EP2903800A1

EP2903800A1 - Method and device for producing moulded parts made of fibre material

Info

Publication number: EP2903800A1
Application number: EP13780090.0A
Authority: EP
Inventors: Egon FÖRSTER
Original assignee: Forster Robin
Current assignee: Forster Robin
Priority date: 2012-10-05
Filing date: 2013-10-01
Publication date: 2015-08-12
Also published as: DE102012019534A1; WO2014053505A1

Abstract

The invention relates to a device and a method for producing three-dimensional moulded parts made of fibre material by using a multipart mould (5), the inner side of which, at least in part, determines the contour of the moulded part, wherein the fibres are blown into the mould (5) by an air stream via at least one nozzle (4) and the air then escapes through openings in the mould (5), such that the fibres build up on the inner side of the mould, whereupon the fibres are optionally densified locally, before they are bonded to one another by the supply of heat and/or the supply of adhesive and finally removed from the mould (5) as a moulded part. An essential aspect of the device is that the mould (5) can be subdivided into at least two mould chambers (15, 25) by at least one partition (7) passing through the interior space of the mould. An essential aspect of the method is that before and/or during the blowing in of the fibres, at least one partition (7) that subdivides the mould (5) into at least two mould chambers (15, 25) is introduced into the mould (5).

Description

Method and device for producing molded parts from fiber material

description

The invention relates to a method and apparatus for producing three-dimensional molded parts made of fiber material using a multi-part mold whose inside at least partially determines the contour of the molded part, wherein the fibers are injected through an air flow through at least one nozzle in the mold and the air then through Openings of the mold escapes, so that the fibers attach to the inside of the mold, whereupon the fibers are optionally locally compressed before they are - preferably by heat supply - glued together and finally removed as a molded part from the opened mold.

Such devices and methods have become known from DE 10324735 and DE 10 2007054424. The content of these documents is also made the subject of the present application in order to avoid repetition.

DE 102011 009137 describes the production of fiber molded parts by blowing fibers into a mold in which the air flow which flows out of the mold is controlled by closable outlet openings. In the form sieve plates can be arranged with flow-through holes, on the one hand to retain the fibers of the fiber material in the mold and on the other hand to allow a flow through the air blower.

From US5569425 a method and a corresponding apparatus for the production of fiber molded parts is known in which penetrate after filling an intended amount of fiber into a form rumen-like arranged gas distribution pipes in the mold space over which the fiber pad is subjected to hot air to a desired crosslinking temperature of the fibers is reached. Subsequently, a passage of cold air takes place in order to shorten the cycle time. In EP 0837168 a method for producing a cushion structure is described in which fibers are filled into a multi-part mold and then fused by the action of heat. The mold has movable mold walls in an upper region, by means of which different degrees of compaction can be achieved.

As far as spoken in this application of a multi-part form, this should also include temporary auxiliary forms that are used only temporarily, especially for controlling the density distribution in the later molding.

Three-dimensional molded parts made of fiber material are used in particular in the automotive industry. They are usually used for sound insulation and are used, for example, to cover the vehicle floor and the connecting walls from the passenger compartment to the trunk as well as to the engine compartment, as door trim and the like. Instead or in addition, the moldings may also have supporting functions, such as instrument panel, parcel shelf, door support and the like. They then have a much harder consistency than the soft insulating parts.

In principle, the molded parts should follow a predetermined contour, such as the molded body parts, relatively precisely, even if the contour is very irregular and has abrupt turns.

For cost reasons, it is endeavored to use as far as possible only a one-piece molded part, even when lining large body parts.

Investigations by the Applicant have now shown that satisfactory filling of the mold with the blown fibers is problematic in large-scale moldings with strong contour changes. Especially in those molding areas where the air flow with the fibers undergoes a strong deflection or where air turbulence occurs, there is an inhomogeneous fiber distribution.

The present invention is therefore based on the object to improve the known device and the known method to the effect that the desired fiber distribution is ensured even in large-scale forms and in particular when contour changes. It should also be areas of Molded part with specifically different density can be produced. Not least, the invention should be characterized by cost-effective and reliable feasibility.

This object is achieved in terms of the method in that before or during the blowing of the fibers at least one bulkhead wall is introduced into the mold, which divides the mold into at least two mold chambers. In this case, the fibers are first blown into at least one first chamber adjoining the bulkhead wall, until a predetermined fiber density is reached at the bulkhead wall or the chamber is at least substantially filled. Subsequently, fibers are blown into a second adjacent to the bulkhead chamber.

The introduction of the bulkhead opens up the possibility of dividing a large-area mold into two or more mold chambers. In addition to drastically shortening the flow paths during the blowing of the fibers, the separate, staggered filling of the individual molding chambers with fibers eliminates unwanted flow disturbances by positioning bulkheads specifically in the critical regions of the mold.

In addition, there is the advantage that individual mold chambers can be filled with different materials, so that the finished molded part consists of regionally different materials.

So that the mold does not have to be opened for installation and removal of the bulkhead walls, it is favorable if the bulkhead walls can be introduced or removed in the mold interior when the mold is closed. For this purpose, it is recommended that the bulkhead is adjustably mounted on the mold. This storage can be realized such that the bulkhead is pivotally mounted on the inside of the mold on a wall of the mold or that it can be pulled out of the mold interior through a slot in the mold. As a result, the bulkhead can then be moved out of the mold interior at least partially, preferably completely, out of the mold interior. Moving out and preferably also the introduction of the bulkhead walls can be done manually, but it is expedient but motor. Retracting the bulkhead wall does not necessarily have to be done before blowing in fibers. Rather, it may also be appropriate to first make a partial filling of the mold and only then retract one or more bulkheads.

During or after the blowing of the fibers into the first chamber adjoining the bulkhead wall and optionally after reaching a predetermined fiber density at the bulkhead, the latter can be pulled out of the mold interior or adjusted in the mold.

By completely or partially removing the separation between adjacent molding chambers during blowing in, the fibers of adjacent molding chambers overlap one another so that during the subsequent heating and bonding, a one-piece molding is formed.

However, it is also within the scope of the invention to leave the bulkhead walls in the mold, possibly even in the finished molded part. As a result, no or only a small bond between the fibers in front of and behind the bulkhead wall is formed. Even during the subsequent compression and heating, a possible predetermined breaking area remains in the molded part. Such predetermined breaking points may be desired for special moldings, such as an instrument panel, to provide clearance for optional instruments or for the airbag.

Furthermore, the invention includes the possibility that the bulkhead is arranged so that it does not completely pass through the shape of the cross-section, but leaves a gap against a mold wall. Only a few fibers can flow through this gap, so that the molded part in the gap region still has a continuous outer side, which, however, is very thin-walled. This thin-walled connection is well suited as a bending edge or predetermined breaking point.

The given fiber density can be measured poorly in the mold. It is therefore usually on parameters such as injection duration or air pressure back to draw conclusions about the fiber density can. In addition, an apparatus for producing three-dimensional molded parts made of fiber material is created, which has a multi-part shape whose inside at least partially determines the contour of the molded part. In addition, at least one fan is provided for blowing the fibers into the mold by means of an air flow over at least one nozzle, the mold having openings through which the air can escape, so that the fibers attach to the inside of the mold. Furthermore, the device comprises means for bonding the fibers by supplying heat, preferably by hot air or infrared radiation, and / or by adhesive supply and at least one bulkhead passing through the mold interior, with which the mold can be subdivided into at least two molding chambers.

According to the invention, a controller is provided which controls the fan (s) in such a way that fibers are first blown into a first chamber adjoining the bulkhead wall until a predetermined fiber density is achieved at the bulkhead wall or the chamber is at least substantially filled, and that after blowing in Fibers are blown into the first chamber adjacent the bulkhead, fibers are blown into a second chamber adjacent the bulkhead.

Preferably, the bulkhead is adjustably mounted on the mold or in closed mold in a dividing the mold interior position and at least partially moved out and has a motor drive for adjusting or moving in and out of the bulkhead, which is so controlled by the controller in that, before the fibers are blown into the second chamber adjoining the bulkhead, the bulkhead is at least partially pulled out of the mold interior or adjusted in the mold.

Conveniently, the controller controls the moving out of the bulkhead timed and / or in dependence on the building up in the air flow pressure.

In order to favor a compound of injected into adjacent mold chambers fibers, it is particularly useful if the bulkheads are perforated. This not only allows the injected air through the bulkhead to close. through, but the fibers can also extend partially through the holes of the bulkhead.

A particularly advantageous embodiment of the bulkheads is that they are designed as rakes with extending in the pull-out tines. As a result, the bulkheads can be pulled out of the more or less filled with fiber form without tearing fibers out of the composite.

The introduction and withdrawal of a bulkhead is expediently carried out by a slot arranged in the mold wall. This slot should be adapted to the contour of the bulkhead so that it remains sealed even when pulled out bulkhead against the injected into the mold fibers. In rake-like design of the bulkhead, the slot is realized as a row of holes.

In addition, the invention offers the possibility to use additional bulkhead walls as a temporary flow guide. As a result, for example, in the flow around sharp edges or sudden changes in direction, an undesirable dead space effect can be avoided, that is, the bulkhead acts on the air flow in such a way that the desired fiber density is achieved even in the critical shaping regions.

Also in this case, the bulkhead can be adjustably mounted on the mold so that it deflects the fiber / air flow more or less depending on the degree of filling. Towards the end of the blowing process, the bulkhead wall should then be largely removed from the mold interior, so that a complete filling of the mold is not hindered. For this purpose, it is recommended that the bulkhead is pivotally mounted on the inside of the mold so that it can be folded against a wall of the mold at the end of the filling process. Alternatively, the bulkhead can be more or less pulled out of the mold interior through a slot in a mold wall.

Further features and advantages of the invention will become apparent from the following description of exemplary embodiments and from the drawing; shows a schematic representation of the entire system;

the process steps during the blowing of the fibers;

an enlarged view of the shape and the bulkhead and the use of a bulkhead as a flow guide element with horizontal deflection of the flow;

a representation similar to Figure 3a and 3b, but with vertical deflection of the flow path;

a plan view of the mold according to Figure 4a and 4b.

FIG. 1 shows on the right a storage container 1 for the fibers. The fibers are possibly reduced by a so-called bale opener and separated and then fed to a fan 2. This fan generates a strong air flow, by means of which the fibers are supplied in a known manner through an inlet channel 3 some nozzles 4 on the circumference of a mold 5. The nozzles can be stationary, swiveling or linearly movable on the mold

- If necessary, also in the interior of the form - be arranged.

The mold 5 consists of an upper mold 5a and a lower mold 5b, which can be brought into contact along their non-visible side walls and their interior

- If necessary, after local compaction with temporary auxiliary forms - defines the contour of the desired fiber molding.

In the embodiment, the lower mold 5b is perforated so that the injected air can escape. Instead, however, both moldings may be perforated. Alternatively, it is also possible to work with more or less impermeable molded parts when the air can escape, for example, through perforated side walls arranged on the circumferential gap 6 of the mold.

It is essential that the mold 5 has a bulkhead 7 in the region where there is great unevenness, ie in the middle of the embodiment. This bulkhead can be moved in the embodiment. It traverses the upper mold along a slot and can be driven by a pneumatic, hydraulic or electric lifting drive 8 into the interior of the mold until it is more or less tight against the lower mold 5b. Finally, Figure 1 shows by arrows, as the air flows into the mold and where it leaves the mold, namely on the one hand over the openings of the lower mold 5b, but also through openings in the bulkhead 7th

The openings in the bulkhead 7 are dimensioned so that the fibers can not flow through. Instead, they deposit themselves on the side of the bulkhead wall which is acted on by the air flow, which is indicated by the hatched area on the right of the bulkhead wall.

The bulkhead 7 is preferably not perforated, but rake-like design (see Figure 3b), such that their rake teeth extend in the stroke direction of the bulkhead. This allows the bulkhead to be pulled out of the partially filled mold without damaging the fiber composite.

FIG. 2 shows the filling process of the mold in five stages. It can be seen in the uppermost figure 2.1, that the bulkhead 7 is shut down, so that the mold 5 is divided into a left chamber 15 and a right chamber 25. The filling process begins with the chamber 25. This is shown in Figures 2.1 and 2.2.

If the filling of the right chamber has progressed far enough so that there is sufficiently densified fiber material on the bulkhead 7, but at the latest after the complete filling of the chamber 25, the bulkhead 7 is raised, the interruption between the two chambers 15 and 25 thus canceled and it begins the filling of the left chamber 15th

For this purpose, the nozzle 4 is connected to the opposite Einblasseite the mold, as shown in Figure 2.3. It can be seen that the fibers injected from the left into the chamber 15 attach directly to the fiber wall of the right-hand mold chambers 25, so that a virtually homogeneous transition occurs there and the position of the bulkhead on the finished molded part can no longer be recognized.

As shown in FIGS. 2.4 and 2.5, the structure of the injected fibers continues in the direction of the injection nozzle 4 until the left mold chamber is completely filled. The filling process can then be ended. Depending on the requirements of the molded part, a mechanical compression can follow - be it by moving together the upper mold 5a with the lower mold 5b, or by using a temporary auxiliary form, which causes locally different degrees of compression of the injected fiber package by a different contour.

The connection of the fibers with each other then takes place in a known manner by heating, so that a binder mixed with the fibers or preferably a self-binding two-component fiber material melts at least on the outside of the fibers and glued to the neighboring fibers. Alternatively, it is possible to work with a liquid binder which is injected into the injected fiber packet; while the heating process can be omitted or shortened.

FIG. 3 shows the use of a bulkhead 7 as a flow guide element 17. According to FIG. 3b, this flow guide element effects the flow in the lateral direction. This is particularly considered when the edge of the molding - in the embodiment, ie the back edge - has a strong kink inwards. Then it is to be feared without flow guide element that this inwardly projecting portion of the molded part has an undesirably high fiber density. This can be avoided by deflecting the flow-conducting element 17 into the area corresponding to the fiber / air flow.

The flow directing element 17 may be fixedly arranged in the mold gap 5; It is expedient, however, pulled out towards the end of the filling process by a lifting drive 18 from the mold interior.

Figures 4a and 4b show the use of a flow guide element 27 for vertical deflection of the fiber / air flow. In this case, the guide element 27 is pivotally mounted on the mold - in the embodiment of the upper mold 5a - and can be placed in a projecting obliquely into the mold interior position, so that the fiber / air flow corresponding to the downwardly bent contour of the mold. 5 even before this bend takes a certain distraction down. With increasing filling, the guide element 27 will then be moved out of the mold cavity I nnenrau m its lifting drive 28, in the exemplary embodiment thus pivoted upwards.

FIG. 5 shows a reduced plan view of the shape shown in FIGS. 4a and 4b with the flow guide element 27 and an injection nozzle 4.

In summary, the invention thus permits a much more reliable filling of large-area molded parts, in particular those molded parts which extend over almost the entire driving width, with optimum influencing of the local fiber density.

Preferably, the production of the fiber moldings in the above besch scribed embodiments is carried out automatically. H here is used in the figures n icht not closer shown control per se conventional type, which the blower or blowers, by means of which the fibers in the form are introduced, and if necessary, the retraction and Verschwen ken the bulkhead or walls.

In such a controller, there is a programmable, processor-controlled control circuit or a versatile computer, which or which you rch corresponding control signals a connection and disconnection of the fan or, if necessary, causes a regulation of the fan power. For putting in place can be controlled accordingly with such a control actuators to m in and out or pivoting the bulkhead wall or walls.

The controller is therefore adapted or programmed so that it controls fans and bulkhead wall drives so that first a first chamber, for. B. chamber 25 in the Figu ren 2.1 and 2.3, is filled, that then a bulkhead 7 is pulled out as shown in Figure 2.3, and that in the Ansch luss it a second chamber, z. B. chamber 1 5 in Figu r 2.3 to 2.5, is filled.

Ansch end end, if necessary, as described above beschreib, a compaction of the fibers, before the fibers are crosslinked by heat supply and / or adhesive supply. For this purpose, you will be the controller of a speaking heating, for example, a hot air blower to m blowing hot air into the form 5 or an infrared radiation source to r heat radiation of the mold 5 activated. In doing so, the fibers melts at least superficially under the action of heat and stick together to form a solid, dimensionally shaped part.

Other ways of activating the fibers are to increase the shape of the contact heat by means of heating plates or to introduce superheated steam from a steam generator.

As already described, additionally or alternatively, an adhesive can be introduced into the mold. This can be done, for example, by mixing the fibers with a glue powder or hot melt adhesive before blowing. After blowing the fiber / adhesive mixture is a thermal activation of the adhesive, sim i lar as previously rubbed.

In addition, it is also possible to crosslink the fibers by the so-called RTM process (Resin Transfer Molding). Here, the fibers are first blown into a solid base mold without adhesive. The air escapes via a perforated injection frame and / or via a perforated injection-molded upper mold. After filling, the injection top mold is exchanged for a massive top mold. Ansch endend is injected via one or more corresponding filling holes a resin adhesive in the closed tool. The adhesive reacts and the finished molded part can then be removed.

Claims

claims

1. A method for producing three-dimensional molded parts made of fiber material using a multi-part mold (5) whose inside at least partially determines the contour of the molded part, wherein the fibers are blown by an air flow through at least one nozzle (4) in the mold (5) and the air then escapes through openings of the mold (5), so that the fibers attach to the inside of the mold, whereupon the fibers are optionally compacted locally, before they are glued together by heat supply and / or adhesive supply and finally as a molded part of the mold ( 5), wherein before and / or during the blowing of the fibers, at least one bulkhead (7) is introduced into the mold (5), which divides the mold (5) into at least two mold chambers (15, 25) characterized dadu rch, that

Fibers are first blown into a first adjacent to the bulkhead wall forming chamber (25) until the bulkhead (7) reaches a predetermined fiber density or the mold chamber (25) is at least substantially filled, and that after blowing the fibers into the first of the Bulkhead (7) adjacent molding chamber (25) fibers are blown into a second adjacent to the bulkhead (7) mold chamber (15).

2. The method of claim 1, wherein the bulkhead (7) is at least partially withdrawn from the mold interior or in the mold (5) before blowing the fibers into the second to the bulkhead (7) adjacent mold chamber (15) ,

3. The method of claim 2, wherein the moving out or adjustment of the bulkhead (7) is time-controlled and / or in response to the building up in the air flow pressure.

4. Apparatus for producing three-dimensional molded parts made of fiber material, with a multi-part mold (5) whose inside at least partially determines the contour of the molded part, with at least one fan (2) for Blower) of the fibers into the mold (5) by means of an air flow over at least one nozzle (4), wherein the mold (5) has openings through which the air can escape, so that the fibers attach to the inside of the mold with Means for bonding the fibers by heat supply and / or adhesive supply, and with at least one bulkhead (7) traversing the mold interior, with which the mold (5) can be subdivided into at least two mold chambers (15, 25),

marked by

a controller which controls the blower or blowers (2) such that fibers are first blown into a first mold chamber (25) adjoining the bulkhead wall until a predetermined fiber density is reached at the bulkhead wall (7) or at least substantially the mold chamber (25) is filled, and that after the blowing of the fibers into the first forming chamber (25) adjoining the bulkhead (7), fibers are injected into a second forming chamber (15) adjacent to the bulkhead (7).

5. The device according to claim 4, wherein the bulkhead (7) adjustably mounted on the mold (5) or in the closed mold can be brought into a dividing the shape interior position and at least partially moved out and a motor drive for adjusting the bulkhead (7 ), wherein the control drives the drive such that before the blowing of the fibers into the second mold chamber (15) adjoining the bulkhead (7) the bulkhead (7) is at least partially pulled out of the mold interior or in the mold (5 ) is adjusted.

6. Apparatus according to claim 5, wherein the control controls the moving out of the bulkhead (7) time-controlled and / or in dependence on the building up in the air flow pressure.

7. Apparatus according to claim 4, wherein the bulkhead (7) is perforated.

8. Apparatus according to claim 4, wherein that the bulkhead (7) is designed as a rake.

9. Apparatus according to claim 8, wherein the rake has extension teeth extending in the withdrawal direction.

10. Apparatus according to claim 4, wherein the mold has a slot through which the bulkhead (7) can be inserted into the mold and pulled out.

11. The device according to claim 10, wherein the slot is sealed even when pulled out bulkhead against the injected into the mold (5) fibers.

12. The apparatus of claim 10, wherein the slot is formed as a row of holes.

13. Device according to claim 4, wherein the bulkhead is part of the mold.

14. The device according to claim 4, wherein the bulkhead passes through the mold interior only partially, leaving an edge gap.