DE102004009744B4 - Process for producing a mold core - Google Patents

Abstract

A process for the production of a contour shape, dimensionally stable, sealed mandrel (4), comprising the following steps:
a) preparing a shape of the mold core (4) adapted, but undersized (L _U ) water-soluble auxiliary mandrel (6) of a water-soluble molding compound (6a) in a first mold (2), which the outer contour of the auxiliary mandrel ( 6) accurately defined, and demoulding the auxiliary mandrel (6) from the first mold (2);
b) arranging (12) of the manufactured undersized water-soluble auxiliary mandrel (6) in a second mold (10), which defines the outer contour of the mold core (4) to be produced with a final contour;
c) filling a castable plastic material (16) which can be hardened into a rubber-elastic material into the second mold (10) and into a gap (Z) between the outer contour of the auxiliary mold core (6) and the inner contour of the second mold (10);
d) curing the filled plastic material (16) to a rubber-elastic mold core outer shell (14), which encloses the water-soluble auxiliary mold core (6) and sealed; and
e) removal of the finished mold core (4) from the second mold (10), ...

Description

TECHNICAL AREA

The The present invention relates to a process for producing a Formkerns, in the manufacture of a fiber composite component (hereinafter referred to as FVW component), in particular a hollow FVW component, is usable. Furthermore, the invention relates to a Intermediate for the production of such a mold core, as well a method for producing an FVW component by means of such Mold core.

STATE OF THE ART

It is known, FVW components with the help of a so-called lost, water-soluble Mold core produce. Here, on the mandrel is a fiber material and one for the fiber material is applied as a matrix material serving resin and the resin afterwards hardened. This creates a dimensionally stable Fiber-composite component. The application of the resin may, for. B. manually in one So-called manual laying method or even mechanically in a mold respectively. In the latter case, the inner contour of the produced FVW component through the outer contour the mold core and the outer contour determined by the inner contour of the mold. As a corresponding machine method is z. The RTM method, d. H. Resin transfer molding process, known. But it is also possible that the fiber material to be processed, the resin already in one contains more or less bound form. Such materials are also known as prepregs. These prepregs are for example in an autoclave under heat hardened to a fiber composite component (prepreg construction). As well are procedures possible where the resin is applied manually.

The water-soluble mold core used in such production methods is usually prepared by introducing a water-soluble, pasty or liquid molding compound into a negative mold and curing it under the action of heat. The resulting hardened, water-soluble mold core usually has a porous, open-pored structure. So that in the subsequent production of the fiber composite component, ie more precisely when impregnating the fiber material with the resin, no resin penetrates into the open pores of the mandrel and an undefined inner contour and increased component weight with deteriorated mechanical properties or impairs the subsequent rinsing of the mandrel, the water-soluble Mold core to be protected against the penetration of the resin. After curing and molding of the mandrel this is therefore by means of a liquid solvent-based sealing medium (eg., AQUASEAL ^™ Fa. Aero Consultants Ltd. AG, PO Box 335, CH-8606 Nänikon / Uster, Switzerland) by brushing, spraying or Diving sealed. The solvent used for the sealing medium is, for example, water.

This However, previously known methods have various disadvantages. So does the seal undefined thick on the outer contour of the water-soluble Formkerns or forms noses or a fold-like structure, what about undefined changes the dimensions or to a dimensional inaccuracy of the mold core leads and in the manufacture of a FVW component by means of such a mold core the removal or removal of the seal difficult. At a Seal by means of the above sealing media is In addition, the shape of the core before drying or renewed Drying of the sealing material is not given, and the mold core with the wet or uncured sealing material can not or only badly handled and further processing steps supplied become. Also, the sealing material after drying is very susceptible against mechanical stress or damage. It can be easy too Sealing breaks come. About that In addition, the tightness of the sealing material or the like sealed mold core very difficult to check. And finally is it is possible using an unsuitable sealing material that the sealing material after curing of the finished FVW component and washing out the water-soluble Mold core adheres to the laminate of the component, which is undesirable.

A generic, all features of the preamble of claim 1 exhibiting method for producing a final contour accurate, dimensionally stable, sealed mandrel, and a generic, all features of the preamble of claim 8 exhibiting method for producing a FVW component by means of a mandrel, is from the EP 0 862 978 B1 known.

PRESENTATION OF THE INVENTION

Of the Invention is the task or the technical problem underlying, a method for producing a final contour accurate and form-containing, sealed mold core to provide, which The disadvantages of the prior art are avoided as far as possible. According to one Another sub-aspect is intended to be a suitable intermediate to create such a mold core. And finally should a method for producing an FVW component, in particular a hollow FVW component provided by means of such a mold core become.

The The aforementioned object is according to a first aspect solved by a method according to the invention with the features of claim 1.

• a) Anfertigen eines der Gestalt des herzustellenden Formkerns angepassten, jedoch untermaßigen wasserlöslichen Hilfs-Formkerns aus einer wasserlöslichen Formmasse in einem ersten Formwerkzeug, welches die Außenkontur des Hilfs-Formkerns passgenau definiert, und Entformen des Hilfs-Formkerns aus dem ersten Formwerkzeug;
• b) Anordnen des angefertigten untermaßigen wasserlöslichen Hilfs-Formkerns in einem zweiten Formwerkzeug, welches die Außenkontur des herzustellenden Formkerns endkonturengenau definiert;
• c) Einfüllen eines zu einem gummielastischen Material aushärtbaren, gießbaren Kunststoffwerkstoffs in das zweite Formwerkzeug und in einen Zwischenraum zwischen der Außenkontur des Hilfs-Formkerns und der Innenkontur des zweiten Formwerkzeugs;
• d) Aushärten des eingefüllten Kunststoffwerkstoffs zu einer gummielastischen Formkern-Außenhülle (Außenhaut), welche den wasserlöslichen Hilfs-Formkern umschließt und versiegelt; und
• e) Entformen des fertigen Formkerns aus dem zweiten Formwerkzeug.

This process for the production of a final contour, dimensionally stable, sealed mandrel comprises the following steps, but not necessarily in the given order:

• a) preparing a shape adapted to the shape of the core to be produced, but undersized water-soluble auxiliary mold core of a water-soluble molding compound in a first mold, which defines the outer contour of the auxiliary mold core accurately and demolding the auxiliary mold core from the first mold;
• b) arranging the manufactured undersized water-soluble auxiliary mold core in a second mold, which defines the outer contour of the mold core to be produced in final contour;
• c) filling a castable plastic material which can be hardened into a rubber-elastic material into the second mold and into a gap between the outer contour of the auxiliary mold core and the inner contour of the second mold;
• d) curing the filled plastic material to a rubber-elastic mold core outer shell (outer skin), which encloses the water-soluble auxiliary mold core and sealed; and
• e) removal of the finished mandrel from the second mold.

in the Step a) is the making of the undersized water-soluble Auxiliary mold core z. B. by filling a water-soluble Molding material in the first mold, which is the shape of the produced Formkerns defined, and then curing the water-soluble Molding material to a water-soluble, undersized Form core realized. The curing the water-soluble If required, molding compound can also be carried out under the action of heat. in the Step c) may be filling the plastic material if necessary under pressure or under pressure accomplished become. The curing In step d) according to the invention also includes a curing of the used Plastic material under heat or Radiation exposure. After curing is also a tempering the mold core possible. The Wall thickness the rubber-elastic mold core outer shell can dependent on the size and shape of the mold core to be produced and the Kind of for the water-soluble Auxiliary mold core used water-soluble material and the surface texture vary the auxiliary mandrel. You can z. B. the fraction of a Millimeters to several millimeters. In the finished mold core forms the hardened water-soluble molding compound an undersized, leachable core element, which of a final contour exact form core outer shell wrapped in rubber-elastic material and sealed.

Of the finished mold core is due to the separating properties of the rubber elastic Easily demould material from the second mold. Of the Form core possesses over it in addition to the o. g. Fashion made rubber elastic Formkern outer shell in conjunction with the water-soluble Core element high dimensional stability and dimensional stability, d. H. he is endkonturengenau. Unlike conventional cores made of water-soluble Material in which subsequently a sealing material is applied, thus changing in the inventive solution, the mold core outer shell not retrospectively the desired external dimension of the mold core. The inventive method guaranteed therefore also a high precision and reproductive ability.

By the rubber-elastic mold core outer shell of Formkerns is the core element of the water-soluble material reliable and wrapped and sealed in a production-friendly way. The tightness This seal is visually easy to check. At the same time guaranteed the rubber-elastic mold core outer shell a comparatively high strength or mechanical resistance, so that sealing breaks In contrast to the prior art per se effectively avoidable are.

The mold core produced by the method according to the invention offers various advantages in the production of an FVW component, in particular a hollow FVW component. Due to the shape of the final contour of the mold core, a very precise, dimensionally accurate and high-strength FVW component with a precisely predetermined fiber architecture can be produced. Due to the rubber-elastic mold core outer shell, the reinforcing fiber material used for the FVW component is not damaged in the unreinforced state or a predetermined fiber orientation is not affected. And the rubber-elastic mandrel outer sheath allows for easier fitting to the particular conditions of the preform and the mold when loading a molding tool with a reinforcing fiber material preform. If the FVW component is cured in the mold under heat, the rubber-elastic mold core outer shell will expand slightly, which is advantageous because the reinforcing fiber material is better compacted in the mold and thus taking into account a required reinforcing resin (matrix), a higher fiber volume content in the FVW component and thus achieve higher strength bar is.

Furthermore offers the mandrel according to the inventive solution in addition to the advantages described above all the benefits of a conventional water-soluble Mold core. That's how it works the mold core according to the invention including the the seal forming rubber-elastic mold core outer shell after curing the FVW component again light and without residue remove the FVW component. Because the water-soluble core element of the mold core let yourself as in a conventional water-soluble mold core completely off Remove the mold core outer shell or Wash. For this purpose, z. B. in hollow, fully closed FVW components z. B. over a mounted in the wall of the FVW component and in the mold core outer shell Auxiliary port, in or on the water-soluble Auxiliary mold core opens, the water-soluble Auxiliary mandrel using water or other suitable medium washed out and thereby formed. This is how it forms an empty mold core outer shell, similar to a bag is easily deformable and easy through the auxiliary opening and completely can be pulled out of the FVW component. Because the rubbery Molded core outer cover in relation on the for the FVW component used reinforcing resin has separating properties, this facilitates the process. The Inner contour of the resulting so in the FVW component cavity has a uniform surface of high quality and has no sealant residue. The removed blank Molded core outer shell can in at least one embodiment the solution according to the invention even reused and with a water-soluble molding compound filled become, whereby again a full inventive mold core arises.

• u) Einfüllen eines zu einem gummielastischen Material aushärtbaren, gießbaren Kunststoffwerkstoffs in eine Negativform eines Schleudergießwerkzeugs;
• v) Schleudern des Schleudergießwerkzeugs und Aushärten des darin eingefüllten Kunststoffwerkstoffs zu einer gummielastischen Formkern-Außenhülle während des Schleudervorgangs;
• w) Einfüllen einer wasserlöslichen Formmasse in die gummielastische Formkern-Außenhülle;
• x) Aushärten der eingefüllten wasserlöslichen Formmasse innerhalb der gummielastischen Formkern-Außenhülle zu einem der Gestalt des herzustellenden Formkerns angepassten, jedoch dem gegenüber untermaßigen wasserlöslichen Hilfs-Formkern, der durch die gummielastische Formkern-Außenhülle umschlossen und versiegelt ist, wodurch der fertige Formkern entsteht.

It should be noted at this point that the end contour-precise, dimensionally stable, sealed mandrel according to the invention can in principle also be produced by a process according to the invention which comprises the following steps, but not necessarily in the given sequence:

• u) filling a castable plastic material which can be hardened into a rubber-elastic material into a negative mold of a centrifugal casting tool;
• v) spinning the centrifugal casting tool and curing the plastic material filled therein to form a rubber-elastic mandrel outer shell during the spin-coating operation;
• w) filling a water-soluble molding compound in the rubber-elastic mold core outer shell;
• x) curing of the filled water-soluble molding compound within the rubber-elastic mold core outer shell to a shape of the mold core adapted, but the undersized underside water-soluble auxiliary mold core, which is enclosed by the rubber-elastic mold core outer shell and sealed, whereby the finished mold core is formed.

The in step v) produced rubber-elastic mold core outer shell can be provided as an intermediate. The filling of the water-soluble Molding compound in step w) can be done both when the rubber-elastic Form core outer shell still in the centrifugal casting tool is located, as well as when the rubber-elastic mold core outer shell already removed from the centrifugal casting mold or possibly in an additional Auxiliary or support form is arranged. The demolding of the rubber-elastic mold core outer shell or the finished mandrel from the centrifugal casting tool is expedient manner either after step v) or after step x), depending according to how the step w) is designed, as already mentioned above. These Process variant is more complex than that according to claim 1 and also requires a larger apparatus Effort. It is therefore not as good for small series as they are aerospace applications are more common. Furthermore the inventors have found that with the method according to claim 1 a better final contour accuracy than in the centrifugal casting comprehensive Method is achievable. The centrifugal casting variant can, depending on the number of pieces, Type and design of the mold core to be produced as well as of it to be produced FVW component but quite a passable / alternative pose.

Further preferred and advantageous embodiments of the inventive method Claim 1 are subject of the dependent claims 2 to 7.

The The object underlying the invention is achieved according to a second aspect by a Inventive intermediate with the features of claim 8.

This Intermediate for producing a mandrel comprises an empty, Contoured form core outer shell out a cured plastic material to a rubber-elastic material, those with a hardenable, water-soluble Fillable molding compound is. The intermediate can also be used as a set together with the curable, water-soluble Be provided molding compound. With the intermediate of the invention are Accordingly, essentially the same advantages can be achieved as they already above in connection with the method according to the invention according to claim 1 discussed were.

The invention underlying Aufga Be is solved according to a third aspect by a method according to the invention with the features of claim 9.

This method for producing an FVW component, in particular a hollow FVW component, by means of a mold core comprises the following steps, but not necessarily in the given order:
Preparing the mandrel by a process according to any one of claims 1 to 7 (or alternatively by the centrifugal casting process described above); Applying a reinforcing fiber material to the mandrel; Impregnating the reinforcing fiber material with hardenable resin; Curing the resin, creating a solid FVW component; and removing the mandrel from the finished FVW component.

The inventive method according to claim 9 allows it is qualitative in a comparatively simple and effective manner manufacture high-quality, dimensionally accurate and high-strength FVW components. About that going beyond are with the inventive method according to claim 9 essentially achieves the same benefits as they already have above in connection with the inventive method according to claim 1 discussed were.

Further advantageous embodiments the method according to the invention according to claim 9 are subject of the dependent claims 10 and 11th

preferred embodiments the invention with additional Design details and other advantages are below Reference to the attached Drawings closer described and explained.

BRIEF DESCRIPTION OF THE DRAWINGS

It demonstrate:

1a to 1c in a schematic cross-sectional view through a first mold a first to third stage of a method according to the invention for producing a mold core according to the invention;

2a to 2d analogous to the representation of 1 a fourth to seventh stage of the method according to the invention;

3a to 3c a schematic cross-sectional view of an open FVW device manufactured according to a method according to a first embodiment of the invention in a substantial first to third stage of this method; and

4a to 4c a schematic cross-sectional view of a produced according to a method of the invention according to a second embodiment, hollow, closed on all sides FVW component in a substantial first to third stage of this method.

PRESENTATION OF PREFERRED EMBODIMENTS

In The following description and in the figures are to avoid of repetitions same components or components with the same Numeral indicated, provided no further differentiation required or useful.

In the 1a to 1c is a schematic cross-sectional view through a first mold 2 a first to third stage of a method according to the invention for producing a final contour accurate, dimensionally stable, sealed mold core 4 (please refer 2d ). In this method, first, one of the shape of the mold core to be produced 4 adapted, but undersized, so "smaller" water-soluble auxiliary mold core 6 in the first mold 2 produced. The first mold 2 In this case, precisely defines the lower outer contour of the auxiliary mandrel 6 , Like in the 1a indicated, first, a water-soluble molding compound 6a in the first mold 2 filled.

In this water-soluble molding compound 6a , which is pasty or liquid in the initial state, it may be, for example, AQUACORE ^™ (pasty) or AQUAPOUR ^TM (liquid or pourable). Also, poly-2-ethyl-2-oxazolines (PEOX) or PVA (polyvinyl alcohol), z. B. as a binder for microballoons or other suitable filler, is as a water-soluble molding material 6a usable. After the water-soluble molding material 6a filled in ( 1a ), becomes the first mold 2 locked ( 1b ). And the molding material 6a becomes the water-soluble, undersized auxiliary molding core under the action of heat 6 hardened ( 1b ). The undersize nature of the auxiliary mandrel 6 is in the 1b by way of example with the length dimension L _U for the length of the auxiliary mandrel 6 indicated. After curing, the first mold 2 reopened and the finished auxiliary mandrel 6 from the first mold 2 formed ( 1c ).

In the above-described production of the auxiliary mandrel 6 For example, it is advantageous for certain embodiments to include a first portion of a ripcord element 8th (please refer 4a to 4c ) in the auxiliary mold core 6 to mold into it. This can be done by making the relevant first section prior to filling the curable what water-soluble molding compound 6a in the first tool 2 inserted, then when filling the molding compound 6a enclosed by this and when they harden in the resulting auxiliary mandrel 6 is formed with. In this ripcord element 8th It may be within the meaning of the invention not only a linen-like part, but z. B. also be a kind of band, tissue or Abreißgewebe or the like. In the 1a to 1c is the ripcord element 8th for better clarity, not shown.

The finished cured and the first mold 2 removed auxiliary mold core 6 may be combined with an undersized first seal (not shown), e.g. B. with AQUASEAL ^™ , by brushing, spraying or dipping. AQUACORE ^™ , AQUAPOUR ^™ and AQUASEAL ^™ are products of Aero Consultants Ltd. AG, PO Box 335, CH-8606 Nänikon / Uster / Switzerland. An undersize first seal means that the sealing material, although slightly on the outer contour of the auxiliary mandrel 6 applies, the resulting dimension of the outer contour of the auxiliary mandrel 6 but still smaller or undersized with respect to the mold core to be produced 4 is. For example, the length of the auxiliary mandrel remains 6 continue approximately on the measure L _U. The application of the water-soluble first seal is usually only necessary or useful if a produced in a later process step mold core outer shell 14 (see below) of the mold core 4 reused later and / or as little as possible material for the mold core outer shell 14 (see below) should be used.

The thus prepared auxiliary mold core 6 will be further processed in additional process steps.

2a to 2d shows here analogous to the representation of 1a to 1c a fourth to seventh stage of the inventive method for producing the mold core 4 , First, the undersized water-soluble auxiliary mold core 6 in a second mold 10 arranged, which the outer contour of the mold core to be produced 4 defined in the final contour ( 2a ). The dimension of the inner contour of the second mold 10 is greater than the dimension of the outer contour of the undersized auxiliary mandrel 6 , For example, based on the length of the mold core to be produced 4 defines the inside length of the second mold 10 the desired length L _{desired of} the mandrel, where L _Soll > L _U (or L _U plus the thickness of a possible initial seal) is.

Arranging the auxiliary mandrel 6 in the second mold 10 is preferably done with the help of spacers 12 which substantially point between the inner contour of the second mold 10 and the under outer contour of the auxiliary mandrel 6 be positioned. The spacers 12 preferably have a tapered shape (the invention is not limited to this shape), as in 2 B is indicated schematically. It has proven to be advantageous, the spacers 12 to arrange so that their conical tips on the inner contour of the second mold 10 issue. The spacers 12 (or the cone height in the installed state) define a gap Z between the undersized outer contour of the auxiliary mandrel 6 and in relation to the mold core to be produced 4 accurately fitting inner contour of the second mold 10 , This intermediate space Z in turn defines a predetermined wall thickness X of a later molded core outer shell 14 of the mold core 4 ,

The cone height of the spacers 12 must not necessarily correspond to the exact wall thickness X, but may optionally be larger, so that the spacers 12 if the auxiliary mold core 6 in the second mold 10 is positioned, can be slightly compressed. The spacers 12 may have the same or different dimensions and thereby, if necessary, the same or different wall thicknesses of the later molded core outer shell 14 define. In the present case, the spacers define 12 a same wall thickness X over the outer contour of the auxiliary mold core 6 , Related, for example, to the desired length L _{desired of} the mold core to be produced 4 applies in this example: L Should = L U + 2X.

If the auxiliary mandrel used 6 a ripcord element 8th (see. 4a to 4c ), the first portion in the auxiliary mandrel 6 is formed in the above-described positioning of the auxiliary mandrel 6 in the second mold 10 a second section of the ripcord element 8th arranged in the intermediate space Z, which, as already mentioned, defines the wall thickness X. The ripcord element 8th is the sake of clarity not in the 2a to 2d shown.

After positioning the auxiliary mandrel 6 in the second mold 10 will this, as in 2 B is indicated, closed. Then it is through an opening 10a a curable to a rubber elastic material, pourable plastic material 16 in the second mold 10 and in the gap Z between the outer contour of the auxiliary mold core 6 and the inner contour of the second mold 10 filled in ( 2 B ). The filling can be done either manually by pouring or also by manual or mechanical injection under pressure. In the used plastic material 16 it is preferably a plastic material which is selected from a group of plastic materials comprising: elastomers including thermoplastic elastomers, polysiloxanes, in particular in the form of silicone resins or silicone molding compounds, polyurethanes, unsaturated polyester resins, epoxy resins, natural rubber and synthetic rubber.

In the present example, as a plastic material 16 a silicone resin 16 used. It should be noted at this point that the previous arrangement of the auxiliary mold core 6 in the second mold 10 used spacers 12 in the context of the invention preferably made of the same plastic material 16 are now made in the second mold 10 and the gap Z is filled. The spacers 12 In this case, they are made of silicone resin 16 produced. This has the advantage that the spacers 12 with the filled silicone resin 16 connect to a homogeneous part, and that the spacers 12 after the production of the mold core 4 as an integral part in its mold core outer shell 14 can remain.

Then the filled silicone resin 16 in the second mold 10 to a rubber-elastic mold core outer shell (or outer skin) 14 cured, which is the water-soluble auxiliary mold core 6 encloses and seals ( 2c ). The curing can be done under heat as needed. This results in the inventive mold core 4 , the at least one undersized core element (here: the auxiliary mandrel 6 ) of a cured water-soluble molding composition, wherein the core element 6 from a contoured form core outer shell 14 from a cured plastic material to a rubber-elastic material 16 (here: silicone resin) is wrapped and sealed. The undersize nature of the auxiliary mandrel 6 or the core element is from a comparison of the dimensions of the outer contour of the finished mandrel 4 and the dimension of the core member and the auxiliary mandrel 6 clear.

If in the above-described production of the mold core 4 an auxiliary mold core 6 with a ripcord element 8th was used, so is the second section of the ripcord element 8th due to the filling of the silicone resin 16 in the space Z and the subsequent curing of the silicone resin 16 now in the mold core outer shell 14 formed and firmly connected to this (not shown).

The finished mold core 4 with its hardened mold core outer shell 14 can now open the second mold 10 be removed or demolded from this (see 2d ).

It should be noted at this point that in the 2c and 2d a gap between the outer contour of the mold core outer shell 14 or of the mold core 4 and the inner contour of the second mold 10 is shown. This serves merely to improve the representation of the individual lines and is not meant to be based on specific relative size or dimension ratios of the mandrel 4 , the auxiliary mold core 6 and the second mold 10 represent. The actual size ratios between these components are given solely by the above definitions.

Although in the above example, a mold core according to the invention 4 was made, the only one water-soluble auxiliary mold core 6 contains, it is understood that with the described method according to the invention mold cores with a plurality of water-soluble auxiliary molding cores can be realized. In this way, the mold core outer shell 14 z. B. enclose several hollow chambers, each with a water-soluble auxiliary mandrel 6 are filled.

The finished mold core 4 now stands for a method according to the invention for producing an FVW component 18 , in particular a hollow FVW component 18 , to disposal. This inventive method for producing a FVW component 18 by means of this mold core 4 includes the following steps: Making the mold core 4 according to the method described above; Applying a reinforcing fiber material to the mandrel 4 (The reinforcing fiber material can also be provided in the form of a reinforcing fiber material preform, in which one or more mandrels 4 to be ordered); Impregnating the reinforcing fiber material with hardenable resin (eg, epoxy resin); Curing the resin, creating a solid FVW component 18 arises; and removing the mold core 4 from the finished FVW component 18 ,

The removal of the mold core 4 from the finished FVW component 18 represents an essential step of the method according to the invention and will be explained below with reference to two embodiments.

The 3a to 3c show a schematic cross-sectional view of a produced according to a method of the invention according to a first embodiment FVW component 18 in a first to third stage of removal of the mold core 4 , The FVW component 18 is in this case an open, ie in the present case on a maximum of five sides of fiber composite material enclosed a FVW component 18 , which in this example has a C-shaped cross-section with undercuts. Like in the 3a recognizable, is a portion of the rubber-elastic mold core outer shell 14 of the mold core 4 through the open side 18a of the FVW component 18 directly accessible. At this side of the mold core outer shell 14 becomes a small passage opening 20 appropriate. This can be z. B. by cutting the mold core outer shell 14 happen. In principle, however, it is also possible in the context of the above-described manufacturing process of the mold core 4 already a closable passage opening 20 (for example, in the manner of a conical plug or the like) is attached.

Then, first, the water-soluble auxiliary mold core 4 through the passage opening 20 through from the mold core 4 formed. This is done by rinsing with water W or a liquid containing mainly water. This creates an empty mold core outer shell 14 , This empty mold core outer shell 14 can through the open side 18a of the FVW component 18 easily removed (eg by manual extraction). This is the mold core 4 completely out of the open FVW component 18 away. The through the mold core 4 Pictured inner contour of the FVW component 18 has a precise and uniform surface without any adhesion of sealing material.

The 4a to 4c show a schematic cross-sectional view of a produced according to a method of the invention according to a second embodiment, hollow, closed on all sides FVW component 18 at a significant first to third stage of this process.

As with this FVW component 18 the mold core 4 is completely enclosed, the steps to remove the mandrel differ 4 from the FVW component 18 slightly different from those of the variant according to the 3a to 3c , As in 4a is indicated, first by a wall 18b the hollow FVW component 18 and the mold core outer shell 14 passing auxiliary opening 22 prepared on or in the auxiliary water-soluble mold core 6 empties. This happens z. B. with a drill 24 , a hole saw or other suitable tool. Then, the water-soluble auxiliary mold core 6 analogous to that already in connection with 3b way described by the auxiliary opening 22 molded or washed out by means of water W or the like (see 4b ). If the mold core used in this process 4 a ripcord element 8th contains, as in the 4a to 4c is indicated by way of example, when washing out the water-soluble auxiliary molding core 6 the first section of the ripcord element 8th uncovered ( 4b ). By washing out the auxiliary mold core 6 In turn, an empty mold core outer shell is created 14 (please refer 4c ).

The empty mold core outer shell 14 can through the auxiliary opening 22 , which is still expandable if needed, are removed. Removing the empty mold core shell 14 is in this case by pulling on the exposed second portion of the ripcord element 8th causes (cf. 4c ).

Both in the embodiment of the 3a to 3c as well as after 4a to 4c can the mold core 4 , ie more precisely its empty mold core outer shell 14 after forming the water soluble auxiliary mandrel 6 be reused. For the production of a full-fledged molding core 4 As described above, it is necessary to re-apply a water-soluble molding compound into the empty mandrel outer shell 14 fill in and inside the mold core outer shell 14 cure. The filling of the water-soluble molding material may, for. B. by the said (closable) passage opening 20 or through the auxiliary opening 22 (in the mold core outer shell 14 ) respectively. The closing of the passage opening 20 or the auxiliary opening 22 is preferably carried out immediately after the filling of the water-soluble molding composition, but in certain cases only after the curing of the molding composition. When filling and curing of the water-soluble molding composition, the mold core outer shell used 14 be arranged within a stabilizing mold (eg, the second mold) or a separate support means (not shown), so that again an exact, accurate to the final contour and well reproducible outer contour of the finished mandrel 4 results.

Instead of an already used empty mold core outer shell 14 For example, it is also possible to provide an (as good as new) intermediate product for producing a mold core that has an empty end contour-conforming mold core outer casing 14 from a cured plastic material to a rubber-elastic material 16 which comprises a curable, water-soluble molding compound 6a is fillable. This intermediate can also be used according to the invention as a set, ie the intermediate plus the curable, water-soluble molding compound 6a to be provided.

reference numeral in the claims, The description and the drawings are only for the better understanding of the invention and are not intended to limit the scope.

2

first mold

4

mold core

6

Auxiliary mandrel

6a

Water-soluble, hardenable molding compound for 6

8th

Ripcords element

10

second mold

10a

opening

12

spacer

14

Mold core outer shell

16

To a rubber-elastic material curable, pourable plastic material

18

FVW component

18a

Open side of 18

18b

Wall of 18

20

Passage opening in 14

22

auxiliary opening

24

drill

L _should

Target length of 4

L _U

Undersize length of 6

X

Wall thickness of 14

Z

gap

Claims (11)

Process for the production of a contoured, dimensionally stable, sealed mandrel ( 4 ), comprising the following steps: a) producing one of the shape of the mold core to be produced ( 4 ) adapted, but undersized (L _U ) water-soluble auxiliary molding core ( 6 ) of a water-soluble molding composition ( 6a ) in a first mold ( 2 ), which the outer contour of the auxiliary mandrel ( 6 ) accurately defined, and demolding the auxiliary mandrel ( 6 ) from the first mold ( 2 ); b) Arranging ( 12 ) of the manufactured undersized water-soluble auxiliary molding core ( 6 ) in a second mold ( 10 ), which the outer contour of the mold core to be produced ( 4 ) defined in the final contour; c) filling a castable plastic material that can be hardened into a rubber-elastic material ( 16 ) in the second mold ( 10 ) and in a gap (Z) between the outer contour of the auxiliary mandrel ( 6 ) and the inner contour of the second mold ( 10 ); d) curing of the filled plastic material ( 16 ) to a rubber-elastic mold core outer shell ( 14 ) containing the water-soluble auxiliary molding core ( 6 ) encloses and seals; and e) demolding the finished mandrel ( 4 ) from the second mold ( 10 ), characterized in that in the mold core outer shell ( 14 ) a closable passage opening ( 20 ), through which the water-soluble auxiliary mandrel ( 6 ) is in a later step (W) formable, so that by the molding (W) an empty mold core outer shell ( 14 ) formed after forming (W) the water-soluble auxiliary mandrel ( 6 ) is reused. A method according to claim 1, characterized in that for the reuse of the mold core outer shell ( 14 ) a water-soluble molding composition ( 6a ) through the closable passage opening ( 18 ; 20 ) in the empty mold core outer shell ( 14 ) and within the mold core outer shell ( 14 ) is cured. A method according to claim 1 or 2, characterized in that - in step b) the water-soluble auxiliary mandrel ( 6 ) by means of spacers ( 12 ), which substantially point between the inner contour of the second mold ( 10 ) and the outer contour of the lower auxiliary mandrel ( 6 ), in the second mold ( 10 ), these spacers ( 12 ) in conjunction with the undersized outer contour of the auxiliary mandrel ( 6 ) and the precisely fitting inner contour of the second mold ( 10 ) a predetermined wall thickness (X) of the later mold core outer shell ( 14 ) define. Method according to claim 3, characterized in that - the spacers ( 12 ) made of the same curable plastic material ( 16 ), which in step 1c) into the second mold ( 10 ) is filled; and - the spacers ( 12 ) after the production of the mandrel ( 4 ) as an integral part in its mold core outer shell ( 14 ) remain. Method according to one of the preceding claims, characterized in that - in step 1a), a first section of a ripcord element ( 8th ) in the auxiliary mold core ( 6 ) is formed in cross-section; and then - before step 1c), a second section of the ripcord element ( 8th ) in the for the filling of the hardenable plastic material ( 16 ) provided intermediate space (Z) is inserted. Method according to one of the preceding claims, characterized in that the curable, castable plastic material ( 16 ) is a plastic material selected from a group of plastics materials comprising: elastomers including thermoplastic elastomers, polysiloxanes (silicone resin, also silicone molding compounds), polyurethanes, unsaturated polyester resins, epoxy resins, natural rubber, synthetic rubber. Method according to one of the preceding claims, characterized in that after the Step 1a) a with respect to the mold core to be produced ( 4 ) undersized, water-soluble first-sealant layer on the water-soluble auxiliary mandrel ( 6 ) is applied. Intermediate for the production of a mold core ( 4 ), comprising an empty, end contour exact mold core outer shell ( 14 ) of a cured plastic material to a rubbery material ( 16 ) with a curable, water-soluble molding compound ( 6a ) is fillable. Method for producing an FVW component ( 18 ) by means of a mold core ( 4 ), comprising the following steps: - production of the shape of the final contour ( 4 ) according to a method according to one of claims 1 to 7; - Applying a reinforcing fiber material to the mandrel ( 4 ); Impregnating the reinforcing fiber material with hardenable resin; Curing of the resin, whereby a solid, dimensionally stable FVW component ( 18 ) arises; and - removing the mold core ( 4 ) from the finished FVW component ( 18 ) characterized in that for the removal of the mandrel ( 4 ) first the water-soluble auxiliary mandrel ( 6 ) by means of a working medium, in particular water (W) or a liquid containing mainly water, from the mold core ( 4 ), whereby an empty mandrel outer shell ( 14 ), and that after forming (W) the water-soluble auxiliary mandrel ( 6 ) from the mold core ( 4 ) remaining empty mold core outer shell ( 14 ) from the FVW component ( 18 ) Will get removed. A method according to claim 9, characterized in that in a hollow, closed on all sides FVW component ( 18 ) molding the water-soluble auxiliary molding core ( 6 ) comprises the following steps: - manufacturing ( 24 ) one through a wall ( 18b ) of the FVW component ( 18 ) and the mold core outer shell ( 14 ), or into or into the water-soluble auxiliary molding core ( 6 ) opening auxiliary opening ( 22 ); and - shaping (W) the water-soluble auxiliary molding core ( 6 ) through the auxiliary opening ( 22 ) through. A method according to claim 9 or 10, characterized in that the empty mandrel outer shell ( 14 ) by pulling on the ripcord element ( 8th ) from the FVW component ( 18 ) Will get removed.