EP3302851B1 - Sprue system for a diecasting die - Google Patents

Description

The invention relates to a gating system for a die casting mold, wherein the gating system includes at least one runner channel which extends from an inlet-side gate opening to an outlet-side gate opening, which extends into a mold cavity formed between a fixed mold half and a movable mold half of the die casting mold or into one of these upstream gate area opens. In particular, this can be a so-called hot runner gating system. The sprue mouth opening on the inlet side can in particular be designed in such a way that a mouthpiece nozzle or the like of an upstream part of the casting system can be placed on it.

The applicant has a hot runner gating system with the designation Frech-Gießlauf-System or Frech-Gating-System (FGS) for die-casting molds on the market, as is also the case, for example, in the journal article L. H. Kallien and C. Böhnlein, Druckguss, Gießerei 96, 07/2009, pp. 18-26. Compared to other conventional gating systems, hot runner gating systems generally have the advantage that the proportion of melted material that falls on the so-called sprue or gate or the sprue/gate area upstream of the mold cavity and has to be separated from the cast product can be significantly reduced. In addition, the proportion of air in the casting system can be kept low, which enables the casting of parts with correspondingly low porosity, and the thermal balance is improved because the heat losses up to the cavity in the mold are lower and the melt is therefore not overheated as much to compensate for the losses got to. Machine productivity increases because the sprue is significantly smaller and less massive.

In the patent specifications EP 1 201 335 B1 and EP 1 997 571 B1 The applicant discloses hot runner gating systems which are, for example, of a comb or fan gating type or have sprue block units with integrated melt channel heating that can be used independently in a respective casting mold.

It is known that liquid melt material can be prevented from escaping when the mold is opened by a mechanical locking system. However, such closure systems are relatively susceptible to wear and tear, especially when used in metal die casting, and tend to leak. It has therefore already been proposed on various occasions to prevent this undesired escape of molten material by forming a solidified plug of molten material in the area of the sprue mouth opening of the sprue system or in the area of a mouthpiece nozzle applied thereto or an upstream casting chamber outlet channel, see eg the patent specification 100 64 300 C1 , the disclosure document WO 2007/028265 A2 and the aforementioned patent EP 1 201 335 B1 .

Next it is, for example, from the disclosure document U.S. 2007/0131376 A1 It is known to prevent liquid melt material from escaping when the mold is opened by forming a plug of solidified melt material at a distance from the narrow point by means of a corresponding plug-forming mechanism in a runner channel section, which connects upstream to a constriction functioning as the sprue mouth on the outlet side, wherein the The constriction acts as a geometrically defined separation area where the melt material breaks off when the mold is opened. Melt material located between the constriction and the slug is held there because the slug is stuck until in a next casting cycle the slug is advanced by pressing melt material and, depending on the casting volume, remains in the runner channel section or liquefies and is pressed into the mold cavity.

In the patent DE 196 11 267 C1 discloses a sprue bushing having a molten metal passageway inserted into and supported on a tool part for use on a hot chamber metal die casting machine. The sprue bush is designed in particular for use on a zinc die-casting machine. The through-channel is connected on the one hand to a metal feed device and on the other hand to a cavity of the tool and is cylindrical over its main course from the feed opening to just before the opening to the cavity, with a constriction and then a conical widening to open into the has cavity. The sprue bushing has electrical heating over almost the entire length of the cylindrical channel formation and a cooling zone in the area of the constriction. The cooling zone is formed by an air gap introduced into the sprue bush. The electrical heating of the cylindrical channel formation ends at a distance in front of a conically narrowing entry area of the constriction.

In the patent U.S. 6,745,821 B1 discloses a hot runner gating system of the type mentioned at the outset, which includes two sprue inserts lying face to face against one another, one of which is arranged on the fixed mold half and the other on the movable mold half, and which leave between them a region of the runner channel that is bent by 90°, this area functioning as a separation point area, in which the solidification point of the melted material occurs through appropriate adjustment of the temperature of the sprue inserts is at the end of a respective casting process. For this purpose, a cooling channel structure is integrated in the sprue insert of the movable mold half. A heating device is assigned to a section of the runner channel that is connected in a straight line upstream of the 90° bend. From the 90° bend, the runner channel continues in a straight line to the sprue mouth on the exit side.

Recently, there has been an increased need for die casting techniques in a relatively high temperature range of up to approximately 700°C or 750°C. This increased temperature also increases the risk of undesired oxide formation, particularly in the outlet opening areas of the pouring system where the melted material can come into contact with oxygen from the air. Among other things, this places corresponding demands on gating systems that work on the basis of hot runner technology.

The invention is based on the technical problem of providing a gating system of the type mentioned at the outset, which is also suitable for relatively high die-casting temperatures in terms of process reliability and can be implemented as a hot-runner gating system if required.

The invention solves this problem by providing a sprue system with the features of claim 1. In this sprue system, the runner channel has a geometrically and/or thermally defined separation point area, which is formed upstream of the sprue mouth and downstream of the sprue mouth opening in the direction of flow of the melt material to be cast. This means that the separation point area has a certain, predetermined distance both from the exit-side sprue opening and from the entry-side sprue opening of the runner channel. The separation point area is that area of the runner channel which is designed as a target point for separating or tearing off the solidified or partially solidified melt material on the mold side from the still liquid or even less solidified melt material in the runner channel when the mold is opened. This separation can be an actual tearing off of solid-solid phases of the melt material or melting or pulling off, in which the solid part of the melt material separates from the liquid phase by the melt carried along on its surface solidifying and the liquid part in the runner channel surface tension remains.

This predetermined separation point is defined geometrically, ie by appropriate geometric configuration of the course of the runner channel, and/or thermally, ie by corresponding thermal configuration of the course of the runner channel. For the person skilled in the art, this means that he designs the runner channel in such a way that the molten metal solidifies more easily or more quickly downstream of the area of the separation points than upstream of the area of the separation points, so that when the mold is opened, the already solidified or relatively strongly partially solidified melt material downstream of the separation point area is pulled out of the runner channel with the opening movement of the movable mold half as a component adhering to the cast product and is thereby separated or torn off from the still liquid or at most weakly partially solidified melt material upstream of the separation point area. Knowing this requirement, the person skilled in the art is familiar with suitable geometric and thermal measures for realizing the separation point area, so that he can provide suitable channel configurations, if necessary using simple tests and/or computer simulations, depending on the other configuration of the die and depending on the melt material used. Common molten salts as well as common molten metal alloys, in particular non-ferrous alloys based on magnesium, aluminum, zinc, tin, lead or brass as the respective main component, can be used as melt materials.

According to the invention, the defined determination of the area of the separation point ensures that the solidified or partially solidified melt is reproducibly separated precisely at this point and not accidentally somewhere or at changing points of the runner channel. The gating system according to the invention does not require a mechanical closure system. The design of the temperature profile along the runner, which includes the thermal definition of the interface region, can also be designed to form a temperature transient section of the runner from an upstream heated region to a cooled, contouring part of the mold. This can counteract undesirable oxide formation and fire hazards, particularly in the case of highly reactive or oxidizing melts.

According to one aspect of the invention, the runner channel has an S-shaped course with a bend or kink in the area of the separation point. This geometric measure is suitable for supporting the functionally reliable separation of the melted material precisely in the separation point area defined for this purpose.

According to an additional or alternative aspect of the invention, a region of the movable mold half opposite the sprue opening of the runner channel has a cooling channel structure. This thermal measure can be used to support the solidification or partial solidification of the melt material in the runner channel downstream of the area of the separation point.

According to a further additional or alternative aspect of the invention, a heating device is assigned to a runner channel section between the area of the separation point and the sprue mouth on the exit side. This allows the exit-side part of the runner channel if required, actively heat in a controlled manner. This represents an advantageous geometric-thermal measure for defining the area of the separation point at this point. The heating device can be, for example, a known electric or inductive heating device which is arranged in the runner channel itself or at a sufficiently small radial distance outside the same.

In a further development of the invention, a heating device is assigned to a runner channel section which adjoins the area of the separation point upstream and tapers conically towards the area of the separation point. As a result, the section of the runner channel which is designed as a conical constriction and which adjoins the area of the separation point upstream can be actively heated in a controlled manner if required. This represents a further advantageous geometric-thermal measure for defining the area of the separation point at this point. The heating device can be, for example, a known electric or inductive heating device which is arranged in the runner channel itself or at a sufficiently small radial distance outside of it.

In a further development of the invention, the runner channel has a constriction in the area of the separation point, from which its flow cross section increases downstream and/or upstream. This geometric measure supports the reliable separation of the melt material in the area of the separation point. The runner channel can, for example, be configured in such a way that its flow cross-section widens from the area of the separation point to the sprue mouth, i.e. the flow cross-section no longer decreases from the area of the separation point to the sprue mouth, but increases steadily or at most remains constant in sections. This geometric measure of the runner design can facilitate the extraction of the solidified or heavily partially solidified melt material from the section of the runner channel from the separation point area to the sprue mouth on the outlet side and thus also the separation of this part of the melt material from the melt material upstream of the separation point area. For example, the runner channel can have a funnel-shaped widening course from the constriction to the spout mouth.

The distance of the separation point region from the sprue opening of the runner channel on the exit side is preferably very small and in particular significantly smaller than from that on the entry side Sprue mouth opening of the runner, in the present case these mentioned distances are to be understood in relation to the length of the flow path of the melt material conveyed in the runner. This takes into account the goal of minimizing the proportion of melt that solidifies as a sprue on the cast part and is removed from the mold with it. The system can be built so compactly that there is hardly any solidified runner or sprue on the cast part. Specifically, according to a further development of the invention, the separation point area is at a distance between 0.3 times and 3 times the diameter of the runner channel in the separation point area and is therefore correspondingly close in front of the sprue mouth.

In a further development of the invention, a cooling channel structure is assigned to a runner channel section between the area of the separation point and the sprue opening on the outlet side. In this way, too, the thermal definition of the separation point area and consequently the reliable separation of the melt material in this area can be further improved in a targeted manner.

In a further development of the invention, the runner channel runs in an area adjoining the separation point area upstream at an angle of between 0° and 45°, in particular between 3° and 20°, to the normal direction of a parting plane between the fixed and movable mold halves, specifically increasing in the direction of the separation point area . This course of the runner channel, which rises in the flow direction of the melt in this section, can contribute to avoiding an undesired escape of melt material from the runner channel when the mold is opened after the melt material has been separated in the area of the separation point. With this system design, the aforesaid rising course of the runner channel also occurs when the mold halves are arranged with the parting plane lying vertically.

In a further development of the invention, the gating system is configured as a hot-runner gating system and comprises, in a manner known per se, a melt distribution block which has the sprue mouth opening on the inlet side, and a sprue block which adjoins the melt distribution block in the direction of flow and has the sprue mouth on the outlet side. In this case, the separation point area is formed in the section of the runner channel which runs in the sprue block. The separation point area is consequently located at a relatively small distance in front of the parting plane of the fixed and movable mold halves close to the gate.

In a further development of the invention, the gating system is configured as a hot-runner gating system, and the at least one runner channel comprises at least two runner channels that are parallel in terms of flow, with temperature control means being provided which are used independently for the controllable or adjustable temperature of the melt material in the separation point areas of the runner channels are set up from one another to a predeterminable desired temperature between 0.9 times and 1.1 times, in particular between 0.98 times and 1.02 times, a melt material liquidus temperature.

With these temperature control means, in such a hot runner gating system with a plurality of flow-technically parallel runners, the melt material in the area of the separation points of each runner can be kept at a desired temperature in a very advantageous manner, which lies in the associated solidification temperature interval. Due to the individual melt material temperature control in each of the separation point areas, any differences in the geometry of the runner channels and different temperature influences can be specifically taken into account for each individual runner channel or separation point area, so that in each of the separation point areas that are spatially separated from one another but are fluidically connected via the runner channels optimal temperature for separating the melted material can be set.

In an embodiment of the invention, the temperature control means comprise a temperature control unit or temperature control unit and, for the respective runner channel, a temperature sensor system between the area of the separation point and the sprue mouth on the outlet side and/or the heating device between the area of the separation point and the sprue mouth on the outlet side and/or the heating device in the runner channel section adjoining the area of the separation point upstream and /or the cooling channel structure in the area of the movable mold half opposite the sprue opening and/or the cooling duct structure between the area of the separation point and the sprue opening on the exit side. This represents advantageous variants of the realization of the temperature control means.

In a further development of the invention, the runner channel section which adjoins the area of the separation point upstream and tapers conically towards the area of the separation point merges at an associated transition point into a cylindrical casting plunger section of constant diameter which adjoins upstream. The axial length of the runner channel section that tapers conically towards the separation point area is smaller than the axial length of the runner channel section between the separation point area and the gate on the outlet side, i.e. smaller than the distance of the separation point area from the gate on the outlet side. This measure can further optimize the course of the runner channel and the separation or tearing off of the melt in the runner channel in the area of the separation points.

In a further development of the invention, the area of the movable mold half which is opposite the sprue opening has a recess or is flat. Both variants can advantageously support the melt tear-off behavior depending on the other system conditions.

In a development of the invention, the runner channel section located between the area of the separation point and the sprue opening on the outlet side branches into a plurality of channel branches that are parallel in terms of flow. These lead to associated gate openings on the exit side and from there to associated gate areas or gate cavities. This can be advantageous for corresponding configurations of the mold to be cast and thus the mold halves used for this purpose.

Fig. 1

eine schematische, teilweise geschnittene Seitenansicht eines vorliegend interessierenden Teils einer Druckgießform,

Fig. 2

eine Detailansicht aus Fig. 1 mit einem Gießlaufkanal mit einem Trennstellenbereich, der eine Biegung/Knickung beinhaltet,

Fig. 3

eine schematische Schnittansicht eines vorliegend interessierenden Teils einer weiteren Druckgießform mit einem Gießlaufkanal mit geometrisch und thermisch definiertem Trennstellenbereich,

Fig. 4

eine Ansicht entsprechend Fig. 3 für eine Variante mit zusätzlicher Kühl- und Heizmöglichkeit eines austrittsseitigen Gießlaufkanalabschnitts,

Fig. 5

eine Ansicht entsprechend Fig. 4 für eine Variante mit zylindrischem Gießlaufkanalabschnitt konstanten Durchmessers,

Fig. 6

eine Ansicht entsprechend Fig. 5 für eine Variante mit flacher Gestaltung des einer Angussmündung des Gießlaufkanals gegenüberliegenden Bereichs einer beweglichen Formhälfte,

Fig. 7

eine Ansicht entsprechend Fig. 6 für eine Variante mit einer modifizierten Heiz-/Kühlanordnung,

Fig. 8

eine Ansicht entsprechend Fig. 7 für eine Variante mit sich verzweigendem Gießlaufkanalabschnitt zwischen Trennstellenbereich und austrittsseitiger Angussmündung,

Fig. 9

eine Schnittansicht längs einer Linie IX-IX von Fig. 8,

Fig. 10

eine Ansicht entsprechend Fig. 8 für eine weitere Variante mit sich verzweigendem Gießlaufkanalabschnitt zwischen Trennstellenbereich und austrittsseitiger Angussmündung und

Fig. 11

eine Schnittansicht längs einer Linie XI-XI von Fig. 10.

Advantageous embodiments of the invention are shown in the drawings and are described below. Here show:

1

a schematic, partially sectioned side view of a part of a die casting mold that is of interest here,

2

a detailed view 1 having a runner channel with an interface area that includes a bend/kink,

3

a schematic sectional view of a part of another die-casting mold that is of interest here with a runner channel with a geometrically and thermally defined separation point area,

4

a view accordingly 3 for a variant with additional cooling and heating options for a runner channel section on the outlet side,

figure 5

a view accordingly 4 for a variant with a cylindrical runner channel section of constant diameter,

6

a view accordingly figure 5 for a variant with a flat design of the area of a movable mold half opposite a sprue mouth of the runner channel,

7

a view accordingly 6 for a variant with a modified heating/cooling arrangement,

8

a view accordingly 7 for a variant with a branching runner channel section between the separation point area and the sprue opening on the outlet side,

9

a sectional view taken along a line IX-IX of FIG 8 ,

10

a view accordingly 8 for a further variant with a branching runner channel section between the separation point area and the sprue opening on the outlet side and

11

a sectional view taken along a line XI-XI of FIG 10 .

a in 1 shown part of a die-casting mold, which is particularly suitable for the die-casting of salts and metals, e.g. magnesium, aluminum, zinc, tin, lead and brass, contains in a conventional manner a fixed mold half 1 and one opposite this, perpendicular to a parting plane 2 Movable mold half 3. For this purpose, for example, the fixed mold half 1 is clamped in a conventional manner on a fixed platen of a die casting machine and the movable mold half 3 is held on a clamping plate of the machine that is movable relative to the fixed clamping plate, for which purpose a preferably hydraulic drive is assigned to the movable clamping plate. In the parting plane 2, the two mold halves 1, 3 abut against each other when the mold is closed. To open the mold, the movable mold half 3 is retracted in the normal direction of the parting plane 2, ie perpendicular to it. Unless otherwise stated below, the die is of any conventional construction known per se to those skilled in the art. The die-casting mold also includes a gating system, a part of which is of interest in the present part in the part-cut area of 1 can be seen. Moreover, the gating system is also of one of the configurations known per se to a person skilled in the art.

How out 1 and the associated detail view of 2 As can be seen, the gating system comprises a melt distribution block 4 and a gating block 5 adjoining this in the direction of flow. The gating system is preferably of a hot-runner type in which at least the melt distribution block 4 is actively heated, for example by means of an electrical or inductive heating device or by means of a Heating fluid, which is passed through a heating channel structure of the melt distribution block 4, as is known per se. The melt distribution block 4 and the sprue block 5 are built into or attached to the fixed mold half 1 .

The sprue system has at least one runner channel 6, which extends from a sprue mouth opening, not shown, on the inlet side to a sprue mouth 7 on the outlet side. With its sprue opening 7, the runner channel 6 opens into a gate area 8 formed between the fixed mold half 1 and the movable mold half 3, i.e. a gate cavity, which in turn, as usual, opens into a mold cavity (not shown) which defines the volume and the contour of the pouring product reflects.

The runner channel 6 runs from the sprue mouth opening on the inlet side, first in the melt distribution block 4 and then in the sprue block 5, which extends to the mold parting plane 2 and forms the sprue mouth 7 of the runner channel 6 there. The sprue mouth opening on the inlet side (not shown) forms the inlet for the melt into the melt distribution block 4, to which an upstream mouthpiece nozzle can usually be applied, which represents the outlet-side end of an upstream casting chamber or a riser leading out of a melt reservoir. It goes without saying that the die casting mold can have several such melt distribution blocks and/or several such sprue blocks and thus also several such runner channels, e.g. realized by a branching runner channel structure, depending on the requirement and application. The mold may then be fed with a multi-distributed sprue block system from a casting vessel, e.g., via a pouring system tip nozzle attached to the sprue block system.

Like in particular 2 As can be seen, the runner channel 6 has an at least geometrically defined separation point region 9 upstream of the sprue mouth 7 and downstream of the sprue mouth opening (not shown). The geometric definition of the separation point area 9 includes the formation of a bend 9a or buckling of the runner channel 6, in that a lower channel wall part first bends upwards and then horizontally or slightly downwards, while correspondingly an upper channel wall part first bends upwards runs, in order to then run again with a lower upward component up to the sprue opening 7 . Overall, this provides an approximately S-shaped profile of the runner channel 6 , as can be seen from a dashed center line 6 c , which approximately reproduces the center line of the cross-sectional profile of the runner channel 6 . In alternative implementations, the geometric definition of the separation point area can include a less pronounced curvature and/or a cross-sectional narrowing of the runner channel instead of such a bend/buckling; in particular, the bend does not have to be sharp-edged as in the example shown.

The separation point area 9 is located inside the sprue block 5, wherein in the separation point area 9 an upstream adjoining section 6a of the runner channel 6 merges into a downstream section subsequent Gießlaufkanalabschnitt 6b passes. The downstream runner section 6b ends in the sprue opening 7 of the runner 6 on the exit side, ie its flow path length defines a predetermined distance which the separation point region 9 maintains from the sprue opening 7 . In the example shown, this distance is much smaller than the remaining, upstream length of the runner channel 6 and, in particular, also smaller than the remaining length of the runner channel in the sprue block 5. In the example shown, the downstream end section 6b of the runner channel 6, which adjoins the separation point region 9, has a funnel-shaped, ie like a hollow cone, widening in the direction of the sprue mouth 7.

As explained above, the separation point region 9 defines the target point for the separation or tearing off of the solidified or partially solidified melt material when the mold is opened after a casting process. Thus, the melt material present in the downstream end section 6b of the runner channel 6 behind the separation area 9 remains on the cast product or the solidified melt material of the sprue or gating area 8, while the melt material remains in the runner channel 6 upstream of the separation area 9. The course of the runner end section 6b, which widens in the shape of a funnel, makes it easier for the residual melted material there to escape from the runner channel 6.

How to proceed in particular 2 0° and approx. 45°, preferably between approx. 3° and approx. 20°, to the direction normal to the parting plane 2 . This contributes to avoiding an undesired escape of any still liquid or viscous melt material from the runner channel 6 when the mold is opened. Provision can also be made for the fixed mold half 1 and therefore the parting plane 2 to be inclined relative to the vertical, so that the runner channel 6 rises by a corresponding additional amount in the direction of melt flow.

If necessary, the separation point area 9 can also be thermally defined, i.e. the temperature profile along the runner channel 6 can be influenced by active cooling and/or heating temperature control measures in such a way that the precise separation of the melt material in the separation point area 9 is supported, which is otherwise due to the geometric definition is provided by means of the bend/buckle 9a. As a thermal measure, the sprue block 5 can form an area that is transient in terms of temperature between the heated melt distribution block 4 on the one hand and the cooled mold cavity or gate cavity 8, which is not, or at most, upstream of the separation point area 9 actively heated and not or only in the area downstream of the separation point area 9 is actively cooled. Alternatively, provision can be made to heat the runner channel section in the sprue block 5 according to a predeterminable temperature profile, with the temperature in the sprue block being kept lower than in the melt distribution block and/or being set to decrease gradually in the melt flow direction.

3 shows a further exemplary embodiment of the invention, again only schematically with its components of interest here, the remaining structure of the die casting mold being that according to FIGS 1 and 2 and can correspond to the explanations given above. For easier understanding are in 3 for functionally equivalent, not necessarily identical elements, the same reference numerals are chosen, so that in this respect in addition to the above explanations on the 1 and 2 can be referred.

In the case of the die casting mold 3 the gating system includes a runner channel 6' having a parting area 9' which is geometrically defined by a throat 9'a of the runner channel 6'. From this constriction 9', the channel cross-section widens both in the runner channel section 6'a adjoining upstream and in the runner channel section 6'b adjoining downstream, in each case in the shape of a funnel or hollow cone. As above for the embodiment of 1 and 2 mentioned, a distance A maintained by the separation point region 9' from the sprue opening 7' is also much smaller than the remaining, upstream length of the runner channel 6' and in particular also smaller than the remaining runner channel length in an associated runner block 5'. Specifically, in advantageous embodiments, this distance A is between 0.3 times and 3 times a diameter D of the runner channel 6' in the area of the separation point 9'.

In addition, the separation point area 9' is thermally defined in that the runner channel section 6'b downstream of the separation point area 9' remains unheated, while a heating device 10 is assigned to the runner channel section 6'a that follows the separation point area 9' upstream, with which the melt material is heated in This runner channel section 6'a can be actively heated up to before the separation point area 9', for example in the direction of melt flow following a likewise actively heated melt distribution block. The heating device 10 can be of any type known per se to those skilled in the art, for example in the form of an electric or inductive heating device, which can be arranged in the runner channel 6' itself or, as shown, in a region of the sprue block 5' surrounding it with a small radial distance can. Alternatively, heating by a heating fluid is possible, for which purpose a region radially surrounding the relevant runner channel section 6'a is provided with a corresponding fluid channel structure. The heating of the melt in the runner channel section 6'a adjoining the separation point area 9' upstream while at the same time there is no heating of the runner channel section 6'b downstream of the separation point area 9' can support the reliable, process-reliable separation of the melt material in the separation point area 9' configured for this purpose in conjunction with the geometric constriction design and guarantee.

As a further thermal measure, the gating system according to 3 a cooling channel structure 11 in a region 17 of the movable mold half 3' opposite the sprue mouth 7', this region 17 having a recess in the example shown and being correspondingly deepened. The recess can, for example, be pot-shaped, with various other cross-sectional shapes being possible in addition to a round cross-sectional shape, for example oval or star-shaped. This cooling channel structure 11 can be used to actively cool the melt material in the sprue/gate area 8' leading to a mold cavity 12 and in particular in the part of the gate area 8' directly adjoining the sprue mouth 7' of the runner channel 6'. This supports the cooling and thus the solidification or partial solidification of the melt material in the end runner section 6'b downstream of the separation point area 9', while at the same time the melt material in the runner channel section 6'a adjacent to the separation point area 9' upstream is prevented from solidification by the heating device 10 can. As a result, the molten material reliably tears off at the separation point area 9' when the mold is opened.

At an in 4 shown embodiment are in addition to the embodiment of 3 an active cooling device in the form of a cooling channel structure 13 and an active heating device 14 are assigned to the runner channel section 6′b between the separation point area 9′ and the sprue opening 7′ on the outlet side. The heating device 14, like the heating device 10, can be of any type known per se to a person skilled in the art, for example an electric or inductive heating device located in said channel section 6'b or, as shown, in an area of the sprue block 5' surrounding it with a small radial distance. or a sprue insert contained in the runner channel 6' can be arranged. Here, too, heating by means of a heating fluid with a corresponding fluid channel structure is alternatively possible. The cooling channel structure 13 can be fed with the same cooling fluid as the cooling channel structure 11 or alternatively with a different cooling fluid.

By means of the active cooling device 13 and the active heating device 14 in the section between the separation point area 9' and the sprue mouth 7', the thermal definition of the separation point area 9' can be further improved in corresponding applications. For example, in a corresponding mode of operation, this pouring channel section 6'b can be replaced by the cooling device 13 are actively cooled, which supports the bonding of the melted material in this section to the melted material adjoining the mold, ie to the sprue of the cast part. This is because the additional cooling promotes the solidification of the melted material in this channel section 6'b.

If the cooling effect provided by the cooling channel structure 11 in the movable mold half 3' is relatively strong in corresponding applications and could cause the melt material to solidify upstream beyond the separation point area 9', this can be counteracted in a corresponding operating mode by activating the heating device 14 and thereby the melt material in the exit-side runner channel section 6'b is kept at a sufficiently high temperature.

In a further possible operating mode, the cooling device 13 and the heating device 14 of the runner channel section 6'b can be operated in a clocked manner. A type of cycle-synchronous solidification of the melt material can thus be forced, which in turn actively supports the melt separation process in the separation point region 9'.

In further embodiment variants that are not shown, only one heating device without a cooling device or only one cooling device without a heating device is assigned to the runner channel section 6'b. In addition, in further modified embodiments, the heating device 10 and/or the cooling channel structure 11 can be omitted.

It goes without saying that all cooling and heating devices 10, 11, 13, 14 mentioned are assigned a control and/or regulation unit which suitably controls the cooling/heating devices 10, 11, 13, 14 mentioned in accordance with the respectively desired operating mode.

An example of this is in 4 a control unit 15 is shown as an example, which controls the heating device 10, the cooling channel structure 11, the cooling channel structure 13 and the heating device 14 via corresponding control lines 15a, 15b, 15c, 15d. In corresponding embodiments, the gating system also includes, as further in 4 shown, a temperature sensor 16 between the separation point region 9 'and the exit-side sprue mouth 7'. The temperature sensor system 16 is connected to the control unit 15 via an associated sensor line 15e and is designed in such a way that it can inform the control unit 15 about the temperature conditions in at least part of the runner channel 6' and in particular in the environment upstream and downstream of the separation point region 9'. Depending on the system design, the temperature sensor system 16 can contain one or more temperature sensors arranged one behind the other along the runner channel 6′, especially in the one shown Part of the runner channel 6', which comprises the conically narrowing section 6'b, the separation point area 9' and the section between the separation point area 9' and the sprue opening 7'. For example, the heating device 10, the cooling device 11, the cooling device 13 and the heating device 14 can each be equipped with one or more temperature sensor elements.

In this implementation, the gating system therefore has temperature control means that can be set up to a predeterminable setpoint temperature for controllable or adjustable melt material temperature in the separation point area 9' of the runner channel 6', with this setpoint temperature expediently being set to a value between 0.9 times and 1. 1 times the liquidus temperature of the melt material to be cast, preferably at this liquidus temperature or in a narrow range between 0.98 times and 1.02 times the same.

With these temperature control means, a dedicated temperature control for the melted material can be achieved from the separation point area 9' to the sprue opening 7'. In this way, the temperature of the melt material in the vicinity of the separation point region 9' can advantageously be kept in the melt solidification temperature interval. The melt temperature in the runner channel 6' in an inflow section upstream of the separation point area 9' can certainly be selected higher in order to provide good flow properties for the melt there and reliable melt guidance, which protects against undesirable melt solidification effects in the runner channel 6' upstream of the separation point area 9'.

The heating and cooling devices 10, 11, 13, 14 can thus be switched on and off individually by the control unit 15 depending on the sensed temperature in the outlet-side part of the runner channel 6'. This targeted melt temperature control in the gate area can be used, among other things, to prevent the melt material remaining in the runner channel 6' from cooling down too much or even solidifying when the casting mold is open while the cast part is being removed as a result of heat flow to the cooled components of the die casting mold. For this purpose, the control unit 15 can suitably limit the cooling effect of the cooling device 11, 13 in terms of its influence on the melt supplied at a controlled temperature on the outlet-side casting channel section 6'b up to the separation point area 9', while at the same time controlling the casting channel section 6'a adjoining the separation point area 9' upstream can be actively heated by means of the heating device 10 and thus kept at the liquidus temperature.

In corresponding embodiments of the invention, the gating system can be configured as a hot runner gating system with a plurality of fluidically parallel runner channels, which open into the mold cavity with spatially separate sprue openings at different points and each of which has a sprue unit of one of the in the Figures 1 to 4 shown types is assigned. In particular, each of the runner channels, which are fluidically connected in parallel with one another, can be equipped with a gating unit according to 3 and 4 be equipped, which has the temperature control means explained above. In this case, a plurality of decentralized control or regulation units or, alternatively, a common central control or regulation unit can be provided for the cooling and heating devices of the various runner channels. With this multi-channel system design, the temperature control means with the cooling and/or heating devices that can be controlled separately for each runner channel in the manner of the cooling and/or heating devices 10, 11, 13, 14 of 4 optimally adjust the melt temperature in the outlet-side section for each runner channel individually, so that the desired separation of the melt material in the separation point area 9′ is reliably effected in each of the runner channels.

For this purpose, the associated control/regulation device ensures by appropriate activation of the respective existing cooling/heating devices that the separation of the melt material for each of the several spatially separated sprue mouths of the different runner channels takes place reproducibly at the respective predetermined separation point with reproducible temperature conditions. In addition, the sprue openings are thermally coordinated with one another, so that the separation of the melt material does not result in solidified melt material remaining in one of the separation point areas of the various runner channels when the mold is opened. Rather, the temperature conditions for each of the several, spatially separated areas of separation points are adjusted in such a way that the entire solidified melt material is completely pulled out of the sprue mouth at all separation points when the mold is opened. This ensures that during the next casting process, the melt flows into the mold cavity with the same flow distribution via the multiple sprue openings, where it forms the same flow fronts in a reproducible manner.

For this purpose, the temperature is controlled by the associated decentralized control/regulating units or alternatively the central Control / regulation unit 15 regulated individually for each of the separation points to the optimal setpoint, which, as mentioned, is approximately at the liquidus temperature of the melt material or in the range of 0.9 times to 1.1 times and preferably 0.98 times to 1.02 times the same.

It is also taken into account that the temperature in the runner channels not only depends on backflows or repercussions of the mold cavity or mold cooling devices for the mold cavity, but also on the diameter and the geometry of the runner channels. Furthermore, melt energies of different mass flows of the melt can have different effects on the temperature balance and thus also on the temperature conditions of the melt material in the respective separation area if it is necessary for flow reasons to fill the mold cavity, the two or more flow-technically parallel runner channels with different geometries, such as different diameters, curvatures, kinks etc. Such effects can also be compensated for by the gating system according to the invention in the system design with the temperature control means explained, so that even in such system implementations the melt temperature in each separation point area of the several runner channels can be set or maintained at the optimal setpoint by the individually assigned and controllable cooling/heating devices. can be held on this.

It goes without saying that the active cooling and/or heating measures mentioned for the melt material in the sprue/gate cavity and in particular near the sprue mouth of the runner channel, as described above for the examples from 3 and 4 were explained, also with the gating system 1 and 2 can be provided.

the Figures 5 to 11 illustrate further variants of the embodiments of the 3 and 4 , wherein the same reference numerals are used for identical and functionally equivalent elements and insofar to the above explanations to the 3 and 4 can be referred. In the following, therefore, these embodiment variants are essentially only referred to as differences compared to the exemplary embodiments of FIG 3 and 4 received.

In the embodiment of figure 5 the runner channel section 6'a, which tapers conically towards the separating point area 9' and adjoins the separation point area 9' upstream, merges at an associated transition point 18 into a cylindrical runner channel section 6'd of constant diameter, which adjoins upstream. The runner channel section 6'a extends in the axial direction over a length L6a, which is smaller than the distance A of the separation point region 9' from the sprue mouth 7' on the outlet side and is therefore smaller than the axial length of the runner channel section 6'b between the separation point region 9' and the exit-side sprue mouth 7'. For active heating, the cylindrical runner channel section 6'd has a heating device 10' analogous to the heating device 10 of the conically tapering runner channel section 6'a in the examples in FIG 3 and 4 assigned. Optionally, the heating device 10' can also be in the area of the conically tapering runner channel section 6'a extend and there the function of the heating device 10 according to the examples of 3 and 4 take over. In corresponding alternative realizations, the runner channel section 6'b between the separation point region 9' and the sprue mouth 7' on the outlet side remains without active cooling and heating, or it has the active cooling device 13 and/or the active heating device 14 in accordance with the example in FIG 4 assigned.

6 shows an embodiment that differs from that of figure 5 differs in that the area of the movable mold half 3' opposite the exit-side sprue mouth 7' is designed as a flat area 17' instead of the cup-shaped depression of the area 17 of figure 5 is trained. In this case, the associated cooling channel structure 11 additionally comprises cooling channels directly opposite the sprue opening 7′ on the outlet side.

7 shows a variant that differs from the embodiment of 6 differs in that an active heating device 10″ extends both in the cylindrical runner channel section 6′d and in the conically tapering runner channel section 6′a and the function of the above to the exemplary embodiments of FIG Figures 4 and 5 explained heating devices 10 and 10 'takes over. Furthermore, in 7 explicitly the active cooling device 13 and the active heating device 14 for the runner channel section 6'b between the separation point region 9' and the sprue mouth 7' on the outlet side, as shown above for the exemplary embodiment in FIG 4 explained.

the Figures 8 and 9 show an embodiment that corresponds to that of 7 is similar, with the difference being that the runner channel section extending from the separation point region 9' to the sprue mouth 7' on the outlet side branches into a plurality of channel branches 6'b1, 6'b2 which are parallel in terms of flow. In the example shown, this runner channel section comprises the two channel branches 6′b1 and 6′b2, in alternative embodiments it can also contain more than two flow-technically parallel channel branches and/or a plurality of channel branches lying one behind the other in the direction of flow.

In the embodiment of Figures 8 and 9 each of the two channel branches 6'b1, 6'b2 forms a runner channel branch that tapers conically from the exit-side sprue orifice 7' to the separation point region 9', and each channel branch 6'b1, 6'b2 is designed as in particular 9 visible, surrounded by several heating elements of the active heating device 14 . The active cooling device 13 contains circular cooling channels, which are arranged radially outside the two runner channel branches 6'b1, 6'b2, surrounding them. The sprue opening 7' on the exit side correspondingly comprises the two exit openings of the runner channel branches 6'b1, 6'b2, and an opposite area 17' modified in this respect, which contains the active cooling channel structure 11 contains, is provided on the mold cavity side with a gate area _8'1 , _8'2 for each of the runner channel branches 6'b1, 6'b2. In this way, melt is conducted into the mold cavity 12 via the runner branches 6'b1, 6'b2 and the gate areas _8'1 , _8'2 at associated different locations.

the Figures 10 and 11 illustrate an embodiment similar to that of FIG Figures 8 and 9 with the difference that the two runner branches 6'b1, 6'b2, into which the runner channel section branches between the separation point region 9' and the sprue opening 7' on the outlet side, are realized in a different way. In particular, the pouring channel section 6'b is analogous to the embodiment variants of FIG Figures 3 to 7 designed in the shape of a truncated cone. A correspondingly frustoconical extension 19 protrudes from a modified opposite region 17" of the movable mold half 3' into this runner channel section 6'b, which tapers conically in a truncated cone shape from the sprue opening 7' on the exit side to the separation point region 9', which has two axial grooves located opposite one another in the circumferential direction which in this case form the two channel branches 6'b1, 6'b2 and merge into the cut areas _8'1 , _8'2.In the example shown, a cooling channel 11a extends as part of the active cooling device 11 into the area of the extension 19, whereby the cooling effect for the runner branches 6'b1, 6'b2 can be enhanced.

As the exemplary embodiments shown and explained above make clear, the invention provides an advantageous sprue system that enables a defined separation of the melt in the runner channel with a preferably relatively small distance from its sprue mouth on the outlet side into the mold cavity or, as shown, into the upstream sprue/gate cavity At the same time, undesired escape of melt material that is still liquid from the solid mold half when the mold is opened can be avoided without a mechanical locking system being absolutely necessary. The gating system according to the invention is suitable for all applications known for conventional gating systems, and in particular also as a hot-runner gating system for die-casting zinc, aluminum and magnesium in an elevated temperature range of up to approx. 750°C.

Claims (12)

1. A sprue system, preferably a hot runner sprue system, for a diecasting die, comprising

   - at least one runner channel (6, 6'), which extends from an entry-side sprue mouth opening to an exit-side sprue opening (7, 7'), which opens into a die cavity (12) of the diecasting die that is formed between a fixed die half (1, 1') and a movable die half (3, 3') or into a gate region (8, 8') arranged upstream thereof and comprises a geometrically and/or thermally defined parting region (9, 9') upstream of the sprue opening (7, 7') and downstream of the sprue mouth opening,

   - wherein the runner channel has a bend or kink (9a) in the parting region and/or

   - wherein a heating device (14) is assigned to a runner channel portion (6'b) between the parting region and the exit-side sprue opening, and/or

   - wherein a region (17, 17') of the movable die half opposite the sprue opening has a cooling channel structure (11).
2. The sprue system as claimed in claim 1, further characterized in that a a heating device (10) is assigned to a runner channel portion (6'a) adjoining the parting region upstream and narrowing conically toward the parting region.
3. The sprue system as claimed in claim 1 or 2, further characterized in that the runner channel has in the parting region a constriction (9'a), from where its through-flow cross section increases downstream and/or upstream.
4. The sprue system as claimed in any one of claims 1 to 3, further characterized in that the parting region is located at a distance (A) in front of the sprue opening of between 0.3 times and 3 times a diameter (D) of the runner channel in the parting region.
5. The sprue system as claimed in any one of claims 1 to 4, further characterized in that a a cooling channel structure (13) is assigned to a runner channel portion (6'b) between the parting region and the exit-side sprue opening.
6. The sprue system as claimed in any one of claims 1 to 5, further characterized in that, in a region adjoining the parting region upstream, the runner channel runs at an angle (α) of greater than 0° and less than or equal to 45°, preferably between 3° and 20°, to the direction of a normal to a parting plane (2) between the fixed die half and the movable die half, rising in the direction of the parting region.
7. The sprue system as claimed in any one of claims 1 to 6, further characterized in that it is configured as a hot runner sprue system and comprises a melt manifold block (4), which on the entry side has the sprue mouth opening, and a sprue block (5, 5'), which adjoins the melt manifold block in the direction of flow and on the exit side has the sprue opening, wherein the parting region is located in a portion of the runner channel that runs in the sprue block.
8. The sprue system as claimed in any one of claims 1 to 7, further characterized in that it is configured as a hot runner sprue system and the at least one runner channel comprises at least two runner channels (6, 6') that are parallel in terms of flow, and temperature control means are provided which are designed for controlling in an open-loop or closed-loop manner the temperature of the molten material in the parting regions of the runner channels independently of one another to a predeterminable setpoint temperature of between 0.9 times and 1.1 times, preferably between 0.98 times and 1.02 times, a liquidus temperature of the molten material.
9. The sprue system as claimed in claim 8, further characterized in that the temperature control means comprise an open-loop temperature control unit or a closed-loop temperature control unit and, for the respective runner channel, a temperature sensor system between the parting region and the exit-side sprue opening and/or the heating device (14) between the parting region and the exit-side sprue opening and/or the heating device (10) in the runner channel portion (6'a) adjoining the parting region upstream and/or the cooling channel structure (11) in the region of the movable die half opposite the sprue opening and/or the cooling channel structure (13) between the parting region and the exit-side sprue opening.
10. The sprue system as claimed in any one of claims 1 to 9, further characterized in that the runner channel portion adjoining the parting region upstream and narrowing conically toward the parting region goes over at an associated transitional location (18) into a cylindrical runner channel portion (6'd) of a constant diameter adjoining upstream and its axial length (L6a) is less than that of the runner channel portion between the parting region and the exit-side sprue opening.
11. The sprue system as claimed in any one of claims 1 to 10, further characterized in that the region (17, 17') of the movable die half that is opposite the sprue opening has a recess or is formed as level.
12. The sprue system as claimed in any one of claims 1 to 11, further characterized in that the runner channel portion extending from the parting region to the exit-side sprue opening branches into multiple channel branches (6'b1, 6'b2) that are parallel in terms of flow.

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