Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
  • B29C70/28—Shaping operations therefor
  • B29C70/30—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core
  • B29C70/34—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core and shaping or impregnating by compression, i.e. combined with compressing after the lay-up operation
  • B29C70/345—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core and shaping or impregnating by compression, i.e. combined with compressing after the lay-up operation using matched moulds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
  • B29C70/28—Shaping operations therefor
  • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
  • B29C70/541—Positioning reinforcements in a mould, e.g. using clamping means for the reinforcement
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
  • B29C70/28—Shaping operations therefor
  • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
  • B29C70/56—Tensioning reinforcements before or during shaping

Definitions

• the invention relates to a device and a method for producing 3-dimensional components made of fiber-reinforced plastic.
• Fiber reinforced plastic components have a structure of reinforcing fibers embedded in a plastic matrix material. For more complex and higher-quality components, a multi-layered fiber structure with fiber orientations arranged as well as possible is often necessary.
• RTM Resin Transfer Molding
• first a fiber preform according to the desired component form is produced, which is held together by small amounts of binder material, by stapling, stapling or sewing.
• This fiber preform is then placed in a closed mold, it is injected the liquid matrix material, so that the fiber preform is completely saturated with matrix material, and the matrix material is usually cured under pressure.
• the component can be removed from the mold.
• a disadvantage of this method is that the complete penetration of the matrix material is difficult for multilayer fiber preforms. There is a risk that dry spots remain, which cause imperfections in the component. Or it must be used very low-viscosity matrix material, which limits the selection and thus the component properties.
• prepregs are strip-shaped fiber tapes or rectangular fiber mats or fiber fabrics that are already impregnated with the required matrix material. From these 2-dimensional prepregs will be cut suitable pieces, draped in or over a mold and pressed together, and cured or consolidated. Prepregs require complicated handling and are expensive. Such with duromer matrix material must be frozen after manufacture to stop the curing process, and are only briefly storable. They must then be thawed before use.
• Prepregs with thermoplastic matrix material are usually heated to high temperatures prior to use, so that they become soft and formable.
• the disadvantage is that the flat prepregs can only be cut and draped automatically to a very limited extent and costly and that they are warped or form wrinkles during the three-dimensional forming, as a result of which the optimum strength is not achieved.
• the object of the invention is to develop an improved, more reliable and easily automatable method and to provide a device suitable for implementing the method, wherein there is no danger of dry spots and so that the complicated handling of prepregs can be dispensed with.
• the goal is to be able to produce components with special requirements and more complex shapes still cost-effective.
• the object is achieved for the device according to the invention by providing a plurality of unwinding stations for the provision of a plurality of yarns or rovings or fiber tapes,
• a plurality of grippers each of which grip one or more yarns or rovings or fiber tapes at their beginning and can span between the first mold and the one or more molds, has;
• Yarn transfer point is movable back and forth
• One or more juxtaposed impregnating stations for applying plastic matrix material between unwinding and Forming tools are provided which can impregnate the yarns or rovings or fiber tapes during clamping,
• first mold can be moved between at least some of the grippers and the yarn transfer point so that the impregnated, stretched yarns or rovings or fiber tapes are draped as a layer over the first mold
• the one or more further forming tools are arranged on the opposite side of the first mold of the clamped yarns or rovings or fiber tapes and are movable so that they can push the draped layer to the first mold and thus reshape.
• the advantage of the invention is that in one device or in a continuous process fibers can be stretched in one layer, impregnated with plastic matrix material, draped and 3-dimensionally formed. Preferably, after draping, no further addition of matrix material which is to pass between the fibers is more necessary. By causing the fibers to stretch during stretching, i. When impregnated, a good penetration without dry spots is guaranteed. And the fact that the fibers are impregnated shortly before draping, eliminates the costly winding / unwinding and storage / transporting the impregnated fiber materials, as is inevitable with prepregs.
• the fibers are preferably carbon, glass or aramid fibers.
• the term "yarn" refers to the use of so-called continuous fibers, ie when the fibers are unwound from a bobbin or ball. Numerous yarns lying next to each other undiluted and unwound at the same time from a spool or from a ball are called yarn bundles or roving.
• the rovings can consist of up to several ten thousand single yarns, also called filaments. Rovings with 3,000, 6,000, 12,000, 24,000 or 48,000 or 50,000 yarns are preferably used.
• Fiber tapes are narrow bands of fabric, scrim or fleece of continuous fibers, which are fixed mechanically or with small amounts of binder material.
• the matrix material may preferably be duromeric plastic, in particular epoxy resin, polyurethane or other resin, or preferably thermoplastic, in particular PEEK, PPS or a polyamide (PA).
• a cast polyamide or an in-situ polymerizable polyamide such as, for example, cyclic butylene terephthalate (CBT) or polybutylene terephthalate (PBT).
• the latter before the gripper grips it, is spread in a spreading device, which is arranged between the unwinding station and the yarn transfer point, so that the individual fibers run parallel next to one another.
• Each gripper can also grasp several rovings next to each other, for example 2, 3, 4 or 5 rovings next to each other, so that a wider band is stretched by a gripper.
• the grippers are moved in a straight line between Maxi times position and pickup position.
• the width of the grippers is preferably between 30 and 600 mm, more preferably between 50 and 200 mm. For smaller widths you need too much mechanics to move the many grippers and for larger widths, the tensile forces are too large or the uniformity in the tension is too difficult to ensure.
• the impregnation station is preferably arranged between the unwinding station and the yarn transfer point.
• the impregnation station can also be arranged between the yarn transfer point and the forming tools. For this, the impregnation station must then be able to be moved or opened in such a way that a passage for the grippers is cleared on their linear path.
• the device can be used when complex, multi-layer components are produced.
• the first mold can be rotated in the device, so that on a draped layer of impregnated yarns or rovings or fiber tapes by means of the gripper another layer of impregnated yarns or rovings or fiber tapes with a different fiber direction, preferably at an angle between 30 ° and 90 ° rotated can be applied.
• different layers including several layers can be applied in the same direction.
• One possible sequence could be, for example, 0 0 + 457 - 457 907 - 457 + 457 07 0 °.
• the rotation of the first forming tool may take place on a lifting table or together with a lifting table which can perform the movement of the first forming tool between the grippers and the yarn transfer point.
• the other molds can be made rotatable.
• One of the other molds may be formed as a hood. By the interaction of the molds thus the layers can be pressed together.
• the hood can optionally be heated, for example, when using duromer to cure the matrix material can. But it can also be optionally cooled to cool when using thermoplastic, this for consolidation can.
• several other molds for example in the form of punches may be provided, so that more complicated shapes with, for example, multi-stage forming are possible. Even if a plurality of molds, such as stamps are provided, they can be designed to be heatable in order to achieve a lighter deformation of the thermoplastic or a faster curing of the thermoset.
• a heating device which can heat the draped layers or the clamped impregnated yarns or rovings or fiber tapes to a temperature between 60 and 400 ° C.
• a particularly preferred range for the temperature is 60 to 200 ° C to cure thermoset. And another preferred range is 200 to 400 ° C to make them malleable.
• the heating device is preferably designed as an IR heater or as a continuous and / or circulating air oven. For preheating prior to deformation, it may be provided in the region of the impregnation station or in the region of the molding tools or in between. For hardening the matrix material, the heating device is preferably arranged in the region of the molding tools.
• thermoplastic When using thermoplastic, it is advantageous to provide a cooling device for cooling the component after or during contact with the or the other molds. Cooling is necessary to consolidate the component.
• the individual grippers can preferably be moved independently of one another at the same time and the yarns or rovings or fiber tapes can each hold at different intermediate positions between the pick-up position and the maximum position, it is possible to approach different component geometries so that little waste of impregnated fiber material is obtained.
• the impregnation stations as a powder application unit or as a spray station or as an extrusion application unit or as a film application unit or as an impregnation bath.
• the various embodiments offer advantages.
• Particularly suitable for thermos is the soaking bath.
• Particularly suitable for thermoplastics is the film application or extrusion applicator.
• Spray station and powder applicator are well suited for both.
• a calendering device can advantageously be present, for example one or more nips formed from two Rollers that press or roll in the plastic matrix material into the fibrous structure.
• At least one doctor device is provided which strips off excess plastic matrix material after application from the yarns or rovings or fiber tapes.
• the doctor device is used in combination with an impregnating bath as impregnating station.
• each gripper can be assigned a separately controllable impregnation station or a separately controllable doctor device.
• spray station and powder coating unit are especially suitable for different application quantities. But the other commissioned works can be carried out accordingly. For example, through narrow thermoplastic film strips.
• Yarns or rovings or fiber tapes are provided by multiple unwinding stations,
• a plurality of juxtaposed grippers engage the yarns or rovings or fiber tapes at an associated yarn transfer point and span them by movement along substantially parallel paths between a first mold and one or more further molds,
• yarns or rovings or fiber tapes are impregnated with plastic matrix material during clamping through one or more impregnating stations arranged side by side, which are located between the unwinding station and the forming tool,
• the first mold is then moved between at least some of the grippers and the yarn transfer point, that the impregnated, spanned yarns or rovings or fiber tapes are draped as a layer over the first forming tool
• the first molding tool is rotated by an angle between 30 and 90 °.
• the advantages of the method according to the invention can be used well.
• the forming takes place together with the help of the or the other molds individually after draping each layer or only after draping several layers together. This depends, among other things, on the matrix material used.
• thermoset in particular an epoxy resin or polyurethane, is particularly preferably used as the plastic matrix material, the layers being heated to a temperature of between 60 and 200 ° C. during forming with the further molding tool or after forming in order to harden the matrix material.
• thermoplastic in particular PEEK or PPS or polyamide (PA)
• PA polyamide
• the layers being heated to a temperature between 200 and 400 ° C. during clamping or draping in order to make the matrix material deformable .
• the component is then cooled to consolidate it.
• the plastic matrix matehal required for the component is preferably predominantly, in particular completely, applied by the impregnation stations. As a result, subsequently no matrix material must be brought between the fibers. However, further matrix material, eg together with fiber syringes, can be cast or applied to the formed component.
• FIG. 2 shows a device according to the invention during draping
• FIG. 3 shows a device according to the invention during forming
• FIG. 4 shows another device according to the invention during clamping - top view
• the yarns or rovings or fiber tapes 20,21 are provided in the form of bobbins or bobbins in the unwind stations 3,4.
• a spreader 1 1 is used.
• the rovings are guided so that the individual yarns flat to lie next to each other.
• the spread yarns or rovings or fiber tapes 22 are passed through an impregnation station 10, which is shown here as a resin bath, as would be suitable, for example, for epoxy resins as a plastic matrix material.
• the fibers take with them the plastic matrix material required for the layer. Excess resin is separated by a squeegee device 13 with top and bottom doctor blades.
• the impregnated yarns or rovings or fiber tapes 23 are clamped or held so that their beginnings can be gripped by the grippers 5 which are in the pick-up position 6.
• the grippers 5 can be formed for example by two jaws. With a guide device 9, the grippers 5 are then moved on mutually parallel paths as far as maximum position 7, as is necessary for the desired component shape. They clamp the impregnated yarns or rovings or fiber tapes 24 between the first mold 1 and the further mold 2.
• the first mold 1 is located on a lifting and rotating table 12 and can be rotated on the table or with the table.
• the further mold 2 is shown in this case as a hood. Also possible would be several other molds that are used simultaneously or sequentially, for example in the form of stamps.
• the yarns or rovings or fiber tapes When clamping, ie when moving the gripper 5 in the direction of maximum position 7 to an intermediate position depending on the component shape, the yarns or rovings or fiber tapes are unwound from the unwinding stations 3,4, spread and pulled through the impregnation station 10, so that with the necessary matrix material impregnated yarns or rovings or fiber tapes 24 are clamped. A subsequent feeding or injecting matrix material is eliminated.
• the fact that the yarns or rovings or fiber tapes are impregnated in individual layers and not as a complete multi-layer fiber preform, a more reliable impregnation without dry spots is achieved.
• first layer 25 which is already stored on the first mold 1.
• the current position of spanned fibers 24 can now be stored at a certain angle, preferably between 30 and 90 °.
• individual layers can also be deposited one after the other at the same angle. For example, to achieve certain anisotropic component properties or to achieve a better and more uniform impregnation at a high fiber content.
• the storage direction can be adjusted via the turntable 12 for the individual layers and can be tailored to the subsequent component load.
• the yarn transfer point 8 and thus the pick-up position 6 between spreader 1 1 and impregnation 10 are provided. If no spreading device is present, as may be the case with the use of fiber tapes, the yarn transfer point 8 is then between the unwinding station 3, 4 and the impregnating station 10. In order to allow the yarns or rovings or fiber tapes to be gripped, the impregnating station 10 must be opened or moved upwards can be moved down that the grippers can be moved on their linear travel from the maximum position 7 to the pickup position 6 at the yarn transfer point 8. After the first pull through until shortly after the impregnation station 10, this is then closed again and is ready for impregnation.
• Fig.1b is the plan view of the device shown in Fig.1. It can be seen that there are several unwinding stations 3, 4 and a plurality of individually and parallel movable grippers 5. The number of unwinding stations depends on the desired density of the fiber structure and on the size of the components.
• the grippers 5 can also be set close to contour on the first mold 1 to different intermediate positions even with non-rectangular or more complex shapes. Depending on the component shape, the width of the gripper 5 can be between 30 and 600 mm. It can also be used side by side with different width gripper.
• an impregnation station 10 for all juxtaposed yarns or rovings or Used fiber tapes.
• the squeegee device 13 can be made uniform over the width or in segments individually adjustable.
• Fig.2 the process of draping is shown with the previously described device.
• the first mold 1 is moved with the lifting table 12 into the clamped cooking or rovings or fiber tapes, so that it is positioned between the grippers 5 and the yarn transfer point 8.
• the yarns or rovings or fiber tapes are draped as layer 26 over the first mold 1.
• the layer 26 is another layer above the layer 25.
• the yarns or rovings or fiber tapes can be retraced - from the unwinding 3.4 by the impregnation 10th
• a tension measurement for the yarn tension can also be provided.
• the further mold 2 is lowered as a hood on the draped yarns or rovings or slivers, and thus generates in cooperation with the first mold 1, the desired component shape.
• the molds 1, 2 can preferably be designed so that a certain pressure is exerted on the component in order to press the layers together and to squeeze existing air.
• the further molding tool 2 and / or the first molding tool 1 can be heated, so that the matrix material can be cured.
• the heating is preferably carried out so that the component can be heated to 60 to 200 ° C.
• a separating device is provided, which cuts the yarns or rovings or fiber tapes between yarn transfer point 6 and mold 1, 2 after forming. Then the molds 1, 2 can be moved apart again and the grippers 5 can again span yarns or rovings or fiber tapes for another layer.
• the first mold 1 can be rotated as needed. Also, the further mold 2 can be rotated or it can be replaced.
• thermoplastic as a plastic matrix material
• a heating device not shown in the figures is provided for heating. This can be arranged in the region of the impregnation station 10 or in the region of the molding tools 1, 2 or in between. Preferably, it is designed as an IR heater. The component should reach 200 to 400 ° C in this case.
• first and / or the further mold 1, 2 may also be the first and / or the further mold 1, 2 heated to support the heating or take over completely. Thereafter, the component must still be cooled by means of a cooling device not shown separately. Alternatively, the first and / or the further mold 1, 2 may be cooled to perform the consolidation in the mold.
• Figures 5 to 8 show various embodiments for impregnating stations as they can be used in devices or methods according to the invention.
• Fig.5 shows a Hechränkbad.
• resin 16 for example, epoxy resin presented.
• guide rollers 14 the splayed yarns or rovings or fiber tapes are performed in the bathroom. With the help of the pulleys 15, the resin is applied to these. With a two-sided doctor device 13 excess resin is stripped off. By the speed and the squeegee device 13, the amount of resin can be controlled. Thereafter, the impregnated yarns or rovings or fiber tapes 23 are received at the yarn transfer point 8 by the grippers. If the yarn transfer point is arranged differently than shown in front of the impregnation station, the resin bath with the lower rollers can downwards and the upper rollers can be moved upwards, so that a passage for the gripper can be opened.
• FIG. 6 describes a film application plant. From supply rolls 18.1 thermoplastic films 16.1 are unwound and applied by means of guide rollers 14.1 on the yarns or rovings or fiber tapes 22. About heated pulleys 15.2, which serve as a calendering and which may be as well as the guide rollers optionally pressed against each other, the thermoplastic films are heated to the extent that they connect well with the yarns or rovings or fiber tapes. The cooled pulleys 17 consolidate the thermoplastic again slightly. The cooling rollers can also be omitted.
• FIG. 7 a spray applicator is shown.
• Matrix material is sprayed by one or more spray nozzles 18.2 as droplets or spray threads 16.2 on the yarns or rovings or fiber tapes 22.
• the guide rollers 14.2 hold the yarns or rovings or fiber tapes 22 at the desired distance.
• the impregnated yarns or rovings or fiber tapes 23.2 are transported to the yarn transfer point.
• a Pulverarguesstechnik can be constructed as impregnation.
• FIG. 8 represents an extrusion application unit.
• Thermoplastic matrix material is plasticized in an extruder 18.3 and applied as layer 16.3 to the yarns or rovings or fiber tapes 22 by means of guide rollers 14.3.
• still cooled deflecting rollers 17 may be provided for partial consolidation. Similar to an extrusion applicator, a melt of thermoplastic can be applied via a slot die instead of the extruder.
• the impregnation station can be designed such that the upper rollers and components can be moved upwards and the lower rollers and components can be moved downwards so that the passage for the grippers is opened can.
• All illustrated variants for the application of the matrix material can be designed as several impregnation stations next to one another, so that different application quantities can be set as required across the width.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Composite Materials (AREA)
• Mechanical Engineering (AREA)
• Reinforced Plastic Materials (AREA)
• Moulding By Coating Moulds (AREA)

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Publications (1)

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Cited By (2)

Citations (4)

• 2013
  • 2013-07-01 WO PCT/EP2013/063771 patent/WO2014012774A1/fr not_active Ceased

Patent Citations (4)

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