic attraction. 1 1. A method according to at least one of claims 8 to 10,  wherein a component blank is created by the forming step. 12. The method according to at least one of claims 8 to 11,  comprising the steps  - Transferring and positioning the preform (1) in the die (10) by means of the gripping device (3), which near a receiving surface (7), which on one of the preform (1) facing underside, a plurality of electromagnets (4) , and - By means of the control device of the preform processing device driving the electromagnets (4) and generating the magnetic fields, while receiving the preform (1) through the receiving surface (7) of the gripping device (3), and - Actuation of the transfer robot (5), then by means of the gripping device (3)  Transferring and positioning the preform (1) in the Ivlatrize (10). 13. The method according to claim 12,  comprising the steps  - After pressing the transfer robot (5) and before transferring and positioning the preform (1) in the die (10), transferring the preform (1) in an impregnator and resin impregnation. 14. The method according to any one of claims 12 or 13,  comprising the steps  after forming the preform (1) actuating the transfer robot (5) and arranging the gripping device (3) in a removal position above the deformed preform (1),  Switching off or reverse polarity of the electromagnets (12) in the die (10) by the control device of the preform forming device,  - Remove the preform (1) from the die (10) with the gripping device (3). 15. The method according to claim 14,  comprising the step  - After removing the preform (1) from the die (10) with the gripping device (3) Transferring into a curing tool.