Device and method for infiltrating and spreading fiber rovings

Abstract

Device for infiltrating and spreading fiber rovings, comprising a feedthrough channel (2) for guiding the fiber roving (10) through it and an inlet section (3) with an inlet (4) for feeding the fiber roving (10) into the feedthrough channel (2) and an injection unit (5) for introducing an infiltration medium, wherein a wave-shaped spreading section (6) is formed immediately following the inlet section (3) in a feedthrough direction, through which the fiber roving (10) can be alternately displaced in a vertical direction, and wherein a spreading means for spreading the fiber roving (10) is formed on at least one elevation (7) of the wave-shaped spreading section (6), characterized in that the device is formed in two parts with a lower part (12) and an upper part (11) that is at least partially complementary in shape.wherein the spreading element, viewed in the direction of passage, is formed by V-shaped or W-shaped spreading legs, wherein the spreading element is formed on the elevations (7) of both the upper part (11) and the lower part (12).

Description

[0001] The invention relates to a device and a method for infiltrating and spreading fiber rovings according to the preamble of claim 1 or the preamble of claim 7.

[0002] Fiber rovings are used to manufacture fiber-reinforced composite components. They consist of bundles of parallel filaments or continuous fibers. Fiber materials used include, but are not limited to, carbon fibers or glass fibers.

[0003] Spreading separates the individual fibers of the fiber roving. Infiltration describes the introduction of an infiltration medium, in particular a resin or resin-hardener mixture, to produce the fiber composite component.

[0004] In the current state of the art, spreading and infiltration are carried out in two separate, sequential processes. A variety of different spreaders are used, such as static spreaders, pneumatic spreaders, or ultrasonic spreaders. The same applies to infiltration, which is carried out, for example, by roller infiltration or immersion infiltration.

[0005] However, a disadvantage is that, depending on the process, varying degrees of splitting occur on the fiber roving during spreading, which significantly impacts the spreading quality. Furthermore, at high spreading speeds, pronounced gaps form, which are exacerbated by discontinuous operation with varying fiber roving feed speeds. The main problem with infiltration lies in foaming at high process speeds. The high feed speed of the fiber roving introduces air into the infiltration medium, leading to unwanted foaming.

[0006] The prior art in the present technical field is disclosed in documents EP 2 589 465 A1, AT 403 448 B, DE 10 2009 004 357 A1 and DE 695 16 795 T2.

[0007] The invention is therefore based on the objective of providing a device and a method with which fiber rovings can be infiltrated and spread at high and discontinuous process speeds without foaming of the infiltration medium.

[0008] This problem is solved by the combination of features according to claims 1 and 7.

[0009] According to the invention, a device for infiltrating and expanding fiber rovings is proposed, comprising a feed channel for guiding the fiber roving through it and an inlet section with an inlet for feeding the fiber roving into the feed channel and an injection unit for introducing an infiltration medium. Immediately following the inlet section in a feed direction, a corrugated expanding section is formed, through which the fiber roving can be alternately displaced in a vertical direction. Furthermore, an expanding element for expanding the fiber roving is formed on at least one projection of the corrugated expanding section. This makes it possible to carry out the infiltration and expanding of the fiber roving simultaneously within a single device, without allowing air to reach the fiber roving wetted with the infiltration medium and expanded.This also allows the infiltration and spreading rates to be significantly increased and even discontinuous. Stops in the conveying of the fiber roving are even possible without negatively affecting its wetting or spreading.

[0010] In one embodiment of the device, it is advantageous that the wave-shaped spreading section is formed by at least two ridges and depressions directly adjacent to one another in the direction of passage. The repeated change of direction of the fiber roving in the vertical direction causes the infiltration medium to be forced through the fiber roving as it slides along the ridges in the vertical direction, thus completely penetrating it. Repeated sliding along the ridges and depressions results in improved homogeneous penetration.

[0011] According to the invention, the spreading element, viewed in the direction of passage, is formed by V-shaped or W-shaped spreading legs. The fiber roving slides into the narrowest section of the V- or W-shape and is accordingly spread out laterally. An advantageous solution is that several spreading legs are formed side by side and, in a top view, form a kind of shell shape. Such a shell shape is formed, for example, by several V-shaped spreading legs arranged side by side, which essentially share a starting point.

[0012] The device is further designed so that the injection unit for introducing the infiltration medium is arranged such that the infiltration medium adheres to the fiber roving as it passes by. Consequently, no active injection is required; instead, the fiber roving can carry the infiltration medium, particularly resin, along with it as it passes. It is also advantageous if the injection unit extends across the entire width of the device and introduces the infiltration medium evenly across this width into the feedthrough channel.

[0013] Furthermore, an advantageous embodiment involves the device being designed as a siphon and the feedthrough channel having a square or rectangular cross-section. The siphon is a closed body with no or almost no air in the feedthrough channel. Another embodiment provides for the feedthrough channel to be vacuum-sealed. The predetermined cross-sectional shape allows the fiber roving to spread laterally.

[0014] According to the invention, the device is designed in two parts, comprising a lower part and a complementary upper part. The wave-shaped spreading section is realized by both parts, each of which has protrusions and depressions. The respective protrusion of the lower part extends into the complementary depression of the upper part, and vice versa.

[0015] The invention also includes a method for infiltrating and spreading the fiber rovings, wherein a fiber roving is fed into a device as described above. Therein, the fiber roving is wetted with infiltration medium by the injection unit and immediately afterwards spread by the wave-shaped spreading section.

[0016] According to the method, the fiber roving is alternately offset in the vertical direction within the wave-shaped spreading section, so that the infiltration medium moves through the fiber roving in alternating directions, either once or several times, in the vertical direction.

[0017] Other advantageous embodiments of the invention are characterized in the dependent claims or are described in more detail below together with the description of the preferred embodiment of the invention with reference to the figure. It shows: Fig. 1 a schematic view of a device according to the invention.

[0018] In dem in Fig.Figure 1, a schematic representation of the embodiment, shows the device 1 for infiltrating and expanding a fiber roving 10 in a perspective view. The device is formed in two parts: a lower part 12 and an upper part 11, which have a space between them for the feed channel 2 for guiding the fiber roving 10 through. The device 1 has an inlet section 3 with an inlet 4 for feeding the fiber roving 10 into the feed channel 2 and a wave-shaped expanding section 6 immediately adjoining the inlet section 3 in a feed direction (left to right). The injection unit 5 for introducing the resin is integrated into the upper part of the inlet section 3. As the fiber roving 10 passes by, it takes a predefined quantity of resin from the injection unit. Alternatively, the injection unit can also generate pressure and actively apply a predefined quantity of resin to the fiber roving 10.

[0019] In the illustrated embodiment, the wave-shaped spreading section 6 comprises two protrusions 7 and depressions 8, directly adjacent to one another in the direction of passage, each formed by the upper part 11 and lower part 12. This causes the fiber roving 10 to be alternately displaced vertically, so that as the resin slides along the respective protrusions 7, it moves through the fiber roving 10 multiple times in alternating vertical directions, completely penetrating it. In particular, upon initial contact of the fiber roving 10 with the individual protrusions 7, pressure is exerted on the resin, causing it to move vertically through the fibers. The number of protrusions 7 and depressions 8 is not limited to the illustrated embodiment with two protrusions 7 and two depressions 8; rather, the number can also be increased, for example, if the number of fibers in the fiber roving increases.

[0020] On the raised sections 7 of both the upper part 11 and the lower part 12, spreading means for the fiber roving 10 are formed in the form of V-shaped, W-shaped, or, viewed from above, shell-shaped spreading arms. These arms spread the individual filaments of the fiber roving 10 in a transverse direction perpendicular to the feed direction, thereby promoting resin penetration. As the fibers pass by, the arms grasp the individual fibers of the fiber roving 10 and move them laterally outwards from a substantially central position in the transverse direction into the grooves formed by the arms, thereby spreading them. The intensity of the spreading is adjustable via the respective spreading means.

[0021] The feedthrough channel 2 has a substantially rectangular cross-sectional shape and provides sufficient space for the fiber roving 10 to spread laterally. The upper part 11 and lower part 12 have a complementary shape in certain sections, which determines the movement path of the fiber roving 10.

[0022] In the inlet section 3, a pre-tensioning device 13 is also provided, by means of which the fiber roving 10 is guided and tensioned before sliding past the injection unit 5. After leaving the device 1, the fiber roving 10 is further processed, including being deposited.

[0023] The invention is not limited in its implementation to the preferred embodiments specified above. Rather, a number of variants are conceivable that utilize the illustrated solution even in fundamentally different designs. For example, further means for processing the fiber roving or devices for influencing the ambient pressure in the feedthrough channel can be provided in or on the device.

Claims

[1] Device for infiltrating and spreading fiber rovings, which forms a feedthrough channel (2) for passing the fiber roving (10) through it and has an inlet section (3) with an inlet (4) for feeding the fiber roving (10) into the feedthrough channel (2) and an injection unit (5) for introducing an infiltration medium, wherein a wave-shaped spreading section (6) is formed immediately following the inlet section (3) in a feedthrough direction, through which the fiber roving (10) can be alternately displaced in a vertical direction, and wherein a spreading means for spreading the fiber roving (10) is formed on at least one elevation (7) of the wave-shaped spreading section (6), characterized by, that the device is formed in two parts with a lower part (12) and an upper part (11) which is at least partially complementary in form, wherein the spreading means is formed by V-shaped or W-shaped spreading legs in the direction of passage, wherein the spreading means is formed on the projections (7) of both the upper part (11) and the lower part (12). [2] Device according to claim 1, characterized by , that the wave-shaped spreading section (6) is formed by at least two elevations (7) and depressions (8) immediately adjoining each other in the direction of passage. [3] Device according to claim 1 or 2, characterized by that several spreading legs are formed next to each other and form a shell shape in a top view. [4] Device according to at least one of the preceding claims, characterized by, that the injection unit (5) for introducing the infiltration medium into the device (1) is arranged such that the infiltration medium adheres to the fiber roving as the fiber roving (10) passes by. [5] Device according to at least one of the preceding claims, characterized by , that it is designed as a siphon and the passage channel (2) has a square or rectangular cross-section. [6] Device according to at least one of the preceding claims, characterized by , that the injection unit (5) extends over the entire width of the device (1) and introduces the infiltration medium over this width into the feedthrough channel (2). [7] Method for infiltrating and spreading fiber rovings, wherein a fiber roving is fed into a device (1) according to one of the preceding claims, is wetted therein by the injection unit (5) with infiltration medium and is immediately subsequently spread by the wave-shaped spreading section (6), characterized by , that the fiber roving (10) in the wave-shaped spreading section (6) is alternately displaced in the vertical direction, so that the infiltration medium moves through the fiber roving (10) once or several times in alternating directions in the vertical direction.

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