EP4208323A1

EP4208323A1 - Injection mould

Info

Publication number: EP4208323A1
Application number: EP21770152.3A
Authority: EP
Inventors: Christian Wagner; Peter Süß; Christian Tilsner
Original assignee: MHT Mold and Hotrunner Technology AG
Current assignee: MHT Mold and Hotrunner Technology AG
Priority date: 2020-09-02
Filing date: 2021-08-26
Publication date: 2023-07-12
Also published as: DE102020122968A1; WO2022048982A1; US20230271362A1

Abstract

The present invention relates to an injection mould for producing mouldings, having a cavity plate which has cavities, the inner contour of which corresponds at least to a portion of the outer contours of the mouldings to be produced, and a core plate which has cores, the outer contour of which corresponds at least to a portion of the inner contours of the mouldings to be produced, wherein the cavity plate and the core plate are movable back and forth relative to one another between a closed position, in which each core is respectively arranged in a cavity, and an open position, in which no core is arranged within a cavity, wherein, in the closed position, a moulding space for receiving a plasticized melt is formed by each cavity and the core arranged therein, wherein each moulding space is assigned a neck-ring pair made up of two neck rings, wherein the inner contour of the neck-ring pair corresponds to a portion of the outer contour of the moulding to be produced, wherein the neck-ring pair is arranged on the core plate and can be moved back and forth between a holding position, in which the two neck rings of the neck-ring pair are in contact with one another, and a releasing position, in which the two neck rings of the neck-ring pair are not in contact with one another. In order to provide an injection mould with which mouldings can be produced and provided for a further processing process as efficiently as possible, the invention proposes that the cores and the cavities are arranged on a curved path.

Description

injection mold

The present invention relates to an injection mold for producing a plurality of molded parts with a cavity plate, which has a plurality of cavities, the inner contour of which corresponds to at least one section of the outer contours of the molded parts to be produced, and a core plate, which has a plurality of cores, the outer contour of which corresponds to at least one Section corresponds to the inner contours of the molded parts to be produced, with the cavity plate and the core plate reciprocating relative to one another between a closed position, in which each core is arranged in a cavity, and an open position, in which no core is arranged within a cavity are movable, wherein in the closed position of each cavity and the core arranged therein, a mold space for receiving a plasticized melt is formed, each mold space being assigned a pair of neck jaws consisting of two neck jaws, the inner contour of the neck jaw pair corresponds to a section of the outer contour of the molded part to be produced, the pair of neck blocks being arranged on the core plate and between a holding position in which the two neck blocks of the pair of neck blocks are in contact with one another and a release position in which the two neck blocks of the pair of neck blocks are not in contact with one another stand, can be moved back and forth.

Injection molding is one of the most important processes for producing molded parts. In this process, the molding compound, which is generally originally in the form of powder or granules, is heated, plasticized and pressed into a corresponding mold under high pressure. The molding compound solidifies in the mold and is then removed from the opened mold as a molded part.

Molded parts are understood to mean, for example, containers or preforms that are further processed in further processing steps to form the desired object. An example of a preform is a hollow body preform for the production of PET bottles. The present invention is explained using the example of such a hollow body preform, but in principle it can also be used with other shaped parts.

Commercially available PET bottles are generally made by stretch blow molding a parison body. The hollow body preform is in a first step by means created by injection molding. The stretch blow molding that follows the injection molding process then takes place in a further production step. It is quite common that the locations for the individual manufacturing steps are spatially distinct. For example, the hollow body preform is produced at a first location, packaged and shipped to a second production location where stretch blow molding takes place.

In recent years, the trend has been towards processing the hollow body preforms in a production line from injection molding to the finished product. On the one hand, this saves time and transport costs, on the other hand, the processing of the preforms at the production site offers the further advantages of saving energy and space, since, for example, additional sorters or other machines for handling the preforms are no longer required. A further advantage is that the ability of the preform to be stretch-blown is improved, since it is still uniformly heated through by the preceding injection molding process and therefore only tempering of the preform is required, but no renewed heating is required. Even with aseptic applications, a production site offers the advantage that the probability of contamination is reduced. For this purpose, production lines are already known from the prior art which, in addition to the actual injection mold, also have devices for further processing such as coating or stretch blow molding of the hollow body preforms.

The problem at this point, however, is transporting the preforms from one machine section to the next machine section. If, for example, the preforms produced with the injection molding tool are discharged unsorted onto a conveyor belt, the preforms produced have to be aligned again in the next production step. This in turn costs additional time, which should be kept as short as possible, especially when producing several thousand preforms within a very short time.

The object of the present invention is therefore to provide an injection mold with which molded parts can be produced as efficiently as possible and made available for a further processing step.

This object is achieved by an injection mold for producing a plurality of molded parts with a cavity plate, which has a plurality of cavities, the inner contour of which corresponds to at least one section of the outer contours of the molded parts to be produced, a core plate, which has a plurality of cores, the outer contour of which corresponds to at least one Section corresponds to the inner contours of the molded parts to be produced, with the cavity plate and the core plate reciprocating relative to one another between a closed position, in which each core is arranged in a cavity, and an open position, in which no core is arranged within a cavity are moved forth, wherein in the closed position of a mold space for receiving a plasticized melt is formed in each cavity and the core arranged therein, with each mold space being assigned a pair of neck jaws consisting of two neck jaws, the inner contour of the pair of neck jaws corresponding to a section of the outer contour of the molded part to be produced, the pair of neck jaws being arranged on the core plate and can be moved back and forth between a holding position in which the two neck jaws of the pair of neck jaws are in contact with one another and a release position in which the two neck jaws of the pair of neck jaws are not in contact with one another, with the cores and the cavities on a curved Railway are arranged.

In a preferred embodiment, the injection mold according to the invention works according to the principle of a vertical mold known from the prior art. Vertical means that the core plate is arranged on a vertical axis above or below the cavity plate, so that when the cavity plate and/or the core plate are moved on the common axis, the cores that are arranged on the core plate dip into the cavities of the cavity plate , when the cavity plate and the core plate move towards each other.

In the closed position of the injection mold, a core of the core plate is then arranged in each cavity of the cavity plate. The core and cavity are designed in such a way that the core does not completely fill the cavity, but instead the so-called mold space forms between the cavity and the core, which is filled with a plasticized melt and determines the shape of the molded part.

Pairs of neck blocks are typically used to form a thread on a molded part. In order to demould the molded part after injection molding has taken place, it is necessary to remove the molded part from the mold space, for example by moving the mold core out of the cavity and the pairs of neck jaws strip the molded part from the mold core before the pairs of neck jaws move apart into a release position, and the molded part becomes free.

In order to remove the molded parts from the injection mold, one embodiment provides that the core plate can be pivoted about a pivot axis in the open position.

In a further embodiment, a removal device is provided which is movable in the open position between the core plate and the cavity plate and is intended to remove a plurality of molded parts produced from the cores or the cavities.

In the open position, there is no core within a cavity, allowing an extraction device to be moved between the core plate and the cavity plate. This removal device can be positioned, for example, below the core plate and with remove the molded parts produced by the injection mold that are still attached to the cores and feed them to a further processing step or to a transport device. Alternatively, the molded parts produced that are still in the cavities could also be sucked in by the removal device.

According to this embodiment, it is therefore provided that the core plate and the cavity plate can be moved apart at least far enough for a removal device to be guided between the core plate and the cavity plate.

The arrangement of the cores and cavities on a curved path also offers the advantage that the removal device can be arranged at a central position in the injection mold and thus all cores or cavities for removal of the molded parts can be reached within a short time. In one embodiment, the removal device is designed in such a way that several molded parts can be removed simultaneously with the removal device.

According to the invention, it is not necessary to move the core or cavity plates beyond the movement between the closed and open position, since the removal device transfers the molded parts from the injection mold to further process devices. This offers the advantage that the injection molding tool can be designed to be stationary, as a result of which, for example, the supply of the plasticized melt is significantly simplified since the supply lines do not have to be moved. This makes it easier to seal the hot runner, there are fewer leaks and the hot runner is less complex to manufacture because no rotary union is required.

In a further embodiment, two slide elements are provided, which are arranged and configured in such a way that one neck jaw of the pair of neck jaws interacts with one slide element, while the other neck jaw of the pair of neck jaws interacts with the other slide element, so that when the injection mold is moved from the closed position to the open position by movement of the slider members moving the neck cheeks from their connected position to the release position.

It is possible for a slide element to actuate the neck blocks of several adjacent pairs of neck blocks, for example, at the same time, so that several neck blocks are moved at the same time by the movement of a slide element.

In a further embodiment, it is also conceivable for each mold space to be assigned two individual slide elements which only move the pair of neck blocks of the respective mold space. In this way, a demolding process can be carried out individually for each mold cavity. In a further embodiment, the slide elements are integrated in the pairs of neck blocks, ie the pairs of neck blocks themselves have a corresponding possibility of moving the neck blocks relative to one another.

In a further embodiment it is provided that the cores and the cavities are arranged on an arc of a circle, with the slide elements preferably being in the shape of an arc of a circle. This offers the advantage that a removal device that is arranged in the center of such a circular arc can reach all molded parts that have been produced in a pair of cavity and core equally quickly. For example, only a rotary movement of the removal device is necessary. An individual approach to each core-cavity pair is therefore not necessary, which saves time. In a further embodiment, the pivot axis of the core plate can also be arranged in the center point of the circular arc.

The movement axis of the slide elements corresponds to a radial direction of the circular arc. This offers the advantage that the slide elements do not impede each other's movement when they are moved from the connected position to the release position.

In a further embodiment, the cores and the cavities are arranged on a circular arc with a central angle, the central angle being <180° and preferably <120°. This ensures that movement of the slide elements is not impeded by adjacent pairs of cavities and cores. In addition, the injection mold thus offers a side on which no cores or cavities are arranged, so that the molded parts produced can be removed particularly easily here if the removal device is arranged in a center point of the circular arc or the core plate is arranged so that it can pivot about a central pivot axis in the center point of the circular arc is.

In a further embodiment, the cores and the cavities are arranged on two concentric circular arcs with different radius. This offers the advantage that more mold cavities can be made available on the same area, so that more molded parts can be produced in one injection molding process.

In a further embodiment, in this case a removal device is designed and set up in such a way that the removal device can remove molded parts from cavities or cores on the outer arc of a circle as well as from cavities or cores on the inner arc of a circle. This is done by adapting the removal device to the radius of the respective circular arc. In particular, when the removal device has a plurality of individual removal elements, each removal element removes a molded part, the radius of the Removal device can be changed, for example, by either individual or all extraction elements are movably arranged and thus can be arranged on circular arcs with the same radii as the circular arcs on which the cores or cavities are arranged. For example, every second extraction element can be extended in such a way that it can be moved from the inner arc to the outer arc, or the arc length of an arc on which the extraction elements are arranged can be adapted to the radius of the concentric arcs by means of movable extraction elements.

In a particularly preferred embodiment, the adjustment movement of the removal elements is initiated automatically by the movement of the removal device between the cavity plate and the core plate. If the removal device is moved away from the space between the cavity plate and the core plate, the removal elements can be automatically moved back to a specific initial radius.

This offers the advantage that the molded parts can be removed from both concentric circular arcs with the same removal device.

In a further embodiment, ends of the cavities or cores which are arranged together on an outer arc of the concentric arcs span a first plane, with ends of the cavities or cores which are arranged together on an inner arc of the concentric arcs spanning a second plane span, wherein the first and the second plane are arranged parallel and at a distance from each other. This means that the cavities or cores are arranged at different heights on the two different circular arcs. For example, the cavities or cores on the inner circular arc can be arranged lower than those on the outer circular arc.

Such a configuration offers the advantage that the slide elements, which are also arranged on the respective circular arcs, do not impede each other in their movement, but rather a slide element of the core-cavity pairs on the inner circular arc via a slide element of the core-cavity pairs can be moved on the outer arc or vice versa.

In a further embodiment, a hot runner is provided which has an inlet for receiving a plasticized melt and a plurality of outlets for delivering the plasticized melt to the cavities, the hot runner being arranged in such a way that the inlet is arranged in a center point of the circular arc, each Cavity is associated with a hot runner section, which extends from a port provided in the cavity to the entrance, wherein preferably all hot runner sections are straight and of equal length. This arrangement can be implemented particularly easily with cavities or cores arranged on a circular arc by arranging the inlet of the hot runner in the center point of the circular arc. This ensures that the distance from the hot runner entrance to the individual cavities is the same everywhere. In this case, few or no deflections and also no crossings or arrangements on different levels in the hot runner are necessary, the pressure loss in the hot runner is lower and less volume has to be guided in the hot runner. Furthermore, tubular heaters for tempering the hot runner can be arranged around the hot runner in such a way that the tubular heaters do not cross one another or with the hot runner sections, so that a very homogeneous temperature distribution in the hot runner is ensured. This means that the plasticized melt also has the same temperature in each mold space, since the same distance has to be covered to each mold space and therefore identical cooling takes place. This in turn leads to greater homogeneity within the molded parts produced, which are produced in an injection molding process.

In a further embodiment, the pairs of cavity and associated core form two groups, the inner contour of the cavity and/or the outer contour of the core of one group differing from the inner contour of the cavity and/or the outer contour of the core of the other group. Molded parts with different contours can be produced in one injection molding process.

In a further embodiment of the injection molding tool according to the invention, a transfer chain with gripping elements is provided for holding a molded part that has been produced. The core plate is designed in such a way that the molded parts produced can be transferred from the cores to the gripping elements with the core plate in the open position, or the removal device is designed in such a way that the molded parts produced can be transferred from the cores or out with the removal device in the open position can be removed from the cavities and transferred to the gripping elements.

This offers the advantage that the molded parts produced do not fall in a random order onto a conveyor belt, for example, but are held in a defined position by the gripping elements. This eliminates the need to re-sort the molded parts produced before the next processing step, so that time can be saved.

In the case of an injection mold with cavities and cores that are arranged on two concentric circular arcs, the transfer chain can also be designed in two rows, so that molded parts from one circular arc are transferred to the first row of the transfer chain and molded parts from the other circular arc to the second row of the transfer chain. When the circular arcs are arranged on parallel, spaced apart planes, the rows of the transfer chain can in particular also be arranged on different planes or the rows of the transfer chain are arranged on one plane and the difference in height of the mold parts removed due to the different planes of the circular arcs is compensated for by the removal device.

In a further embodiment, the transfer chain has at least one transfer chain section in which the gripping elements are arranged in a straight line and the molded parts produced can be transferred to the gripping elements within this transfer chain section using the removal device.

By using a separate removal device that moves between the cavity and core plates and the transfer chain, movement of the cavity and core plates beyond movement between the closed and open positions is not required to convey the formed parts to the transfer chain .

But even if the core plate is pivotably arranged in order to transfer the mold parts to the transfer chain, no movement of the injection mold is provided during the actual injection molding process, i.e. when the pairs of cavities and cores are arranged in the closed position. In one embodiment, therefore, all mold cavities of the injection mold are filled simultaneously with the plasticized melt, while the injection mold is not moving.

In a further embodiment, a further processing element is provided, with the removal device transferring the molded parts removed from the injection mold to the further processing element, and with the further processing element transferring the molded parts to the transfer chain. In this embodiment, for example, the molded parts in the further processing element can first cool down further before they are fed to further processing steps. Furthermore, it is conceivable that the molded parts produced in the further processing element are tempered, coated, formed, sterilized, printed, pressurized, irradiated, filled, sealed, labeled, measured, checked for quality, cleaned, chemically treated, packed, weighed, realigned, sorted, sorted out or (temporarily) stored. In addition, the molded parts produced can also be supplemented with a different plastic in a further injection molding process if, for example, molded parts are to be manufactured with different plastics. In a further embodiment, the cores and the cavities are arranged on a circular arc, the removal device being designed in the shape of a circular arc and being moved between the cavity plate and the core plate by a rotary movement, preferably about a center point of the circular arc. The rotary movement also offers the advantage that the molded parts can be transferred to a section of a transfer chain on which the gripping elements are arranged in a line.

In order for the removal device to be able to perform a rotary movement, it must be ensured that the space between the cavity plate and the core plate is free and is not limited in places, for example by spars. Such bars, which extend between the cavity plate and the core plate, are often used in vertical tools in order to increase the positioning accuracy of the cores in relation to the cavities and thus to minimize wear on the tool parts due to friction. However, the tie bars would impede a rotary movement of the removal device, so that in a preferred embodiment of the injection molding tool according to the invention it is a tie bar-less tool or, overall, a tie-bar-less injection molding machine.

In a further embodiment, the core plate and the cavity plate are designed to be movable relative to one another in such a way that the core plate is also moved in the cavity during the injection molding process, so that, for example, very thin-walled molded parts, in particular thin-walled containers, can be produced and material costs can thus be saved. The general principle of this injection molding of thin-walled molded parts is described in EP 2 483 050 B1.

In addition, the problem on which the invention is based is solved by an injection molding system with at least one injection mold according to one of the embodiments described above and an extruder, the extruder being connected to the injection mold via a melt channel, so that when the injection molding system is in operation, the plasticized melt is extruder is fed into the injection mold.

In one embodiment, the mold space is arranged stationary relative to the extruder when the cavity plate and the core plate are in the closed position. This offers the advantage already described that no connection has to be created between a moving component, for example the mold space, and the hot runner in order to guide the plasticized melt into the mold space. Such connections are complex to manufacture and also prone to leaks. These disadvantages can be avoided by arranging the mold space in the closed position in a stationary manner opposite the extruder, so that the injection mold does not move during the injection molding process, in which all mold spaces are preferably filled at the same time. In a further embodiment, the injection molding system has at least two injection molds and injection cylinders assigned to the at least two injection molds, the at least two injection molds being connected to the injection cylinder via a melt channel, the injection cylinders being connected to the extruder via at least one further melt channel, wherein in a Operation of the injection molding system, the injection cylinders are alternately supplied with the plasticized melt from the extruder, so that either one of the at least two injection molds is in the closed position and the other injection mold of the at least two injection molds is in the open position, or vice versa.

It goes without saying that more than two injection molds can also be combined in one system. Feeding two or more injection molds with one extruder offers the advantage that the extruder can continuously produce plasticized melt. If, on the other hand, only one injection mold is filled, the extrusion has to be stopped again and again until the injection molding process in the mold is complete and can start again. If two or more injection molding tools are available, one tool can be charged with plasticized melt while the other tool is already filled and the injection molding process is complete.

Further advantages, features and application possibilities become clear from the following description of preferred embodiments and the associated figures. Identical components are provided with the same reference symbols.

FIG. 1 shows a schematic representation of an embodiment of the injection molding tool according to the invention in a plan view.

FIG. 2 shows a schematic representation of a cross section of a section of the injection molding tool according to the invention at different times of the demoulding process.

FIG. 3 shows a schematic representation of an embodiment of the injection molding tool according to the invention with separate slide elements.

FIG. 4 shows a schematic representation of the hot runner of an embodiment of the injection molding tool according to the invention. FIG. 5 shows the schematic illustration from FIG. 4 with additional tubular heating elements which are arranged around the hot runner.

FIG. 6 shows a schematic representation of an embodiment of the injection molding tool according to the invention, the cores or cavities being arranged on two concentric circular paths.

FIG. 7 shows a schematic representation of a cross section of an embodiment of the injection molding tool according to the invention.

FIG. 8 shows a schematic representation of an embodiment of the injection molding tool according to the invention with a further processing element.

FIG. 9 shows a schematic representation of an embodiment of the injection molding system according to the invention at a first point in time in the method.

FIG. 10 shows the injection molding system from FIG. 8 at a second point in time in the method.

FIG. 11 shows the injection molding system from FIG. 8 at a third point in time in the method.

The injection mold according to the invention, which is shown in a top view in FIG. 1, has a cavity plate 2 with a plurality of cavities 3 and a core plate 4 with a plurality of cores 5 . As can be seen from the cross section of a tool section in Figure 2, the cavities 3 of the cavity plate 2 are supplied with plasticized melt via a hot runner 9 in order to produce a plurality of preforms 1 when the cores 5 are in the closed position of the tool in the cavities 3 are arranged (Fig. 2 left).

The injection mold is shown in an open position on the right in FIG. 2, i.e. no core 5 is arranged within a cavity 3 . If, on the other hand, the cavity plate 2 or the core plate 4 is moved into a closed position relative to the other plate in each case, a core 5 is arranged in each cavity 3, so that a mold space for receiving the plasticized melt is formed (Figure 2 left).

According to the embodiment shown in FIG. 1, the cores 5 and the cavities 3 are arranged on a circular path 6 . A removal device 14 is designed in the shape of a circular arc and can be moved between the two plates 2, 4 by a rotary movement when the core plate 4 and the cavity plate 2 are in the open position in order to remove the preforms 1 produced from the cores 5 or the cavities 3. When this is done, the extraction device 14 gives the Preforms 1 to a transfer chain 12 on. The transfer chain 12 transports the preforms produced to a subsequent machine section in which the preforms 1 are processed further.

For this purpose, the transfer chain 12 has gripping elements with which the preforms 1 produced are held. As a result, it is not necessary to sort the preforms 1 produced in the subsequent processing step, rather the preforms 1 are passed on directly to the subsequent processing step in the correct orientation.

The transfer chain 12 also has a transfer chain section in which the gripping elements are arranged in a straight line, as can be seen from the figures. In the embodiments shown in FIGS. 1 to 5, the removal device 14 transfers the manufactured preforms 1 to the gripping elements within this transfer chain section.

The injection mold according to the embodiments shown also has pairs of neck jaws 15, 16, which are associated with each pair of core 5 and cavity 3 and are arranged on the core plate 4 and whose inner contour has an internal thread, the inner contour corresponding to a section of the outer contour of the preform 1 to be produced .

The pair of neck blocks 15, 16 is positioned between a holding position, in which the two neck blocks 15, 16 of the pair of neck blocks are in contact with one another, and a release position in which the two neck blocks 15, 16 of the pair of neck blocks are not in contact with one another, with the aid of slide elements 7, 8 stand, move back and forth. In the two illustrations on the left of FIG. 2, the slide elements 7, 8 and the pairs of neck jaws 15, 16 are in the holding position. In the second image from the right in FIG. 2, on the other hand, the slide elements 7, 8 perform a movement which displaces the pairs of neck blocks 15, 16 from the holding position and the release position, which is shown in the right-hand image in FIG.

The injection molding process thus proceeds in such a way that initially the core 5 is completely arranged in the cavity 3 and a plasticized melt is filled into the mold space. As soon as the plasticized melt begins to solidify, the core plate 4 is moved away from the cavity plate 2, the preform initially still being held on the mold core 5 by the pair of neck jaws 15, 16. When the mold core 5 has been guided out of the cavity 3, the slide elements 7, 8 perform a movement which moves the pairs of neck jaws 15, 16 from the holding position to the release position, so that the preform 1 can be removed.

The slide elements 7, 8 are designed in such a way that a slide element 7 interacts with a neck block 15 of a pair of neck blocks, while the other neck block 16 of the Pair of neck cheeks interacts with the other slide element 8 . According to the embodiments shown in Figures 1 and 4 to 6, a slide element 7 moves several neck blocks 15, 16 of different pairs of neck blocks, so that with one movement of the slide elements 7, 8 several pairs of neck blocks are moved from their holding position to the release position or vice versa.

In contrast to this, FIG. 3 shows an embodiment in which individual slide elements 7, 8 are assigned to each pair of core 5 and cavity 3 or the mold space formed therefrom. Each slide element 7 , 8 thus causes only one movement of a single neck block 15 , 16 , so that the pairs of neck blocks are opened independently of the adjacent pairs of core 5 and cavity 3 .

During the opening movement, the slide elements 7, 8 are moved in the radial direction to the circular path 6, with the slide elements 7, 8 being designed in such a way that they do not impede each other's movement. For this purpose, the slide elements 7, 8 are designed in the shape of a circular arc.

In addition, the cores 5 and the cavities 3 are arranged on a circular arc 6 in such a way that a central angle of the circular arc 6 is less than 180°. This primarily ensures that a pair of core 5 and cavity 3 does not impede the opening movement of the slide elements 7, 8 when the movement of the slide element, as shown for example in FIG.

FIG. 4 shows how the cavities 3 are connected to the hot runner 9 in order to direct a plasticized melt into the mold cavities when the injection mold is in its closed position.

For this purpose, the hot runner 9 has an inlet 10 for receiving the plasticized melt and several outlets 11 for delivering the plasticized melt to the cavities 3, with the hot runner 9 being designed in such a way that each cavity 3 is assigned a hot runner section 9'. In addition, the inlet 10 of the hot runner is arranged in the center of the circular arc 6 .

The hot runner section 9' extends from the inlet 10 of the hot runner 9 to a port provided in the cavity 3 for the entry of the plasticized melt. Due to the arrangement of the inlet 10 of the hot runner 9 in the center of the circular arc 6, all the hot runner sections 9' are of the same length. This has the advantage that the plasticized melt when entering the cavities 3 at every cavity is exposed to the same environmental influences. This in turn leads to greater homogeneity of preforms 1 produced within an injection molding process.

FIG. 5 also shows how tubular heating elements 17 are arranged around the hot runner 9 in order to keep the temperature in the hot runner 9 homogeneous. The configuration of the hot runner 9 according to the invention offers the advantage that the tubular heating elements 17 can be arranged in a serpentine manner around the hot runner sections 9', which means that the tubular heating elements do not cross one another or with the hot runner sections 9', so that a very homogeneous temperature distribution in the hot runner 9 is ensured

FIG. 6 shows a further embodiment of the injection molding tool according to the invention, with the cores 5 and the cavities 3 being arranged on one plane on two concentric circular arcs 6, 6' with different radii.

An additional slide element 8' is provided, which moves both the pairs of neck jaws of the pairs of cores 5 and cavities 3, which are arranged on the outer circular path 6, and the pairs of neck jaws of the pairs of cavities 3 and cores 5, which are on the inner circular path 6' are arranged.

In order to demold the preforms 1 that have been produced, in one embodiment the slide elements 8' and 8' are first removed from the slide element 7 so that the preforms 1 can be demolded on the outer circular path 6, and then the slide elements 7 and 8' are removed from the slide element 8 , so that the preforms 1 produced can be removed from the mold on the inner circular path 6'. The process of removing the preforms 1 from the mold on the outer circular arc 6 therefore takes place at a later time than the process of removing the preforms 1 from the mold on the inner circular arc 6'.

The removed preforms 1 are forwarded to a transfer chain 12 with the aid of the removal device 14 in this embodiment as well. In the embodiment shown in FIG. 6, however, the transfer chain 12 consists of two parallel tracks, on each of which gripping elements for receiving the preforms 1 are arranged. The preforms 1 of the outer circular path 6 are arranged on a different path of the transfer chain 12 than the preforms 1 of the inner circular path 6'.

Alternatively, as shown in Figure 7, the slide elements 7, 8 of the concentric circular arcs 6, 6' can also be arranged on different levels, so that both the cavities 3 and cores 5 on the inner circular path 6' and the cavities 3 and cores 5 pairs of slide elements 7, 8, 7', 8' are assigned to the outer circular path 6 and demoulding of the preforms 1 can take place simultaneously in that a slide element 7, 8, which is assigned to the outer circular path 6, can be moved over a slide element 7', 8', which is assigned to the inner circular path 6'.

In addition, for example, the inner contours of the cavities 3 and/or the outer contours of the cores 5 on the inner circular track 6' can be designed differently than on the outer circular track 6, so that in the closed position a different mold space is formed and preforms 1 have a different exterior - and inner contour are produced. However, it would also be conceivable for the preforms that are produced in the upper right quadrant of the injection mold to have a different outer contour than preforms 1 that are produced in the upper left quadrant of the injection mold. In both embodiments, different preforms 1 are produced in one injection molding process.

FIG. 8 shows a further embodiment of the injection mold according to the invention, the injection mold essentially corresponding to the injection mold shown in FIG the preforms 1 produced are, for example, further cooled or post-treated in some other way. The further processing element 13 then transfers the further processed preforms 13 to the transfer chain 12.

An embodiment of an injection molding system according to the invention with two injection molds, an extruder 18 and two injection cylinders 19, 20 assigned to the injection molds is shown in FIGS.

The extruder 18 is connected to the injection cylinders 19, 20 via melt channels 21. The connection is designed by valves 22 in such a way that either one injection cylinder 19, 20 is supplied with plasticized melt or the other injection cylinder 20, 19.

FIG. 9 shows the case in which the injection cylinder 19 of the left of the two injection molds is being filled with plasticized melt while the preforms 1 produced in the injection mold are transferred to the transfer chain 12 using the removal device 14 . The left-hand injection molding tool is therefore in the open position at the point in time illustrated in FIG. The right one of the two injection molding tools, on the other hand, is in the closed position and is supplied with plasticized melt by the injection cylinder 20 . FIG. 10 then shows the process time at which the injection process in the right-hand injection mold is completed, ie the injection cylinder 20 is completely emptied. In addition, all preforms 1 produced have been transferred to the transfer chain 12 in the case of the left-hand injection mold.

FIG. 11 then shows the correspondingly inverse behavior to FIG. The injection cylinder 20 of the right-hand injection mold is filled, while the preforms produced in this mold are transferred to the transfer chain 12 with the aid of the removal device 14 of the right-hand injection mold. For this purpose, the right tool is found in its open position. At the same time, a new injection process takes place in the left injection mold, i.e. the left mold is in its closed position.

It can thus be made possible for plasticized melt to be extruded with the extruder 18 without interruption, so that more preforms 1 of higher quality can be produced within a shorter time.

Reference sign preform cavity plate cavity core plate core curved path/outer circular arc 'inner circular arc 8, 7', 8' slide elements hot runner 'hot runner section 0 inlet hot runner 1 outlet hot runner 2 transfer chain 3 further processing element 4 removal device 5.16 neck jaws 7 tubular heating element 8 extruder 9.20 injection cylinder 1 melt channel 2 valve

Claims

P a t e n t claims Injection mold for producing a plurality of molded parts (1) with a cavity plate

(2) showing a plurality of cavities

(3), the inner contour of which corresponds to at least a section of the outer contours of the molded parts (1) to be produced, and a core plate (4) which has a plurality of cores (5), the outer contour of which corresponds to at least a section of the inner contours of the molded parts (1 ) corresponds, wherein the cavity plate (2) and the core plate

(4) to and fro relative to each other between a closed position in which each core (5) is respectively arranged in a cavity (3) and an open position in which no core (5) is arranged within a cavity (3). in the closed position of each cavity (3) and the core (5) arranged therein, a mold space for receiving a plasticized melt is formed, each mold space being assigned a pair of neck jaws (15, 16), wherein the inner contour of the pair of neck blocks corresponds to a section of the outer contour of the molded part (1) to be produced, the pair of neck blocks being arranged on the core plate and between a holding position, in which the two neck blocks (15, 16) of the pair of neck blocks are in contact with one another, and a release position, in which the two neck blocks (15, 16) of the pair of neck blocks are not in contact with each other, can be moved back and forth, characterized in that that the cores

(5) and the cavities (3) on a curved path

(6) are arranged. Injection mold according to the preceding claim, characterized in that the core plate (4) can be pivoted about a pivot axis in the open position in order to remove the molded parts produced from the injection mold or that a removal device (14) is provided which, in the open position is movable between the core plate (4) and the cavity plate (2) and is provided for removing a plurality of molded parts (1) produced from the cores (5) or the cavities (3). Injection mold according to one of Claims 1 or 2, characterized in that two slide elements (7, 8) are provided, which are arranged and configured in such a way that one neck block (15, 16) of the pair of neck blocks is connected to one slide element

(7) cooperates, while the other neck block (16, 15) of the pair of neck blocks cooperates with the other pusher element (8) so that when the injection mold is moved from the closed position to the open Position by a movement of the slide elements (7.8), the neck blocks (15, 16) are moved from their holding position to the release position. Injection mold according to one of the preceding claims, characterized in that the cores (5) and the cavities (3) are arranged on a circular arc (6), the slide elements (7, 8) preferably being in the shape of a circular arc. Injection mold according to one of the preceding claims as far as dependent on claim 3, characterized in that a single slide element (7, 8) of the two slide elements (7, 8) moves neck jaws (15, 16) of several pairs of neck jaws, so that the movement of the individual slide element (7, 8) several neck blocks (15, 16) are moved or that each mold space has two individual slide elements (7,

8) are assigned, which only move the pair of neck cheeks of the respective mold space. Injection mold according to one of the preceding claims, characterized in that the cores (5) and the cavities (3) are arranged on a circular arc (6) with a central angle, the central angle being less than 180° and preferably less than 120°. Injection mold according to one of the preceding claims, characterized in that the cores (5) and the cavities (3) are arranged on two concentric circular arcs (6, 6') with different radii, the removal device (14) preferably being designed and set up in this way that molded parts can be removed from the cores (5) or the cavities (3) of both concentric circular arcs (6, 6') with the same removal device (14) by the removal device (14) being attached to the radius of the circular arcs (6, 6' ) is adjusted. Injection mold according to Claim 7, characterized in that the ends of the cavities (3) or cores (5), which are arranged together on an outer arc (6) of the concentric arcs (6, 6'), span a first plane, the ends of the Cavities (3) or cores (5), which are arranged together on an inner circular arc (6') of the concentric circular arcs (6, 6'), span a second plane, the first plane and the second plane being parallel and at a distance are arranged to each other.

9. Injection mold according to one of the preceding claims if dependent on claim 5, characterized in that a hot runner (9) is provided which has an inlet (10) for receiving a plasticized melt and a plurality of outlets

(11) for delivering the plasticized melt to the cavities (3), the hot runner (9) being arranged in such a way that the inlet (10) is located in a center point of the circular arc, each cavity (3) having a hot runner section (9 ') is assigned, which extends from a port provided in the cavity (3) to the entrance (10), all the hot runner sections (9') being of the same length.

10. Injection mold according to one of the preceding claims, characterized in that the pairs of cavity (3) and associated core (5) form at least two groups, with the inner contour of the cavity (3) and/or the outer contour of the core (5) which distinguishes one group from the inner contour of the cavity (3) and/or from the outer contour of the core (5) of the other group.

11 . Injection mold according to one of the preceding claims, characterized in that a transfer chain (12) with gripping elements for holding a manufactured molded part (1) is provided, wherein the core plate (4) is designed such that with the core plate (4) the manufactured molded parts ( 1) can be transferred from the cores (5) to the gripping elements in the open position, or the removal device (14) is designed in such a way that the molded parts (1) produced with the removal device (14) can be removed from the cores in the open position (5) or can be removed from the cavities (3) and passed to the gripping elements.

12. Injection mold according to claim 1 1, characterized in that the transfer chain

(12) has at least one transfer chain section, in which the gripping elements are arranged on a straight line and wherein the mold parts (1) produced can be transferred to the gripping elements within this transfer chain section with the removal device (14).

13. Injection mold according to one of the preceding claims, insofar as it is dependent on claim 2, characterized in that a further treatment element (13) is provided, the core plate (4) or the removal device (14) attaching the molded parts (1) removed from the injection mold to the further treatment element

(13) and wherein the further treatment element (13) transfers the molded parts (1) to the transfer chain (12). 21 Injection mold according to one of the preceding claims insofar as it is dependent on Claims 2 and 4, characterized in that the removal device (14) is designed in the shape of a circular arc and can be moved between the cavity plate (2) and the Core plate (4) is moved. Injection molding system with at least one injection molding tool according to one of the preceding claims and an extruder (18), wherein the extruder (18) is connected to the injection molding tool via a melt channel (21), so that during operation of the injection molding system the plasticized melt from the extruder (18) into the injection mold. Injection molding system according to claim 15, characterized in that in the closed position of the cavity plate (2) and the core plate (4) the mold space is arranged stationary relative to the extruder (18). Injection molding system according to one of Claims 15 or 16, the injection molding system having at least two injection molds and injection cylinders (19, 20) assigned to the at least two injection molds, the at least two injection molds being connected to the injection cylinder (19, 20) via the melt channel (21). , wherein the injection cylinders (19, 20) are connected to the extruder (18) via at least one further melt channel (21), wherein when the injection molding system is in operation, the injection cylinders (19, 20) alternately receive the plasticized melt from the extruder (18). are supplied, so that either one of the at least two injection molds is in the closed position and the other injection mold of the at least two injection molds is in the open position, or vice versa.