DE202020006061U1 - Channel system for the continuous injection of a plasticized molding compound into a molding tool and injection molding device - Google Patents

Abstract

Channel system (14) for continuously injecting a plasticized molding compound (12) into a molding tool (16) by means of an injection molding device (10) with at least two injection units (18, 20) and at least one plasticizing unit (22), having a first channel (36) which can be connected to a first injection unit (18), a second channel (38) which can be connected to a second injection unit (20), an injection channel (42) for injecting a plasticized molding compound (12) into a molding tool (16), which is connected to the first channel (36) and the second channel (38), and a filling channel (40) which is connected to the first channel (36) and the second channel (38) and can be connected to a plasticizing unit (22) in order to fill the first injection unit (18) with the plasticized molding compound (12) via the first channel (36). and to fill the second injection unit (20) with the plasticized molding compound via the second channel (38), and wherein valve means (46, 48, 50, 52) are provided for the controlled feeding of the plasticized molding compound (12) to the injection channel (42).

Description

The present invention relates to a channel system for continuously injecting a plasticized molding compound into a molding tool by means of an injection molding device with at least two injection units and at least one plasticizing unit. The invention further relates to an injection molding device for continuously injecting a plasticized molding compound into a molding tool with such a channel system.

To produce molded parts made of plastic, for example from a thermoplastic or an elastomer, the plastic is heated and plasticized in an extruder in an injection molding device and then injected into a mold cavity of a molding tool via an injection unit. The molding compound is heated under the influence of temperature so that it changes into a solid state through cross-linking. After cross-linking, the molding tool can be opened and the hardened molded part removed.

For the production of multi-layered objects, it is known to use two injection units that inject the plasticized molding compound into the mold cavity one after the other. Such injection molding devices are made of EP 0 657 268 A2 , DE 10 2014 002 728 B3 , DE 10 2014 207 591 B4 and DE 10 2015 012 747 A1 known.

US 4,052,497 A shows an injection nozzle arrangement with three plasticizing units that plasticize different materials. The plasticizing units open into a nozzle via channels. The nozzle is connected to a feed channel through which the different materials are injected into a cavity one after the other. In order to inject the three different materials into the cavity one after the other, the channels are provided with valves.

Furthermore, US 5,922,363 A a coinjection device that enables coinjection molding of multi-layered objects. The coinjection device has two plasticizing units that are connected to hot runners via non-uniform hot runners. Each hot runner opens into a cavity via a sprue and a nozzle. A time-controlled valve mechanism is arranged between the non-uniform hot runners and a hot runner, via which the inflow of material from one of the non-uniform hot runners is controlled.

Furthermore, US 4,789,318 A an injection head for producing plastic moldings with an outer skin made of plastic containing a blowing agent and with a porous core made of plastic containing a blowing agent.

Finally, DE 21 59 383 A a method for producing laminated articles in which skin and core materials are successively injected into a mold cavity via sprue channels and the core material is injected into the interior of the skin material so that the latter is expanded by the core material. To achieve a desired distribution of skin and core material in the molding, the sprue channels are connected to conveyor channels via valves.

In addition, two injection units can be used to produce large-volume objects by injecting the plasticized molding compound into the mold cavity one after the other. Examples of this are given in DE 36 32 185 A1 and DE 10 2013 015 800 A1 out.

The present invention is based on the object of creating a channel system and an injection molding device which enable a continuous injection of a plasticized molding compound into a molding tool.

To solve the problem, a channel system with the features of claim 1 and an injection molding device with the features of claim 7 are proposed.

Advantageous embodiments of the channel system are the subject of the dependent claims.

According to one aspect, a channel system is proposed for continuously injecting a plasticized molding compound into a molding tool by means of an injection molding device with at least two injection units and at least one plasticizing unit. The channel system has a first channel that can be connected to a first injection unit, a second channel that can be connected to a second injection unit, an injection channel for injecting the plasticized molding compound into the molding tool, which is connected to the first channel and the second channel, and a filling channel that is connected to the first channel and the second channel and can be connected to a plasticizing unit in order to fill the first injection unit with the plasticized molding compound via the first channel and the second injection unit with the plasticized molding compound via the second channel, and wherein valve means are provided for the controlled supply of the plasticized molding compound to the injection channel.

Through the combination of valve means and filling channel, the flow process of the plasticized molding compound can be controlled in such a way that the flow process is not interrupted. This makes it possible to continuously inject a plasticized molding compound into a mold cavity of a molding tool. The flow process can be controlled via the valve means in such a way that one of the injection units is filled with the plasticized molding compound and the other injection unit injects the plasticized molding compound into the mold cavity without the flow process coming to a standstill. This makes it possible to create large-volume components with a homogeneous structure.

In the channel system, the channels can be opened and/or closed via the valve means in such a way that one of the two injection units is filled with the plasticized molding compound via the filling channel and the channel connected to it, and that at the same time the plasticized molding compound in the other injection unit is injected via the channel and the injection channel into the mold cavity of a molding tool. Valve means are advantageously provided for the controlled feeding of the plasticized molding compound to the first channel, the second channel and/or the injection channel. In an advantageous embodiment, the valve means, in particular one valve means each, control the feeding of the plasticized molding compound from the filling channel via the first channel to the first injection unit, the feeding of the plasticized molding compound from the filling channel via the second channel to the second injection unit, the feeding of the plasticized molding compound from the first injection unit via the first channel to the injection channel and the feeding of the plasticized molding compound from the second injection unit via the second channel to the injection channel.

In an advantageous embodiment, the channel system has a channel block in which the channels are incorporated.

The molding compound can be plastic, which can be in the form of granules. The plastic can be a thermoplastic, thermoset or elastomer.

In an advantageous embodiment, the valve means are arranged within the channels.

In an advantageous embodiment, a first valve means is arranged between the first channel and the filling channel, a second valve means is arranged between the second channel and the filling channel, a third valve means is arranged between the first channel and the injection channel and a fourth valve means is arranged between the second channel and the injection channel.

This achieves the technical advantage that the flow process of the plasticized molding compound can be controlled in such a way that it does not come to a standstill. The first valve means and the second valve means are advantageously arranged within the filling channel. Further advantageously, the third valve means and the fourth valve means are arranged within the injection channel. In an advantageous embodiment, the first valve means is arranged within the filling channel in front of a node between the filling channel and the first channel. Further advantageously, the second valve means is arranged within the filling channel in front of a node between the filling channel and the second channel. The third valve means is advantageously arranged within the injection channel after a node between the first channel and the injection channel. The fourth valve means is advantageously arranged within the injection channel after a node between the fourth channel and the injection channel. The node corresponds to a connecting section or connecting region between two channels.

In an advantageous embodiment, the valve means are designed as controllable valves.

This achieves the technical advantage that the channels can be opened and/or closed by controlling the valves in order to enable filling of one of the injection units and simultaneous injection of the plasticized molding compound in the other injection unit into a molding tool. The controllable valves can be mechanically controllable valves, electrically controllable valves, hydraulically controllable valves, electromagnetically controllable valves and/or pneumatically controllable valves.

In an advantageous embodiment, the valves are designed as controllable needle valve nozzles.

This provides the technical advantage of achieving precise opening and closing behavior. It also creates consistent sprue quality over a longer period of time. Needle valve nozzles are also available as cost-effective standard components.

In an advantageous embodiment, the channel system has a channel block in which the channels are incorporated.

This provides the technical advantage that the channel system can be used universally. The channel block can be one-piece or multi-piece. In an advantageous embodiment, the injection units are connected to the channel block. The injection units can be connected to the channel block via connecting nozzles. The connecting nozzles can be connected to the channel in a form-fitting and/or force-fitting manner. block. In particular, the connecting nozzles can be screwed to the channel block. In addition, the channel block can be made of metal. The channel block can be a cold runner block or a hot runner block. A cold runner block is used for injecting thermosets or elastomers, whereas a hot runner block is used for injecting thermoplastics.

In an advantageous embodiment, the injection channel opens into a nozzle assembly.

This achieves the technical advantage that the temperature of the plasticized molding compound flowing through the nozzle block can be increased. The nozzle block advantageously has a nozzle body and a nozzle channel introduced into the nozzle body. The nozzle channel can have the same or a smaller diameter than the injection channel. In an advantageous embodiment, the cross-section of the nozzle channel can be adjusted. The nozzle channel can be closed and opened using a closing needle. The nozzle block can be formed in one piece from the channel block of the channel system. Furthermore, the nozzle block can be a separate part that is connected to the channel system by form force and/or material bonding. The nozzle block can be screwed to the channel block.

According to a further aspect, an injection molding device for continuously injecting a plasticized molding compound into a molding tool with at least two injection units, at least one plasticizing unit and the channel system is proposed.

By means of the injection molding device and the channel system, it is thus possible to continuously inject plasticized molding compound into a mold cavity of a molding tool.

The injection molding device can have a plasticizing unit, an injection unit, an operating unit and a closing unit for closing and holding the molding tool. The plasticizing unit can have a screw or extruder arranged within a cylinder, a screw drive device, a funnel for filling the molding compound to be processed, a heating device for plasticizing the filled molding compound and a nozzle for filling the injection unit with the plasticized molding compound. The injection unit can have a cylinder with a nozzle and an injection piston that can move within the cylinder. By moving the injection piston, the plasticized molding compound in the cylinder is injected via the nozzle into the mold cavity of a molding tool. In an advantageous embodiment, the injection molding device heats the molding tool during injection.

In an advantageous embodiment, the injection molding device has a control device that is designed to open and/or close the valve means on the basis of detected operating parameters. In order to detect the operating parameters, the control device can be connected to sensors that detect the injection pressure of the respective injection unit, the position of the injection piston of the respective injection unit, the fill level of the plasticized molding compound within the respective injection unit, the pressure within the channels and the temperature within the channels. Furthermore, in order to detect the operating parameters, the control device can be connected to sensors that measure the speed and torque of the extruder of the plasticizing unit.

In a method for controlling and regulating a continuous injection process of an injection molding device, the first injection unit is first filled with a plasticized molding compound via the filling channel connected to the plasticizing unit and the first channel by opening the first valve means and closing the second valve means and the third valve means. The molding compound located in the first injection unit is then injected into the molding tool by closing the first valve means and opening the third valve means, while at the same time the second injection unit is filled via the filling channel connected to the plasticizing unit and the first channel by opening the second valve means and closing the fourth valve means. The molding compound located in the second injection unit is then injected into the molding tool by closing the second valve means and opening the fourth valve means.

The closing and opening of the valve means can be controlled via a control device. The control device can open and/or close the valve means depending on detected operating parameters. For this purpose, the control device can be connected to sensors that detect the injection pressure of the respective injection unit, the position of the piston of the respective injection unit, the fill level of the plasticized molding compound within the respective injection unit, the pressure within the channels, the temperature within the channels, and the speed and torque of the extruder of the plasticizing unit. Furthermore, the control device can be connected to sensors that measure the speed and torque of the extruder of the plasticizing unit in order to detect the operating parameters.

During the injection process of the first injection unit and after reaching a filling quantity of the second injection unit, the second valve means can be closed and a predetermined injection pressure can be built up against the closed fourth valve means.

This achieves the technical advantage that the actual injection pressure of the first injection unit is built up as a target pressure for the second injection unit against the still closed fourth valve means.

Before the injection process of the first injection unit is completed, the fourth valve means can be opened so that both injection units inject the plasticized molding compound into the molding tool.

This provides the technical advantage of achieving the most uniform injection speed possible, even when switching between injection units.

The third valve means can be closed after a delay time has elapsed or after a predetermined position of an injection piston of the first injection unit has been reached.

During the injection of the plasticized molding compound by the second injection unit, the first valve means can be opened to fill the first injection unit with the plasticized molding compound via the filling channel.

This provides the technical advantage that the first injection unit can be refilled with the plasticized molding compound in order to be available for another injection process.

After the first injection unit has been filled, it is available for injection again by the first injection unit first building up pressure against the closed third valve means before the injection process of the second injection unit ends, and shortly before the injection process of the second injection unit ends, the third valve means is opened so that both injection units inject the plasticized molding compound into the molding tool, as previously described for the second injection unit. The fourth valve means is then closed and the second injection unit is filled again by opening the second valve means.

The steps described above can be repeated as often as required. This enables continuous injection of a plasticized molding compound into a molding tool.

• 1 einen Ausschnitt eines Querschnitts durch eine Spritzgussvorrichtung mit einem Kanalsystem und einem Formgebungswerkzeug, wobei eine erste Spritzeinheit eine plastifizierte Formmasse in das Formgebungswerkzeug einspritzt und eine zweite Spritzeinheit mit der plastifizierten Formmasse befüllt wird;
• 2 einen Ausschnitt eines Querschnitts durch die Spritzgussvorrichtung von 1, wobei beide Spritzeinheiten die plastifizierte Formmasse in das Formgebungswerkzeug einspritzen;
• 3 einen Ausschnitt eines Querschnitts durch die Spritzgussvorrichtung von 1, wobei die erste Spritzeinheit befüllt und die zweite Spritzeinheit die plastifizierte Formmasse in das Formgebungswerkzeug einspritzt; und
• 4 einen Querschnitt durch die Spritzgussvorrichtung von 3 entlang der Linie IV-IV.

A channel system, an injection molding device, a method for injecting a plasticized molding compound into a molding tool and other features and advantages are explained in more detail below using an embodiment that is shown schematically in the figures.

• 1 a detail of a cross section through an injection molding device with a channel system and a molding tool, wherein a first injection unit injects a plasticized molding compound into the molding tool and a second injection unit is filled with the plasticized molding compound;
• 2 a section of a cross section through the injection molding device of 1 , whereby both injection units inject the plasticized molding compound into the molding tool;
• 3 a section of a cross section through the injection molding device of 1 , wherein the first injection unit fills and the second injection unit injects the plasticized molding compound into the molding tool; and
• 4 a cross-section through the injection molding device of 3 along line IV-IV.

In the 1 to 4 an injection molding device 10 is shown, which serves to inject a plasticized molding compound 12 into a molding tool 16.

The injection molding device 10 has a first injection unit 18, a second injection unit 20, a plasticizing unit 22 and a channel system 14.

The first and second injection units 18, 20 have a housing 24, an injection piston 26 movable within the housing 24 and a connecting nozzle 28 for connecting the injection units 18, 20 to the channel system 14.

As in 4 As can be seen, the plasticizing unit 22 has an extruder housing 30 and an extruder screw 32 that can be moved rotationally and/or translationally within the extruder housing 30. In the present case, a plastic granulate (not shown) is plasticized into the molding compound 12 by rotation of the extruder screw 32 and pressed into a connecting channel 33.

The channel system 14 has a channel block 34, a first channel 36, a second channel 38, a filling channel 40 and an injection channel 42. The channel block 34 is designed as a cold channel block in the present case. However, the channel block 34 can also be designed as a heat channel block.

As in the 1 to 3 As can be seen, the first channel 36 is connected to the first injection unit 18 and the second channel 38 to the second injection unit 20. Both the first channel 36 and the second channel 38 are connected to the filling channel 40, which is connected to the plasticizing unit 22 via the connecting channel 33, as shown in 4 can be seen. In addition, the first channel 36 and the second channel 38 open into the injection channel 42, which opens into a nozzle assembly 44.

The nozzle assembly 44 has a nozzle body 45 and a nozzle channel 47 introduced into the nozzle body 45. The nozzle assembly 45 is connected to the channel block 34 in a form-fitting, force-fitting and/or material-fitting manner. The plasticized molding compound 12 is injected into the molding tool 16 via the injection channel 42 and the nozzle assembly 44.

According to the 1 to 3 a first valve means 46 is arranged between the first channel 36 and the filling channel 40, a second valve means 48 is arranged between the second channel 38 and the filling channel 40, a third valve means 50 is arranged between the first channel 36 and the injection channel 42, and a fourth valve means 52 is arranged between the second channel 38 and the injection channel 42. The valve means 46, 48, 50, 52 are designed as controllable valves, in particular as controllable needle valve nozzles.

To control the valve means 46, 48, 50, 52, the injection molding device 10 has a control device (not shown) which opens and/or closes the valve means 46, 48, 50, 52.

A method for injecting the plasticized molding compound 12 into the molding tool 16 using the injection molding device 10 and the channel system 14 is described below. First, the first injection unit 18 is filled via the filling channel 40 connected to the plasticizing unit 22 by opening the first valve means 46 and closing the second valve means 48 and the third valve means 50. As a result, the plasticized molding compound 12 produced in the plasticizing unit 22 flows via the filling channel 40 and the first channel 36 into the first injection unit 18 and fills it up.

After filling the first injection unit 18, the first valve means 46 is closed and the third valve means 50 is opened, so that the plasticized molding compound 12 is injected into the molding tool 16 by means of the first injection unit 18 via the first channel 36, the injection channel 42 and the nozzle channel 47 by moving the injection piston 26 downwards within the housing 24, as shown in 1 can be seen. At the same time, the second injection unit 20 is filled with the plasticized molding compound 12 produced in the plasticizing unit 22 via the filling channel 40 and the second channel 38 by opening the second valve means 48 and closing the fourth valve means 52.

After the filling quantity of the second injection unit 20 has been reached and before the injection process of the first injection unit 18 has ended, for example when the remaining volume of plasticized molding compound 12 is 100 cm ³ , the second valve means 48 is closed and a predetermined injection pressure is built up against the closed fourth valve means 52 by moving the injection piston 26 downwards within the housing 24 of the second injection unit 20.

Shortly before the end of the injection process of the first injection unit 18, when there is only a small residual volume of injectable plasticized molding compound 12 in it, for example 40 cm ³ , the fourth valve means 52 is opened so that both injection units 18, 20 inject the plasticized molding compound 12 into the molding tool 16, as in 2 This ensures that the injection speed is as uniform as possible, even when switching the injection units 18, 20.

After a delay time or a predetermined position of the injection piston 26 of the first injection unit 18 has elapsed, the system switches to the second injection unit 20 by closing the third valve means 50. From this point on, the second injection unit 20 injects the plasticized molding compound 12 into the molding tool 16 via the second channel 38 and the injection channel 42. At the same time, the first injection unit 18 is refilled by opening the first valve means 46, as shown in 3 is evident.

After the first injection unit 18 has been filled, it is available for injection again by first building up pressure against the closed third valve means 50 before the injection process of the second injection unit 20 ends and then opening the third valve means 50 shortly before the injection process of the second injection unit 20 ends, so that both injection units 18, 20 inject the plasticized molding compound 12 into the molding tool 16, as previously described for the second injection unit 20. The fourth valve means 52 is then closed and the second injection unit 20 is filled again by opening the second valve means 48.

The method described above can be repeated as often as required to ensure continuous injection of a plasticized mold mass 12 into a forming tool 16.

By providing valve means 46, 48, 50, 52 in a channel system 14 and their targeted control, the flow process is not interrupted, so that a plasticized molding compound 12 can be continuously injected into a molding tool 16. This makes it possible to create large-volume components with a homogeneous structure.

List of reference symbols

10

injection molding device

12

plasticized molding compound

14

sewer system

16

forming tool

18

first injection unit

20

second injection unit

22

plasticizing unit

24

Housing

26

injection piston

28

connection nozzle

30

extruder housing

32

extruder screw

33

connecting channel

34

channel block

36

first channel

38

second channel

40

filling channel

42

injection channel

44

nozzle holder

45

nozzle body

46

first valve means

47

nozzle channel

48

second valve means

50

third valve means

52

fourth valve means

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0657268 A2 [0003]
• DE 102014002728 B3 [0003]
• DE 102014207591 B4 [0003]
• DE 102015012747 A1 [0003]
• US 4052497 A [0004]
• US 5922363 A [0005]
• US 4789318 A [0006]
• DE 2159383 A [0007]
• DE 3632185 A1 [0008]
• DE 102013015800 A1 [0008]

Claims (7)

Channel system (14) for continuously injecting a plasticized molding compound (12) into a molding tool (16) by means of an injection molding device (10) with at least two injection units (18, 20) and at least one plasticizing unit (22), having a first channel (36) which can be connected to a first injection unit (18), a second channel (38) which can be connected to a second injection unit (20), an injection channel (42) for injecting a plasticized molding compound (12) into a molding tool (16), which is connected to the first channel (36) and the second channel (38), and a filling channel (40) which is connected to the first channel (36) and the second channel (38) and can be connected to a plasticizing unit (22) in order to fill the first injection unit (18) with the plasticized molding compound (12) via the first channel (36). and to fill the second injection unit (20) with the plasticized molding compound via the second channel (38), and wherein valve means (46, 48, 50, 52) are provided for the controlled feeding of the plasticized molding compound (12) to the injection channel (42). sewer system according to Claim 1 , characterized in that a first valve means (46) is arranged between the first channel (36) and the filling channel (40), wherein a second valve means (48) is arranged between the second channel (38) and the filling channel (40), wherein a third valve means (50) is arranged between the first channel (36) and the injection channel (42), and wherein a fourth valve means (52) is arranged between the second channel (38) and the injection channel (42). canal system (14) to Claim 1 or 2 , characterized in that the valve means (46, 48, 50, 52) are designed as controllable valves. canal system (14) to claim 3 , characterized in that the valves are designed as controllable needle valve nozzles. Channel system (14) according to one of the preceding claims, characterized by a channel block (34) in which the channels (36, 38, 40, 42) are introduced. Channel system (14) according to one of the preceding claims, characterized in that the injection channel (42) opens into a nozzle assembly (44). Injection molding device (10) for continuously injecting a plasticized molding compound (12) into a molding tool (16) with at least two injection units (18, 20), at least one plasticizing unit (22) and a channel system (14) according to one of the Claims 1 until 6 .

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