Device And Process For Producing Composite Components Comprising At Least One Wound Fiber Reinforced Polymer Layer

Abstract

Disclosed herein is a device for producing composite components including at least one wound fiber reinforced polymer layer, including: a support with a first holding device and a second holding device for mounting a liner in between, where the first and the second holding device are such that the liner can rotate around a central rotation axis which extends through the first holding device and the second holding device, and at least two movable arms for feeding a fiber structure, where the support is established such that the liner can be moved axially parallel to the central rotation axis and each movable arm for feeding the fiber structure can be moved perpendicular to the central rotation axis. Further disclosed herein is a process for producing composite components using the device.

Claims

1. A device for producing composite components comprising at least one wound fiber reinforced polymer layer, comprising: a support with a first holding device and a second holding device for mounting a liner in between, wherein the first and the second holding device are established such that the liner can rotate around a central rotation axis which extends through the first holding device and the second holding device, and at least two movable arms for feeding a fiber structure, wherein the support is established such that the liner can be moved axially parallel to the central rotation axis and each movable arm for feeding the fiber structure is a robotic arm which comprises at least two joints which each allow bending and twisting.

2. The device according to claim 1, wherein each movable arm for feeding the fiber structure comprises a device for impregnating the fiber structure.

3. The device according to claim 2, wherein the device for impregnating the fiber structure comprises a device to adjust fiber content by volume.

4. The device according to claim 2, wherein at least one device for impregnating the fiber structure is placed at an end of each movable arm for feeding the fiber structure which can be moved perpendicular to the central rotation axis.

5. The device according to claim 2, wherein the movable arm for feeding the fiber structure is established such that the device for impregnating the fiber structure keeps a horizontal orientation independently of the position of the end of the movable arm for feeding the fiber structure.

6. The device according to claim 1, wherein the support and the movable arms for feeding the fiber structure are arranged such that the central rotation axis runs in an angle in the range from 65 to 90° with respect to the horizontal.

7. The device according to claim 1, wherein each movable arm for feeding the fiber structure is assigned to a supply for a fiber structure.

8. The device according to claim 1, wherein each movable arm for feeding the fiber structure comprises a cutting device for cutting the fiber structure and/or each movable arm for feeding the fiber structure comprises a pincer for placing the fiber structure on the liner.

9. The device according to claim 1, wherein a cutting device and a sleeve with pincers for attaching impregnated fibers on the liner are placed on the first holding device or the second holding device.

10. The device according to claim 1, wherein the support is mounted to a movable arm which allows for taking a liner from a liner supply, moving the liner into a position for applying the fiber structure, and placing the liner after application of the fiber structure to a following working unit.

11. The device according to claim 2, further comprising a device for mixing and metering the matrix material, the device for mixing and metering the matrix material comprising a mixing head which is positioned in close proximity to the device for impregnating the fiber structure.

12. A process for producing a composite component comprising at least one wound fiber reinforced layer, comprising: (a) taking a liner from a liner supply with the first holding device and the second holding device of the device according to claim 1; (b) moving the liner into a position for applying a fiber structure; (c) attaching the fiber structure on the liner; (d) applying the fiber structure on the liner by means of the movable arms for feeding the fiber structure, wherein the fiber structure is impregnated with a matrix material in a device for impregnating the fiber structure before being applied on the liner, the liner being rotated around the central rotational axis and being moved axially parallel to the central rotational axis during application of the fiber structure to apply the fiber structure in a predefined pattern on the liner; (e) cutting each fiber structure after application of the fiber structure is finished; (f) placing the liner with the applied fiber structure to a curing station; (g) optionally injecting a resin into a mold of the curing station in which the liner with the applied fiber structure is placed to produce a surface coating layer; and (h) curing the matrix material and the resin, if injected.

13. The process according to claim 12, wherein the liner is a stiff liner or an inflatable bladder.

14. The process according to claim 12, wherein the liner is moved to a predefined position before cutting the fiber structures.

15. The process according to claim 12, wherein the liner with the applied fiber structure rotates around a horizontal rotation axis during curing the matrix material.

16. The device according to claim 1, wherein each movable arm for feeding the fiber structure comprises a device for impregnating the fiber structure, wherein the device for impregnating the fiber structure comprises a bath for receiving a matrix material, a deflection unit for pressing the fiber structure into the bath, and a draining unit.

Description

[0087] In the figures:

[0088] FIG. 1 shows a process for producing a pressure tank comprising a fiber reinforced layer;

[0089] FIG. 2 a cutting device and a sleeve with pincers for attaching impregnated fibers on the liner;

[0090] FIGS. 3 to 6 show process steps of a process for producing a pressure tank comprising a fiber reinforced layer;

[0091] FIG. 7 shows a device for impregnating a fiber structure in the plan view

[0092] FIG. 8 shows a sectional view of the device for impregnating a fiber structure;

[0093] FIGS. 9 and 10 show a device to adjust the fiber content by volume in a closed and an opened position;

[0094] FIG. 11 shows a side view of a device for impregnating a fiber structure with a device for mixing and metering the matrix material.

[0095] FIG. 1 shows a process for producing a pressure tank comprising a fiber reinforced layer.

[0096] For producing a pressure tank, a liner 1 is fixed between a first holding device 3 and a second holding device 5. The first holding device 3 and the second holding device 5 are part of a support 7. The support 7 with the first holding device 3 and the second holding device 5 are designed in such a way that the liner 1 can rotate around a central axis 9 which extends through the first holding device 3 and the second holding device 5. To fix the liner 1 between the first and second holding devices 3, 5, it is for example possible to move the holding devices 3, 5 along the central axis 9 and to clamp the liner 1 between the first and second holding devices 3, 5. The holding devices 3, 5 in this case for example comprise a pin or a flat plate which presses on the liner when the liner 1 is fixed by the holding devices 3, 5 in the support 7.

[0097] The support 7 is mounted to a movable arm 11 which can move in such a way that the liner is moved parallel to the central axis 9. While the liner 1 is moved parallel to the central axis 9, a fiber structure 13 is attached on the liner 1. During attaching the fiber structure 13 to the liner 1, the liner rotates around the central axis 9. Simultaneously, the liner is moved back and forth parallel to the central axis 9. By this movement, the fiber structure 13 is wound around the liner 1. The fiber structure preferably comprises continuous fibers such that a woven pattern 15 is formed on the liner. To achieve a fiber reinforced polymer layer, the fiber structure 13 is impregnated with a matrix material, for example monomers or oligomers which form a polymer when cured or a molten thermoplastic polymer or fibers produced from a thermoplastic polymer.

[0098] For reducing the cycle times, the fiber structures 13 are applied at more than one position. The positions for applying the fiber structures 13 therefore preferably are in the same plane perpendicular to the central axis 9. Particularly preferably, the fiber structures 13 are applied at 3 to 8 positions, wherein at each position up to 12 fiber structures can be applied.

[0099] For cutting the fibers after finishing the application on the liner, it is preferred that a cutting device 12 is provided on the support, preferably on the first holding device 3 as shown here or on the second holding device 5. Further, a sleeve with pincers 14 is provided for attaching the fibers on the liner 1 on starting the winding process. The sleeve with pincers 14 preferably is a single use sleeve which is picked up by the movable arm 11 by one of the holding devices 3, 5 before picking up the liner 1. Particularly preferably, the sleeve with the pincers 14 is picked up from the same holding device 3, 5 on which the cutting device 12 is attached.

[0100] The cutting device 12 and the sleeve with pincers 14 are shown in more detail in FIG. 2.

[0101] For attaching impregnated fiber structures on a new liner, a sleeve 16 is used on which pincers 18 are attached. The sleeve 16 preferably is a single-use sleeve which is picked up by the first holding device 3 or the second holding device 5 of the movable arm 11 before picking up the liner 1. If a single-use sleeve is used, the fiber structures 13 also are wound at least partly around the sleeve 16 during the winding process and that part of the sleeve 16 which protrudes from the finished wound composite component is cut off.

[0102] The cutting device 12 is mounted on the first holding device 3 or to the sleeve 16, respectively, in such a way that after finishing winding the impregnated fiber structure on the liner, a device for feeding the impregnated fiber structure can be moved to the cutting device 12. The cutting device can be for example a knife or a blade. In this case, by moving the impregnated fiber structure on the knife or the blade, the impregnated fiber structure is cut. Due to the position of the cutting device 12 close to the liner, long fibers hanging from the liner after cutting are avoided.

[0103] To attach the fiber structure 13 on the liner 1, the fiber structures are moved toward the position of the pincers 18 by movable arms. With the movement of the movable arm, one fiber structure 13 is threaded into one pincer 18 and then the liner starts to rotate and the winding process starts.

[0104] Besides using a single-use sleeve, it is also possible to use a multi-use sleeve. However, even when using a multi-use sleeve it is preferred to pick-up the sleeve 16 before starting the winding process, to remove the liner with the sleeve 16 after finishing the winding process and use a new sleeve 16 with the next liner 1. After the winding process, the multi-use sleeve is removed from the liner with the wound fiber structure 13, optionally cleaned and then reused.

[0105] If it is possible to completely remove the fiber structure from the pincers 18 after finishing the winding process or during the winding process, it is further possible to mount the pincers 18 directly on the first holding device 3 or the second holding device 5. In this case it is not necessary to use a sleeve 16.

[0106] The steps for producing a pressure tank as composite component comprising at least one wound fiber reinforced polymer layer are shown in FIGS. 3 to 6.

[0107] In a first step, which is shown in FIG. 3, the liner 1 is taken from a liner supply by the support 7 with the first and second holding devices 3, 5. The support 7 is mounted on the movable arm 11, preferably as shown here a robotic arm.

[0108] The device for producing the composite component shown in FIGS. 3 to 6 comprises the robotic arm with the supply and three movable arms 17 for feeding the fiber structure. For feeding the fiber structure, the movable arms 17 are connected with feed points 19 for the fiber structure 13. The fiber structure 13 can be any fiber structure which can be used for producing the fiber reinforced polymer layer. The fiber structure for example may comprise single fibers or rovings. If rovings are used, it is possible to either wind the rovings around the liner 1 or to separate the fibers of the roving before winding the separated fibers on the liner.

[0109] The movable arms 17 for feeding the fiber structure are robotic arms which allow a precise positioning of the feed point 19 for the fiber structure with respect to the liner. Each movable arm 17 for feeding the fiber structure is connected with a supply 21 for the fibre structure 13. The fiber structure 13 is taken from the supply 21, runs along the movable arm 17 for feeding the fiber structure and through a device 23 for impregnating the fiber structure 13.

[0110] For taking the liner 1, the first and second holding devices 3, 5 each are placed on one side of the liner 1 and the liner 1 is fixed between the first and second holding devices 3, 5. For fixing the liner, no manual work or use of tools is necessary.

[0111] After the liner 1 is fixed between the first and second holding devices 3, 5, the liner 1 is moved with the movable arm 11 on which the support 9 is mounted into a position in which the fiber structures 13 are applied on the liner 1. This is shown in FIG. 4.

[0112] For applying the fibers, after the liner 1 is moved into the position for winding the fiber structure 13, the feed points 19 for the fiber structure are moved close to the liner 1 to fix the end of the impregnated fiber structure 13 on the liner. After the fiber structures 13 are fixed on the liner 1, the liner 1 starts to rotate and the fiber structure 13 is wound on the liner 1, wherein the liner 1 is moved parallel to the central axis as shown in FIG. 1.

[0113] After finishing winding the fiber structure 13 on the liner, the wound fiber reinforced polymer layer is completed and the liner with the wound fiber structure applied on it is moved to a curing station. This is shown in FIG. 5. For moving the liner with the wound fiber structure 25 to the curing station, the movable arms 17 for feeding the fiber structure move away from the liner with the wound fiber structure 25. Afterward the movable arm 11 with the support rotates for bringing the liner with the wound fiber structure 25 to the curing station 27.

[0114] For continuous production of composite components and if curing lasts longer than winding the fiber structure 13 around the liner 1 it is preferred if the curing station 27 comprises a plurality of molds 29 in each of which one composite component can be cured. For an automatized production it is necessary that after placing one liner with wound fiber structure 25 into the mold 29, the next mold 29 is moved into a position in which the next liner with wound fiber structure 25 can be placed into the mold. For this purpose, the curing station particularly is in the form of a horizontal or vertical rotating table as shown in FIG. 6. To avoid formation of tears on the composite component, particularly for axially symmetrical components like pressure tanks, it is preferred that the composite component rotates around the symmetry axis during curing.

[0115] Optionally after placing the liner 1 with the wound structure 25 into the mold 29, a resin may be injected into the mold 29 to form a thin coating on the surface of the wound structure 25. The thin coating preferably has a thickness in the range from 0.1 mm to 5 mm. The resin may be an unsaturated polyester, a vinyl ester, an epoxy or a polyurethane. In a preferred embodiment the resin is a polyurethane. After injecting the polyurethane resin, it is cured in the mold 29.

[0116] After curing the fiber reinforced polymer layer and optionally the resin the composite component is removed from the mold. Removing also may take place before the polymer is fully cured. In this case the polymer must be cured to a condition in which the polymer precursor is no longer liquid and sticky.

[0117] If a sleeve 16 has been used to produce the composite component, for example a pressure vessel, it is removed after curing. At this stage other mountings such as valves are installed.

[0118] FIG. 7 shows a device for impregnating a fiber structure in the plan view.

[0119] For impregnating the fiber structure, the fiber structure 13 is guided through a bath 31 which contains the matrix material with which the fibers are impregnated. If a number of fibers is fed into the device for impregnating the fibers preferably are separated and guided along deflection units 33. The deflection units 33 are placed in the bath in such a way that the fiber structures 13 are pressed by one deflection unit 33 against the neighboring deflection unit 33. This results in a zig-zag guiding of the fiber structure through the bath 31. Such a zig-zag guiding of the fiber structure 13 is particularly preferred if the fiber structure is in the form of flat fiber tapes or carbon fiber rovings. The deflection units 33 simultaneously act as wipers for adjusting the fiber content by volume.

[0120] FIG. 8 shows a sectional view of the device for impregnating the fibers;

[0121] The device 23 for impregnating the fibers preferably comprises a lower part 35 and a lid 37. The bath 31 having the matrix material with which the fiber structure 13 is impregnated is located in the lower part 35. In order for the fiber structure 13 to be as far as possible completely impregnated and for gas, in particular air, that is still contained in the fiber structure, to be expelled, wipers are additionally provided in the bath 31. The wipers herein, as is illustrated here, are preferably disposed above and below the fiber structure 13, wherein the wiping edges along which the fiber structure 13 is guided, are aligned such that the wipers 39.1 which act on the fiber structure 13 from above, press the fiber structure 13 onto the wipers 39.2, which act on the fiber structure 13 from below, and in a corresponding manner the wipers 39.2 that act on the fiber structure 13 from below push the fiber structure 13 against the wipers 39.1 that act on the fiber structure 13 from above. The pressure that acts on the fiber structure 13 and thus the effectiveness of the wipers 39.1, 39.2 for expelling the gas can be set by the height by way of which the wipers 39.1, 39.2 engage in one another.

[0122] The fiber structure 13 is guided by way of a deflection roller 41 from above into the bath 31. In order for the fiber structure 13 after the deflection roller 41 to be guided into the bath 31, a wiper 39.1 is first provided in the running direction 43 of the fiber structure 13, said wiper 39.1 acting on the fiber structure 13 from above. The fiber structure 13, after passing the deflection roller 41, is pushed into the bath 31 by way of the wiper 39.1 which acts on the fiber structure from above. The first wiper 39.1 which acts on the fiber structure 13 from above is adjoined by at least one wiper 39.2 which acts on the fiber structure 13 from below, and by a further wiper 39.1 which acts on the fiber structure 13 from above. Even further wipers can also be provided, wherein the last wiper in the running direction 43 of the fiber structure 13 is a wiper 39.1 that acts on the fiber structure 13 from above. The fiber structure 13 after the last wiper 39.1 is guided through a device for adjusting the fiber content by volume 100, said device by way of one side being submerged in the matrix material and by way of the other end, through which the fiber structure 13 exits the device for adjusting the fiber content by volume 100, lying outside the matrix material. Subsequent to the device for adjusting the fiber content by volume 100, the impregnated fiber structure is guided by way of a further deflection roller 45.

[0123] Instead of the deflection rollers 41, 45 which are illustrated here, it is also possible to use a bar which preferably has only rounded edges in at least that region in which contact with the fiber structure 13 takes place and is particularly a round bar.

[0124] In order for the fiber content by volume of the impregnated fibers to be set, the device for adjusting the fiber content by volume 100 in the embodiment illustrated here has a nozzle 123 and a duct 125. The nozzle has the minimal cross-sectional face which is dimensioned such that the desired fiber content by volume is achieved. The nozzle 123 is adjoined by the duct 125, wherein the duct 125 has a cross-sectional face which is so large that the impregnated fiber structure which is guided through the duct 125 does not contact the walls of the duct 125. In order to prevent that air bubbles or gas bubbles are incorporated into the fiber structure when impregnating, the device for adjusting the fiber content by volume 100 by way of the nozzle 123 submerges into the matrix material in the bath 31. The impregnated fiber structure, after passing the nozzle 123, can be guided out of the matrix material in the bath 31 through the duct 125 that adjoins the nozzle 123, without said fiber structure once again coming into contact with the matrix material, such that the fiber content by volume after passing the nozzle 123 is no longer changed. To this end, the duct 125 is connected to the nozzle 123 in a liquid-tight manner such that no matrix material can make its way out of the bath 31 into the duct 125. The end of the duct 125 through which the fiber structure exits, in operation is located outside the matrix material.

[0125] In order for the fibers to be able to be placed into the device 23 for impregnating fiber structure in a simple manner, the wipers 39.1 that act on the fiber structure from above, and the device for adjusting the fiber content by volume 100, are preferably fitted so as to be retrievable from the bath 31. The fiber structure 12 to be impregnated is first located outside the matrix material, above the bath 31. The fiber structure 13 is first placed into the device for adjusting the fiber content by volume 100. The wipers 39.1 which act on the fiber structure 13 from above are likewise still located outside the bath 31. Once the fiber structure 12 has been placed into the device for adjusting the fiber content by volume 100, said fiber structure 13 by way of the wipers 39.1 that act on the fiber structure 13 from above is pressed downward. To this end, the wipers 39.1 preferably are fitted to the lid 37 which is placed onto the lower part 35 that contains the bath 31. In order for the device for adjusting the fiber content by volume 100 to be positioned such that said device for adjusting the fiber content by volume 100 by way of one side, preferably the side that has the nozzle 123, can submerge into the matrix material that is contained in the bath 31, and the other end of the device for adjusting the fiber content by volume 100, from which the impregnated fiber structure can exit again, is outside the matrix material, the device for adjusting the fiber content by volume 100 is preferably fitted so as to be movable on a suitable mounting by way of which the device for adjusting the fiber content by volume 100 can be fitted to the container that contains the bath 31.

[0126] For this purpose, the device for adjusting the fiber content by volume 100 herein by way of a first arm 127 is fitted to the lid 37, and by way of a second arm 129 is fitted to the lower part 35.

[0127] The first arm 127 and the second arm 129 are in each case fastened to the duct 125 of the device for adjusting the fiber content by volume 100 so as to be rotatable about an axis that runs perpendicularly to the fiber structure 13. On account thereof, the device for adjusting the fiber content by volume 100, when closing the lid 37, is moved to the desired position. The fiber structure is pressed into the matrix material in the bath 31 by way of the wipers 39.1 which are fastened to the lid 37 and act on the fiber structure 13 from above, wherein the fiber structure in the case of a closed lid by way of the wipers 39.1 that act on the fiber structure 13 from above is pressed against the wipers 39.2 that act on the fiber structure from below. The wiper 39.2 that acts on the fiber structure 13 from below herein is fastened to the lower part 35.

[0128] The fiber structure can be fed as a fiber bundle or as a bundle from a plurality of individual rovings, and can be split in the bath 31 into individual fibers, units from a lower number of fibers, or individual rovings, in order for the fibers to be able to be completely impregnated, wherein the fibers or rovings after soaking are gathered again, before said fibers or rovings are guided through the device for adjusting the fiber content by volume. Splitting herein can be performed by using deflection units 33 along which the individual fibers, units from a lower number of fibers, or rovings are guided.

[0129] FIGS. 9 and 10 show a device to adjust the fiber content by volume in a closed and an opened position.

[0130] The device for adjusting the fiber content by volume 100 comprises an upper part 101 and a lower part 103. In each case one clearance 105 is located in the upper part 101 and in the lower part 103. When the upper part 101 and the lower part 103 are assembled, the clearances 105 form one opening 107. In the operation, fibers that are impregnated with matrix material are guided through the opening 107, and excess matrix material is wiped on the periphery 109 of the opening.

[0131] On account of the construction of the device for adjusting the fiber content by volume 100, having the upper part 101 and the lower part 103, it is possible for the unit for setting the fiber content by volume 100 to be opened, as is illustrated in FIG. 10. This enables the fibers to be placed into the unit for setting the fiber content by volume 100 in a simpler manner.

[0132] The minimum opening cross section herein during impregnation meets the following condition:

[00001]$A=\frac{n\cdot Tex}{\phi \cdot \rho }$

where [0133] n = number of fibers which in the operation are guided through the opening; [0134] Tex = the fiber count Tex in g/1000 m; [0135] φ = fiber content by volume; [0136] ρ = density of the fibers.

[0137] It applies to the fiber content by volume φ that

[00002]$\phi =\frac{V_{Fiber}}{V_{Fiber}+V_{Matrix}}$

with the fiber volume V.sub.Fiber and the matrix volume V.sub.Matrix.

[0138] When rovings or planar fibrous structures are impregnated, it is possible for the number and the Tex count of the rovings or of the planar fibrous structures, respectively, which are guided through an opening to be inserted instead of the number and the Tex count of the fibers.

[0139] To allow a continuous process, it is necessary to continuously provide the matrix material. For this purpose, it is preferred to provide a metering unit for the matrix material on the device 23 for impregnating the fibers. Particularly if a two or more component resin is used, the components must be mixed before impregnating the fiber structure 13. For this purpose, it is preferred to use a device 201 for mixing and metering the matrix material.

[0140] A side view of a device for impregnating a fiber structure with a device for mixing and metering the matrix material is shown in FIG. 11.

[0141] As in a two component resin generally the two components start to react forming the polymer after being brought into contact, it is necessary that the mixture only has a short residence time. Therefore, the bath of the device 13 for impregnating the fiber structure only contains a small amount of the two component resin as matrix material. Therefore, for a continuous process it is necessary to continuously add new matrix material into the bath.

[0142] For feeding the components of the two component resin, the device 201 for mixing and metering the matrix material comprises a first circulation 203 for the first component and a second circulation 205 for the second component. During operation the first component is circulated through the first circulation 203 and the second component through the second circulation 205.

[0143] A part of the first and second components which are circulated through the first and second circulations 203, 205 is fed into a mixing head 207. In the mixing head 207 the first and second components are mixed and then metered into the bath of the device 23 for impregnating the fiber structures via a feed line 209. For a residence time of the mixed first and second components as short as possible, the mixing head 207 is positioned as close as possible to the device 23 for impregnating the fiber structure. For this purpose, the feed line 209 also is as short as possible. Alternatively, it is possible to omit the feed line 209 and to mount the mixing head 207 directly on the device 23 for impregnating the fiber structure.

[0144] The mixing head 207 may comprise any suitable mixer for mixing the first and second components of the two component resin. Such mixer may be dynamic mixers or static mixers. Particularly preferably, the mixing head 207 comprises a static mixer.

TABLE-US-00001 List of reference numbers 1 liner 129 second arm 3 first holding device 201 device for mixing and metering the matrix material 5 second holding device 203 first circulation 7 support 205 second circulation 9 central axis 207 mixing head 11 movable arm 209 feed line 12 cutting device 13 fiber structure 14 sleeve with pincers 15 woven pattern 16 sleeve 17 movable arm 18 pincer 19 feed point for the continuous fiber 21 fiber supply 23 device for impregnating the fibers 25 liner with wound fiber structure 27 curing station 29 mold 31 bath 33 deflection unit 35 lower part 37 lid 39.1 wiper acting on the fiber structure from above 39.2 wiper acting on the fiber structure from below 41 deflection roller 43 running direction 45 deflection roller 100 device for adjusting the fiber content by volume 101 upper part 103 lower part 105 clearance 107 opening 109 periphery of opening 123 nozzle 125 duct 127 first arm