WO2018172141A1

WO2018172141A1 - Method and device for producing a part from thermoplastic material and a part produced in accordance with said method

Info

Publication number: WO2018172141A1
Application number: PCT/EP2018/056233
Authority: WO
Inventors: Oliver DÜNKELMANN; Hartmut Wolf
Original assignee: Kautex Textron Gmbh & Co. Kg
Priority date: 2017-03-22
Filing date: 2018-03-13
Publication date: 2018-09-27
Also published as: DE102017204797A1; CN110709224A

Abstract

The invention relates to a method for producing a part from a thermoplastic material by means of injection moulding, comprising at least two tubes that extend parallel to each other and are integrally formed on a connection part that connects them, using at least one extruder and an injection moulding tool (2) the cavity of which has at least two barrels (8) as mould cavities that each mould the contour of one of the tubes, and the cavity of which has a further mould cavity (9) that communicates with the barrels (8) and that moulds the connection part, and using at least one injection device (4) for injecting a fluid directly into at least one barrel (8) of the cavity and/or against at least one projectile (7) to be driven through the barrel (8) of the cavity, wherein the cavity is first filled with a thermoplastic moulding mass and then a fluid and/or projectile (7) is driven in parallel through each of the barrels (8) of the cavity, with a fluid centre of the moulding mass thereby being displaced.

Description

Method and device for producing a component made of thermoplastic material and component produced by the method

The invention relates to a method for producing a component from thermoplastic material by injection molding.

The invention further relates to an injection molding apparatus for the production of the component as well as a component, which was obtained before ^¬ preferably according to the method according to the invention. The invention particularly relates to a Einfüllvor ^¬ direction for a liquid container in a motor vehicle. The filling device is designed as a so-called double tube and comprises a filling tube forming a filling channel and a vent pipe extending parallel thereto.

Such filling devices are known from the prior art. For example, from EP 2 923 875 AI a filling device for filling fuel in a motor vehicle tank is known, which is a filler pipe and a

Venting tube comprises, wherein the vent tube is formed integrally with the filler pipe and the vent tube is connected by a pinch with the filler pipe. The filling device according to EP 2923875 Al is formed by blow molding, wherein the pinch seal forms a the two tubes ver ^¬ binding material bridge. The ^¬ be specified in this publication are method is basically suitable for the manufacture double pipes monolithically connected in one operation and from a preform.

In principle, filling tubes require a so-called "head volume" for absorbing excess liquid, which pushes upwards out of the venting line when switched off The venting line is connected to this head volume and runs as far as possible parallel to the filling tube as far as the container to be filled In the prior art methods of extrusion blow molding of double tubes, the two tubes which serve to fill and vent the container are often made from separate tube sections because a connection component such as an injection molded head part is attached to them.

The invention is therefore based on the object to provide a method for producing a component made of thermoplastic material comprising at least two parallel zuei ^¬ nander extending tubes which are integrally formed on a connecting component connecting them.

The invention further has for its object to provide a ent ^¬ speaking injection molding tool and by the method ago ^¬ posed component.

The object is solved by the features of the independent claims. Advantageous embodiments of the invention will become apparent from the dependent claims. One aspect of the present invention relates to a method for producing a component made of thermoplastic material comprising at least two tubes that are integrally formed on a connecting component connecting them, using an extruder and an injection molding tool, whose cavity has at least two runs as mold cavities, that molding in each case the contour of the tubes, and the cavity has an outlet communicating with the runs further mold cavity abformt the connection component, as well as un ^¬ ter using at least one injection device for injecting a fluid directly into the at least one run of the cavity and / or against at least a projectile to be driven by the barrel of the cavity, wherein first the cavity is filled with a thermoplastic molding compound and then a fluid and / or a projectile is driven through each of the cavities, displacing a liquid core of the molding compound.

The method according to the invention utilizes the so-called fluid injection technique and / or projectile injection technique. In such an injection molding process, for example, a projectile placed on an injector is driven through the cavity of the injection molding tool filled with a thermoplastic molding compound, wherein the molten substance of the thermoplastic molding compound is displaced, for example, into a secondary cavity. Tubes produced in this way have a defined inner diameter and can be produced relatively easily and reproducibly with a defined constant inner diameter. Alternatively, the fluid may displace the thermoplastic molding composition directly.

The invention skilfully combines the injection technique (WIT, GIT, PIT) with a conventional one

Injection molding, so that can be produced integrally with the method according to the invention in an advantageous manner, relatively complex structures with two or more integrally connected to these pipes.

According to the invention, the molding compound is displaced synchronously and in parallel from both runs of the cavity. For this For example, the molding compound will be immediately replaced respectively by the fluid in one or more Läu ^¬ fen the cavity. Alternatively it can be provided to directly displace the molding compound in one of the runs through the fluid, whereas a projectile is driven by another one of the barrels. Finally, it can also be provided within the scope of the invention to drive projectiles through several runs of the cavity.

Unitary in the sense of the present invention is to be understood that the tubes and the respective connection component are monolithic.

A connection component in the sense of the present invention may be formed, for example, as a connection housing, a filling device or a filler pipe for a fluid container. The method is particularly suited to produce a component having a terminal housing with the opening into ^¬ ses tubes which are integrally formed on the connection component.

The injection device according to the invention is designed for the injection of a pressurized fluid, for example for the injection of water or a gas into the cavity, wherein the injection device expediently has at least one projectile carrier which can be interspersed with one or more fluid channels and at its formed to receive the projectile end an injection nozzle. As injection device according to the present invention, a gas or water injection device (GIT Inj ector / WIT Inj ector) may be provided.

As the injection mold for the purposes of the present patent applica ^¬ dung those parts of the injection molding apparatus are referred to, that form a cavity defining the article to be manufactured. The injection mold according to the invention may have other movable moldings such as slides, movable mandrels and the like.

Any thermoplastic polymer can be provided as the thermoplastic molding composition in the sense of the invention. In ^¬ example, as a thermoplastic molding material

be provided thermoplastic plastic, which is selected from a group comprising high density polyethylene, poly ^¬ amide, polyamide 6, polyamide 12, polyurethane, polycarbonate, acrylonitrile-butadiene-styrene copolymer, polyketones,

Polystyrene, PPA (partially aromatic polyamides), thermoplasti ^¬ specific olefin-based polymers, crosslinked thermoplastic elastomers based on olefin, thermoplastic elastomers, urethane-based thermoplastic polyester elastomers and thermoplastic copolymers.

In an expedient variant of the method according to the invention ^¬ It is envisaged that several projectiles are synchronously driven by the runs of the cavity, wherein a projectile is driven by in each case a run.

In principle, the displaced molding compound can be conveyed into a secondary cavity provided in the injection molding tool. In an advantageous embodiment of the invention, however, it is provided that the displaced molding composition is returned to the extruder. This has proven to be advantageous, in particular with regard to a resource-saving handling of the thermoplastic molding composition. According to the invention it can be provided at ^¬ play to provide the sprue into the cavity of the injection molding on one side of the injection mold, while the injection device is provided on an opposite side of the injection mold.

The displaced molding compound can be returned to the extruder via a cold distributor or via a hot runner. If the projectiles and the associated runs of the cavity have a different clear width or a different cross section, it is expedient to control the speed with which the projectiles are driven through the runs. The invention therefore also provides such Steue ^¬ tion.

In a variant of the method according to the invention, provision is made for controlling the velocity of the projectiles in each case via the pressure and / or the volume flow of the fluid to be injected.

Alternatively hen provided for in the method according to the invention, the speed of the projectile is to be ^¬ digit factory by controlling the back pressure generated by the extruded molding composition.

For example, it can be provided according to the invention that the volume flow of the projectiles driving fluid is controlled or regulated such that the projectiles are synchronously driven by the barrels, especially when the cross section or the inside diameter of the barrels and so that the cross ^¬ cut or outer dimensions of the projectiles

are different.

Alternatively, it can be provided that at least one volume flow of the molding compound displaced by the projectile is controlled or regulated in such a way that the projectiles are driven synchronously through the runs. Synchronous means that the projectiles reach the intended end position, for example an end stop, at about the same time. In a preferred variant of the process according to the OF INVENTION ^¬ dung is contemplated that a single pump is used for injection of the fluid with which the projectiles are simultaneously applied in parallel in the sense of the fluid.

Another aspect of the invention relates to a device for producing a component made of thermoplastic material comprising at least two preferably mutually parallel ^¬ lel to each other extending tubes which are integrally formed on a connecting component connecting them, comprising we ^¬ least one extruder, an injection mold, the Kavi at least two runs as mold cavities, which in each case shape the contour of one of the pipes, and whose cavity has a further mold cavity communicating with the runs, which molds the connection component, as well as a cavity

Injection device with at least one injector for injecting a fluid directly into one of the runs of the cavity and / or against a projectile to be driven by at least one of the runs of the cavity.

The device is expediently designed for carrying out the method according to one of the claims 1 to 7.

When the produced according to the method component as beispiels- as a connection member comprises a connection housing, in which are to open with this pipes to be connected, requires a relatively small distance between the at ^¬ circuit housing opening into the pipes to each other, a special configuration of the injection device.

An injection device for carrying out the method according to the invention requires the use of tool ^inserts as injectors. To meet the requirements of the To become part justice, such as combi Natio ^¬ nen of gas and water injectors may be provided as a separate tool inserts. Preferably, the injection device comprises a plurality of ^juxtaposed injectors, of which at least one has a projectile carrier.

Further preferably, the device is characterized according to the invention by a single injection block Asinj injector, which has a plurality of juxtaposed projectile ^¬ carrier.

In a further advantageous embodiment of the device according to the invention it is provided that water is supplied as fluid to a plurality of projectile carriers by means of a common pump. As a pump is conveniently a

High pressure pump provided, which may be connected via a distributor to a plurality of projectile carriers.

In an advantageous embodiment of the device according to the invention, provision is made for an adjustable throttle to be provided in at least one water supply to a projectile carrier.

Alternatively or additionally, it can be provided that a hot runner is arranged between the cavity and the extruder, to which the runs are each connected to a ^drain .

In at least one outlet, a quill with needle closure can be provided as an adjustable throttle. The back pressure of the melt or of the displaced thermoplastic molding compound can be adjusted via the restrictor in such a way that the velocity of the projectile can be controlled via it. The runs and the projectiles may have a symmetrical cross section, for example a round cross section. Alternatively it can be provided that the runs and the profiles each have a non-rotationally symmetrical cross section. In this way, for example, a double tube with an approximately round overall cross-section can be produced in an advantageous manner. The term total cross section refers to the envelope of an arrangement of two parallel tubes.

Although the method is suitable to produce multiple pipes having mutually parallel extending tube sections, the invention is generally to be understood that the tubes of the component extend pa rallel ^¬ each other or only over a partial length. Accordingly, it is not necessarily required that the runs of the cavity extend parallel to each other. Another aspect of the invention relates to a component made of thermoplastic material which has preferably been produced by the method according to one of claims 1 to 7 and furthermore preferably by using a device according to one of claims 8 to 15. The component comprises at least two preferably mutually parallel erstre ^¬ ckende tubes made of thermoplastic material, which are integrally formed on a connecting component connecting them, where ^¬ in the connection component is designed as a connection housing of a filling ^¬ tube for a fluid container.

Although the component preferably comprises two tubes which extend parallel to each other over at least a partial length, it is within the scope of the invention that the tubes of the component do not run or only partially parallel to one another. The tubes of the component can be integrally connected to each other at least over part of their length, at least insofar as they extend approximately parallel to one another, via at least one material bridge.

Furthermore, the tubes may have a non-rotationally symmetrical cross section.

Conveniently, the tubes form between them at least one constriction whose width is between 2 and 6 mm.

Advantageous embodiments of the invention will be explained below with reference to the accompanying drawing figures.

Show it:

Figure 1 tung a simplified sectional view through an injection mold tool ^¬ as part of Vorrich- invention, which comprises two separate injectors,

Figure 2 is a similar to Figure 1 view of an alterna ^¬ tive embodiment of the injection mold with an injector, which is designed as water injection block with two pro j ektilträgern, a Figures 1 and 2 corresponding view of an alternative embodiment of the injection mold with an injector as Water injection block is formed with two projectile carriers,

FIG. 4 a shows a schematic representation of the component ^contour to be produced by the method according to the invention, wherein parts of the injection molding tool are not shown, FIG. 4b is an end view of the component contour shown in FIG. 4A;

Figure 5 is a view corresponding to FIG 4 of a alterna tive embodiment of the device according to the invention ^¬ and

FIGS. 6a

to 6c different cross sections through the component

according to the invention. To explain the method according to the invention, reference is initially made to Figures 1 and 5. Figure 1 shows parts of the apparatus for carrying out the method and for the production of the component according to the invention. The device is referred to below as injection molding device 1. The injection molding apparatus 1 comprises an injection molding tool 2, an extruder 3, and an injection device 4. The injection device 4 includes one or more injectors 5. In the embodiment according to Figure 1, the Injekti ^¬ onsvorrichtung 4 comprises two injectors 5, one of which ser as water injector (WIT method) and the other as a gas injector

(GIT method) is formed. The water injector 5 comprises a projectile carrier 6 for receiving a projectile 7.

Figures 1 to 3 show only that part of the injection molding apparatus to which the injection device 4 is connected, whereas Figures 4a and 5 show that part of the injection molding apparatus to which the extruder 3 is connected. The injection molding tool 2 is composed in a known manner of several tool parts and forms a Kavi ^¬ ity, which is divided into a plurality of mold cavities. The shape ^¬ cavities communicating with each other, define the

Shape of the component to be manufactured 11. The cavity comprises two runs 8 as mold cavities and a further mold cavity ^¬ space 9, which defines the contour of a connection housing 10 of the component 11. The projectile 7 has a cross-sectional profile that corresponds to the cross-sectional profile of a barrel 8 of the cavity, namely that barrel 8 (left in FIG. 1) in which the so-called PIT injector 5 can be inserted. The other barrel 8 of the cavity has a smaller inside diameter or a smaller diameter than the barrel 8 into which the PIT injector 5 can be inserted. The injector 5 assigned to this barrel 8 is designed as a gas injector (GIT injector).

According to the method according to the invention, it is provided to first fill the cavity of the injection mold by means of the extruder 3 with a thermoplastic molding compound. Then, about the same time pushed the thermoplastic molding mass from both Läu ^¬ fen 8 of the cavity on the one hand by means of the fluid-driven projectile 7, and on the other hand by a fluid directly into the extruder 3 back, wherein the projectile is driven through the shown in Figure 1 left running 8 7 and synchronously in the parallel extending barrel 8 of the cavity, the thermoplastic molding material is displaced directly by the pressure of the fluid. The fluid, in one case water, in the other case gas is provided by fluid channels 14 which pass through the injectors 5.

As shown schematically in FIG. 4 a, the two runs 8 are connected to the extruder 3 via a gate or via a cold distributor 19. FIG. 4 a shows the contour of the component 11 to be produced without the surrounding parts of the injection molding tool 2. The component 11 constituting excluded, for example, as a dop ^¬ pelläufige dispensing device for a fluid container, comprising a first pipe 12 and the filler pipe and a second pipe 13 as a ventilation pipe and the connector case 10 mentioned above, to which the first and the second pipe 12, 13 are integrally formed. As can be seen in particular from the combination of FIGS. 4a and 4b, the first tube 12 and the second tube 13 are guided into the connection housing 10 and open into it.

Figure 2 shows an alternative embodiment of the injection molding ^¬ device 1 according to the invention. In Figure 2 and in all other figures, the same components are provided with the same Bezugszei ^¬ chen.

The injection device 4 comprises a single injector 5 which is equipped as a water injector with two projectile carriers 6. The injector 5 forms a single tool insert or water injection block. Each of the projectile carrier 6 is equipped with a projectile 7.

The term injection device 4 according to the present invention comprises means for storing the fluid and we ^¬ nigstens a high pressure pump for pressurizing the Flu ^¬ ids.

The injector 5 of the embodiment according to FIG. 2 comprises two fluid channels 14, which can be connected to different pressure medium sources or to a single pressure medium source, for example to a common high-pressure pump.

Incidentally, the method for producing the component 10 using the injection molding apparatus 1 according to FIG Figure 2 approximately to that method using the injection molding device 2 according to figure 1. The processes differ in that two projectiles 7 synchronously and paral lel ^¬, ie at the same time, are driven by the parallel extending legs 8 of the cavity. Both runs 8 have a different clear width so that in each case a melt ^¬ zefront with different cross-section is to displace.

Controlling the speed of the projectile 7 may be done at ^¬ play such a manner that in a feeder 15 of one of the legs 8, as shown for example in Figure 5, a throttle 16 is provided always with which the volume flow of the displaced thermoplastic molding composition is controllable. The throttle 16 may be formed, for example, as a quill with needle closure.

As can be seen from Figure 5, the throttle 16 is provided in that outlet, which is associated with the barrel 8 with the larger cross section or with the larger clear width. The outlets 15 of the runs 8 of the cavity are connected to a hot runner 17, which in turn communicates with the extruder 3.

Another variant of the injection molding apparatus 1 according to the invention is shown in FIG. Also in Figure 3, components corresponding to those in Figures 1 and 2 are given the same reference numerals. The embodiment according to Figure 3 differs only to the effect against the off ^¬ operation example according to FIG 2 is that in a water supply or in a fluid channel 14 an adjustable throttle is seen 16 before ^¬ with which the volume flow of the projectile carrier 5 supplied water is controllable. By controlling the volume flow of the water, the speed can be Setting of the relevant projectile 7 so sicherge ^¬ provides is that both projectiles are synchronously driven by the 7 extending parallel runs. 8 The variant of the injection molding apparatus 1 according to FIG 3 may be formed on sides of the assembly of the extruder 3 according to the Dar ^¬ position shown in FIG 4a, alternatively, this variant, the injection molding apparatus 1 also be formed as shown in FIG. 5 A regulation of the volume flow of the supplied water or fluid can be provided to ^¬ addition or alternatively for controlling the back pressure of the melt or for controlling the flow rate through one of the outlets 15. Figure 4b illustrates for example, as end-side at ^¬ view of the component 11, the arrangement of the filler pipe 12 and the vent tube 13 in the connector housing 10th

Figures 6a to 6c show various cross sections through the component 11, which is obtained with the method according to the invention. The device 11 according to the Figures 6a to 6c includes fully, as described above, the connector case 10 so ^¬ as a filling tube 12 and a vent tube 13. Shown is a cross section through the filler pipe 12 and the vent tube 13, via a material bridge 18 are interconnected.

The cross-sections shown in Figures 6a to 6c are un ^¬ symmetrical and 7 were obtained with non-rotationally symmetrical cross-section by means of tilen projectile injection of projects. Reference sign list

Injection molding device

injection mold

extruder

Inj ektionsVorrichtung

Inj ector

Proj ectile carrier

Project ektil

Runs of the cavity

another mold cavity

connection housing

component

filler pipe

vent pipe

Fluid channels

leaving

throttle

hot runner

material bridge

cold distribution

Claims

claims

1. A method for producing a component from thermoplasti ^¬ sch plastic by injection molding comprising at least two tubes which are integrally formed on a connecting connecting ^{¬ this} part, using at least one Extruder (3) and an injection mold (2) whose cavity has at least two runs (8) as mold cavities, which respectively form the contour of one of the pipes, and whose cavity has a further mold cavity (9) communicating with the runs (8), which molds the connection component, and using at least one injection device (4 ) is filled for injection of a fluid directly into the at least one drive (8) of the cavity and / or against at least one (through the barrel 8) of the cavity to driving projectile (7), to ^¬ next overall the cavity with a thermoplastic molding composition and then through each of the runs (8) of the cavity to displace a liquid soul of the molding material a fluid un d / or a projectile (7) is driven.

2. The method according to claim 1, characterized in that GR are driven nigstens two projectiles (7) in synchronism through which preference ^¬ parallel extending legs (8) of the cavity.

3. The method according to any one of claims 1 or 2, character- ized in that the displaced molding material in the extruder

(3) is returned or promoted in a Nebenkavität.

4. The method according to any one of claims 1 or 2, characterized in that the displaced molding compound via a cold distributor ^¬ (19) or via a hot runner (17) is fed back into the extruder (3).

5. The method according to any one of claims 1 to 4, characterized in that the volume flow of the projectiles (7) trei ^¬ benden fluid is controlled or regulated so that the

Projectiles (7) simultaneously reach an end position.

6. The method according to any one of claims 1 to 5, characterized in that at least one volume flow of the displaced molding material is controlled or regulated so that the projectiles (7) simultaneously reach an end position.

7. The method according to any one of claims 1 to 6, characterized by the use of a single pump, with which the projectiles (7) are acted upon in parallel with the fluid.

8. An apparatus for producing a component (11) made of thermoplastic plastic ^¬ plastic comprising at least two pipes connecting these to a terminal member are integrally formed ^¬ comprising at least one extruder (3), an

Injection molding tool (2), the cavity having at least two barrels (8) as the form of cavities which mold each contour ei ^¬ nes of the tubes, and the cavity communicating one with the barrels (8) further mold cavity (9) which forms the terminal member and an injection ^device (4) with at least one injector (5) for injecting a fluid directly into one of the runs (8) of the cavity and / or against a projectile to be driven by at least one of the runs (8) of the cavity.

9. Apparatus according to claim 8, characterized by a plurality of juxtaposed injectors (5), of which at least one has a projectile carrier (6).

10. The device according to claim 8, characterized by a single injection block Asjection injection unit (4), which has a plurality of juxtaposed projectile carrier (6).

11. The device according to claim 10, comprising a common

Pump, by means of which water as a plurality of Projektilträ ^¬ like fuel (6) is supplied.

12. Device according to one of claims 8 to 11, character- ized in that in at least one water supply to a

Projectile carrier (5) an adjustable throttle (16) is provided.

13. Device according to one of claims 8 to 12, characterized by a hot runner (17) between the cavity and the extruder (3), to which the runs (8) are each connected to an outlet (15).

14. The apparatus according to claim 13, characterized in that in at least one outlet (15) a controllable throttle (16) is provided.

15. Device according to one of claims 8 to 14, characterized in that at least one of the barrels (8) and at least one of the projectiles (7) not one

have rotationally symmetrical cross-section.

16. A component made of thermoplastic material, preferably prepared by the method according to one of claims 1 to 7, at least two zuei ^¬ Nander extending tubes of thermoplastic material are preferably comprising parallel ^¬ integrally formed on a connecting these connection member, the terminal member as a connection housing (10) is formed of a filler pipe for a fluid container.

17. Component according to claim 16, characterized in that the tubes are at least over part of their length via at least one material bridge (18) integrally connected to each other.

18. Component according to one of claims 16 or 17, characterized in that at least one of the tubes has a non-rotationally symmetrical cross section.

19. Component according to one of claims 15 to 17, characterized ge ^¬ indicates that the tubes between them have at least one constriction whose width is between 2 and 6 mm.