Exemplary embodiments of the present invention relate to a semi-finished textile for producing a fiber composite component part, a device for producing a semi-finished textile for producing a fiber composite component part, and a method for producing a semi-finished textile and the use of a semi-finished textile.
Fiber composite component parts are used in aircraft, due to a favorable relationship between static properties and weight. However, fiber composite component parts are also gaining increasing interest in automotive engineering and other applications for these reasons. Fiber composite parts have high-performance fibers, for example, carbon or glass fibers, which are embedded in a matrix structure. In the production of a fiber composite component part, the high-performance fibers are provided in the form of semi-finished textiles and precut according to the component part geometry. The precut parts are placed into a mold, or also onto a mold, that already has, as a rule, the three-dimensional dimensions of the completed component part. The precut parts placed into the mold are described as preform. The term preform relates to joined, semi-finished dry fiber materials, whereby the semi-finished materials can have a binder to connect the reinforcement-fibers or high-performance fibers with each other for better handling, to be able to fixate the preform, or to modify the material properties. After insertion of the precut pieces, the matrix material is added into the mold, usually by suction, injection or force fitting, and a subsequent hardening, for example, by subjecting it to temperature and pressure. During hardening, a connection takes place between the high-performance fibers and the matrix material into a fiber composite material.
German Patent Document DE 10250826B4 discloses a method for the production of a three-dimensional preform consisting of textile starting materials that are deposited two-dimensionally in one layer and subsequently, the three-dimensional target shape of the preform is produced by shaping or draping of the two-dimensional fabric. It has been shown, however, that the handling of the precut parts of the semi-finished textile is difficult and thereby labor-intensive because of the instability of the textile. Moreover, inaccuracies can occur during placement in the assembly of the preform. As the result of the two-dimensional application of a binder on the semi-finished material, the precut can be handled easier, but such a semi-finished material is no longer suitable for use in complex component part shapes, as the binder limits the deformability.
Thus, there is a need to provide a semi-finished textile that can be handled easily and which is suitable for use in complex shapes of component parts.
This is achieved in accordance with exemplary embodiments of the present invention by a semi-finished textile, a device for the production of a semi-finished textile, as well as a method for producing a semi-finished textile, and the use of a semi-finished textile as cited in one of the independent claims.
According to an exemplary embodiment of the invention, a semi-finished textile for the production of a fiber composite is provided that has a textile structure and a fixation structure. The textile structure has a first multitude of reinforcement-fiber bundles comprising or consisting of high-performance fibers, whereby displacement sections are formed between two adjacent reinforcement-fiber bundles, and adjacent reinforcement-fiber bundles can be displaced against each other. The fixation structure fixates the reinforcement-fiber bundles—depending on the textile structure—with a fixation pattern in such a way, that the reinforcement-fiber bundles are at least partially fixated and the displacement sections remain at least partially free.
Reinforcement-fiber bundles include, for example, a number of individual carbon or glass fibers, which are assembled into a bundle.
According to an additional exemplary embodiment of the invention, the reinforcement-fiber bundles are connected with each other. The fixation structure has a binder, which fixates the reinforcement-fiber bundles with the fixation pattern at least partially.
According to a further aspect of the invention, the binder is a powder or a liquid.
According to a further aspect of the invention, the binder is applied in a coating pattern.
According to a further aspect of the invention, the coating pattern corresponds to the fixation pattern.
According to a further aspect of the invention, the reinforcement-fiber bundles are located parallel to each other.
According to a further aspect of the invention, the reinforcement-fiber bundles are woven together or are present in several, although parallel internally, in layers that are not parallel to each other.
According to a further aspect of the invention, the textile structure is located in a first layer, and the fixation structure in a layer that is adjacent to the first layer.
According to a further aspect of the invention, the fixation structure lies two-dimensionally against the textile structure.
According to a further aspect of the invention, the displacement sections are designed as displacement zones.
According to a further aspect of the invention, several layers of reinforcement-fiber bundles are provided, and the fixation takes place only at the outer layers.
According to a further aspect of the invention, several layers of reinforcement-fiber bundles are provided, and the fixation is provided at the outer layers as well as at one or more inner layers.
According to a further aspect of the invention, the fixation takes place by means of the fixation structure at the reinforcement-fiber bundles in the section of the center of the reinforcement-fiber bundles. The term “center” relates, for example, to the center of that lateral surface, at which the fixation structure lies against the respective reinforcement-fiber bundle.
According to a further aspect of the invention, the fixation structure has a connection structure, which connects the reinforcement-fiber bundles with each other.
According to a further aspect of the invention, the connection structure has a multitude of connection elements.
According to an exemplary embodiment of the invention, the connection structure includes a second multitude of connection elements that have a binder. The connection elements are connected by melting the binder with the reinforcement-fiber bundles.
According to a further aspect of the invention, the connection elements are conglutinated with the reinforcement-fiber bundles.
According to a further aspect of the invention, the fixation structure has a melting pattern in the form of the fixation pattern.
According to a further aspect of the invention, the connection elements are connected with the reinforcement-fiber bundles by a binder, whose compositing effect or adhesive effect is activated by the application of pressure.
For example, a binder that develops its adhesive or connecting effect by way of other types of exposures can also be used.
According to an exemplary embodiment of the invention, the fixation pattern is a line pattern or a dot pattern that is formed in relation to the textile structure.
In other words, a fixation pattern is provided that depends on the predetermined structure of the reinforcement-fiber bundles that are arranged into a textile structure. Thereby, the fixation pattern is independent of the precut shapes, i.e., formed independent of its subsequent use.
According to a further aspect of the invention, the textile structure is a woven fabric, in which the fiber bundles cross. For example, a dot pattern is provided as a fixation pattern.
According to an exemplary embodiment of the invention, the fixation pattern extends over the entire surface of the semi-finished material. Thus, the fixation pattern is not only provided for certain shapes on the semi-finished material, but independent thereof, and only in direct dependence of the textile structure.
According to an exemplary embodiment of the invention, the fixation structure has a multitude of meltable binder yarns.
According to a further aspect of the invention, the meltable binder yarns have binding material extending over their entire length, which is activated during the application of the fixation pattern only at those positions, however, at which a fixation is to take place.
According to a further exemplary embodiment of the invention, the fixation structure has a meltable fibrous web binder.
According to a further aspect of the invention, the meltable fibrous web binder has binding material extending over its entire (open) surface, which is activated during the application of the fixation pattern only at those positions, however, at which a fixation is to take place.
According to a further aspect of the invention, meltable binder yarns are combined with a meltable fibrous web binder.
According to a further exemplary embodiment of the invention, the fixation structure is a binder powder.
For example, a fixation structure can also exist independent of the binder, which is itself not partially melted, but is activated to connect by the binder.
The binder is, for example, only fixated in the sections of the fiber bundles at which no displacements occur, so that it affects the deformability in the least possible way.
For example, in the case of a fibrous web, the objective of holding the semi-finished material together can be primarily performed by something different, e.g., by a textile yarn that holds together a non-crimp fabric in the direction of through-thickness.
According to one aspect of the invention, the fibrous web binder is fixated on the textile structure so that it does not fall off, but just so, that this fibrous web binder does not impair the deformation. The textile would also hold together itself, even without the fibrous web binder, exactly because it also has a different fixation structure, or because in the case of a woven fabric, it consists of reinforcement-fibers that are woven together. In the case of a binder yarn it is actually often the case that it also holds the textile together, but it must not necessarily be so.
According to one aspect of the invention, the powder is first applied two-dimensionally, and then fixation takes place only at the positions of the corresponding pattern.
According to a further aspect of the invention, the un-fixated part of the powder then remains on the semi-finished material.
According to a further aspect of the invention, a removal of the un-fixated part takes place, for example, by suction, shaking off, or the powder simply falls off.
According to one aspect of the invention, the powder is applied precisely only in the provided pattern and fixated at those positions.
According to a further aspect of the invention, the binding material is applied, for example, in hot, molten form in the corresponding pattern. The binder can also be applied in a different form, for example, in liquid or at least viscous form, i.e., as viscous mass, which can be achieved, for example, by a solvent.
For example, the binder is thereby applied according to a pattern, which is guided by the textile structure, so that the displacement sections remain free.
According to a further aspect of the invention, the semi-finished textile includes a binder component that is needed in a subsequent processing step for binding several layers of textiles.
The invention also relates to the use of a semi-finished textile according to one of the embodiments described above.
According to the invention, a device for producing a semi-finished textile for producing a fiber composite part is also provided with a system for feeding a semi-finished textile and a system for applying the fixation pattern. The semi-finished textile has a textile structure and a fixation structure, whereby the textile structure has a first multitude of reinforcement-fiber bundles consisting of high-performance fibers. Between adjacent reinforcement-fiber bundles, displacement sections are formed, so that the adjacent reinforcement-fiber bundles can be displaced against each other. Further, a system for applying a fixation pattern for fixating the reinforcement-fiber bundles is provided, whereby the fixation pattern is formed depending on the textile structure in order to fixate the reinforcement-fiber bundles in such a way that the reinforcement-fiber bundles are at least partially fixated and the displacement sections remain at least partially free.
According to a further aspect of the invention, the reinforcement-fiber bundles are located parallel to each other. For example, the textile structure consists of a layer with reinforcement-fibers that are located exclusively parallel.
According to a further aspect of the invention, the textile structure has several layers with different orientation. Within one layer, the fibers are respectively parallel, for example, but the respective layers are not parallel.
According to a further aspect of the invention, the reinforcement-fiber bundles are woven together or are present in several, although within the layer parallel, but in layers that are not parallel to each other.
The fixation pattern is for the connection of the fixation structure with the reinforcement-fiber bundles, whereby the fixation pattern is designed depending on the textile structure, in order to fixate the fixation structure at the reinforcement-fiber bundles in such a way that the displacement sections between adjacent reinforcement-fiber bundles are formed, so that adjacent reinforcement-fiber bundles can be displaced against each other.
According to an exemplary embodiment of the invention, the system for applying the fixation pattern has sections having different temperatures, whereby first sections are provided with higher temperatures that bring about a melting of a binder which is in the connection elements, and second sections with lower temperatures that prevent a melting of the binder or preclude it.
According to one aspect of the invention, the system for applying the fixation pattern is a roller with some hotter and some cooler sections.
To apply the powder or binder mass only in a certain pattern, the roller can also be designed in such a way that it only takes on binder at hot positions and applies such to the textile only at these positions.
The roller can also be completely hot and the binding material discharges from the roller only at certain positions.
According to a further example, the roller is smooth and on a side facing away from the textile, binding material is applied to the roller according to the pattern, for example, applied by brush or dripped on, and the binding material is then applied onto the textile after rotating the roller.
According to a further aspect of the invention, the roller also applies pressure to the semi-finished textile. For example, as a result of the sections having different temperatures, different levels of pressure are also applied to the semi-finished textile.
According to a further aspect of the invention, the hotter and cooler sections form a linear pattern, whereby the line structure of the roller is located radially in the circumferential direction.
According to a further aspect of the invention, the line structure is arranged axially, i.e., perpendicular to the direction of rotation.
According to a further aspect of the invention, the line structure is designed at an angle to the direction of production, for example 30°, 45°, 60° or at a different angle.
According to a further aspect of the invention, the hotter and cooler sections form a dot-shaped pattern.
The invention also relates to the use of a semi-finished textile according to one of the embodiments described.
According to the invention, a method for producing a semi-finished textile for producing a fiber composite part is also provided, which includes the following steps:
a) Assembling a textile structure from a first multitude of reinforcement-fiber bundles consisting of high-performance fibers, whereby displacement sections are formed between adjacent reinforcement-fiber bundles and adjacent reinforcement-fiber bundles can be displaced against each other;
b) Placing a fixation structure on the textile structure; and
c) Fixating the reinforcement-fiber bundles with the fixation structure by applying a fixation pattern depending on the textile structure, whereby the fixation structure fixates the reinforcement-fiber bundles in such a way that the reinforcement-fiber bundles are at least fixated partially and the displacement sections remain at least partially free and, for example, adjacent reinforcement-fiber bundles can be displaced against each other.
For example, the displacement sections between adjacent reinforcement-fiber bundles are left free or un-fixated. Adjacent reinforcement-fiber bundles can continue to be displaced against each other.
For example, the textile structure already has displacement zones, namely between adjacent fiber bundles. As a result of the fixation structure, the displacement sections are, for example, not created, but precisely in this section there is no fixation. The reinforcement-fiber bundles themselves are not displaced in the process, only the possibility of displacing them continues to exist. The displacement of the reinforcement-fiber bundles then takes place, for example, upon depositing on the component part geometry. If the semi-finished material were to be fixated two-dimensionally, i.e., without displacement sections, this possibility of displacement would no longer exist, i.e., there would also not be any deformability that is as free as possible.
According to one aspect of the invention, the term “placing” in step b) also relates to other methods in which the fixation structure is brought into contact with the textile structure as two-dimensionally as possible or is positioned in such a way in direct proximity to the textile structure that subsequently, the connection according to step c) can take place.
The previously described aspects for applying the fixation structure also relate to the application of a powder binder or a liquid binder, as has already been explained in detail above.
One aspect of the invention involves a semi-finished textile in which the individual reinforcement-fiber bundles, although they are connected with each other, and can thus be handled easier, however the fixation depending on the textile structure is designed in such a way that the semi-finished textile is still deformable. In a deformation of the semi-finished textile, displacements occur most often only at border positions between adjacent fiber bundles, which are also described as rovings. This is also the case when this roving structure is not even directly visible any longer. As it is provided according to the invention that these displacement positions are not fixated, the semi-finished material can be deformed. This is, for example, achieved thereby, that a binder lies only loosely above the displacement positions, or is not present at all.
One advantage of the invention is that when producing a fiber composite component part, the semi-finished textile can be cut into the required precut shape, and can subsequently be easily handled and directly placed into the preform. Thereby, the semi-finished textile according to the invention is also suitable for use in more complex component part shapes, as the semi-finished textile can also be adapted to those types of shapes because of the displacement sections that have been left free. Stabilization adapted to the respective precut part of a precut textile is not required.
In addition to the better manageability, according to a further aspect of the invention a binder is provided, that is used in the production of the preform, in order to, after a deformation process, for example, while being placed onto component part geometries, conglutinates several layers of textile with each other. For example, the binder is to be available prior to conglutination, but during deformation prior to conglutination, it is to disrupt as little as possible.
According to a further aspect of the invention, the binder yarns have binding material only at those position at which subsequently also a connection is to be established during the application of the fixation pattern.
It should be noted that the characteristics of the exemplary embodiments of the semi-finished textile of the device for producing the semi-finished textile also apply to the embodiment forms of the method and the use of a semi-finished textile and the reverse.