Device and method for spreading a fibre filament bundle

Abstract

The invention relates to a device for spreading a fibre filament bundle (1) to form a flat fibre strip, comprising a spreading roller (3) having a roller axle and a cylindrical lateral surface for contacting the fibre filament bundle (1) in a spreading manner, wherein at least one lateral surface section of the cylindrical lateral surface is provided with a groove group (5) formed by a plurality of grooves lying next to one another in the axial direction, and the grooves each have a start region and an end region, and the axial extent of the groove group (5) increases from one groove to the next from their start regions to the end regions. According to the invention, an adjustable rotary drive or an adjustable rotary brake is provided for the spreading roller (3), each of which is designed to adjust a relative speed between the translational speed of the incoming fibre filament bundle and the circumferential speed of the spreading roller. Furthermore, a method is proposed in which the spreading roller (3) is set in rotation with the aid of a rotary drive or a rotary brake, said rotation being adjustable independently of the translational speed of the fibre filament bundle (1).

Description

[0001] The invention relates to a device for spreading a fiber filament bundle into a flat fiber ribbon, comprising a spreading roller with a roller axis and a cylindrical outer surface for spreading the fiber filament bundle, wherein at least one section of the cylindrical outer surface is provided with a set of grooves formed from a plurality of axially adjacent grooves, and the grooves each have a starting region and an end region in the circumferential direction of the outer surface, and the axial extent of the set of grooves increases progressively from its starting regions to its end regions along the course of the grooves, according to the preamble of claim 1. The invention further relates to a method for spreading a fiber filament bundle into a flat fiber ribbon with a device according to the invention, according to the preamble of claim 13.

[0002] A generic device is described in EP 3280664 B1. Spreading rollers are used in spreading devices and serve to spread bundles of fiber filaments made of endless filaments so that the filaments are arranged uniformly and as flat as possible next to each other as a fiber band. The fiber filament bundles are typically formed from several thousand to several tens of thousands of (mono-)filaments and, before spreading, have several layers of fibers arranged one above the other and a variable entry width. Such fiber filament bundles are also called rovings. The fibers can be selected, for example, from the group consisting of carbon fiber, glass fiber, Kevlar fiber, basalt fiber, plastic fiber, ceramic fiber, natural fibers (such as hemp fiber and / or flax fiber), and mixtures of at least two of the aforementioned fiber types.The aim of the spreading process is to align the fibers as parallel as possible, forming a fiber band with a defined final width, also known as a roving band. The fiber band has fewer fiber layers than the initial fiber filament bundle, with the fiber layers of the fiber band containing a greater number of fibers and arranged more closely and preferably without gaps next to each other than the fiber layers of the unspread fiber filament bundle. Ideally, all fibers in a fiber band lie next to each other in a single fiber layer, making the fiber band monolayered.

[0003] Fiber or roving tapes, in turn, allow for the production of fiber-reinforced plastics with improved mechanical properties in a subsequent manufacturing step. For this purpose, a widened fiber tape is first produced by spreading the fiber filament bundle. This tape is then temporarily stored on spools as an intermediate product. This semi-finished product is subsequently unwound and fed to downstream manufacturing steps, for example, for the production of fiber-reinforced plastics. In practice, this process is referred to as "off-line spreading." In contrast, with "online spreading," the spreading device is integrated with downstream manufacturing steps and operates in sync with them.

[0004] Known spreading devices, for example, have several rods or rollers around which a fiber filament bundle can be guided. Non-rotating, passive spreading rods are also called "spreader bars." When a fiber filament bundle is deflected under tensile stress over a spreading rod, typically by a wrap angle of 60°–180°, the radially outer layers have a longer path and are therefore subjected to a higher load on the filaments. The outer filaments can escape this load by migrating along the spreading rod into inner layers and thus outwards, thereby moving the radially outer, non-stretchable filaments into a more energetically favorable position. This results in a widening of the fiber filament bundle.This process depends essentially on the tensile force on the fiber filament bundle and the friction between the fiber filament bundle and the spreading rod; in addition, factors such as the positioning of the spreading rods relative to each other and the diameter of the spreading rods also play a role. A similar principle underlies the radius spreader, in which a fiber filament bundle is first deflected by means of a curved rod and then by means of a straight rod.

[0005] However, the translational speed of the fiber tape in these mechanical spreading processes is limited to a maximum of approximately 0.4 m / s, and the maximum spreading ratio is typically 3. The comparatively high tensile stress in the fiber tape also promotes fiber breakage. For practical applications, a higher throughput and lower fiber stress would be advantageous.

[0006] Furthermore, pneumatic spreading methods using vacuum are known, which, although they allow higher spreading ratios of up to about 6-7 with less fiber breakage, are limited in their throughput and are comparatively complex from a technical standpoint. Spreading methods based on vibratory spreaders or ultrasonic fiber spreaders are also characterized by a comparatively high level of technical complexity.

[0007] The object of the invention is therefore to improve the spreading of fiber filament bundles in such a way that, with comparatively low technical effort, the highest possible throughput is achieved while simultaneously minimizing fiber stress and thus reducing fiber breakage. Furthermore, a consistent product quality of the produced fiber ribbons should be ensured, regardless of variations in the input width of the fiber filament bundle.

[0008] These objectives are achieved by a spreading roller according to claim 1 and a method for spreading a fiber filament bundle according to claim 13. Claim 1 relates to a device for spreading a fiber filament bundle into a flat fiber ribbon, comprising a spreading roller with a roller axis and a cylindrical outer surface for spreading the fiber filament bundle, wherein at least one outer surface section of the cylindrical outer surface is provided with a set of grooves formed from a plurality of axially adjacent grooves, and the grooves each have a starting region and an end region in the circumferential direction of the outer surface, and the axial extent of the set of grooves increases progressively from their starting regions to their end regions along the length of the grooves.According to the invention, it is proposed that an adjustable rotary drive or an adjustable rotary brake is provided for the spreading roller, each designed to adjust a relative speed between the translational speed of the incoming fiber filament bundle and the circumferential speed of the spreading roller.

[0009] In this context, a set of grooves, analogous to the mathematical concept of a family of curves, is defined as a group of grooves that are similar in their orientation and arranged side by side. The large number of grooves, as required by the invention, ensures that the relevant section of the cylindrical surface is almost completely covered by grooves. This cylindrical surface section literally represents a portion of the cylindrical surface of the expanding roller. The axial extent of a set of grooves can be measured along a generatrix of the expanding roller. Since, according to the invention, the grooves of the set of grooves are arranged side by side in the axial direction, they generally run circumferentially, but undergo an axial displacement because the axial extent of the set of grooves increases progressively from its initial to its final regions.The term "increasingly expanded" encompasses both the case of increasing expansion with respect to an initial size of the axial extent and the case of increasing expansion with respect to a local value in the sense of a differential expansion of the axial extent. The axial displacement can also be referred to as the slope, although according to the invention none of the grooves extends around the entire circumference of the outer surface of the spreading roller.

[0010] According to the invention, such a spreading roller is used in a device for spreading a fiber filament bundle into a flat fiber ribbon with an adjustable rotary drive, so that a relative speed can be set between the translational speed of the incoming fiber filament bundle and the peripheral speed of the spreading roller. Alternatively, the spreading roller can also be set into rotation by the frictional contact of the fiber filament bundle, whereby a relative speed between the translational speed of the incoming fiber filament bundle and the peripheral speed of the spreading roller is set by means of an adjustable rotary brake for the spreading roller.The inventive design of the spreading roller with axially adjacent grooves forming a set of grooves, the axial extent of which widens progressively from the beginning to the end of the grooves, ensures that the fiber filament bundle is spread transversely to the direction of travel of the fiber filament bundle. The fiber filament bundle is fed perpendicular to the roller axis of the spreading roller and wraps around a portion of the outer surface of the spreading roller. The angle of this wrapping is also referred to as the wrapping angle, which will be discussed in more detail below.The rotation of the spreading roller is controlled so that the fiber filament bundle initially comes into contact with the beginning of the grooves, which are subsequently referred to as the entry area. It is then combed through the set of grooves and, due to this, spread out circumferentially on the fanning set of grooves until the end of the grooves is reached, which are subsequently referred to as the exit area. The axial extent of the set of grooves in the entry area is selected to approximately correspond to the width of the entering fiber filament bundle. The axial extent of the set of grooves in the exit area corresponds to the width of the exiting fiber strip. In this way, the spreading of the fiber filament bundle to the defined final width of the fiber strip is made possible with only one roller.This results in a simpler and more robust technical design compared to the prior art. Furthermore, it offers excellent controllability, with the control parameter derived from the ratio of the circumferential speed of the spreading roller to the translational speed of the fiber tape. This allows for setting a final width of the fiber tape that is largely independent of the input width of the fiber filament bundle. In addition, the gentle deflection of the fibers and the reduced number of deflections minimize fiber breakage, thus contributing significantly to high product quality and high product throughput.

[0011] The design of the groove set can vary in shape and number. As already mentioned, the grooves of a groove set generally run circumferentially around the expanding roll with an axial offset. Preferably, it is proposed that the groove set be divided into two groove set sections by a normal plane perpendicular to the roll axis, wherein the grooves of a first groove set section wind around the roll axis from their respective starting region to their respective end region with an increasing axial offset towards a first, closer roll end, and the grooves of a second groove set section wind around the roll axis from their respective starting region to their respective end region with an increasing axial offset towards a second, closer roll end and opposite the first roll end.Here too, the term "increasing axial displacement" encompasses both the case of increasing axial displacement with respect to an initial value and the case of increasing axial displacement with respect to a local value in the sense of a differential displacement. Preferably, the set of grooves is symmetrical with respect to the normal plane. In this case, one can speak of two halves of the set of grooves, in which the grooves of a first, for example, left half of the set of grooves approach the left end of the roller that is closer to them in their axial displacement, and the grooves of a second, for example, right half of the set of grooves approach the right end of the roller that is closer to them in their axial displacement. The set of grooves thus fans out symmetrically in the relevant section of the cylindrical surface, with the relevant section of the cylindrical surface preferably being arranged in the center of the spreading roller.

[0012] According to a first embodiment, a single set of grooves can be provided, extending over a section of the surface encompassing approximately the entire circumference. This section of the surface preferably covers a circumferential area of ​​the surface of a maximum of 355°. In this case, the starting and ending regions of the grooves are preferably located close to each other in the circumferential direction and are separated by a narrow, axially extending, groove-free section of the surface, with the set of grooves having a smallest axial extent in the starting regions of the grooves and a largest axial extent in the ending regions of their grooves.According to a second embodiment, at least two successive circumferential surface sections can also be provided, each equipped with a set of grooves, wherein the successive surface sections are separated by axially extending, groove-free surface areas, and the grooves of one surface section are a continuation of the grooves of an adjacent circumferential surface section. This embodiment can also be described as a set of grooves extending around approximately the entire surface is divided by at least two groove-free surface areas.

[0013] According to a third embodiment, at least two successive circumferential surface sections can also be provided, each equipped with a set of grooves, wherein the successive surface sections are separated by axially extending, groove-free surface areas, and the set of grooves of one surface section is identical to those of the other surface sections. In this case, the surface sections represent, in a sense, repetitive sections.

[0014] The grooves themselves can preferably each have a triangular or semicircular cross-section.

[0015] The depth of a groove is preferably 50-100% of its width. The depth and width of a groove are preferably each in the range of 0.1 mm.

[0016] Furthermore, it is proposed that the spreading roller be designed to be heated or cooled. The applicant has determined that the spreading process, and in particular the repositioning of the fibers within the fiber filament bundle during spreading, is also temperature-dependent. The heated or cooled spreading roller takes advantage of this temperature dependency by allowing the setting of those temperature ranges in which the spreading process is particularly favored. Preferably, the inventive device for spreading a fiber filament bundle also includes a feed positioning roller for feeding the fiber filament bundle in a defined axial position relative to the spreading roller. The positioning roller and the spreading roller are arranged parallel to each other, with the positioning roller feeding the fiber filament bundle in such a way that it meets the spreading roller precisely in the sections of the cylindrical surface provided with a fanning set of grooves.For this purpose, the positioning roller can, for example, be equipped with two positioning discs, between which the incoming fiber filament bundle is received and fed to the spreading roller in a defined manner.

[0017] Furthermore, at least one guide rod can be provided for guiding the fiber ribbon, wherein the spreading roller and the at least one guide rod are arranged parallel to each other and with a wrap angle of no more than 90° each. The comparatively small wrap angle reduces the stress on the fibers and thus also reduces fiber breakage.

[0018] Furthermore, a method for spreading a fiber filament bundle into a flat fiber ribbon using a device according to the invention is proposed, wherein the fiber filament bundle is drawn over the outer surface of the spreading roller in a spreading system at a translational speed. According to the invention, it is proposed that the spreading roller be set into rotation by means of a rotary drive or a rotary brake, the rotation speed of which can be adjusted independently of the translational speed of the fiber filament bundle. As already explained, the adjustable rotary drive allows a relative speed between the translational speed of the incoming fiber filament bundle and the circumferential speed of the spreading roller to be set.Alternatively, the spreading roller can be set in rotation by the frictional contact of the fiber filament bundle, and a relative speed between the translational speed of the incoming fiber filament bundle and the peripheral speed of the spreading roller can be set using an adjustable rotary brake for the spreading roller. These measures also allow for precise control of the spreading process, with the control parameter being the ratio of the peripheral speed of the spreading roller to the translational speed of the fiber strip. As already mentioned, this makes it possible to set a final width of the fiber strip that is largely independent of the incoming width of the fiber filament bundle. Furthermore, the gentle deflection of the fibers and the reduced number of deflections reduce the number of fiber breaks, thus contributing significantly to high product quality and high product throughput.

[0019] In particular, it is proposed that the bandwidth of the fiber tape be measured and the rotation of the spreading roller be controlled based on the measured bandwidth. This could, for example, be a laser measuring system. Optionally, quality control systems, such as a camera system, can also be integrated into this arrangement.

[0020] The invention will be explained in more detail below with reference to exemplary embodiments and the accompanying drawings. These drawings show the following:

[0021] Fig. 1 shows a perspective view of an embodiment of a device for spreading a fiber filament bundle into a flat fiber ribbon with a spreading roller according to the invention, a feeding positioning roller and two outgoing guide rods.

[0022] Fig. 2 shows a side view of the device according to Fig. 1,

[0023] Fig. 3 shows a top view of the device according to Fig. 1.

[0024] Fig. 4a shows a first embodiment of a spreading roller within the scope of the invention for a first rotational position of the spreading roller,

[0025] Fig. 4b shows the first embodiment of a spreading roller according to Fig. 4a for a second rotational position of the spreading roller, Fig. 5a shows a second embodiment of a spreading roller within the scope of the invention for a first rotational position of the spreading roller,

[0026] Fig. 5b shows the second embodiment of a spreading roller according to Fig. 5a for a second rotational position of the spreading roller,

[0027] Fig. 6a shows a third embodiment of a spreading roller within the scope of the invention for a first rotational position of the spreading roller, and the

[0028] Fig. 6b shows the third embodiment of a spreading roller according to Fig. 6a for a second rotational position of the spreading roller.

[0029] First, reference is made to Figures 1-3, which show an embodiment of a device according to the invention for

[0030] Figure 4.1, 4.2 shows the spreading of a fiber filament bundle 1 into a flat fiber ribbon with a spreading roller 3, a feeding positioning roller 2, and two discharge guide rods 4.1, 4.2. The positioning roller 2, the spreading roller 3, and the

[0031] Guide rods 4.1 and 4.2 are arranged parallel to each other and with a maximum wrap angle of 90° around the fiber filament bundle 1. The positioning roller 2 guides the fiber filament bundle 1 to the spreading roller 3 such that the fiber filament bundle 1 meets the spreading roller 3 precisely in the cylindrical surface sections provided with a fanning groove set 5. For this purpose, the positioning roller 2 is provided with two positioning discs 6, between which the incoming fiber filament bundle 1 is received and guided to the spreading roller 3 in a defined manner. The tensile force on the fiber filament bundle 1 is exerted by a tensioning device, not shown in detail in Figures 1-3, which is arranged on the right side of the device shown in Figures 2 and 3 and guides the fiber filament bundle 1 into the grooves shown in Figure 3.

[0032] The fiber filament bundle 1 is pulled in the direction of the arrow shown in Figure 1 or Figure 3. This results in a translation of the fiber filament bundle 1 in the direction of the arrow shown. To spread the fiber filament bundle 1 into a flat fiber ribbon, the fiber filament bundle 1 is drawn over the outer surface of the spreading roller 3 on a spreading device, as shown in Figures 1-3. The spread fiber ribbon is then guided over the two guide rods 4.1, 4.2 and subsequently wound up or processed directly, for example into a so-called "tape".

[0033] In the embodiment shown in Figures 1 to 3, the spreading roller 3 itself is designed according to the aforementioned third embodiment by means of three repetitive sections, in that three successive circumferential surface sections are provided, each of which is equipped with a set of grooves 5.1, 5.2, 5.3, whereby one set of grooves 5.3 is not visible in Figures 1-3 due to the rotational position of the spreading roller 3. Successive surface sections are each separated by axially extending, groove-free surface areas, and the set of grooves 5.1, 5.2, 5.3 of each surface section is identical to those of the other surface sections.

[0034] This design of the spreading roller 3 is also shown in Figs. 6a and 6b for two different rotational positions.

[0035] Further embodiments of the spreading roller 3 are shown in Figures 4 and 5. Figures 4a and 4b show a first embodiment of the spreading roller 3. In this embodiment, a single set of grooves 5 is provided, which extends over a section of the cylindrical surface encompassing approximately the entire surface. In this case, the beginning and end regions of the grooves are preferably located close to each other in the circumferential direction and are separated by a narrow, axially extending, groove-free section of the cylindrical surface 7, wherein the set of grooves 5 has a minimum axial extent Ei in the beginning regions of the grooves and a maximum axial extent E2 in the end regions of its grooves.

[0036] Figures 5a and 5b show a second embodiment of the spreading roller 3. According to this second embodiment, three successive circumferential sections of the cylindrical surface are provided, each equipped with a set of grooves 5.1, 5.2, 5.3. The successive cylindrical surface sections are separated by axially extending, groove-free cylindrical surface areas 7.1, 7.2, 7.3, and the grooves of one cylindrical surface section are a continuation of the grooves of an adjacent cylindrical surface section. This embodiment can also be described as follows: a set of grooves 5 extending around approximately the entire cylindrical surface is divided by three groove-free cylindrical surface areas 7.1, 7.2, 7.3 into a first set of grooves 5.1, a second set of grooves 5.2, and a third set of grooves 5.3.

[0037] The grooves themselves preferably have a triangular or semicircular cross-section; alternatively, rectangular, elliptical, or trapezoidal groove cross-sections are also possible. The depth of a groove is preferably 50–100% of its width. The depth and width of a groove are preferably each in the range of 0.1–1 mm. The groove depth can also vary along the length of the groove; in particular, continuous transitions to the outer surface can be provided at the beginning and end of the groove.

[0038] Furthermore, the grooves in the inlet area can optionally have a constant or a variable spacing, for example, increasing towards the outside. The axial offset of the grooves can also preferably increase towards the outside. The grooves are preferably arranged symmetrically relative to the center plane of the spreading roller 3.

[0039] The axial extent Ei of a groove set in its entry area can be adapted to the respective fiber filament bundle, in particular to the number and diameter of the individual filaments. The axial extent E2 of a groove set in its exit area can be adapted to the desired bandwidth. The axial extent Ei of a groove set in its entry area preferably corresponds to at least the width of the fiber filament bundle to be spread. The axial extent E2 of a groove set in its exit area can extend to the full width of the roller. The minimum width of the spreading roller 3 is determined by the desired maximum width of the fiber strip after spreading. It is not necessary to utilize the full width of the spreading roller 3; as a rule, the spreading roller 3 is significantly wider than the fiber strip to be produced.

[0040] The roller diameter can be selected according to the application and tailored to the fiber material or the spread ratio. Generally, larger diameters are gentler on the fibers, but at the same time increase material costs. The optimal roller diameter is therefore determined by optimizing both acceptable fiber damage and plant costs.

[0041] The design of the assembly is preferably chosen such that the wrapping angles of the positioning roller 2, the spreading roller 3 and the guide rods 4.1, 4.2 do not exceed the value of 90° .

[0042] The guide rods 4.1, 4.2 can be rigid or rotatable. Optionally, it can also be advantageous to actively control the temperature of the spreading roller 3, i.e., to heat or cool it. The heated or cooled spreading roller 3 allows the temperature ranges to be set in which the spreading process is particularly favored.

[0043] The spreading width in the device according to Fig. 1-3 can be continuously and flexibly adjusted as a function of the translational speed of the fiber tape, which is externally specified and usually constant, relative to the adjustable circumferential speed of the rotating spreading roller 3.

[0044] For this purpose, the spreading roller 3 is preferably equipped with a continuously variable rotary drive, for example, an electric motor. Depending on the desired degree of spreading and the desired strength of the fibers, this actively driven spreading roller 3 can rotate in the same direction as the fiber strip or in the opposite direction. Alternatively, the spreading roller 3 can also be equipped with an adjustable brake instead of the rotary drive. In this case, the spreading roller 3 is passively driven by the movement of the drawn fiber strip, and the relative speed to the strip speed required for homogeneous spreading across the grooves is controlled by the braking intensity. With this design, obviously only synchronous rotation is possible, which, however, is sufficient for the majority of applications.

[0045] Preferably, a system for in-line measurement of the bandwidth is arranged downstream of the spreading roller 3, for example in the area of ​​the guide rods 4.1, 4.2, the measurement results of which can be used directly to control the rotational speed of the spreading roller 3. This can be, for example, a laser measuring system. Optionally, it is also possible to integrate quality control systems into this arrangement, for example a camera system.

[0046] As already mentioned, these measures enable precise control of the spreading process, with the control parameter being the ratio of the circumferential speed of the spreading roller 3 to the translation speed of the fiber tape. This allows, as already mentioned, the setting of a final width of the fiber tape that is largely independent of the input width of the fiber filament bundle 1. Furthermore, the gentle deflection of the fibers and the reduced number of deflections reduce the number of fiber breaks and thus contribute significantly to high product quality while maintaining high product throughput.

[0047] With the help of this invention, the spreading of fiber filament bundles 1 is improved by enabling high throughput with comparatively low technical effort, while simultaneously reducing fiber stress and thus fiber breakage. Furthermore, flexible control of the spreading process is possible, ensuring consistent product quality of the generated fiber ribbons regardless of fluctuations in the input width of the fiber filament bundle 1. Due to the lightweight

[0048] The interchangeability of the spreading roller 3 also allows for quick conversion to other roving properties.

Claims

Patent claims:

1. Device for spreading a fiber filament bundle (1) into a flat fiber ribbon comprising a spreading roller (3) with a roller axis and a cylindrical outer surface for spreading the fiber filament bundle (1) onto, wherein at least one section of the cylindrical outer surface is provided with a set of grooves (5) formed from a plurality of axially adjacent grooves, and the grooves each have a starting region and an end region in the circumferential direction of the outer surface and the axial extent of the set of grooves (5) increases progressively from its starting regions to its end regions along the course of the grooves, characterized in that an adjustable rotary drive or an adjustable rotary brake is provided for the spreading roller (3),The respective tasks are to adjust the relative speed between the translational speed of the incoming fiber filament bundle and the circumferential speed of the spreading roller.

2. Device according to claim 1, characterized in that the groove section (5) is divided into two groove section sections by a normal plane extending perpendicular to the roller axis, wherein the grooves of a first groove section section wind around the roller axis from their respective starting region to their respective end region with an increasing axial displacement in the direction of a first roller end closer to them, and the grooves of a second groove section section wind around the roller axis from their respective starting region to their respective end region with an increasing axial displacement in the direction of a second roller end closer to them and opposite the first roller end.

3. Device according to claim 2, characterized in that the set of grooves (5) is symmetrical with respect to the normal plane.

4. Device according to one of claims 1 to 3, characterized in that a single set of grooves (5) is provided, which extends over a section of the lateral surface encompassing almost the entire surface area.

5. Device according to claim 4, characterized in that the lateral surface section comprises a circumferential area of ​​the lateral surface of a maximum of 355°.

6. Device according to one of claims 1 to 3, characterized in that at least two successive circumferential surface sections are provided, each of which is provided with a set of grooves (5.1, 5.2, 5.3), wherein the successive surface sections are each separated by axially extending, groove-free surface areas (7.1, 7.2, 7.3) and the grooves of a surface section are a continuation of the grooves of a surface section located adjacent to it in the circumferential direction.

7. Device according to one of claims 1 to 3, characterized in that at least two successive circumferential surface sections are provided, each of which is provided with a set of grooves (5.1, 5.2, 5.3), wherein the successive surface sections are each separated by axially extending, groove-free surface areas (7.1, 7.2, 7.3) and the set of grooves (5.1, 5.2, 5.3) of one surface section is identical to those of the other surface sections.

8. Device according to one of claims 1 to 7, characterized in that the grooves each have a triangular or semicircular cross-section.

9. Device according to one of claims 1 to 8, characterized in that the depth of a groove is 50-100% of its width.

10. Device according to one of claims 1 to 9, characterized in that the depth of a groove and the width of a groove are each in the range of 0.1-1mm.

11. Device according to one of claims 1 to 10, characterized in that the spreading roller (3) is designed to be heated or cooled.

12. Device according to one of claims 1 to 11, characterized in that at least one guide rod (4) is provided for the removal of the fiber strip and the spreading roller (3) and the at least one guide rod (4) are arranged parallel to each other and with a wrapping angle of at most 90° each.

13. Method for spreading a fiber filament bundle (1) into a flat fiber ribbon with a device according to one of claims 1 to 12, wherein the fiber filament bundle (1) is drawn over the outer surface of the spreading roller (3) at a translational speed in a spreading system, characterized in that the spreading roller (3) is set into a rotation that is independently adjustable from the translational speed of the fiber filament bundle (1) by means of a rotary drive or a rotary brake.

14. Method for spreading a fiber filament bundle (1) into a flat fiber ribbon according to claim 13, characterized in that the bandwidth of the fiber ribbon is measured and the rotation of the spreading roller (3) is controlled on the basis of the measured bandwidth.

Images