DE102017118494A1 - Method and device for determining the material quality of a matrix material - Google Patents

Abstract

The invention relates to a method and a device for determining the material quality of a matrix material, wherein the matrix material is transilluminated by means of a light source and the light guided through the matrix material is detected by means of a sensor. In this case, a deviation of an actual beam path is determined by a predetermined target beam path using an evaluation and then determines the material quality as a function of this deviation.

Description

The invention relates to a method and an apparatus for determining the material quality of a matrix material, which is part of a fiber composite material for producing a fiber composite component. The invention also relates to a method and an apparatus for producing a fiber composite component from a fiber composite material, which comprises a fiber material and a matrix material.

Fiber composites from which fiber composite components are produced are virtually indispensable as lightweight materials due to their weight-specific strength and rigidity. In this case, a matrix material infused into a fiber material is cured by temperature and, if appropriate, pressure, so as to produce the fiber composite component with its desired shape and geometry.

As a rule, a fiber composite material has two main constituents, namely a fiber material and a matrix material. Optionally, further components integrated components are conceivable. The fiber material in this case has reinforcing fibers, which give the fiber composite component in the respective fiber direction its particular strength and rigidity. As a result of the curing of the matrix material infused into the fiber material, the reinforcing fibers of the fiber material are embedded in the desired fiber orientation and thus form an integral unit together with the matrix material. Depending on the application or use of the fiber composite material, the fiber material and the matrix material can be present separately from each other and thus provided, in which case an additional infusion process is necessary, through which the matrix material is infused into the fiber material. However, it is also known to use so-called prepregs as a fiber composite material in which the matrix material is already infused into the fiber material and thus provided for further processing, for example for insertion into a molding tool.

A frequently used manufacturing method of fiber composite components, wherein the fiber material and the matrix material of the fiber composite material are initially provided separately, is the LCM (Liquid Composite Molding) method or RTM (Resin Transfer Molding) method in which a dry fiber material is introduced into a mold and the matrix material is injected by means of a pressure gradient into the fiber material or infused. Matrix systems which consist of two or more components and are mixed before or during infusion can also be used as the matrix material.

Only a sufficiently good resin quality allows the production of faultless, the requirements corresponding fiber composite components. An examination of the resin quality carried out prior to the infusion process leaves many unaltered changes in the quality of the resin (for example due to mixing processes, pressure conditions and temperature changes, transport and storage, etc.) only arising from the infusion process itself. An examination of the resin quality carried out after the infusion process may already have led to a faulty process and a faulty component, which does not make economic sense and significantly increases the overall process times.

It is therefore an object of the present invention to specify an improved method and a device corresponding thereto, with which the quality of the matrix material can be monitored, in particular during the infusion process, and thus, if necessary, responded in good time to changing quality features.

The object is achieved by the method for determining the material quality of a matrix material according to claim 1, the method for producing a fiber composite component according to claim 8, a device for determining the material quality of a matrix material according to claim 11 and a system for producing a fiber composite component according to claim 13.

According to claim 1, a method for determining the material quality of a matrix material, which is part of a fiber composite material for producing a fiber composite component proposed, wherein determining the material quality using the inventive method both in the production of a matrix system of a two or more components and in the Production of a fiber composite component, in which the matrix material is injected into a fiber material, can be performed. Thus, the material quality can already be determined at the beginning of the entire process and thus monitor the resin quality, since already in the production of matrix systems, which are provided at a later time another process, determines the material quality and thus the resin quality can be monitored.

According to the invention, it is proposed for this purpose that the matrix material is transilluminated by means of a light source, wherein the light beam guided through the matrix material due to the transillumination of the matrix material is detected by means of a sensor, for example an optical sensor, such as a digital image sensor. For this is advantageously the matrix material in a translucent container, such as a reservoir or a tube or tube-like device, so that a light beam can be passed through the matrix material by means of the light source without the light source having to come into contact with the matrix material. According to an advantageous embodiment, which is to be preferred, the matrix material is located between the light source and the sensor, so that the light beam can preferably be guided centrally (within tolerances) through the vessel or tube-shaped or tubular structure.

The sensor is in this case connected to an evaluation unit in signaling technology, wherein a deviation of the actual beam path, which results from the detected transmitted light beam of the light source, with respect to a predetermined desired beam path then using the evaluation, depending on this so determined deviation of Is-beam path of the desired beam path then the material quality of the matrix material at the current time can be determined.

In this case, the inventors have recognized that the material quality of a matrix material correlates with the beam path of a light beam that transilluminates and passes through the matrix material, so that, based on a deviation of the current beam path of a light beam from a predetermined target beam path representing, for example, optimum material quality or best possible material quality . has a known material quality, finally, the material quality at the current time of fluoroscopy can be determined. Thus, the material quality of the matrix material can be determined quickly, easily and without contamination of other objects, as well as without production of specimens.

Thus, it was recognized that by a deterioration of the material quality of the matrix material, the refractive index correlates with the deterioration of the material quality, so that the deterioration of the material quality both qualitatively and quantitatively in the deviation of the beam path compared to an ideal beam path of fluoroscopy shows.

For the purposes of the present invention, a quality of material is understood to mean a quality measure that relates in particular to one or more properties of the matrix material. The material quality can indicate whether the property is present or not. The quality of the material can also indicate the relationship between the property and a given or idealized property in the matrix material. Properties which relate to the quality of the material are in particular those properties which correlate with the density of the matrix material, such that a change in the property also results in a change in the density of the matrix material.

In an advantageous embodiment, the nominal beam path is a beam path of a light beam guided through a matrix material with a known material quality, wherein the material quality to be determined is determined based on the determined deviation between the actual beam path and desired beam path relative to this known material quality or absolute.

Thus, in a first calibration process, first of all the desired beam path is determined in which, in particular, a matrix material is used which represents an optimum or an ideal with regard to the material quality to be determined. Based on this optimum or idealized matrix material with regard to the material quality (relating to one or more properties of the matrix material), the predetermined nominal beam path can now be determined and then the method for determining the material quality in the production system can subsequently be used. This has the advantage that the method and the device for determining the material quality can always be adapted to the given conditions and thus calibrated to changing matrix systems, so that it can be used flexibly for various matrix systems.

In particular, the presence of segregation and / or degree of segregation of the components mixed in the matrix material can be determined as material quality. With an optimal matrix system, there is a homogeneous material with regard to the mixing quality, which has a substantially homogeneous distribution of the density (within tolerances). If there is a segregation of the matrix system due to various causes such as aging, poor storage or the like, then this homogeneous density changes to an inhomogeneity, which is then determined by a deviation of the actual beam path from a predetermined target beam path in the The remainder would also be analytically determinable. It was recognized that the degree of segregation correlated with the degree of deviation from the actual and desired beam path, so that not only is it determined whether there is a deviation between desired and actual beam path, but also how large is the deviation, the value of this deviation is then a measure of the degree of segregation. Since this relationship inevitably does not have to be linear, it is conceivable that a demodulation characteristic can be used to determine and provide the correlation between deviation and degree of segregation.

In a further advantageous embodiment, the presence and possibly the frequency of pores, bubbles, foam and / or foreign bodies as material quality can be determined based on the deviation, since these properties affecting the material quality of the matrix material lead to an inhomogeneity of the density distribution in the matrix material and thus leads to a deviation of the beam path with respect to an idealized beam path.

In the context of the present invention, a beam path is understood in particular to be any mathematical equivalent describing the path of a light beam starting from the light source to the sensor. In the simplest, and most of all, most advantageous embodiment, the beam path is defined by the relationship between the light source on the one hand and the detection position on the sensor on the other hand. Since the arrangement of the sensor relative to the light source is known and does not change on the basis of the given geometrical relationships, the course of the light beam can also be detected on the sensor from the light source until it is detected, on the basis of this geometrical relationship Determine the beam path. In the simplest form, the beam path can thus be defined by the detection position on the sensor, since the remaining geometric relationships are known.

Based on the determined deviation between the actual beam path and the desired beam path, it is furthermore conceivable that the density of the matrix material and / or the refractive index is determined, wherein then the material quality is determined from the density of the matrix material or from the refractive index itself.

In a further advantageous embodiment, the transillumination of the matrix material by means of a laser is carried out as a light source, whereby parallel beam with particularly sharp focusing and focusing can be passed through the matrix material.

Incidentally, the object is also achieved with the device according to claim 11 for determining the material quality of a matrix material, the device having a light source for illuminating the matrix material and a sensor for detecting a light beam of the light source passed through the matrix material. The apparatus further comprises an evaluation unit which is technically in communication with the sensor signal and is adapted to receive a sensor signal from the sensor, wherein the sensor signal relates to the detection of the light beam passed through, a deviation of an actual beam path of the sensor beam which has passed through it and detected light beam relative to a predetermined desired light beam to determine and determine a material quality of the matrix material as a function of the detected deviation.

The sensor can be, for example, an optical sensor that can detect the light of the light beam. In particular, the sensor is designed such that it can detect a detection position within the sensor surface, so that the deposition between the emitted light beam with respect to the light source and the detection position within the sensor relative to the light source can be determined. Based on this storage between the light source and the detection position can then derive the actual beam path of the light beam. Of course, other physical properties of the device, such as the angle at which the light beam strikes the matrix material or its container, as well as optionally the wavelength and phase of the light beam also play a role here. In a very simple and particularly advantageous embodiment, the beam path is only the relative deviation (deposit) between the imitating light source on the one hand and the detection position in the sensor on the other hand, the light source and sensor have a predetermined known geometric relationship and are aligned relative to each other.

Incidentally, the object is also achieved by the method according to claim 8 for the production of a fiber composite component and a corresponding system according to claim 13, wherein initially the fiber composite material is provided for producing the fiber composite component from a fiber composite material comprising a fiber material and a matrix material the fiber material and the matrix material are present separately. Subsequently, the fiber material of the fiber composite material is introduced into a provided mold and the matrix material is then infused, after the infusion of the matrix material into the fiber material, the matrix material is consolidated.

According to the invention, the material quality is determined before or during the infusion of the matrix material by means of the method according to the invention using the device according to the invention and then the infusion process is monitored as a function of the material quality. The monitoring of the infusion process can be done in such a way that in a very simply stored case only the material quality of the matrix material is deposited in a data memory during the infusion process. It is also conceivable that using a control unit depending on one or more parameters of the infusion process are controlled or regulated the particular material quality of the matrix material and / or the infusion process is terminated, if it appears that the quality of the material is so poor quality that irreversible damage to the component would arise.

The invention will be explained in more detail by way of example with reference to the attached figures.

• 1 - Schematische Darstellung einer Infusionsvorrichtung;
• 2 - Schematische Darstellung des Strahlengangs in einem einphasigen Matrixmaterial;
• 3 - Schematische Darstellung eines Strahlengangs in einem Mehrphasigen Matrixmaterial.

Show it:

• 1 - Schematic representation of an infusion device;
• 2 - Schematic representation of the beam path in a single-phase matrix material;
• 3 - Schematic representation of a beam path in a multi-phase matrix material.

1 schematically shows a device 1 , with which a fiber composite component can be produced from a fiber composite material. The fiber composite material is initially present separately, ie a fiber material 2 and a matrix material 3 are separated before the start of the process, so that the fiber material 2 not yet with the matrix material 3 soaked or infused.

The device 1 has a mold 4 on, which in the embodiment of the 1 is a closed mold consisting of at least two mold halves. In the closed state of the mold 4 forms inside a cavity due to the geometry of the forming tool surface 5 , which by the previously in one of the mold halves of the mold 4 introduced fiber material 2 is or is occupied. Furthermore, the device 1 a reservoir 6 on, in which the matrix material 3 is stored. Via a supply line 7 is the reservoir 6 connected to the mold such that the at the reservoir 6 located matrix material 3 over the supply line 7 in the mold 4 and then into the cavity 5 of the mold 4 located fiber material 2 can be infused.

For this purpose, the attachment 1 in the supply line 7 in the embodiment of 1 a resin pump with which the matrix material from the reservoir 6 in the supply line 7 and then the mold 4 can be injected. The resin pump 8th thus generates the injection pressure necessary for infiltration.

It should be noted that it is in the 1 is only one embodiment, so that many different ways for generating an injection pressure are conceivable. Thus, for example, it is possible to pressurize the reservoir so as to generate the pressure gradient. It is also conceivable that through a drain line 9 (Steiger / Ventingport - resin exit from the mold), a pressure difference is generated by means of a pressure sink, so that in the mold 4 exactly in the cavity 5 , creates a vacuum and a possibly pre-set vacuum can be maintained while the matrix material is being forced into the cavity. In addition, combinations of different means for generating the pressure difference are conceivable.

The resin pump 8th is also with a control device 10 so as to set the parameters for the infiltration of the matrix material 3 into the fiber material 2 to regulate or control. In the simplest case, the control device switches 10 the resin pump 8th on or off. In practice, the control device 10 the resin pump 8th Furthermore, also with regard to the speed of the material flow and the supply line and with regard to the pressure control or regulate.

According to the invention, the plant 1 a monitoring device 20 on, with the material quality of the matrix material 3 monitored during the infusion process. For this purpose, the supply line 7 a transparent area 21 on, which is designed so that a visual inspection of the in the supply line 7 promoted matrix material is possible. The transparent area 21 in the supply line 7 is at least designed so that at least part of the visible or invisible light in the supply line 7 and can get out of this again, so as to be able to detect the material quality of the matrix material based on this accordingly. Furthermore, the monitoring device 20 a light source 23 on, in the embodiment of the 1 is designed as a laser light source. The light source 23 is on the transparent area 21 the supply line 7 aligned so that a laser beam or light beam 26 through the matrix material 3 in the supply line 7 passed through and the matrix material can be so illuminated.

On the opposite side of the laser light source 23 is a sensor 22 arranged by the matrix material 3 passed laser light 26 can capture. This sensor 22 stands in communication with an evaluation unit in terms of signaling technology, the functional principle being incorporated into the 2 and 3 will be explained in more detail.

Alternatively or additionally, it is conceivable that the light source 23 and the sensor 22 also in a transparent area 24 the drainage line 9 is arranged so as to also the matrix material To monitor discharge from the mold with regard to its material quality.

The evaluation unit is advantageously, as in 1 shown with the controller 10 in connection, so that the entire infusion process can also be controlled or regulated based on the determined material quality of the matrix material. Thus, it is conceivable that, in the case of a steadily deteriorating material quality, that of the evaluation unit 25 was detected, the control device 10 then the resin pump 8th switches off and thus ends the process completely.

In the 2 and 3 the operating principle of the present invention is shown schematically greatly simplified. The matrix material 3 is located in the supply line 7 the in 1 illustrated plant. It is conceivable that any container can be used here, as long as a light beam from the outside can be passed through the matrix material.

Below a given angle is the light source 23 so opposite the supply line 7 aligned that the light beam on the supply line 7 meets. At the boundary layer between the inner wall of the supply line 7 and the matrix material 3 becomes that of the laser light source 23 generated light beam 26 broken, ie deflected with respect to its propagation direction (the refractive behavior with respect to the material used in the supply line 7 can be disregarded here).

On the opposite wall, after the light beam 26 through the matrix material 3 was passed, the light beam 26 broken again at a predetermined angle, and then leaves the supply line 7 towards the sensor 22 where he hits accordingly.

2 shows an idealized beam path of the light beam 26 , which always exists when the material quality has the given properties or the desired properties. In this case, in 2 the material quality such that there is no segregation of the matrix material and thus a single-phase matrix material in the supply line 7 is included.

Due to the geometric relationship between the light source 23 and the sensor 22 can thereby the beam path of the light beam 26 be determined because light source 23 and sensor 22 have a predetermined relative arrangement to each other, so that from the position of the light exit at the light source 23 on the one hand and the detection point 30 on the sensor 22 then according to the beam path (possibly taking into account the illumination angle) results. If a property of the matrix material, for example the mixing quality of the matrix material, changes, as a rule the density of the matrix material changes, which leads to a change in the refraction of light. This is in a highly schematically simplified representation in the 3 shown where the matrix material has segregated, so that now at least two phases are present in the matrix material. As a result, the beam path changes, as in the idealized form in 2 is shown, causing the in 3 shown light beam 26a (Actual beam path) is an actual detection position 31 with respect to the sensor 22 has that of the ideal detection position 30 (Nominal detection position) deviates. Under the basic condition that the geometric relationship between light source 23 and sensor 22 has not changed, the deviation between the target detection position 30 and the actual detection position 31 the actual beam path 26a only due to the fact that the refractive index of the matrix material has changed, which suggests a change in the density of the material. In this case, a reduced material quality of the matrix material can therefore be assumed.

This also makes it possible to detect other properties which change the density of the matrix material, such as, for example, pores, bubbles, foam and foreign bodies, since these ultimately result in a deviation when detecting a light beam 26 . 26a with respect to a sensor 22 result.

The present invention thus makes it possible to determine the material quality of a matrix material before or during injection into a fiber material, without having to produce specimens or contaminating other auxiliaries. Rather, it is possible to determine the material quality of the matrix material in particular contactless.

In the 2 and 3 shown embodiments with respect to the determination of the deviation from a target detection position 30 and an actual detection position 31 is from the evaluation unit 25 ( 1 ) realized with the sensor 22 is technically connected. The evaluation unit 25 receives it from the sensor 22 generated sensor signals that advantageously encode the illumination position within the sensor. The evaluation unit 25 is a nominal detection position 30 predetermined, for example, results from a previously performed calibration process. This predetermined target detection position 30 with respect to the sensor 22 now becomes continuous with the transmitted actual entry positions 31 In the case of a deviation beyond a tolerance dimension, a deterioration of the material quality is then concluded.

It is conceivable that, depending on a measure of the deviation between the target detection position 30 and actual entry position 31 is concluded to a degree of material quality reduction in terms of an ideal material quality, so that it can be determined during the process, to which extent the material quality has deteriorated.

The inventors have recognized that using the present method, the material quality of the matrix material can be determined as far as accurate, since it is suitable for a possible use in aviation, where with different, usually very strict specifications, a certain material quality for the safe operation of the later Fiber composite component is required.

LIST OF REFERENCE NUMBERS

1 -

investment

2 -

fiber material

3 -

matrix material

4 -

mold

5 -

cavity

6 -

reservoir

7 -

supply

8th -

resin pump

9 -

drain line

10 -

control device

20 -

monitoring device

21 -

transparent area

22 -

sensor

23 -

light source

24 -

transparent area in drain line

25 -

evaluation

26, 26a -

beam of light

30 -

Target detection position on the sensor

31 -

Actual detection position on the sensor

Claims (14)

Method for determining the material quality of a matrix material (3), which is part of a fiber composite material for producing a fiber composite component, characterized by the steps: - scanning the matrix material (3) by means of a light source (23) and detecting the light beam guided through the matrix material (3) (26, 26a) of the light source (23) by means of a sensor (22), - determining a deviation of an actual beam path of the passed light beam (26, 26a) of the light source (23) with respect to a predetermined desired beam path and - determining the material quality of Matrix material (3) as a function of the detected deviation by an evaluation unit (25). Method according to Claim 1 in that the desired beam path is a beam path of a light beam (26, 26a) guided through a matrix material (3) with a known material quality, the material quality to be determined being determined relative to the determined deviation between actual beam path and desired beam path this known material quality or absolutely determined. Method according to Claim 2 , characterized in that the desired beam path is previously determined in an initialization step by means of a matrix material (3) with a known material quality. Method according to one of the preceding claims, characterized in that the presence of segregation and / or a degree of segregation of the components mixed in the matrix material (3) is determined as material quality. Method according to one of the preceding claims, characterized in that the presence and optionally the frequency of pores, bubbles, foam and / or foreign bodies is determined as material quality. Method according to one of the preceding claims, characterized in that the density of the matrix material (3) and / or the refractive index is determined as material quality. Method according to one of the preceding claims, characterized in that the transillumination of the matrix material (3) by means of a laser as the light source (23). Method for producing a fiber composite component from a fiber composite material, which comprises a fiber material (2) and a matrix material (3), comprising the steps of: - providing a fiber composite material in which the fiber material (2) and the matrix material (3) are initially present separately, Introducing the fiber material (2) of the fiber composite material into a provided molding tool (4), Infusing the matrix material (3) of the fiber composite material into the fiber material (2) introduced into the molding tool (4), and - consolidating the matrix material (3) infused into the fiber material (2), characterized by - determining the material quality of the matrix material (3) or during infusion into the fiber material (2) by means of the method according to one of the preceding claims and - monitoring of the infusion process as a function of the quality of the material. Method according to Claim 8 , characterized in that in an inflow line to the mold (4), in a drain line (9) from the mold (4) and / or in a reservoir (6) for providing the matrix material (3), the material quality of the matrix material (3) is determined , Method according to Claim 8 or 9 Characterized in that a means of a control unit in dependence on the particular material quality of the matrix material (3) or more parameters of the infusion process, in which the matrix material (3) in the fiber material (2) is infused, controlled or regulated and / or Infusion process may be canceled. Device for determining the material quality of a matrix material (3), which is part of a fiber composite material for producing a fiber composite component, characterized in that a light source (23) for transilluminating the matrix material (3) and a sensor (22) for detecting a through the matrix material ( 3) is passed through the light source (23), wherein the device further has an evaluation unit (25), which is in signal communication with the sensor (22) and is set up, - by the sensor (22). to obtain the sensor signals relating to the detection of the light beam (26, 26a) passed through, - to determine a deviation of an actual beam path of the passed and detected light beam (26, 26a) from a predetermined desired light beam, and - a material quality of the matrix material (3) as a function of the detected deviation. Device after Claim 11 , characterized in that the device for carrying out the method according to one of Claims 1 to 7 is designed and furnished. Plant (1) for producing a fiber composite component from a fiber composite material, comprising a fiber material (2) and a matrix material (3), wherein the plant (1) - a molding tool (4) into which the unimpregnated fiber material (2) can be introduced - at least one storage container (6) in which the matrix material (3) can be provided, and - an inflow line (7) from the storage container (6) to the molding tool (4) to remove the matrix material (3) from the storage container (6) in the in the mold (4) introduced fiber material (2) to infuse, and optionally a drain line (9) from the mold (4) for discharging excess matrix material (3), characterized in that - a device according to one of Claims 11 or 12 for determining the material quality before or during the infusion of the matrix material (3) is provided. Annex (1) to Claim 13 , characterized in that the system (1) for carrying out the method according to one of Claims 8 to 10 is trained.

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