DE102016216831B3 - Method and arrangement for producing a fiber composite component - Google Patents

Abstract

The present invention provides a method and apparatus for making a fiber composite component (10). The method comprises the steps of introducing (S101) a ferrofluidic matrix material (151) into a component cavity (12) with a fiber material (14) and applying (S102) a magnetic field (20) to the component cavity (12).

Description

The present invention relates to a method and an arrangement for producing a fiber composite component. A fiber composite component is to be understood in particular as a component which has a fiber composite material or consists of a fiber composite material.

An advantageous basic method for producing a fiber composite component is a so-called infiltration or infusion method, which is also referred to as a resin infusion method. In such a method, usually a fiber material, for example a semi-finished fiber product, is arranged in a component cavity, which serves as a negative mold. A plastic film can be placed over the edge of the component cavity and used to hermetically seal the component cavity. Within the component cavity, a vacuum can then be established. In a first region of the component cavity, a resin supply is arranged, by means of which a resin is introduced as a matrix material in the Bauteilkavität. At a suction usually arranged as far away as possible from the resin supply, the vacuum is generated and maintained by permanent suction, thus creating or increasing a flow of the resin in the component cavity. Challenges arise in this process by the sometimes difficult predictable flow behavior of the resin on component edges, vaults, corners and the like.

For example, there may be a local advance of the matrix material in certain areas, which is also referred to as race tracking. It can happen that the matrix material flows over the fiber material in a wide range. Race tracking can occur, for example, when there are local areas between the resin feed, which is also referred to as feed or as a sprue, and the suction, which offer the matrix material a much lower resistance to flowing through than the surrounding areas. Depending on the arrangement of sprue and suction, race tracking may also occur outside of the fiber material. Race tracking can lead to dry spots within the fiber composite component.

Furthermore, an insufficiently controlled movement of the matrix material outside the fiber material, which is also referred to as a fiber preform or as a preform, can occur, in particular at the lateral edges of the component cavity.

In the DE 10 2013 012 005 A1 a method is described according to which an auxiliary material is introduced into a component cavity with a fiber preform, wherein the auxiliary material is intended to influence the flow path of the matrix material during the infusion process.

The DE 10 2005 030 613 A1 describes a magnetorheological formulation containing at least one base oil, at least one magnetizable particle, a dispersant and a thixotropic agent.

In the US 2010/0 092 419 A1 There are described magnetic fluids and uses for such magnetic fluids.

The US 2016/0 230 894 A1 describes methods and devices using magnetic fluids for seals.

US 2012/0 321 835 A1 describes a method for producing a core stabilized structure with a honeycomb core.

The present invention provides a method with the features of claim 1, and an arrangement with the features of claim 6.

Provided is a method for producing a fiber composite component, comprising the steps of: introducing a ferrofluidic matrix material into a component cavity with a fiber material; and applying a magnetic field to the component cavity. The introduction of the ferrofluidic matrix material can take place before, after, and / or during the application of the magnetic field to the component cavity.

A ferrofluidic matrix material is to be understood as meaning, in particular, a substance which can be used at the same time as a matrix material, ie, for example. B. curable, and at the same ferrofluidische properties, d. H. can also be classified as ferrofluid at the same time. Whenever reference is made to a ferrofluid in the following, unless explicitly stated otherwise, according to variants, this can also be understood as referring to a ferrofluidic matrix material.

The term "component cavity" refers in particular to that space in which the fiber material is located and is to be mixed with matrix material.

Furthermore, an arrangement for producing a fiber composite component is provided, comprising: a component cavity with a fiber material; an introducing device adapted to introduce a ferrofluidic matrix material into the component cavity; and a magnetic field device configured or adapted to apply a magnetic field to the device cavity, in particular to generate a magnetic field in the region of the introduced ferrofluidic matrix material.

The introduction device may have two spatially separate introduction elements, of which a first introduction element is designed for introducing the ferrofluidic matrix material and a second introduction element for introducing the non-ferrofluidic matrix material. Alternatively, the introduction device may comprise two separate introduction elements, of which a first introduction element is designed for introducing the ferrofluidic matrix material, and a second introduction element is designed for introducing the ferrofluid, which is not usable as matrix material.

A ferrofluid is a liquid that reacts to a magnetic field. A ferrofluid may consist, for example, of a carrier fluid and ferromagnetic and / or ferrimagnetic particles dispersed therein. Advantageously, the particles are so-called floating articles and are evenly distributed over the long term in the fluid. Preferably, the particles are colloidally suspended. The ferrofluid is also preferably a dispersion.

These particles are advantageously so small that they do not sink in the liquid, clump together or attract each other under the action of magnetic forces. The size of the particles in the ferrofluid is preferably between one and ten nanometers, in particular between five and ten nanometers. The ferrofluid may have a superparamagnetic behavior. Superparamagnetic is a substance, if it has the magnetic property, even at temperatures below the Curie temperature no permanent magnetization to hold when a previously applied magnetic field has been turned off.

Ferrofluids do not solidify under magnetic influence and differ, for example, from magnetorheological fluids which change their viscosity under a magnetic influence.

Thus, by using a ferrofluid according to the invention in producing a fiber composite component, combined with a suitable magnetic field formed in a desired shape and in a desired field strength, in each case a desired flow profile for the matrix material within the component cavity can be produced, in particular for a multiplicity of differently shaped fiber composite components if an infusion method, preferably a vacuum infusion method, is used for producing the fiber composite component.

The introduction of the ferrofluid is preferably preceded in time by the introduction of the matrix material, with the two method steps also being able to overlap completely or partially. In particular, globally or locally, the flow properties of the ferrofluid, in particular directions of movement and / or movement speeds, can be specifically changed by applying the magnetic field.

In particular, a magnetic field can be applied in the region of a flow front of the ferrofluid. The ferrofluid can be repelled or attracted by this magnetic field, whereby the flow speed of the ferrofluid can be correspondingly reduced or increased, and / or the direction of movement of the ferrofluid can be changed.

By applying the magnetic field in the region of the flow front of the ferrofluid, which is referred to here as the first region, also movement properties of a subsequent fluid are changeable, which is not, or not yet, or not significantly affected by the magnetic field, d. H. which is located in a second area in which no or no significant magnetic field acts. The subsequent fluid may be in contact with the ferrofluid in the first region in particular; it may also be the ferrofluid itself, which may be present in both the first and second regions.

For example, as the ferrofluid propagates, on which the magnetic field acts, the subsequent fluid, such as a matrix material and / or more of the ferrofluid, within the device cavity may be drawn or braked in the second region. Such effects may occur with the same or similar fluids z. B. on cohesion and at different phases z. B. based on adhesion.

When the ferrofluidic matrix material is introduced instead of separately introducing a ferrofluid and a matrix material, it is advantageous to use a single initiator. Furthermore, the number of required starting materials is reduced, whereby further economic and technical advantages can be achieved. Furthermore, the ferrofluidic matrix material can remain in the component cavity even after completion of the fiber composite component, without fundamentally resulting in any other mechanical and / or physical relevant properties of the fiber composite component, for example. As a coefficient of thermal expansion, elasticity and the like.

Furthermore, in this variant, the flow method of the matrix material in the entire Component cavity during the manufacturing process particularly precisely controllable by a temporally and / or spatially applied to the respective fiber composite component out magnetic field is applied to the Bauteilkavität to correspondingly temporally and / or spatially the movement properties, in particular movement speeds and / or directions of movement of the ferrofluidic matrix material influence.

Further advantages will become apparent from the subclaims and from the description with reference to the figures.

According to a preferred development, the application of the magnetic field takes place in such a way, in particular at such a time and / or with such a duration and / or with such a spatially formed magnetic field, that a movement property, in particular a movement direction and / or a movement speed, of the ferrofluidic Matrix material controlled in at least one region of the Bauteilkavität, in particular changed, increased or decreased.

The at least one region may in particular be a region of the component cavity which is arranged closer to a suction device on the component cavity than to an introduction device for introducing the ferrofluidic matrix material into the component cavity. In particular, the at least one region can be arranged in the immediate vicinity of the suction device, that is to say the suction device. This can prevent or reduce the likelihood that the ferrofluidic matrix material penetrates into the suction device, which may necessitate a sometimes very complicated removal of at least partially cured matrix material from the suction device after completion of the fiber composite component.

The at least one region, or one of a plurality of such regions, may also be provided in the vicinity of a sealing element in order to prevent or reduce the likelihood that the ferrofluidic matrix material will penetrate into the sealing element.

For example, for a first time period, an amount of the ferrofluidic matrix material may be greatly slowed or even stopped by the magnetic field near the aspirator, while air and / or other gases are removed from the component cavity via the aspirator or are removable. At a second time after the first period, for example after the ferrofluidic matrix material has completely infiltrated and / or exits the fibrous material, the magnetic field holding the ferrofluidic matrix material in the at least one region may be at least temporarily removed. It can thereby be achieved that the ferrofluidic matrix material in the region moves again, or again faster, and closes any remaining leaks in front of the suction device.

Alternatively or additionally, for example, in the entrance area of the suction device, a second magnetic field activated, d. H. can be applied to close with the ferrofluidic matrix material, the suction device. In this way, penetration of matrix material or of ferrofluidic matrix material into the suction device can be avoided. This is particularly advantageous when the ferrofluid is used in addition to a non-ferrofluidic matrix material.

According to a further preferred development, the ferrofluidic matrix material is introduced at least into a region between the fiber material and a lateral boundary of the component cavity. In this way, in particular a race tracking can be reduced or avoided.

According to yet another preferred development, the introduction of the ferrofluid can be carried out before a hermetic sealing of the component cavity. Such hermetic sealing may in particular precede the formation of a vacuum in the component cavity.

According to a further preferred development, non-ferrofluidic matrix material can also be introduced into the component cavity in addition to the ferrofluidic matrix material.

The invention is explained below with reference to embodiments in the drawing. In a partially schematic representation

1a) a schematic flowchart for explaining a method for producing a fiber composite component according to an example;

1b) schematically an arrangement for producing a fiber composite component according to another example;

2a) a schematic flowchart for explaining a method for producing a fiber composite component according to an embodiment of the present invention;

2 B) schematically an arrangement for producing a fiber composite component according to a another embodiment of the present invention;

3a) a schematic flowchart for explaining a method for producing a fiber composite component according to yet another embodiment of the present invention;

3b) schematically an arrangement for producing a fiber composite component according to yet another embodiment of the present invention;

4a) a schematic flowchart for explaining a method for producing a fiber composite component according to yet another example; and

4b) schematically an arrangement for producing a fiber composite component according to yet another example.

In all figures, the same or functionally identical elements and devices - unless otherwise stated - have been given the same reference numerals. Unless otherwise explicitly described, numbering, including procedural steps, does not necessarily imply an order, even though the method steps may advantageously be performed in an order according to their numbering. In particular, several method steps can be carried out simultaneously.

1a) shows a schematic flow diagram for explaining a method for producing a fiber composite component 10 according to an example. The method according to 1a) is in particular by means of a in 1b) schematically illustrated arrangement 1 for producing a fiber composite component 10 executable according to another example.

In a step S01, a ferrofluid becomes 51 in a component cavity 12 with a fiber material 14 initiated. In a step S02 becomes a magnetic field 20 to the component cavity 12 created, for example by means of a magnetic field device 22 , In particular, the magnetic field 20 to the ferrofluid 51 within the component cavity 12 be applied, in particular to a flow front of the ferrofluid 51 within the component cavity 12 ,

In a step S03 becomes a matrix material 52 the component cavity 12 which is preferably not a ferrofluid, ie has no ferrofluidic properties. Introducing S01 of the ferrofluid 51 and / or the introduction S03 of the matrix material 52 For example, by an initiator 32 the arrangement 1 respectively.

The magnetic field device 22 can for generating the magnetic field 20 In particular, have a coil and an AC power source, wherein the coil is acted upon by the AC power source with an AC. With a magnetic core, for example an iron rod, which is arranged - completely or partially - in the coil, the magnetic field can be amplified and / or brought into advantageous forms. A magnetic field 20 with desired geometric arrangements of the field lines of the magnetic field 20 is, for example, by an arrangement of acted upon by different electrical DC and / or alternating currents electrical lines to the Bauteilkavität 12 can be generated around.

2a) shows a schematic flow diagram for explaining a method for producing a fiber composite component 10 according to an embodiment of the present invention. The method according to 2a) is in particular by means of a in 2 B) schematically illustrated arrangement 101 for producing a fiber composite component 10 according to another embodiment of the present invention feasible.

In a step S101, a ferrofluidic matrix material is formed 151 in a component cavity 12 with a fiber material 14 initiated. As the ferrofluidic matrix material 151 For example, a polymer, in particular a duromer, an elastomer and / or a thermoplastic, with ferromagnetic and / or ferrimagnetic particles suspended therein can be used. The size of the particles can be for example between 5 and 10 nanometers.

For this purpose, a matrix material is advantageous before the start of infiltration, ie before introduction S101 of the ferrofluidic matrix material 151 , admixed with the ferromagnetic and / or ferrimagnetic particles, preferably before a preceding degassing operation of the matrix material. As a result, any technically complicated arrangements for handling the particles can be temporally and / or spatially separated from the provisions for introducing S101 of the ferrofluidic matrix material 151 to be hit.

In a step S102, a magnetic field becomes 20 to the component cavity 12 applied, in particular to the ferrofluidic matrix material 151 created, for example by means of a magnetic field device 22 about how they relate to 1b) has been described.

The initiation S101 may be in the arrangement 101 according to 2 B) for example, by an initiator 132 the arrangement 101 respectively. The initiator 132 has a first container 136 in which the ferrofluidic matrix material 151 is stored prior to introduction into the Bauteilkavität. Between the first container 136 and the component cavity 12 may be formed a pressure gradient, for example, a pressure drop of 1 bar.

The method according to 2a) can be designed as a vacuum infusion method. In the arrangement 101 according to 2 B) can this purpose a suction device 134 at the component cavity 12 be arranged, which for sucking in particular of air from the Bauteilkavität 12 as well as for forming the pressure gradient between the first container 136 and the component cavity 12 designed or set up.

The suction device 134 In particular, it can be as far away as possible from the introduction device 132 at the component cavity 12 be arranged. The magnetic field is preferred 20 so to the Bauteilkavität 12 created S102, or is the magnetic field device 22 thus formed, the magnetic field lines of the magnetic field 20 to produce such that these in particular in the vicinity of the suction device 134 in the component cavity 12 are arranged.

The magnetic field is preferred 20 so created, or is the magnetic field device 22 designed or arranged such that a movement of the ferrofluidic matrix material 151 at least in one area of the component cavity 12 is controlled. This area can be variable and, for example, always around a flow front of the ferrofluidic matrix material 151 be arranged.

Alternatively or additionally, this area may be an area which is closer to the suction device 134 as at the initiator 132 is arranged. Thus, as already described above, it can be prevented or reduced the likelihood that the ferrofluidic matrix material 151 premature the suction device 134 achieved and, for example, in the suction device 134 can penetrate before all the residual air from the Bauteilkavität 12 through the suction device 134 sucked off and / or the entire fiber material 14 with the ferrofluidic matrix material 151 was infiltrated.

Also, other advantageous embodiments of the magnetic field described in the foregoing or hereinafter 20 through the magnetic field device 22 in the step S102, in the embodiments according to FIG 2a) and or 2 B) will be realized.

As residual air, an amount of air is referred to, which in the Bauteilkavität 12 due to the fact that this air with the help of a suction device 134 such as a vacuum unit such as a vacuum pump, can not be sucked off. Usually it is assumed that the residual air in the form of many small air packets in the fiber material 14 , For example, between individual rovings and / or filaments, distributed and there is so stable that they are alone with the help of the suction device 134 can not be aspirated. One possible solution is, during the infiltration process, the residual air with the help of the matrix material 151 from the fiber material 14 to slide out.

3a) shows a schematic flow diagram for explaining a method for producing a fiber composite component 10 according to yet another embodiment of the present invention. The method according to 3a) is for example by means of a in 3b) illustrated arrangement 201 for producing a fiber composite component 10 according to yet another embodiment of the present invention feasible.

In a step S201, a ferrofluid becomes 251 in a component cavity 12 with a fiber material 14 initiated. The ferrofluid 251 is prior to introducing S201 into the component cavity 12 in a first container 236 an initiator 232 the arrangement 201 arranged.

In a step S203, a matrix material becomes 252 into the component cavity 12 initiated. The matrix material 252 is prior to introducing S203 into the component cavity 12 in a second container 238 the initiator 232 arranged.

The ferrofluid 251 consists of the same matrix material, eg. As resin, such as the matrix material 252 wherein, to form the ferrofluid 251 in this matrix material ferromagnetic and / or ferrimagnetic particles are suspended, for example, such particles as described above. In other words, this is ferrofluid 251 a ferrofluidic matrix material, approximately as described above 2a) and 2 B) described.

Between the component cavity 12 and the first container 236 and / or the second container 238 can, again through a suction device 134 the arrangement 201 which like the suction device 134 the arrangement 101 may be formed, a respective pressure difference between the first and / or the second container 236 . 238 and the component cavity 12 be generated. In this way, for example by forming different pressure differences, the flow rates of the ferrofluid 251 (ie, the ferrofluidic matrix material) and the matrix material 252 without ferromagnetic and ferrimagnetic properties be initiated differently, even without a magnetic field 20 is created. The effect of pressure differences can be achieved by applying the magnetic field 20 , for example by magnetic attraction of the ferrofluid 251 to be strengthened.

The magnetic field 20 can by a magnetic field device 22 the arrangement 201 generated as described above. Also because the ferrofluid 251 and the matrix material 252 have substantially the same curing properties, since the ferrofluid is realized as ferrofluidic matrix material, in the embodiment according to 3a) and / or the embodiment according to 3b) both the ferrofluid 251 as well as the matrix material 252 after completion of the fiber composite component 10 in the component cavity 12 remain.

In the method according to 3a) may be application S202 of the magnetic field 20 to the component cavity 12 in particular, as described above with respect to steps S02, S102.

4a) shows a schematic flow diagram for explaining a method for producing a fiber composite component 10 according to another example, which is not according to the invention. 4b) schematically shows an arrangement 301 for producing a fiber composite component 10 according to yet another embodiment. The method according to 4a) is in particular by means of the arrangement 301 according to 4b) feasible.

In a step S301, a ferrofluid becomes 351 in a component cavity 12 with a fiber material 14 initiated. Before initiating S301 is the ferrofluid 351 in a first container 336 an initiator 332 the arrangement 301 arranged. In a step S303, a matrix material becomes 352 into the component cavity 12 initiated. Before initiating S303 is the matrix material 352 preferably in a second container 338 the initiator 332 arranged.

In the method according to 4a) and / or in the arrangement 301 is the ferrofluid 351 preferably not usable as matrix material, that is, the ferrofluid 351 For example, it may in particular have no curing properties.

In a step S302, a magnetic field 20 to the component cavity 12 created, for example by means of a magnetic field device 22 the arrangement 301 , which may be formed as well as in the foregoing with respect to 1b) , of the 2 B) and / or the 3b) described.

Forming the ferrofluid 351 and the matrix material 352 made of different materials allows, for example, the ferrofluid 351 to select only on the basis of its magnetic properties and not about - at least - due to its mechanical and / or physical properties in a fate in the Bauteilkavität 12 , As a result, the selection of a suitable ferrofluid is subject 351 lower restrictions.

The ferrofluid 351 can in the examples according to 4a) and or 4b) in particular before finishing the fiber composite component 10 from the component cavity 12 be removed, for example by means of a suction device 134 the arrangement 301 from the component cavity 12 be sucked off. The suction device 134 may in particular be designed or set up as in the preceding with respect to 1b) , of the 2 B) and / or the 3b) described.

The method according to 4a) includes the further steps: turning off S304 of the magnetic field 20 ; and discharging S305, particularly suction, of the ferrofluid 351 from the component cavity. The ferrofluid is preferred 351 selected and / or generated such that it is as far as possible without residue by the fiber material 14 guided and / or by the subsequently introduced matrix material 352 pushed out as well as possible and / or can be flushed out. Among other things, this may include polarity and cohesion of the ferrofluid 351 play an important role.

For example, steps S301, S302, S303, S304, S305 may be performed in this order. It should be understood that, depending on the particular application, it may also be provided that a magnetic field 20 S302 is created several times and / or S304 is switched off again. In each case, the same magnetic field 20 , that is to say with identical magnetic field lines, or at least two different magnetic fields can be applied 20 , that is, with magnetic field lines different from each other, are applied S302.

The application S302 of at least one magnetic field 20 may be prior to introducing S301 of the ferrofluid 351 after initiating S301 of the ferrofluid 351 or during initiation S301 of the ferrofluid 351 into the component cavity 12 respectively. It is also possible that a first magnetic field is applied before the initiation S301, and a second magnetic field is applied during the initiation S310, that the magnetic field applied before the initiation S301 20 is turned off during initiation S301, that during the initiation S301 first a first magnetic field 20 and then a second magnetic field 20 is created and the same variants more.

Which order and / or respective repetitions of the method steps S301 to S305 is advantageous also depends on the respective geometric shape and the physical and chemical properties of the selected ferrofluid 351 and the matrix material 352 from. The switching off S04 of the magnetic field 20 may in particular take place at a time at which the matrix material 352 the fiber material 14 has completely infiltrated and / or exits from it again. By turning off S304 of the magnetic field 20 can be achieved that the ferrofluid, which was previously held in position, for example by the magnetic field, can move and close any remaining leaks before the suction.

Although the present invention has been described above with reference to preferred embodiments, it is not limited thereto, but modifiable in a variety of ways.

For example, in relation to 4a) described process steps of switching off S304 of the magnetic field 20 and deriving S305 of the ferrofluid and / or according to the ferrofluidic matrix material, together, or separately, also in the methods according to 1a) . 2a) and or 3a) be used.

In all the embodiments described, it may be advantageous, for example in the production of sandwich structures, that initially a cover layer of the component 10 For example, a bottom layer is infiltrated by the matrix material, be it a ferrofluid or non-ferrofluidic, before the flow front of the matrix material closes within another cover layer, such as an upper cover layer.

This can be advantageous, for example, if on top of the fiber composite component to be produced 10 a semipermeable membrane is provided. By means of the possible applications of the ferrofluid or the ferrofluidic matrix material described above, the propagation of the matrix material or of the ferrofluidic matrix material can be delayed in corresponding regions, for example in the upper cover layer. In this way, even technically very challenging infiltration of sandwich structures can be realized well.

Claims (6)

Method for producing a fiber composite component ( 10 ), comprising the steps of: introducing (S101) a ferrofluidic matrix material ( 151 ) in a Bauteilkavität ( 12 ) with a fiber material ( 14 ) and and applying (S102) a magnetic field ( 20 ) to the component cavity ( 12 ). A method according to claim 1, characterized in that except the ferrofluidic matrix material ( 151 ) also a non-ferrofluidic matrix material in the Bauteilkavität ( 12 ) is initiated. Method according to claim 1 or 2, characterized in that the application (S102) of the magnetic field ( 20 ) such that a direction of movement and / or a movement speed of the ferrofluidic matrix material ( 151 ) in at least one region of the component cavity ( 12 ) is controlled. A method according to claim 3, characterized in that the at least one region in which by the application (S102) of the magnetic field ( 20 ) the direction of movement and / or the speed of movement of the ferrofluidic matrix material ( 151 ), closer to a suction device ( 134 ) at the component cavity ( 12 ) is arranged as at an initiator ( 132 ) for introducing (S101) the ferrofluidic matrix material ( 151 ) in the component cavity ( 12 ). Method according to one of claims 1 to 4, characterized in that the ferrofluidic matrix material ( 151 ) in at least one region between the fiber material ( 14 ) and a lateral boundary of the component cavity ( 12 ) is initiated. Arrangement ( 1 ; 101 ; 201 ; 301 ) for producing a fiber composite component ( 10 ), comprising: a component cavity ( 12 ) with a fiber material ( 14 ); an initiator ( 32 ; 132 ; 232 ; 332 ), which is designed to be a ferrofluidic matrix material ( 151 ) in the component cavity ( 12 ) to initiate; and a magnetic field device ( 22 ), which is adapted to a magnetic field ( 20 ) to the component cavity ( 12 ).

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