WO2015181296A1 - Device and method for fibre injection moulding of injection moulded parts - Google Patents

Abstract

The invention relates to a device (1) for fibre injection moulding of injection moulded parts - having an injection mould (2) comprising a first and a second housing wall section (4a, 4b), in which injection mould a first and a second inlet (3a, 3b) are provided for introducing a plastic (11, 11a, 11b) into an interior (7) of the injection mould (2), - having a first through-hole (5a) provided in the first housing wall section (4a), said first through-hole being surrounded by a first actuator receiving element (6a) on the side of the first housing wall section (a) facing away from the interior (7), wherein said actuator receiving element (6a) projects away from the first housing wall section (4a), wherein a first actuator element (9a) is arranged in a displaceable manner in the first actuator receiving element (6a), - having a second through-hole (5b) provided in the second housing wall section (4b), said through-hole being surrounded by a second actuator receiving element (6b) on the side of the second housing wall section (4b) facing away from the interior (7), wherein said actuator receiving element (6b) projects away from the second housing wall section (4b), wherein a second actuator element (9b) is arranged in a displaceable manner in the second actuator receiving element (6b).

Description

 Apparatus and method for fiber injection molding of injection molded parts

The invention relates to an apparatus and a method for fiber injection molding of injection molded parts.

A common method for the production of plastic parts is the so-called. Injection molding is a primary molding process in which the plastic to be processed is liquefied in an injection molding machine and then injected under pressure into an injection mold. Injection is typically followed by controlled cooling whereby the plastic solidifies so that it can be removed from the injection mold as a finished part.

Against this background, DE 39 34 1 15 A1 describes an injection mold for injection molding for injection molded parts of plasticizable liquid crystal polymers. The injection mold comprises at least two sprue bores, to each of which a plasticizing and injection unit is assigned. For filling the injection mold with plasticized thermoplastic material to be supplied alternately by the plasticizing or injection units, the injection mold has a Heizkanalblock with at least two holes, each with a bore is in fluid connection with a sprue. Both holes open into a respective associated plasticizing and injection unit associated further bore. Between these gate bores and the further bores, an arrangement of one-way valves is arranged, so that the plasticized thermoplastic material alternately flows from one of the two plasticizing and injection units into the respective other aggregate.

A special variant of injection molding is the injection molding of short- and long-fiber reinforced plastics, the so-called fiber injection molding Fiber injection molding are under the principle application of the above-mentioned injection molding plastic plastics from a thermoplastic by means of suitable fiber materials - known from the prior art as glass, carbon, natural or aramid fibers - reinforced. Problematic in injection molding prove to be occurring during injection of the plastic in the injection mold, from a flow perspective complex flow patterns, especially in injection molds with complex shape geometry, as they increasingly occur in the production of modern injection molded parts. Such complicated geometric shapes, often with a plurality of apertures and recesses, can lead to a division of the flow fronts of the propagating in the injection mold plastic. When rejoining the temporarily separated flow fronts, flow and weld lines are formed, which are reduced in strength over the remaining areas. The same applies if the plastic melt is introduced into the injection mold via two or more inlet openings and the respective melts meet within the injection mold.

The formation of said flow or weld lines has a particularly disadvantageous effect on the distribution and orientation of the fibers present in the thermoplastic, since in the region of such a seam they typically orient orthogonally to the flow direction of the thermoplastic. The increase in the strength of the injection-molded injection-molded part which is actually to be expected from the fibers is in this way partially reversed - in the worst case even completely. This can lead to a considerable reduction in the lifetime of the injection molded part produced by means of fiber injection molding.

Against this background, JP 04-415 6322 A describes an injection mold with an actuator which is forced back under the pressure of the plastic melt introduced into the injection mold. A further concept followed JP 1 1 -070 541, in which two actuators are provided on opposite housing walls of the Spritzgießfornn. These are alternately moved in the orthogonal direction to the housing wall into the Spritzgießfornn in and out again, whereby the plastic melt is quasi "stirred", which leads to improved alignment of the fibers in the plastic.

It is an object of the present invention to provide an improved embodiment for an apparatus and method for fiber injection molding of injection molded parts, which permits the manufacture of injection molded parts having improved strength.

This object is solved by the subject matter of the independent patent claims. Preferred embodiments are subject of the dependent claims.

The basic idea of the invention is accordingly to provide a device for fiber injection molding of injection-molded parts with at least one movable element which generates turbulence and / or transverse flows in the plastic melt spreading in the casting mold. In this way, a targeted influencing of the volume flow of the plastic, especially in the critical Bindenahtbereich be achieved. A strength-reducing orientation of the fibers in the thermoplastic can be largely or even completely avoided in this way. As a result, the device presented here imparts to the finished injection-molded parts a homogeneous strength, which in particular includes the critical region of the said weld lines. A device according to a first aspect of the invention comprises a first and a second housing wall section comprising an injection mold in which a first and a second inlet are provided, through which liquid plastic can be introduced into an interior of the injection mold. The two inlets may be in fluid communication with one or more injection units known to those skilled in the art. It is understood that the injection mold can not only have a simple geometric shape, such as in the manner of a hollow cylinder, but also more complex geometries are possible, such as when injection molded parts are to be produced with openings, recesses or other geometric features.

In the first housing wall portion, a first passage opening is provided, which is bordered on a side facing away from the interior side of a first actuator Aufnahmeelennent. In the first actuator-receiving element, a first actuator element is arranged to be movable, which serves to generate the above-described turbulence in the introduced into the injection mold liquid thermoplastics.

Essential to the invention is now the geometric arrangement of the first receiving element relative to the injection mold, which projects outwardly away from the first housing wall portion. The same applies mutatis mutandis for a provided in the second housing wall portion second passage opening which is bordered on a side facing away from the interior side of a second Aktuator- receiving element: this also protrudes outwardly from the second housing wall portion away, wherein in the second actuator receiving element, a second actuator movable is arranged. Computer-aided simulation calculations have shown that the adjustment of the two actuator elements during the injection of the plastic into the injection moldings leads to particularly advantageous turbulence and / or transverse flows in the plastic melt, by which an unfavorable orientation of the individual fibers in the plastic can be suppressed particularly effectively. This results in the production of the desired homogeneous strength moldings, and in particular without localized areas of reduced strength.

In a preferred embodiment, the first and second housing wall portions may face each other. A concomitant arrangement of the two rotatable wall elements in opposite housing walls of the injection mold generates flow patterns in the plastic material, which result in a particularly homogeneous strength of the plastic which has been transferred to the solid state after cooling by injection. Alternatively, the two housing wall sections may be provided adjacent to each other in the same housing wall. In this way, the space required for the device can be reduced.

Particularly pronounced turbulence and also transverse flows in the region of the weld line can be produced if the first actuator receiving element protrudes obliquely from the first housing wall in a longitudinal section of the device and the second housing wall section projects in an analogous manner obliquely from the second housing wall section. The term "oblique" in the present context expressly includes all embodiments in which the direction of movement of the actuator receiving element extends obliquely to a direction of extension of the interior of the injection molded part. The direction of extension can be defined by a connecting virtual straight line for the two inlets. Alternatively, however, the two actuator receiving elements can also be arranged on said housings such that they protrude at a right angle from the respective housing wall sections. In this case, reduces the cost of manufacturing the injection molding tool, resulting in cost advantages.

In a preferred embodiment, the actuator elements which are adjustably mounted in the respective actuator receiving element are designed such that they act as turbulence generators on the plastic introduced into the interior. The above-presented, inventive arrangement of the actuator-receiving elements on opposite mold walls of the injection mold and - with respect to the direction of extension of said injection mold - oblique arrangement generates flow patterns in the plastic, which cause a particularly homogeneous strength of the cured after injection plastic.

An improved fiber orientation in the plastic can be achieved by providing the device with a tempering device, by means of which the temperature of the plastic introduced into the injection mold can be varied. Such a tempering device permits, in particular, a locally variothermic process control in the area of the weld line. In this case, the term "variothermic process control" is understood to mean a cyclical heating of the injection molding tool and in particular of the injection mold during the injection of the liquid plastic so that its temperature oscillates between its melting and demolding temperatures, which are specified for the material In the case of a suitable design, no separate cooling device is required in order to cool the injection mold again, but rather, in such a scenario, the desired response is achieved. Düsierung the temperature already effected by switching off the heater. Alternatively, the desired temperature can be realized by integration of an oil circuit in the injection mold, so that then the desired temperature in the injection mold is achieved by thermal interaction with the oil acting equally as heating and cooling agent.

Particularly expedient, the actuator-receiving elements can be formed in the manner of receiving tubes. In this case, a variety of design options opens up for the person skilled in the art within the scope of development, in particular with regard to the attachment of the receiving tubes to the injection mold. To think about form-fitting fastening method in the form of a welded joint. In another variant, however, said receiving tubes can also be integrally formed on the injection mold.

In a preferred embodiment, the first receiving tube extends along a first tube direction and the second receiving tube along a second tube direction. Particularly advantageous is the arrangement of the two receiving tubes relative to the direction of extension of the injection mold proves such that the first and the second pipe direction in a longitudinal section of the device each form an acute angle, in particular an angle between 10 ° and 45 °, with the extension direction. However, the oblique arrangement of the two receiving tubes need not be limited to the said preferred angular range; Rather, embodiments are conceivable in which the said angle interval above the limiting angle of 45 ° is exceeded. In general, all acute angles <90 ° are possible.

In another preferred embodiment, the two receiving tubes can each have a circular or oval or polygonal profile in a cross section defined orthogonally to the respective tube direction. While With a circular or oval profile, they are relatively simple and therefore cost-effective to manufacture, an embodiment with a polygonal profile results in an improved mixing effect in the liquid plastic. In principle, the desired mixing increases with increasing number of profile corners.

Their advantageous with regard to the generation of turbulent flows effect unfold the two actuator elements to a particular extent in a geometric configuration in which the two passage openings along the direction of extension offset from each other in the first and second housing wall portion are arranged.

With regard to the constructional design of the actuator elements, various options also open up for the person skilled in the art. For example, the use of stamp-like trained actuator elements, which can be slidably mounted within the receiving tubes, lends itself. However, an embodiment of the two actuator elements in the respective actuator receiving element is particularly recommended such that they are each adjustable between a first position, in which they partially project into the injection mold, and a second position, in which are arranged completely in the actuator receiving element , For precisely when an actuator element enters the injection mold, the concomitant displacement of the plastic introduced into the mold favors the formation of turbulent flows.

In this context, simulation calculations have shown that in order to avoid strength-reducing fiber orientations in the plastic, the formation of eddy currents in the area of successive flow fronts of the liquid plastic is advantageous. Such eddy currents can be generated in the device according to the invention by the two actuator elements with a Coupling device to be equipped. This causes a coupling of the two elements in such a way that an adjustment of the first actuator element from the first to the second position is accompanied by an adjustment of the second actuator element to the first position and vice versa. If such a coupling device is used, then exactly one of the two actuator elements is arranged alternately within the injection mold. Due to the forcibly resulting reciprocating movement of the two actuator elements and the associated alternating volume displacement of not yet solidified plastic within the injection mold, a flow pattern is generated in the plastic melt, which shows the properties of an eddy current.

As production technology particularly advantageous, because it can be produced with commercially available components, an embodiment in which the two actuator elements each comprise an electric drive unit, i. the actuator elements are realized in the manner known to those skilled electric, hydraulic or pneumatic actuators. In a preferred manner, the actuator is electrically controlled in order to realize specific different movement modes for the actuator. For the above-described, so to speak "opposite pole" coupling of the two actuator elements, the coupling device may be equipped with a conventional control unit, which cooperates with the drive units for adjusting the position of the actuator elements between the first and the second position.

The invention further relates to methods of fiber injection molding injection molded parts in a device having one or more of the foregoing features. According to the method, during the injection of plastic into the injection mold, the two actuator elements are substantially the same in each case between the first position, in which they partially in the injection molding. protrude mold, and the second position, in which completely arranged in the actuator-receiving element, reciprocated.

In a preferred embodiment of the method presented here, the temperature of the injection mold is cyclically varied by means of a tempering during injection of the plastic between an upper and a lower limit temperature, in particular such that the temperature of the plastic varies cyclically between its melting temperature and its Entformungstem- temperature.

A device for fiber injection molding of injection-molded parts comprises, according to a second aspect of the invention, an injection mold comprising a first and a second housing wall section. In the injection mold, a first and a second inlet for introducing a plastic into an interior of the injection mold are provided, and this interior is bounded by the two housing wall sections. In the first housing wall portion, a first passage opening is provided, which is closed by an adjustable first wall element. According to the invention, the first wall element is designed to be rotatable relative to the first housing wall section. Essential to the invention of the device presented here is thus the Drehversteilbarkeit a first passage opening closing the first wall element relative to the first housing wall portion in which the passage opening is provided. Experimental investigations have shown that a rotational movement of the wall element during the injection of the plastic into the injection mold leads to advantageous transverse and turbulent flows in the plastic melt, by which an unfavorable orientation of the individual fibers in the plastic can be suppressed particularly effectively. This results in the production of the desired moldings with homogeneous strength and in particular without local areas of reduced strength result. It goes without saying that the Spritzgießfornn not only a simple geometric shape, such as in the manner of a hollow cylinder, may have, but also more complex geometries are possible, such as when injection molded parts with breakthroughs, recesses or other geometric features to be produced.

In a preferred embodiment, a second through-opening may also be provided in the second housing wall section, which is closed by a correspondingly adjustable second wall element. Also, the second wall element is rotatable relative to the second housing wall portion. Experimental investigations have shown that a combined rotational movement equal to two wall elements during the injection of the plastic into the injection mold leads to particularly advantageous transverse and turbulence flows in the plastic melt. In advantageous developments of the invention, it is also possible to provide further wall elements which can be adjusted relative to a housing wall section of the injection mold and which are realized analogously to the first or second wall element.

In a preferred embodiment, the first and second housing wall portions may face each other. A concomitant arrangement of the two rotatable wall elements in opposite housing walls of the injection mold generates flow patterns in the plastic, which cause a particularly homogeneous strength of the transferred after cooling by cooling in the solid state plastic. Alternatively, the two housing wall sections may be provided adjacent to each other in the same housing wall. In this way, the space required for the device can be reduced.

It is particularly simple to realize structurally in a further preferred embodiment, in which the first wall element is rotatable about a first axis of rotation is, which is orthogonal to a defined by the first housing wall portion in the region of the first passage opening first wall plane. In a corresponding manner, the second wall element, if present, is rotatable about a second axis of rotation which is orthogonal to a second wall plane defined by the second housing wall section in the region of the second passage opening.

An improved homogenization of the strength in the plastic formed in the injection mold can be achieved by the first wall element flush with the first housing wall portion and / or the second wall element is flush with the second housing wall portion.

Particularly effective transverse flows in the plastic injected into the injection mold can be achieved in the area of the weld line by providing the two inlets on opposite end housing walls, so that an extension direction of the interior is defined by a virtual connecting straight line between the two end housing walls. In order to generate said transverse currents, the first and the second passage openings are then arranged offset relative to one another in the first or second housing wall section with respect to the extension direction.

For the purpose of a technically simple as possible realization of Drehversteilbarkeit the two wall elements, an embodiment is recommended in which the first passage opening is bordered on a side facing away from the interior side of the first housing wall portion of a first actuator-receiving element, which protrudes away from the first housing wall portion. In the first actuator receiving element, a first actuator element comprising the first wall element is arranged. Correspondingly, the second passage opening can also be located on a side of the second housing facing away from the interior. sewandabschnitts be bordered by a second actuator-receiving element, which protrudes away from the second housing wall portion. In the second actuator receiving element, a second actuator element comprising the second wall element can be arranged. In the production of this embodiment of the device according to the invention, not inconsiderable cost advantages arise.

In a further advantageous embodiment, the first actuator element can be arranged linearly adjustable in the first actuator receiving element and / or the second actuator element linearly adjustable in the second actuator receiving element. The associated combined linear and rotary movement of the actuator elements comprising the wall elements generates particularly pronounced transverse and turbulence flows in the liquid plastic introduced into the injection mold in the region of the weld line forming between the two plastic streams.

Cost advantages in the production of the injection mold are also obtained if the first actuator element is designed to be linearly adjustable along a first adjustment axis defined by the first axis of rotation and / or the second actuator element is designed to be linearly adjustable along a second adjustment direction defined by the second axis of rotation.

Particularly expedient, the actuator-receiving elements can be formed in the manner of receiving tubes. In this case, the person skilled in the art offers a variety of design options, in particular with regard to the attachment of the receiving tubes to the injection mold. To think about in this context as to form-fitting fastening method in the form of a welded joint. According to another variant can however, said receiving tubes also be formed integrally on the injection mold.

In a preferred embodiment, the first receiving tube extend along a first tube direction and / or the second receiving tube along a second tube direction. The arrangement of the receiving tubes relative to the direction of extension of the injection mold proves to be particularly advantageous such that the first or second tube direction forms an acute angle or a right angle, in the former case preferably between 10 ° and 45 °, with the direction of extent in a longitudinal section of the device ,

With regard to the constructional design of the actuator elements, various options also open up for the person skilled in the art. For example, the use of stamp-like trained actuator elements, which can be slidably mounted within the receiving tubes, lends itself. However, an embodiment of the actuator element in the actuator receiving element is particularly recommended such that it is adjustable in each case between a first position, in which it protrudes partially into the injection mold, and a second position in which it is arranged completely in the actuator receiving element. For precisely when an actuator element enters the injection mold, the concomitant displacement of the plastic introduced into the mold favors the formation of turbulent flows.

In this context, simulation calculations have shown that in order to avoid strength-reducing fiber orientations in the plastic, the formation of eddy currents in the area of successive flow fronts of the liquid plastic is advantageous. Such eddy currents can be generated in the device according to the invention by the two actuator elements are equipped with a coupling device, which is a coupling of the two Elements effected in such a way that with an adjustment of the first actuator element from the first to the second position, an adjustment of the second actuator element in the first position is accompanied and vice versa. If such a coupling device is used, then exactly one of the two actuator elements is arranged alternately within the injection mold. By forcibly resulting reciprocating movement of the two actuator elements and the associated alternating volume displacement of not yet solidified plastic within the injection mold, a flow pattern can be generated in the plastic melt, which shows the properties of an eddy current.

As production technology particularly advantageous, because it can be produced with commercially available components, an embodiment in which the two actuator elements each comprise an electric drive unit, i. the actuator elements are realized in the manner known to those skilled electric actuators. For the above-described, almost opposite polarity coupling of the two actuator elements, the coupling device can be equipped with a conventional control unit, which cooperates with the drive units for adjusting the position of the actuator between the first and the second position.

However, a further improved fiber orientation in the plastic can be achieved, in which the device is equipped with a tempering device, by means of which the temperature of the plastic introduced into the injection mold can be varied. Such a tempering device allows, in particular, a locally variothermic process control in the area of the weld line. In the present context, the term "variable-temperature process control" is understood to mean cyclical heating of the injection molding tool and in particular of the injection mold during the injection of the liquid plastic, so that the temperature of which oscillates between its melting and demolding temperatures, which are specified in terms of material. The temperature control device may comprise a heating device, for example in the form of an electrical resistance heater, for heating the injection mold. With a suitable design, no separate cooling device is required to cool the injection mold again; rather, in such a scenario, the desired reduction in temperature is already effected solely by turning off the heater. Alternatively, the desired temperature can be realized by integration of an oil circuit in the injection mold, so that then the desired temperature in the injection mold is achieved by thermal interaction with the oil acting equally as heating and cooling agent.

The invention further relates to methods of fiber injection molding injection molded parts in a device having one or more of the foregoing features. According to the method, during the injection of plastic into the injection mold, at least the first wall element is rotated relative to the first housing wall section. The same applies to optionally existing, extended wall elements, in particular a second wall element provided in the second housing wall section.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention. Preferred embodiments of the invention are illustrated in the drawings and will be explained in more detail in the following description.

It show, each schematically:

1 shows an example of a device according to the first aspect of the invention in a longitudinal section along an extension direction,

2a-c different embodiments of the receiving tubes of the device of Figure 1 in a profile perpendicular to the tube direction,

3 shows an example of a device according to the second aspect of the invention in a longitudinal section,

Fig. 4 shows a variant of the example of Figure 3 with linearly adjustable wall elements.

FIG. 1 illustrates in a schematic representation the basic structure of a device 1 according to the invention according to the first aspect for fiber injection molding of injection-molded parts. The device uses the operating principle of a common injection molding process for plastifiable thermoplastics and comprises an injection mold 2 for this purpose. In the extending injection mold 2, a first and a second inlet 3a, 3b are provided on the front side into which a first one designated 1a Partial volume flow or designated with 1 1 b second partial flow of plastic to be plasticized in liquid form in the interior of the injection mold 2 is injected. This can be done using one or more suitable, not shown in Figure 1 injection units. In FIG. 1, a first housing wall section 4a and a second housing wall section 4b substantially opposite the first housing wall section 4a, which are both part of the injection mold 2 and bound an interior space 7 of this injection mold 2, can also be seen. In a variant, the two housing wall sections 4a, 4b may also be provided adjacent to each other in the same housing wall (not shown).

As can be seen from FIG. 1, the two inlets 3 a, 3 b can lie substantially opposite one another with respect to an extension direction E of the inner space 7.

As can be seen further from FIG. 1, the two inlets 3 a, 3 b may face each other with respect to an extension direction E of the inner space 7. In the example, the two inlets 3a, 3b are provided on opposite end-side housing walls. By a virtual connecting line between the two end-side housing walls thus an extension direction E of the interior 7 is defined.

The introduced through the first inlet 3a into the injection mold 2 plastic 1 1 a thus meets within the injection mold 2 on the introduced through the second inlet 3b in the injection mold 2 plastic 1 1 b. Thus, the first flow front 18a of the plastic 11a strikes the flow front 18b of the plastic 11b so that a weld line 10 is formed in this region.

Essential to the invention is a first through-opening 5a provided in the first housing wall section 4a, which is enclosed by a first actuator-receiving element 6a on a side remote from the interior 7 of the injection mold 2. As the longitudinal section of Figure 1 reveals, this may be formed in the manner of a receiving tube 8a. In this case, the actuator receiving element 6a projects obliquely away from the first housing wall section 4a. In an analogous manner, a second through-opening 5b is provided in the second housing wall section 4b, which in turn is bordered by a second actuator-receiving element 6b on one side of the housing wall section 4b facing away from the interior 7 of the injection mold 2. This may also be formed in the manner of a receiving tube 8b. Regardless of its chosen geometric shape and the second actuator-receiving element 6b is in an oblique direction from the second housing wall portion 4b away.

As shown in FIG. 1, the two passage openings 5a, 5b can be arranged offset in the first and second housing wall sections 4a, 4b along the extension direction E. In a variant, the actuator receiving elements 8a, 8b can protrude at a right angle from the respective housing wall section 4a, 4b.

The first receiving tube 8a extends along a first tube direction Ri, the second receiving tube 8b along a second tube direction R ₂ . In the example scenario, the two pipe directions Ri, R ₂ run parallel to each other. In the longitudinal section of the device 1 shown in FIG. 1, the first and the second pipe direction Ri, R ₂ each form an acute angle α with the direction of extent E. Preferably, the angle α is between 10 ° and 45 °; However, all acute angles <90 ° are generally considered. In one variant, the values of the two angles may also differ from each other.

As Figure 1 clearly demonstrates, the first actuator-receiving member 6a, a first actuator element is arranged movable along the pipe direction R 9a, and the second actuator receiving element 6b corresponding to a second actuator element 9b along the pipe direction _R.sub.2. The actuator elements 9a, 9b generate turbulence or cross flows in the liquid plastic 11 introduced into the injection mold 2 in the region of the weld line 10 forming between the two plastic streams 11a, 11b. These are indicated schematically in Figure 1 by the designated by the reference numeral 12 arrows. Said turbulence or transverse flows prevent an undesirable, strength-reducing orientation of the fibers of the plastic 1 1 in the region of the weld line 10 during the solidification of the plastic melt. As a result, this leads to an improved strength of the plastic 1 1 in the region of the weld line 10. The decisive factor in the improved fiber orientation in the area of the weld line 10 compared to conventional actuator geometries is the arrangement of the actuator elements presented above with respect to the direction of extent E of the injection mold 2 oblique orientation.

FIG. 1 further shows that the two actuator elements 9a, 9b in the respective actuator receiving element 6a, 6b are adjustable between a first position, in which they partially protrude into the injection mold 2, and a second position, in which they are completely in the respective one Actuator receiving element 6a, 6b are arranged. In FIG. 1, the first actuator element 9a is thus in the first position, while the second actuator element 9b is in the second position. By the entry of an actuator 9a, 9b in the interior 7 of the injection mold 2, a local displacement of the introduced into the injection mold 2 plastic 1 1 is effected. In this way, the already explained cross flows (arrows 12) are generated in the region of the weld line 10.

Particularly advantageous is the formation of transverse flows in the form of eddy currents. Such eddy currents can be generated in a particularly pronounced form, by the two actuator elements 9a, 9b alternately and gegengleich between the first and the second position back and forth to be moved. This can be done with the aid of a coupling device 15, which may have a conventional control unit 16, for example, in the manner of a microcontroller, which in turn serves to control the two actuator elements 9a, 9b. It is conceivable, for example, to design the two actuator elements 9a, 9b as electrical actuators, which are controlled by the control unit 16 of the coupling device 15 electrically / electronically via control lines 17a, 17b.

By the alternating reciprocating movement of the two actuator elements 9a, 9b and the associated volume displacement of the not yet solidified plastic 1 1 a, 1 1 b within the injection mold 2, a flow pattern is generated in the plastic, which has the properties of an eddy current (arrows 12). has.

The device 1 can optionally be equipped with a tempering device 13, which allows a variation of the introduced into the injection mold 2 plastic. This allows a cyclical heating of the injection mold 2 and thus also injected into the injection mold 2 liquid plastic 1 1, 1 1 a, 1 1 b, so that its temperature between its - material-specific - set melting and demolding temperature. Such a targeted variation of the temperature of the plastic 11 is known to those skilled in the art of injection molding under the term "variothermic process control" and leads in particular in the region of the weld line 10 to an improved strength of the plastic 11.

For heating the injection mold 2, the temperature control device 13 may also have a heating device 14, which is indicated only schematically in the figure and integrated into the injection mold 2, which heating device may be realized, for example, in the manner of a conventional electrical resistance heater. With suitable confi- guration of the heater 14 can be dispensed with a separate cooling device to cool the injection mold 2 and thus also the plastic 1 1 again; in this case, it is sufficient to achieve the required reduction in temperature by turning off the heater 14.

In a variant also shown only schematically in Figure 1, the desired temperature of the injection mold 2 and thus of the injected plastic 1 1 - alternatively or in addition to an electric heater - can be realized by integration of an oil circuit, not shown in Figure 1 in the injection mold 2. In this case, the desired temperature in the injection mold 2 is achieved by thermal interaction with the same acting as a heating and cooling agent and the oil circuit flowing oil. In variants, instead of oil, another suitable fluid can also be used as the heating or cooling agent.

The two receiving tubes 8a, 8b can each have a circular or oval or polygonal profile in a cross section defined orthogonally to the respective tube direction R, or R ₂ , which is roughly sketched in FIGS. 2a-c. While receiving tubes 8a, 8b having a circular or oval profile (compare Figures 2a, 2b) are relatively simple and inexpensive to produce, an embodiment with the polygonal profile shown in Figure 2c has an improved mixing effect on the liquid plastic. In principle, the desired mixing increases with increasing number of profile corners 19.

FIG. 3 illustrates in a schematic representation the basic structure of a device V according to the invention for fiber injection molding of injection-molded parts according to the second aspect of the invention. The device uses the operating principle of a common injection molding process for plastifiable Thermoplastics and includes for this purpose an injection mold 2 '. In the injection mold 2 ', a first and a second inlet 3a', 3b 'are provided. Through the two inlets 3a ', 3b', the plastic to be plasticized is injected into the interior of the injection mold 2 using suitable injection units, not shown in FIG. 3, in liquid form.

A first housing wall section 4a and a second housing wall section 4b 'diametrically opposite the first housing wall section 4a in the example scenario of FIG. 3 can also be seen. Both housing walls 4a ', 4b' are part of the injection mold 2 'and thus limit their interior 7' partially. The two housing wall sections 4a ', 4b' can each be part of two different housing walls which - as illustrated by way of example in FIG. 3 - are arranged at a distance from one another or are connected to one another via a common housing edge. However, it is also conceivable that the two housing walls are part of a single common housing wall, for example when the injection mold is designed in the manner of a hollow cylinder and said housing wall is a peripheral wall of such a hollow cylinder. In a variant of the example, therefore, the two housing wall sections can be provided in the same housing wall.

As can be seen further from FIG. 3, the two inlets 3a ', 3b' may face one another with respect to an extension direction E 'of the inner space 7'. In the example, the two inlets 3a ', 3b' on opposite end-side housing walls 19a ', 19b' are provided. A direction of extension E 'of the interior 7' is thus defined by a virtual connecting straight line between the two end housing walls 19a ', 19b'.

The introduced through the first inlet 3a 'in the injection mold 2 plastic 1 1 a' meets within the injection mold 2 'on the through the second inlet 3b' in the injection mold 2 'introduced plastic 1 1 b'. In this case, the first flow front 18a of the plastic 11a 'strikes the flow front 18b' of the plastic 11b ', so that a weld line 10' is formed in this region.

Essential to the invention is a first through-opening 5a 'provided in the first housing wall section 4a', which is closed by an adjustable first wall element 20a '. The first wall element 20a 'is rotatably formed relative to the first housing wall section 4a', which is symbolized in Figure 3 by an arrow with the reference numeral 21 a '.

In the same way, optionally, as shown in FIG. 3, the second housing wall section 4b 'may also be provided with a second through opening 5b', which is closed by an adjustable second wall element 20b. The second wall element 20b 'is rotatable relative to the second housing wall section 4b', which is represented by the arrow 21b '.

The first wall element 20a 'is rotatable about a first rotation axis D1', which runs orthogonal to a first wall plane E1 'defined by the first housing wall section 4a in the region of the first passage opening 5a'. The second wall element is rotatable about a second axis of rotation D2 'which is orthogonal to a second wall plane E2' defined by the second housing wall section 4b 'in the region of the second through-opening 5b. In variants of the example, other angles between the axes of rotation D1 ', D2' and the wall levels Ε1 ', E2' are possible. The two rotatable wall elements 20a ', 20b' generate by their rotational movement during the introduction of liquid plastic 1 1 'in the region between the two plastic streams 1 1 a', 1 1 b 'forming Bindenaht 10' transverse and eddy currents, which is an advantageous Reorientation of the fibers in the plastic effect. In variants, analogous to the first and second wall element 20a ', 20b' - also other wall elements may be provided, which is arranged in the first or second housing wall section 4a ', 4b' or another housing wall section of the injection mold 2 '.

As clearly shown in FIG. 3, the first wall element 20a 'is flush with the first housing wall section 4a' and the second wall element 20b 'is flush with the second housing wall section 4b'. It can further be seen that the first passage opening 5a 'is bordered on a side of the first housing wall section 4a' facing away from the interior 7 by a first actuator receiving element 6a 'projecting away from the first housing wall section 4a'. Likewise, the second passage opening 5b 'on a side facing away from the interior 7 side of the second housing wall portion 4b by a second actuator-receiving element 6b' are bordered, which protrudes away from the second housing wall portion 4b '. The first actuator element 9a 'in this case comprises the first wall element 20a' and is arranged in the first actuator receiving element 6a ', whereas the second actuator element 9b' comprising the second wall element 20b 'is arranged in the second actuator receiving element 6b'. The two Aktuator- receiving elements 6a ', 6b' may each be formed in the manner of a housing, which is in each case externally attached to the first and second housing wall portion 4a ', 4b'. The invention-essential rotation of at least the first wall element 20a '- in the present example, even the two wall elements 20a', 20b '- is realized by a rotation of the two actuator elements 9a', 9b 'about the rotation axis D1' or D2 '. The two passage openings 5a ', 5b' can, as shown in FIG. 3, be arranged offset in the first and second housing wall sections 4a ', 4b' along the extension direction E '.

FIG. 4 shows a variant of the example of FIG. 3, in which the first actuator element 9a 'is arranged linearly adjustable in the first actuator receiving element 6a' and the second actuator element 9b 'is linearly adjustable in the second actuator receiving element 6b'. Also in the example of Figure 4, the both passage openings 5a ', 5b' along the extension direction E 'offset from each other in the first and second housing wall portion 4a', 4b 'be arranged. As can be seen from Figure 4, the two Aktuator- receiving elements 6a ', 6b' in the form of receiving tubes 8a ', 8b' are formed. The first receiving tube 8a extends along a first tube direction RT, the second receiving tube 8b 'along a second tube direction R ₂ '. In the example scenario, the two pipe directions R, R ₂ > run parallel to each other. The first and the second pipe direction RT, R ₂ 'form in the longitudinal section of the device 1' shown in FIG. 3 along the extension direction E 'with this extension direction E' a right angle; in variants, other angles, such as acute angles between 10 ° and 45 °, conceivable.

The combined linear and rotary movement of the wall elements 20a ', 20b' comprehensive actuator elements 9a ', 9b' - illustrated in Figure 4 by the arrows 21 a ', 21 b' and the two double arrows 22 a ', 22 b' - generated in the in the injection mold 2 'introduced liquid plastic 1 1' in the region of between the two plastic streams 1 1 a ', 1 1 b' forming weld line 10 'particularly pronounced transverse and turbulence flows. These are indicated schematically in FIGS. 3 and 4 by the arrows designated by the reference numeral 12 '. Such turbulence or transverse flows prevent an undesirable, strength-reducing orientation of the fibers of the plastic 11 'in the area of the weld line 10' during the solidification of the plastic melt. As a result, this leads to an improved strength of the plastic 11 ', in particular in the area of the weld line 10'. In a simplified variant, the second wall element 20b 'can be dispensed with in the example of FIG. 4'. Also in the example of FIG. 4, further wall elements 20a ', 20b' can be provided in alternative fashion analogously to the first and second housing wall sections 4a ', 4b' or another housing wall section of the injection mold 2 '. It can also be seen from FIG. 4 that the two actuator elements 9a ', 9b' are adjustable in the respective actuator receiving element 6a ', 6b' between a first position, in which they partially project into the injection mold 2 ', and a second position, in which they are completely arranged in the respective actuator receiving element 6a ', 6b'. In FIG. 4, the first actuator element 9a 'is consequently in the first position, while the second actuator element 9b' is in the second position. As a result of the entry of an actuator element 9a ', 9b' into the interior 7 of the injection mold 2 ', a local displacement of the plastic 1 1' introduced into the injection mold 2 'is effected, as a result of which the aforementioned turbulence (arrows 12') in the region of the weld line 10 ' be generated. Particularly advantageous is the formation of cross flows in the form of eddy currents. Such eddy currents can be generated in a particularly pronounced form by the two actuator elements 9a ', 9b' alternately and gegengleich between the first and the second position are moved back and forth. This can be realized with the aid of a coupling device 15 'which may have a conventional control unit 16', for example in the form of a microcontroller, which in turn serves to drive the two actuator elements 9a ', 9b'. It is conceivable, for example, to design the two actuators 9a ', 9b' as electrical actuators, which are controlled by the control unit 16 'of the coupling device 15' electrically / electronically via control lines 17a ', 17b'. Due to the alternating reciprocating movement of the two actuator elements 9a ', 9b' and the associated volume displacement of the not yet solidified plastic 1 1 a ', 1 1 b' within the injection mold 2 'is generated in the plastic flow pattern, which has the characteristics of Eddy current (arrows 12 ') has.

The device 1 'according to the invention can optionally be equipped with a tempering device 13' which is shown both in FIG. 3 and in FIG allows a variation of the introduced into the injection mold 2 'plastic. This allows a cyclical heating of the injection mold 2 and thus also of the injected into the injection mold 2 'liquid plastic 1 1', 1 1 a ', 1 1 b', so that its temperature between its - material-specifically determined - melting and demolding temperature oscillates. Such a specific variation of the temperature of the plastic 11 'is known to the person skilled in the art of injection molding under the term "variothermic process control" and leads in particular in the area of the weld line 10' to an improved strength of the plastic 11 '. the tempering device 13 'may also have a heating device 14', which is only schematically indicated in the injection mold 2 'and which may be realized, for example, in the manner of a conventional electric resistance heater Cooling device can be omitted in order to cool the injection mold 2 'and thus also the plastic 1 1' again, then it is sufficient to achieve the required reduction in temperature by switching off the heater 14 '.

In a variant also shown only schematically in FIGS. 3 and 4, the desired temperature control of the injection mold 2 'and thus of the injected plastic 11' -as alternative or in addition to an electric heater-can be integrated into the injection mold by integrating an oil circuit, not shown in the figures 2 'can be realized. In this case, the desired temperature in the injection mold 2 'is achieved by thermal interaction with the oil, which acts equally as heating and cooling medium and flows through the oil circuit. In variants, instead of oil, another suitable fluid can also be used as the heating or cooling agent.

Claims

claims 1 . Device (1) for fiber injection molding of injection-molded parts,  - having a first and a second housing wall portion (4a, 4b) comprising injection mold (2), in which a first and a second inlet (3a, 3b) for introducing a plastic (1 1, 1 1 a, 1 1 b) in an interior (7) of the injection mold (2) are provided,  - With a in the first housing wall portion (4a) provided first  Through opening (5a) which is bordered on a side facing away from the interior (7) side of the first housing wall portion (4a) by a first Aktiebator- Aufnahmeelennent (6a) which projects away from the first housing wall portion (4a), wherein in the first actuator receiving element (6a) a first actuator element (9a) is movably arranged,  - With a in the second housing wall portion (4b) provided second through hole (5b), which on a side facing away from the interior (7) side of the second housing wall portion (4b) by a second actuator receiving element (6b) is bordered by the second housing wall portion (4b) protrudes away, wherein in the second actuator-receiving element (6b), a second actuator element (9b) is arranged to be movable. 2. Apparatus according to claim 1, characterized in that - The first and the second housing wall portion (4a, 4b) are opposite to each other or are provided adjacent to each other in the same housing wall. 3. Apparatus according to claim 1 or 2,  characterized in that  - The first actuator-receiving element (6a) projects obliquely from the first housing wall portion (4a) and the second actuator-receiving element (6b) projects obliquely from the second housing wall portion (4b), or that  - The two actuator-receiving elements (6a, 6b) in each case at a right angle from the respective housing wall portion (4a, 4b) protrude. 4. Device according to one of claims 1 to 3,  characterized in that  the actuator elements (9a, 9b) are designed such that they act on the in the interior (7) introduced plastic (1 1, 1 1 a, 1 1 b) as turbulence generating elements. 5. Device according to one of the preceding claims,  characterized in that  the device (1) comprises a tempering device (13), by means of which the temperature of the introduced into the injection mold (2) plastic is variable. 6. Device according to one of the preceding claims, characterized in that the first actuator receiving element (6a) as a first receiving tube (8a) and the second actuator receiving element (6b) as a second receiving tube (8b) are formed. 7. Apparatus according to claim 6,  characterized in that the first receiving tube (8a) extends along a first tube direction (Ri) and the second receiving tube (8b) extends along a second tube direction (R ₂ ), - The first and the second pipe direction (Ri, R ₂ ) in a longitudinal section of the device (1) each form an acute angle, in particular an angle between 10 ° and 45 °, with an extension direction (E) of the interior (7). 8. Apparatus according to claim 7,  characterized in that the first and second pipe directions (Ri, R ₂ ) are substantially parallel to each other. 9. Apparatus according to claim 8,  characterized in that the two receiving tubes (8a, 8b) in a cross-section orthogonal to the respective tube direction (Ri, R ₂ ) each have a circular or oval or polygonal profile. 10. Device according to one of the preceding claims,  characterized in that the first and the second passage opening (5a, 5b) are arranged offset with respect to the extension direction (E) in the first or second housing wall section (4a, 4b). 1 1. Device according to one of the preceding claims,  characterized in that  the two actuator elements (9a, 9b) in the respective actuator receiving element (6a, 6b) each between a first position in which they partially in the interior (7) of the injection mold (2) protrude, and a second position in which completely in the respective actuator receiving element (6a, 6b) are arranged, are adjustable. 12. Device according to claim 1 1,  characterized in that  the two actuator elements (9a, 9b) are coupled to one another by means of a coupling device (15) such that an adjustment of the first actuator element (9a) from the first to the second position results in an adjustment of the second actuator element (9b) into the first actuator Position causes and vice versa. 13. Device according to claim 12,  characterized in that  the two actuator elements (9a, 9b) each comprise an electric drive unit,  - The coupling device (15) has a control unit (16) which cooperates with the drive units for adjusting the position of the actuator elements (9a, 9b) between the first and the second position. 14. Apparatus (1 ') for fiber injection molding of injection-molded parts, - With a first and a second housing wall portion (4a ', 4b') comprehensive injection mold (2 '), in which a first and a second inlet (3a', 3b ') for introducing a plastic (1 1', 1 1 a , '1 1 b') in an interior (7 ') of the injection mold (2') is provided which is delimited by the two housing wall sections (4a ', 4b'),  - With a in the first housing wall portion (4a ') provided first  Through opening (5a ') which is closed by an adjustable first wall element (20a'), wherein the first wall element (20a ') relative to the first housing wall portion (4a') is rotatable. 15. Device according to claim 14,  characterized in that  - In the second housing wall portion (4b ') a second passage opening (5b') is provided, which is closed by an adjustable second wall element (20b '), wherein the second wall element (20b') rotatable relative to the second housing wall portion (4b ') is  - The first and the second housing wall portion (4a ', 4b') are opposite to each other or adjacent to each other in the same housing wall of the injection mold (2 ') are provided. 16. Device according to claim 14 or 15,  characterized in that  - The first wall element (20 ') about a first axis of rotation (D1') is rotatable, which is orthogonal to a through the first housing wall portion (4a ') in the region of the first passage opening (5a') defined first wall plane (Ε1 '), and / or that  - The second wall element (20b ') about a second axis of rotation (D2') is rotatable, which is orthogonal to a through the second housing wall portion (4b ') in the region of the second passage opening (5b') defined second wall plane (Ε2 '). 1 /.Vorrichtung according to one of claims 14 to 16, characterized in that  - The first wall element (20a ') with respect to a plan view in the direction of the first axis of rotation (D1') rotationally symmetrical to this axis of rotation (D1 ') is formed, and / or  - The second wall element (20b ') with respect to a plan view in the direction of the second axis of rotation (D2') rotationally symmetrical to this axis of rotation (D2 ') is formed. 18. Device according to one of claims 14 to 17,  characterized in that  the first wall element (20a ') is flush with the first housing wall section (4a') and / or the second wall element (20b ') terminates flush with the second housing wall section (4b'). 19. Device according to one of claims 14 to 18,  characterized in that  the two inlets (3a ', 3b') are provided on opposite front-side housing walls (19a ', 19b') and that an extension direction (Ε ') of the interior space (Ε') of the interior space is provided by a virtual connecting straight line between the two end housing walls (19a ', 19b'). 7 ') is defined,  the first and the second passage opening (5a ', 5b') offset with respect to the extension direction (Ε ') in the first or second housing wall portion (4a', 4b ') are arranged. 20. Device according to one of claims 14 to 19,  characterized in that - The first passage opening (5a ') on a side facing away from the interior (7') side of the first housing wall portion (4a ') by a first Aktuator- receiving element (6a') is bordered by the first Gehäusewandab- section (4a ') protrudes away, wherein in the first actuator-receiving element (6a') a first wall element (20a ') comprising the first actuator element (9a') is arranged, and / or  the second through-opening (5b ') is bordered on a side of the second housing wall section (4b') remote from the interior (7 ') by a second actuator receiving element (6b') projecting away from the second housing wall section (4b '), wherein in the second actuator-receiving element (6b ') a second wall element (20b') comprehensive second actuator element (9b ') is arranged. 21. Device according to claim 20,  characterized in that  - The first actuator element (9a ') is arranged linearly adjustable in the first actuator receiving element (6a'), and / or that  - The second actuator element (9b ') is arranged linearly adjustable in the second actuator-receiving element (6b'). 22. Device according to claim 21,  characterized in that  - The first actuator element (6a ') along a by the first axis of rotation (D1') defined first adjustment direction is linearly adjustable, and / or that  - The second actuator element (6b ') along a through the second axis of rotation (D2') defined second adjustment direction is linearly adjustable. 23. Device according to one of claims 20 to 22,  characterized in that the first actuator-receiving element (6a ') as a first receiving tube (8a') and the second actuator-receiving element (6b ') as a second receiving tube (8b') are formed. 24. Device according to claim 23,  characterized in that the first receiving tube (8a ') extends along a first tube direction (R-) and the second receiving tube (8b') extends along a second tube direction (R ₂ '), - The first and the second pipe direction (R-, R ₂ ') in a longitudinal section along the extension direction of the device (1') each have an acute angle, in particular between 10 ° and 45 °, or a right angle with the extension direction (Ε ' ) train. 25. Device according to one of claims 20 to 24,  characterized in that  the first and / or second actuator element (9a ', 9b') in the respective actuator receiving element (6a ', 6b') each between a first position in which it partially into the interior (7 ') of the injection mold (2') protrudes, and a second position in which it is completely in the respective Aktuator- receiving element (6a ', 6b') is arranged adjustable. 26. Device according to claim 25,  characterized in that  the two actuator elements (9a ', 9b') are coupled to one another by means of a coupling device (15 ') such that an adjustment of the first actuator element (9a') from the first to the second position results in an adjustment of the second actuator element (9b ') to the first position and vice versa. 27. The device according to claim 26, characterized in that the two actuator elements (9a ', 9b') each comprise an electric drive unit,  - The coupling device (15 ') comprises a control unit (16)', which cooperates with the drive units for adjusting the position of the actuator elements (9a ', 9b') between the first and the second position. 28. Device according to one of claims 14 to 27,  characterized in that  the device comprises a tempering device (13 '), by means of which the temperature of the introduced into the injection mold (2') plastic is variable. 29. A method for fiber injection molding of injection-molded parts in a device (1) according to one of claims 1 to 14,  according to which during the injection of plastic (1 1, 1 1 a, 1 1 b) through the two inlets (3a, 3b) in the injection mold (2), the two actuator elements (9a, 9b) substantially gegengleich each between a first position in which they partially protrude into the injection mold (2), and a second position in which they are completely arranged in the actuator receiving element (6a, 6b) are reciprocated. 30. A method for fiber injection molding of injection molded parts in a device (1) according to one of claims 14 to 28, according to which at least the first wall element (20a ', 20b') during the injection of plastic (1 1 ', 1 1 a', 1 1 b ') through the two inlets (3a', 3b ') in the injection mold (2 ) rotates relative to the first housing wall portion (4a ', 4b'). .Method according to claim 29 or 30, characterized in that during the injection of the plastic (11, 11a, 11b, 11 ', 11a', 11b ') into the interior (7, 7') of the temperature of the injection mold (2, 2 ') by means of a tempering device (14, 14') the injection mold (2; 2) is cyclically varied between an upper and a lower limit temperature, in particular such that the temperature of the plastic (11, 11a, 11b; 11 ', 11a', 11b ') varies cyclically between its melting temperature and its demolding temperature , *****