EP2205419A1

EP2205419A1 - Gate adapter and gate system for a gate adapter

Info

Publication number: EP2205419A1
Application number: EP08845109A
Authority: EP
Inventors: Joachim Scheffer
Original assignee: MHT Mold and Hotrunner Technology AG
Current assignee: MHT Mold and Hotrunner Technology AG
Priority date: 2007-11-03
Filing date: 2008-10-23
Publication date: 2010-07-14
Also published as: DE102007052597A1; WO2009056486A1; US20110293774A1

Abstract

The present invention relates to a gate distributor block, which can be replaced more easily and thus more rapidly and can additionally be produced with less material. In order to achieve this, according to the invention a gate adapter is proposed for receiving a molten molding compound and discharging the same to a gate distributor block (9), said gate adapter (7) having an inlet (10) for receiving the molten molding compound, a first and a second outlet for the controlled delivery of the molten molding compound, and a first and a second connection channel (18, 18'), which can be closed and each of which connects one outlet to the inlet (10).

Description

Angle adapter and sprue system for a sprue adapter

The present invention relates to a gate adapter, a gate distributor block for connection to a gate adapter, and a system consisting of gate adapter and gate distributor block.

In plastic injection molding a plastic is plasticized and the melt is introduced into a shaping cavity and cooled there under pressure. The cured molding is then ejected from the tool.

Plasticization of the plastic generally takes place with the aid of a screw, which delivers the molten molding compound via a nozzle. In particular, in the production of large moldings, z. As bumpers for the automotive industry, the mold cavity is filled via a plurality of inlets with the molten molding material.

However, since the plasticizing screw discharges the plasticized plastic only via a nozzle, a distributor system is generally provided which transports the molten molding material to the individual inlets of the tool cavity.

The distribution system is also referred to as a runner system. The runner system has a receptacle for the molten molding compound and a series of gates connecting the runner system to the mold cavity or sprue.

The gate system influences the injection process and is therefore crucial for the quality of the molded part to be produced.

When dimensioning the gate system, therefore, not only the molding compound to be processed but also the external shape of the molding must be taken into account.

Sprue systems are often heated and are then alternatively referred to as a hot runner or hot runner system.

In particular, in the injection molding of large moldings over a whole series of gates, weld lines can possibly arise if several in the tool during the filling process Flow fronts meet each other. Such weld lines deteriorate the surface quality and the strength properties of the finished molding.

In order to avoid weld lines, it is already common to inject sequentially. During sequential injection molding, also called cascade injection molding, the cavity is initially filled only via a gate during the filling process. As soon as the melt front flows over another gate, it is also opened, so that additional melt is injected directly into the already existing melt stream via the additional gate. By this measure, it is possible to produce large moldings thin-walled, since due to the large number of gates, the filling pressure over the entire cavity can be well distributed without that during the filling already cooled flow fronts abut each other and form unwanted weld lines.

However, cascade injection molding has the disadvantage that each gate must have its own independently controllable sealing nozzle in order to be able to open and close the respective gates independently of each other.

By way of example, FIGS. 1 and 2 show a typical hot runner in a perspective view (FIG. 1) and in a sectional view (FIG. 2). The hot runner 1 has an inlet 2 for receiving the melt material. The inlet, the so-called sprue bushing 2, is connected to a distribution channel 3 extending substantially perpendicular to the sprue bushing 2, from which in turn a whole series of connecting channels 4 arranged parallel to one another extend. The sprue bush 2 facing away from the end of the connecting channels 4 is the so-called gate. Here is the junction between hot runner 1 on the one hand and Werkzeugkavität (not shown) on the other. The mutually parallel connecting channels 4 are each individually via needle valves 5 driven.

However, the known hot runners are very expensive to manufacture. The needle valves 5 also take up a lot of space, which increases the dimensions of the injection molding machine.

It may happen that other moldings are to be produced with the same injection molding machine. For this purpose, it is necessary to exchange the actual injection mold, which contains the Werkzeugkavität. In addition, however, the hot runner must be replaced, as generally the gates are positioned differently in a different sized shaping. To replace the hot runner, it is therefore necessary to disconnect the drive connections (electrical and / or hydraulic) of the individual closing valves and decouple the entire hot runner at the sprue bushing. The old hot runner can not be easily used again. Instead, now a new hot runner, which again has a plurality of closing valves for controlling the gates, must be made and connected to the connector socket. In addition, each closing valve must be connected to its corresponding control.

Based on this state of the art, it is therefore an object of the present invention to provide a sprue distributor block which can be exchanged more easily and thus more quickly and moreover can be produced with less use of material.

This object is achieved by a sprue distributor block with a sprue adapter.

The sprue adapter serves to receive a molten molding compound and deliver it to a sprue distributor block. According to the invention, the gate adapter has an inlet for receiving the molten molding compound, a first and a second outlet for the controlled release of the molten molding compound and a first and a second closable connecting channel, each connecting an outlet to the inlet. Accordingly, the runner manifold has two inlets for connection to the outlets of the runner adapter and at least two runners for connection to a mold cavity, each run being connected via manifold channels to at least one inlet of the runner manifold block.

In other words, the gate distribution system according to the invention consists of a gate adapter containing the closing elements and a gate distributor block which essentially has only distribution channels which ensure that the liquid melt is supplied from the inlet to the correspondingly arranged gate.

In the event that another molding is to be made, then only the sprue distributor block must be replaced, but not the sprue adapter. When making a new runner manifold, it is then only necessary to ensure that the inlets of the runner manifold block are arranged so that they can be connected to the outlets of the runner adapter.

By means of the measure according to the invention, the closing elements can continue to be used, even if the shape of the molded article changes and, therefore, the position of the sections must be changed.

In principle, it is therefore possible that the sprue adapter, which has only one inlet for receiving the molten molding material, usually directly from the extruder screw, this melt splits stream into a plurality of melt streams, even if a smaller number of melt streams is needed. The sprue adapter is thus universally applicable.

The runner manifold then has a number of inlets, the number of which does not necessarily have to match the number of outlets of the runner adapter. Depending on the application, it may be advantageous if the sprue distributor block uses only a portion of the outlets of the sprue adapter and simply seals the other outlets. In principle, it is also possible to simply leave the unneeded outlets open and close them with the corresponding closing elements of the sprue adapter. In addition, it is also possible to construct the sprue distributor block in such a way that it connects two inlets and thus two outlets of the sprue adapter with one and the same gate. By this measure, a larger amount of molding material can be transported to the relevant gate.

It may also be advantageous for some applications if the closing elements can also partially (or steplessly) close or open, so that the melt quantity and / or the melt pressure can be influenced via the closing elements. In principle, a targeted control of the melt stream is possible by this measure.

In contrast to the prior art casting systems which both divide and distribute the melt, it is thus proposed according to the invention to separate the individual functions of the pouring manifold system so that the runner adapter for the separation of a melt in a plurality of melts, respectively can be controlled by means of a closure element, is responsible, while the sprue distributor block only for the distribution of the melt, d. H. the supply of the melt streams is responsible for the individual gate points. The runner adapter is thus a branching element with flow control through the individual

Branches, while the sprue distributor block is a distributor element.

In a preferred embodiment, it is provided that the connecting channels of the sprue adapter can be closed separately, without affecting the flow through other connecting channels. In other words, the connecting channels are connected in parallel, so that the closing of a connecting channel merely causes no melt to be dispensed at the respective outlet.

In principle, it may also be advantageous for some applications when connecting channels are connected in series, with the result that the closure of a Verbmdungskanals closes several outlets. This can be useful, in particular, in the case of the cascade injection molding mentioned at the outset, since individual sections are often always opened in addition to already opened sections. In other words, a first connection channel connects an inlet the sprue adapter with an outlet and a second connecting channel connects the first outlet to a second outlet. Since both connecting channels are closable, both outlets can be closed by the closing element associated with the first connecting channel. If the closing element associated with the first connecting channel is opened, the closing element assigned to the second connecting channel determines whether only the first outlet or both outlets are open.

Closure elements are preferably closure valves, more preferably needle valves are used.

Although the invention will be described below with reference to a sprue adapter having two outlets and to a gate manifold block having two gates, it should be understood, of course, that more than two outlets may be provided. To replace the hot runner of the prior art shown in Figs. 1 and 2 with the sprue system of the present invention, the runner adapter would have to have at least eight outlets.

In a preferred embodiment, the gate adapter is substantially plate-shaped with a first side surface, a second side surface, and a peripheral edge surface connecting the first side surface to the second side surface. In this case, preferably, the inlet is arranged on the first side surface and the outlets on the second side surface. It is also possible, for example, that at least some closing elements are arranged on the peripheral edge surfaces.

In a particularly preferred embodiment, at least two, preferably all, outlets of the sprue adapter are arranged in a contiguous terminal area, the area of which is preferably less than 200 cm ² , more preferably less than 150 cm ^2, and most preferably less than 100 cm ² . The outlets are arranged on a small area as possible, so that the Anzuschließende sprue distributor block can also arrange its inlets on the smallest possible area, whereby material and thus heating power is saved. Advantageously, in this case, the gate distributor block has a contiguous connection area of approximately the same size, in which at least two, preferably all, inlets are arranged.

If multiple gate adapters are provided, melts of different materials may also be used together in an injection molding operation (e.g., coinjection).

For some applications, it may be advantageous if the sprue adapter additionally has an extension sleeve with at least two essentially parallel channels which connect the one end-side end to the other front end of the extension sleeve. the. The extension sleeve preferably has just as much parallel channels as the sprue adapter has outlets. The extension sleeve is then connected to the outlets of the runner adapter, with the opposite end of the extension sleeve being provided for connection to the runner manifold block.

Usually, the gate system is attached to a machine plate of the injection molding machine. By the embodiment with extension sleeve now the sprue distributor block and the sprue adapter can be arranged on opposite sides of the machine plate, so that the extension sleeve extends through the machine plate, so that on the mold side facing the mold on which the sprue distributor block is, height can be saved.

For many applications, it may also be advantageous if the sprue adapter has a heating element. With the help of the heating element, the sprue adapter and thus all connecting channels formed in it can be brought to a predetermined temperature.

With regard to the sprue distributor block, it is provided in a preferred embodiment that it has no closure elements. According to the invention, as far as possible all closure elements should be arranged in the sprue adapter, since these can then be used further when replacing a sprue distributor block.

In the region of the gate, a nozzle may be provided. In principle, it is advantageous if at least two distribution channels are arranged in the same component, so that, when a heating element is provided, it can be ensured that the at least two distribution channels are kept essentially at the same temperature.

It should be noted, however, that in principle the sprue adapter and the sprue distributor block could also be designed so that they perform melting of different materials, which may mean depending on the application that some distribution channels must be kept at different temperatures. For example, if two different melts are to be supplied to make a molding of two different materials, the gate adapter must have two inlets accordingly. According to the invention, the gate adapter is then designed such that it divides at least one of the two melts into two melt streams.

Of course, the system according to the invention can also be used for cold runners. Further advantages, features and applications of the present invention will become apparent from the following description of a preferred embodiment and the accompanying figures. Show it:

Figure 1 is a perspective view of a hot runner of the prior art,

FIG. 2 is a sectional view of the prior art hot runner of FIG. 1;

FIG. 3 shows a perspective view of a particularly preferred embodiment of the sprue system according to the invention,

FIG. 4 shows a sectional view through the sprue adapter of the embodiment of FIG. 3,

Figure 5 is a sectional view through the gate manifold of the embodiment of Figure 3 and

Figure 6 is a sectional view of the gate system of Figure 3, installed in the injection molding machine state

Figures 1 and 2 show a hot runner of the prior art and have already been described.

Figure 3 shows a perspective view of a gate system 6 according to the invention. The gate system 6 consists of a gate adapter 7 with extension sleeve 8 and gate manifold block 9. The gate adapter 7 has an inlet 10 for receiving the molten molding compound. The recorded molding compound is divided within the gate adapter into two streams, which can be individually opened or closed selectively by means of the needle valves 1 1. The two melt channels leave the sprue adapter 7 via the connection region 12 and are delivered to the sprue distributor block 9 within the extension sleeve 8 in mutually parallel channels. The two channels are distributed in the sprue distributor block 9 to the respective sections 13. In the region of the gates 13, a nozzle 14 is arranged in each case. It can be seen that both Angußadapter 7 and 9 Angußverteilerblock have heating coils 15 for temperature control of the channels. The flow curve of the melt can be better seen in the following sectional views of Figures 4 to 6.

Figure 4 shows a sectional view through the sprue adapter 7. The sprue adapter 7 has an inlet 10, which is also called sprue bushing. In the example shown, the sprue bush 10 is encased with a heating element 16. The inlet or sprue bush 10 has a channel 17 through which the molten molding compound from the screw (not shown) into the sprue adapter 7 flows. The channel 17 is divided into two different connection channels 18 and 18 '. The one connecting channel 18 can be closed by means of the one needle valve 11, which is shown on the left in FIG. 4, while the other connecting channel 18 'can be closed by the other needle valve 11. In the illustrated embodiment, a needle valve is disposed on an edge surface of the gate adapter while the other valve 11 is disposed on the top of the gate adapter 7. In principle, it would also be possible, for example, to attach both closing valves 11 to the edge surfaces. At the sprue adapter 7, the extension sleeve 8 connects, which is also covered with a heater 16. In the extension sleeve 8, the two connecting channels 18 and 18 'extend parallel to each other.

In the situation shown in FIG. 4, both connection channels 18 and 18 'are closed by the two closure needles 19 and 19' of the needle valves 11. For the filling process, either one or both of the needle valves 11 can now be selectively opened so that the melt flows through the feed channel 17 into the two connection channels 18 and 18 ', flows through the gate adapter, and exits at the end of the extension sleeve 8.

FIG. 5 shows a sectional view of the sprue distributor block 9. It can be seen that the sprue adapter 7 facing away from the end of the extension sleeve 8, which is also sheathed with a heating element 16. The connecting channels 18 and 18 'in the extension sleeve 8 are connected to the two inlets of the sprue 9. The inlets are connected via connection channels 20 and 20 'to the two nozzle-shaped sections 21 and 21'. The Angußverteilerblock 9 has no closing elements. The nozzle-shaped gates 21 are encased with a heating element 28. Finally, FIG. 6 shows a sectional view through the entire runner system in the installed state. The sprue bushing 10, the sprue adapter 7, the extension sleeve 8 and the sprue distributor block 9 can be seen. The sprue adapter 7 is accommodated in a hot runner plate 23, which is covered by a hot runner cover plate 22. In the same way, the gate distributor block 9 is accommodated in a hot runner plate 24, which is covered with a hot runner cover plate 25. Between the gate adapter 7 and the gate distribution block 9, a machine plate 26 is arranged, wherein the gate adapter 7 and 9 Angußverteilerblock are connected to each other via a bore in the machine plate 26 by means of the extension sleeve 8. To exactly position the extension sleeve 8 within the bore of the machine plate 26, it has a centering ring 27.

In addition, an anti-rotation device can be provided which prevents a relative rotation between Angu- ßadapter and extension sleeve and / or between extension sleeve and sprue distributor block. In order to fill the mold cavity without the formation of weld lines, for example, a needle valve 11 can now be actuated, for example, so that a melt feed channel starting from the inlet 10 (or the sprue bushing) is opened up to an inlet nozzle 13. Through this channel melt flows into the mold cavity. As soon as the tool cavity is filled with melt so far that the still closed gate is flowed around with melt, the further needle valve 1 1 is actuated, whereby also the other channel are opened and melt through the further gate into the already existing melt stream is injected.

By this measure, the Bindenahtbildung is prevented and at the same time ensures that forms a substantially constant melt pressure within the mold cavity.

When replacing the tool then, if the positioning of the gates changes, only the gate manifold block 9 must be replaced. By contrast, the sprue adapter 7, which contains all the control elements, can continue to be used.

In a further preferred embodiment, the electrical supply of the sprue distributor block can also take place via the sprue adapter or the extension sleeve 8. In this case, the gate adapter 7 would also have to provide a series of electrical control connections which the gate distributor block 9 can access. Basically, then the sprue distributor block is placed only on the sprue adapter 7 and the extension sleeve 8 arranged therebetween, without the need for additional electrical connections. The attachment system is ready for immediate use.

LIST OF REFERENCE NUMBERS

1 hot runner

2 inlet / sprue bush

3 distribution channel

4 connection channels

5 needle valves

6 sprue system

7 sprue adapter

8 extension sleeve

9 sprue distributor block

10 inlet / sprue bush

11 needle valve

12 connection area

13 gates / nozzle tip

14 nozzle

15 heating coils

16 heating element

17 channel

18 connection channels

19 locking pins

20 connection channels

21 gates

22 hot runner cover plate

23 hot runner plate

24 hot runner plate

25 hot runner cover plate

26 machine plate

27 centering ring

28 nozzle heater

Claims

Patent claims

1. Angußadapter for receiving a molten molding compound and its delivery to a gate distribution block (9), characterized in that the Angußadapter (7) a

Inlet (10) for receiving the molten molding compound, first and second outlet for controlled delivery of the molten molding compound, and first and second closable communication channels (18, 18 ') each connecting an outlet to the inlet (10), having.

A sprue adapter according to claim 1, characterized in that the two connection channels (18, 18 ') are arranged so that each is individually closable without affecting the flow through the other connection channel.

3. Angußadapter according to claim 1 or 2, characterized in that closure valves, preferably needle valves (1 1), for closing the connecting channels (18, 18 ') are provided.

4. Angußadapter according to one of claims 1 to 3, characterized in that at least three outlets and at least three the outlets to the inlet (10) connecting connecting channels (18, 18 ') are provided.

5. Angußadapter according to one of claims 1 to 4, characterized in that the sprue adapter is formed in a substantially plate-shaped with a first side surface, a second side surface and a peripheral edge surface.

6. Angußadapter according to claim 5, characterized in that the inlet (10) are arranged on the first side surface and the outlets on the second side surface.

7. Angußadapter according to claim 5 or 6, characterized in that at least two, preferably all the outlets are arranged in a contiguous connection area (12) whose area is smaller than 200 cm ² , preferably smaller than 150 cm ² and more preferably smaller than 100 cm ² is.

8. Angußadapter according to one of claims 1 to 7, characterized in that an extension sleeve (8) with at least two substantially parallel channels, which connect one end face with the other front end of the extension sleeve (8), is provided the extension sleeve (8) with the outlets of Adapters is connected, that a controlled delivery of the molten molding compound via the channels of the extension sleeve (8) is possible.

9. Angußadapter according to one of claims 1 to 8, characterized in that the sprue adapter (7) has a heating element (16).

A runner manifold block for connection to a runner adapter according to any one of claims 1 to 9, characterized in that at least the runner manifold (9) has two inlets for connection to outlets of the runner adapter (7) and at least two runners (13) for connection to a mold cavity wherein each gate (13) is connected via distributor channels to at least one inlet of the gate distributor block (9).

11. Angußverteilerblock according to claim 10, characterized in that the distribution channels have no closure elements.

12. sprue distributor block according to claim 10 or 1 1, characterized in that at least one gate (13) has a nozzle (14).

13. Angußverteilerblock according to any one of claims 10 to 12, characterized in that at least two distribution channels are arranged in the same component.

14. Angußverteilerblock according to any one of claims 10 to 13, characterized in that at least one heating element (15) is provided.

15. Angußverteilerblock according to claim 14, characterized in that the at least one heating element (16) is arranged such that at least two, preferably all distribution channels are maintained at substantially the same temperature.

16. gate distributor block according to one of claims 10 to 15, characterized in that at least two, preferably all the inlets are arranged in a contiguous terminal area (12) whose area is smaller than 200 cm ² , preferably smaller than 150 cm ² and more preferably of less than 100 cm ² .

17. runner system consisting of a sprue distributor block according to one of claims 10 to 16 and a sprue adapter according to one of claims 1 to 9.

18. runner system according to claim 17, characterized in that a plurality of sprue adapters are provided.

19. A sprue system according to claim 17 or 18, characterized in that the sprue distributor block is connected via an extension sleeve with the sprue adapter, wherein sprue distributor block and sprue adapter are arranged on opposite sides of a machine plate, so that the extension sleeve extends through the machine plate.