EP3294477B1 - Method for casting metal, adapter unit and device for casting metal comprising such an adapter unit - Google Patents

Description

The invention relates to a method for casting metal, an adapter unit and a device for casting metal comprising such an adapter unit.

The DE 20 2005 010 125 U1 discloses an apparatus for low pressure casting in an ascending manner of metals.

The DE 10 2012 101 055 A1 discloses a casting method and a casting plant for producing workpieces. Several casting molds are arranged on a rotary table and can be connected to a casting furnace. After the melt has cooled in the casting mold, the casting furnace can be separated and connected to a next casting mold. A recompression of the melt in the casting mold takes place at maximum under furnace pressure. As the melt cools and solidifies, the pressure in the casting mold drops.

The DE 102 33 962 A1 discloses an active feed adapter in which a piston is provided for forcing melt into the casting mold. In order to avoid blocking the casting furnace while the melt is being pressed and solidified in a casting mold, additional expenditure, in particular heating of the riser, is necessary.

The DE 198 21 419 A1 discloses a method for increasing low-pressure casting of metal, wherein a controllable piston is used to push the molten metal in the casting mold.

The DE 198 12 068 A1 discloses a casting apparatus and method with recompaction by means of a first and a second piston. While the melt is solidifying in the casting mold, the casting furnace is blocked for further use.

The DE 43 32 760 A1 discloses a method of low pressure casting of copper or brass.

The molten metal is poured from the furnace into a mold through a riser pipe. After the melt has solidified in the mold, the pressure in the furnace can be reduced. During the solidification of the melt, the casting mold is thermally coupled to the casting furnace.

It is an object of the present invention to improve a method for casting metal, and in particular to reduce the cycle time of a casting, to reduce the energy consumption, to ensure improved material properties of the casting and / or to increase the utilization of the casting furnace.

According to the invention, this object is achieved by a method having the features specified in claim 1.

According to the invention, it was recognized that a fluid connection between a casting furnace and a casting mold is initially interrupted and additionally actively ventilated for emptying. Active ventilation means that air and / or another gas, in particular in a targeted manner, is actively supplied to the fluid connection. The active ventilation takes place, for example, by supplying air into a riser pipe that connects the casting furnace with the casting mold. The invention differs fundamentally from that DE 43 32 760 A1 , in which ventilation of the fluid connection is prevented. The casting furnace is vented before active venting. The active ventilation of the riser and the venting of the casting furnace can take place at the same time. It is also conceivable that the protective gas is pressed into the riser and the casting furnace is then vented. By venting the fluid connection, molten metal can get back into the casting furnace from the fluid connection, that is to say in particular while the casting furnace is being vented. The fluid connection is ensured in particular by a connecting line. The connecting line is designed in particular as a riser. In particular, an adapter unit can be part of the connecting line. In particular, the liquid metal melt can get back into the casting furnace while the metal melt solidifies and / or is pushed down in the casting mold. This makes it possible to separate the casting furnace from the casting mold more quickly. This reduces the cycle time for the casting furnace itself. There is no waiting time for the casting furnace while the molten metal solidifies in the casting mold. This can increase the utilization of the casting furnace. In particular, the casting furnace is available for further use after a shorter period of use.

By interrupting and ventilating the fluid connection, the casting furnace can be thermally and mechanically decoupled from the casting mold. Through the thermal and mechanical Decoupling the casting furnace from the casting mold avoids a further supply of thermal energy into the casting mold, in particular during the cooling of the molten metal in the casting mold. This leads directly to a shortening of the cycle time for the cast part. The shortening of the cycle time is therefore due to the reduction in the cooling time. The faster a casting cools, the higher its strength values. A cast part with increased strength enables a reduced use of material and reduced wall thicknesses in the component design. The method according to the invention enables increased flexibility and diversity in the production of lightweight cast components. One casting cycle is shortened. This improves the overall energy balance of the process. It is possible to use a casting furnace with reduced heat output. Before the fluid connection is interrupted, molten metal is provided in the casting furnace and poured from the casting furnace into the casting mold. The method relates in particular to the casting of light metal, in particular aluminum and its alloys. The method is applicable to low-pressure casting, in particular with rising molten metal, to counter-pressure casting and vacuum casting. The casting mold can be a permanent mold, which is also referred to as a permanent mold. The casting mold can also be a lost mold and is particularly suitable for a sand casting process. The method is particularly suitable for filling a casting mold with low pressure. In the so-called "lost foam" method, molded parts made of foamed plastic, in particular made of expanded polystyrene (EPS), which is known as Styrofoam, are embedded in molding sand. After the mold is ready to be poured, it is filled with the molten metal. The styrofoam molded parts evaporate on contact with the hot molten metal. The volume that has been taken up by the styrofoam moldings is filled by the molten metal. For an additional reduction of the cycle time, several molds can be bundled into a cluster and at the same time filled with increasing pressure using low pressure. The material shrinkage can be compensated for and the pressure in the cast part can be kept constant during solidification, in particular by means of an adapter unit, which is in particular arranged centrally. The bundling of the casting molds to form the grape is particularly applicable to all common sand casting processes.

A method in which the metal melt in the casting mold is pressed down by means of an adapter unit enables pressures of any desired level to be exerted, in particular of up to 100 bar or more. High pressures are required in particular for the production of fiber composite materials. The level of pressure depends in particular on the geometry of the casting mold and / or on the adapter unit, in particular the geometry of individual components of the adapter unit. A workpiece produced in this way has improved material properties and, in particular, increased strength values. The material shrinkage when the molten metal cools is compensated for by pressing down. Subsequent removal of large feeders is not necessary. In particular, the pressing takes place after the fluid connection has been interrupted.

The individual process steps can advantageously be carried out in an integrated manner by means of the adapter unit. The adapter unit has an increased functional density. Alternatively, the process steps, in particular the interruption of the fluid connection between the casting furnace and the casting mold, the active ventilation of the fluid connection, the pressing down on the molten metal, the demolding of the casting from the casting mold and / or the separation of the casting furnace from the casting mold, is possible, to be achieved by individual, separate components.

A method in which the postpressure is carried out by moving a piston in an adapter housing enables the postpressure to be applied directly to the melt. Axial displacement of the piston is easy to implement. A rotary movement of the piston can be superimposed on the axial stroke movement of the piston. In particular, it is possible to variably set the pressure exerted on the molten metal in the casting mold as a function of the holding time. In particular, it is possible to set the pressure in such a way that it is constant during the entire solidification phase. This results in an advantage compared to cooling a molten metal without repressing, that is to say without an active feed, in which the pressure drops during cooling. In particular, the pressing is no longer carried out directly from the casting furnace.

A method in which active cooling of the adapter unit is provided reduces the cycle time of the method, in particular the cooling and solidification of the molten metal in the casting mold. The adapter unit is cooled in particular during and / or after the pressing down. The adapter unit is cooled in particular after the fluid connection has been interrupted. In particular, the cooling of the adapter unit and thus the molten metal in the casting mold has no negative influence on the heated casting furnace and the ones in it molten metal, since the casting furnace is thermally and mechanically separated from the adapter unit, i.e. decoupled, after the fluid connection has been interrupted.

A method in which the casting molds are bundled and then rotated around a horizontal axis under feed pressure enables the melt to solidify in an advantageous manner. Since the feed volume that can be pushed down by the piston stroke might not be sufficient in a bundle of casting molds, it is possible to separate the casting molds from the casting furnace after venting the riser and to turn them by 180 ° around a horizontally arranged axis of rotation, as shown, for example DE 10 2004 043 444 B3 is known. The molds are turned upside down. The melt volume, which leads to the distribution of the individual casting molds, serves as the feed volume. When the casting molds are rotated, the melt located therein can solidify under the action of gravity and / or pressure can be applied from above, in particular by means of compressed air. The advantage over the prior art then lies in the fact that melt is pushed into the casting mold via the piston during rotation. A volume shrinkage as a result of cooling during turning is compensated. The pressurization counteracts cavitation.

This procedure, in particular turning a filled casting mold, is also possible with individual molds or chill molds. It is conceivable to position the adapter unit in a stationary position and to leave the casting molds open. The execution of the method is particularly suitable for a stationary casting furnace and transportable casting molds. The method has a reduced cycle time, since in particular the cooling and / or solidification of the metal melt in the casting mold are not relevant for the cycle time of the casting furnace. A cyclical process sequence in which the casting furnace is used is decoupled from the cooling and / or solidification of the molten metal in the casting mold.

A method in which a maximum filling pressure is provided in the casting furnace for filling the molten metal into the casting mold, the maximum filling pressure being less than 0.5 bar, simplifies the design of the casting furnace. Because the maximum filling pressure is less than 0.5 bar, the casting furnace is not subject to the Pressure Vessel Ordinance. The design and in particular the construction of the casting furnace is simplified as a result. The operation of the casting furnace is simplified. The maximum pressure that has to be provided by the casting furnace can be designed to be significantly lower become. The pressure must be just high enough that the molten metal can rise from the casting furnace, for example via a riser pipe, into a casting mold until the casting mold is filled. Pressing is done by means of the adapter unit. The casting furnace can be designed in an uncomplicated manner and, in particular, does not have to be removed in accordance with a pressure vessel regulation. The investment costs and the follow-up costs are reduced. The planning effort is reduced. A risk potential is reduced.

A process in which a cast part is removed from the casting mold enables the mapping of a complete process chain of a casting process. In particular, the demolding takes place by means of the adapter unit. The adapter unit has increased functional integration. A separate demolding tool is not necessary. Demoulding can be carried out easily. Demolding is possible immediately after the molten metal has solidified to form the cast part. A retrofitting of a casting method known from the prior art by means of a gravity casting frame is thereby particularly advantageously possible.

In a method in which the fluid connection is interrupted isobarically, the fluid connection can be interrupted independently of the melt pressure. Compared with a slide gate valve known from the prior art, it is in particular unnecessary to return the displaced melt. The procedure is simplified. Another great advantage is that the shape in the upper part of the piston in connection with the rotary movement of the piston cuts through the melt cross-section by means of the piston, but not squeezed it off, as is the case with an active feeder according to the prior art, in particular the active feeders that are derived from the DE 102 33 962 A1 or the DE 198 12 068 A1 are known. In particular, it is ensured that the solidification of the metal melt in the casting mold is decoupled from the interruption of the fluid connection. It is possible to interrupt the fluid connection without an additional pressure increase taking place on the molten metal. The interruption of the fluid connection is uncomplicated and not prone to errors. The risk of manufacturing-related material defects in the casting is reduced. The isobaric interruption of the fluid connection takes place by turning the piston in the adapter housing. This means that the piston performs an axial displacement and a rotation about the longitudinal axis of the adapter housing. The displacements can be carried out independently of one another, that is to say either an axial displacement or a rotation or a combined axial-rotational displacement.

A method in which the casting furnace is to be separated from the casting mold simplifies the thermal and mechanical decoupling of the components. In particular, a connection line, which is in particular firmly connected to the casting mold, is disconnected from the casting furnace. The casting furnace is vented in particular after the furnace has been thermally decoupled from the casting mold. After the casting furnace has been vented, it is available for connection to other casting molds.

A method in which further metal melt is provided for subsequent casting cycles during the solidification phase of the casting cycle, in particular by replacing the at least partially emptied casting furnace with a filled casting furnace and / or by refilling the at least partially emptied casting furnace with metal melt, enables the casting furnace to be used effectively, especially during the solidification of the molten metal. An uninterrupted operation of the process is guaranteed. In the event that sufficient molten metal is still present in the casting furnace for a subsequent casting cycle, the sufficiently filled casting furnace can dwell in a position provided for this purpose, in particular in a casting position.

A method in which an opening is provided along the fluid connection at a distance from the casting mold simplifies active venting of the fluid connection. This ensures that after the fluid connection is interrupted, molten metal, which is arranged between the casting mold and the casting furnace, can automatically flow back into the casting furnace, in particular as a result of gravity. A so-called pipette effect, after which the liquid metal melt remains in the riser, is prevented. In particular, the opening is used to ventilate the fluid connection. The opening is released for this purpose.

A method in which a storage volume, in particular in the form of a pressurized gas, in particular air, is supplied through the opening of the fluid connection for active ventilation of the fluid connection leads to an acceleration of the outflow of the molten metal into the casting furnace. The pressurized gas can be supplied with a ventilation pressure of, for example, at least 2 bar, in particular at least 5 bar and in particular at least 10 bar. The storage volume can advantageously be used as a pressurized gas filled tube can be provided. A pipe can be designed in an uncomplicated manner and in particular not as a pressure vessel. When the fluid connection, in particular the riser, is vented, the amount of gas in the storage volume is introduced. The volume of the container and the pressure of the gas cause the molten metal to be quickly returned from the riser to the casting furnace. The casting furnace is prevented from being put under additional pressure. The pressure and quantity of the gas are therefore essential for the storage volume.

As an alternative to active ventilation by supplying pressurized gas, it is also possible to suck in the gas, in particular inert gas, from a gas reservoir which is in particular connected to the opening. In particular, the gas is sucked in through the sinking melt column in the connection. The gas reservoir is in particular a flexible bag in which the gas is under ambient pressure.

A method in which the casting furnace is connected to at least one second casting mold after the first casting mold has been separated enables the resources to be used advantageously. The casting furnace can be used to fill the second casting mold while the molten metal in the first casting mold is pushed in and solidifies. This ensures that the molten metal in the casting furnace can be completely processed in a limited time interval, which in particular is a maximum of 90 minutes. In particular, when the maximum filling pressure is less than 0.5 bar, it is possible to use large-volume casting furnaces. There are no limits to the filling capacity of the casting furnace, at least in terms of the Pressure Vessel Ordinance.

It is another object of the present invention to simplify the practice of the method of casting metal.

This object is achieved according to the invention by an adapter unit having the features specified in claim 11.

It was recognized that the adapter unit enables the direct, in particular thermal and mechanical, decoupling of the casting furnace from the casting mold. This simplifies the implementation of the method. In particular, the interruption of the fluid connection between the casting furnace and the casting mold, as well as venting the fluid connection, are uncomplicated. The casting mold has an adapter housing having a housing longitudinal axis and a piston which can be displaced in the adapter housing. The piston can be designed to be displaceable along the longitudinal axis of the housing. The piston can be rotated about the longitudinal axis of the housing. The piston can be controlled via various types of drive, for example by means of a hydraulic drive, a pneumatic drive and / or an electric drive.

An adapter unit in which the piston has an opening for venting a connecting line that can be connected to the adapter housing has increased functionality. The connection line can be pressurized directly via the piston. In particular, the adapter housing and in particular the connecting line can be ventilated through an opening which is arranged at a distance from the casting furnace. Alternatively, it is conceivable to implement the ventilation via a separate channel, which runs in particular inside the piston. It is also conceivable to implement the ventilation via a separate control unit in the adapter housing. In principle, it is irrelevant how the ventilation takes place in detail. It is essential that the gas used for venting, for example air or another inert gas, is supplied at one position, in particular the riser, so that the molten metal in the riser flows back easily and completely into the casting furnace, in particular automatically. It is also essential that this prevents metal oxides from being able to form in the interior of the molten metal and / or on the molten bath surface and / or that gas bubbles remain dissolved in the molten metal. This prevents material defects in the later cast part.

An adapter unit is arranged in particular along the fluid connection between the casting furnace and the casting mold. The adapter unit can be retrofitted to existing devices for casting metal. This makes it possible to carry out the method according to the invention with a device known from the prior art, which is retrofitted with the adapter unit according to the invention. This enables a particularly cost-effective upgrade of a device known per se, which enables essential advantages by retrofitting the adapter unit, such as cycle time reduction of the cast part, reduced energy consumption, increase in the strength values of the cast part, expansion of the product range, in particular fiber-reinforced cast parts, maintenance of a permanent, uninterrupted casting operation Provide of molten metal during the solidification phase of the casting and operation of Multiple casting equipment with existing air and / or hydraulic networks through the timing of the casting systems.

A device with an adapter unit of this type has a particularly modular structure. The modular structure in particular enables a central hydraulic supply to be simplified. Hydraulic travel movements are necessary, for example, for demolding the casting, that is to say for opening the casting mold, and / or for closing the casting mold for the mold. Crucial for the size of a hydraulic unit are travel speeds and volumes that are required for hydraulic travel movements of several hydraulic cylinders in the retraction or extension direction, in particular for simultaneous hydraulic travel movements. With the device it is possible to switch the casting processes of the various modules one after the other so that the hydraulic movements take place one after the other. It is sufficient to use one hydraulic unit for all casting equipment in a module. The size of the hydraulic unit is determined by the size of the casting station. The size of the hydraulic unit corresponds to the size of the casting station. During the filling and during the solidification phase, no hydraulic driving movements are essentially required, with the exception of the hydraulic operation of the adapter unit, for which, however, only small delivery quantities of hydraulic fluid are required. The low delivery rates for the adapter unit can be made available, for example, via a hydraulic accumulator. It is sufficient to provide pressure control and furnace temperature control. As a result, the compressed air output and current output of the device can be reduced. When a new device is purchased, the system costs are significantly reduced. Because the adapter unit in particular enables a casting to be removed from the mold, the design of removal means, such as a gripping unit for removing a casting from the casting mold, is simplified. In particular, the control and / or regulation effort and in particular the components required for this are reduced.

The device comprises at least one casting furnace and at least one casting mold. Mutual connection of the at least one casting furnace to a casting mold requires a relative movement between the casting furnace and the casting mold. This can take place in particular in that the casting mold is suspended in a frame provided for this purpose, that is to say arranged in a spatially fixed manner. In this case, the casting furnace is arranged to be displaceable in space. It is also conceivable that the at least one casting mold is rotatably arranged in space, for example on a carousel arrangement, the casting mold to be filled in each case being displaced relative thereto for connection to the casting furnace.

It is also conceivable to arrange both the casting furnace and the casting mold so as to be movable in space.

A device with several casting molds enables the efficiency of the device to be increased. The method can be designed to be economically effective. In particular, just enough casting molds are provided that after the last casting mold has been filled in a first casting cycle, the first casting mold is available to start a second casting cycle, since the solidified casting of the first casting mold of the first casting cycle has been completely removed from the mold. The number of casting molds is therefore particularly dependent on the filling time and the solidification time of the molten metal. It is particularly conceivable that two casting molds, five or more casting molds are provided. The casting molds can, for example, be arranged in a grid-like manner or concentrically. In particular, the device has at least one second casting furnace which provides molten metal when the first casting furnace is emptied. This ensures an essentially uninterrupted operation of the device, so that at least one casting furnace with molten metal of optimal quality is always available for casting. After the molten metal has been made available in the first casting furnace, there is approximately a material-dependent processing time of, for example, 90 minutes in order to pour the molten metal into the casting molds. After this processing time has elapsed or when the casting furnace has been emptied, a second furnace with molten metal can be made available immediately and used for further filling of casting molds. A standstill of the device, in particular an interruption of the filling of the casting molds while the first casting furnace is being filled, is avoided. The utilization and the overall efficiency of the device are thereby additionally increased.

A device in which the adapter unit and / or the connecting line are made of ceramic material has a particularly long service life. The service life of the thermally and / or mechanically highly stressed components, i.e. the adapter unit and the connecting line, is increased. In particular, the adapter unit and / or the connecting line are made from silicon nitride. In particular, it is possible for the adapter housing and the connecting line in one piece, i.e. as a one-piece component. It is conceivable to make highly stressed components as ceramic inserts and / or material coated with ceramic material, in particular zirconium dioxide (ZrO2).

Fig. 1

eine Vorrichtung zum Gießen von Metall mit einem zwischen zwei Gießformen verlagerbaren Gießofen,

Fig. 2

einen Längsschnitt durch den Gießofen gemäß Fig. 1 mit der über eine Steigleitung und eine Adaptereinheit verbundene Gießform,

Fig. 3

eine vergrößerte Ansicht des Details III in Fig. 2,

Fig. 4

eine Fig. 3 entsprechende Darstellung einer Anordnung der Adaptereinheit zum Unterbrechen der Fluidverbindung zwischen Gießofen und Gießform,

Fig. 5

eine Fig. 4 entsprechende Darstellung einer Anordnung der Adaptereinheit zum Belüften der Fluidverbindung,

Fig. 6

eine Fig. 5 entsprechende Darstellung in einer Anordnung der Adaptereinheit zum Nachdrücken,

Fig. 7

eine perspektivische, vergrößerte Einzeldarstellung des Kolbens der Adaptereinheit,

Fig. 8

eine Fig. 1 entsprechende Darstellung einer weiteren Ausführung einer Vorrichtung mit einem Gießkarussell,

Fig. 9

eine Fig. 1 entsprechende Darstellung einer weiteren Ausführung einer Vorrichtung mit einer Reihenanordnung der Gießformen,

Fig. 10

eine Fig. 1 entsprechende Darstellung einer weiteren Ausführung einer Vorrichtung mit einer erweiterten Reihenanlage und

Fig. 11

eine Fig. 10 entsprechende Darstellung einer weiteren Ausführung einer Vorrichtung mit einer mehrfach belegten Reihenanlage.

Embodiments of the invention are explained in more detail below with reference to the drawing. Show it:

Fig. 1

a device for casting metal with a casting furnace that can be displaced between two casting molds,

Fig. 2

a longitudinal section through the casting furnace according to Fig. 1 with the casting mold connected via a riser and an adapter unit,

Fig. 3

an enlarged view of the detail III in Fig. 2 ,

Fig. 4

a Fig. 3 corresponding representation of an arrangement of the adapter unit for interrupting the fluid connection between casting furnace and casting mold,

Fig. 5

a Fig. 4 corresponding representation of an arrangement of the adapter unit for venting the fluid connection,

Fig. 6

a Fig. 5 corresponding representation in an arrangement of the adapter unit for pushing down,

Fig. 7

a perspective, enlarged individual representation of the piston of the adapter unit,

Fig. 8

a Fig. 1 corresponding representation of a further embodiment of a device with a pouring carousel,

Fig. 9

a Fig. 1 corresponding representation of a further embodiment of a device with a series arrangement of the casting molds,

Fig. 10

a Fig. 1 corresponding representation of a further embodiment of a device with an extended series system and

Fig. 11

a Fig. 10 Corresponding representation of a further embodiment of a device with a multiple occupancy row system.

One in Figures 1 to 7 The illustrated embodiment of a device 1 is designed as a so-called machine duo. The device 1 is used for the low-pressure casting of aluminum.

The device 1 comprises a first casting furnace 2, in which aluminum is heated and the aluminum melt is provided. The first casting furnace 2 can be displaced linearly along a first casting furnace conveying direction 4 by means of a drivable roller conveyor device 3.

Two casting mold stations 5 are arranged next to one another along the first casting conveying direction 4. The casting mold stations 5 are identical in themselves. Each casting mold station 5 has a frame-like portal 6 with several vertical supports 7 and horizontal beams 8. A casting mold 9 is provided on the portal 6. The roller conveyor device 3 with the first casting furnace 2 is arranged in a lower stand section of the portal 6. The casting mold 9 is arranged in an upper casting mold section of the portal 6. The vertical distance between the casting mold 9 and the roller conveyor 3 is selected such that the first casting furnace 2 can be coupled to the casting mold 9 arranged above it. At the in Fig. 1 The arrangement shown, the first casting furnace 2 is coupled to the casting mold 9 of the casting mold station 5 shown on the left.

The casting mold 9 is made in several parts and has four casting mold side parts 10 which can be displaced relative to one another in one plane. The casting mold side parts 10 can each be displaced in the plane by means of a hydraulic cylinder. A casting mold upper part 11 can be displaced perpendicular to this plane by means of a lifting portal 12. A lower casting mold part 50 is arranged opposite the upper casting mold part 11 on an underside. The lower part 50 of the casting mold is designed in the form of a plate with an access opening for supplying the molten metal. The lower part 50 of the casting mold is in particular held firmly, in particular immovably, on the casting mold station 5. The casting mold side parts are used to close the casting mold 9, which is also referred to as a chill mold 10 and the upper part 11 of the casting mold is displaced.

In the in Fig. 1 The casting mold 9 shown on the left are the side parts 10 and the upper part 11 in a closed arrangement of the casting mold. In this arrangement, the mold 9 can be filled with molten metal. In the Fig. 1 The casting mold station 5 shown on the right shows the casting mold 9 in the demolding arrangement. The side parts 10 and the upper part 11 are arranged at a distance from one another. In this arrangement, a cast part that has been produced can be demolded.

Adjacent to the roller conveyor device 3 and perpendicular to the first casting conveyor device 4, a further roller conveyor device 13 is provided, which is designed essentially identically to the first roller conveyor device 3. A second casting furnace 14 is arranged on the roller conveyor device 13. The second casting furnace 14 can be displaced along the first casting furnace conveying direction 4 on the roller conveying device 13. According to the arrangement shown in Fig. 1 the second casting furnace 14 is arranged in front of the casting mold station 5 shown on the right. Both the roller conveyor 3 and the roller conveyor 13 enable the casting furnaces 2, 14 to be changed perpendicular to the first casting furnace conveying direction 4, that is, along a transverse conveying direction 15. A casting furnace can be exchanged along the transverse conveying direction 15.

The first casting furnace 2 has an inner container 16 with an upper cylinder section and a spherical cap section formed integrally thereon. The inner container 16 can also be referred to as a crucible. The inner container 16 is also available in other geometric shapes as standard. The inner container 16 is surrounded by a thermal insulating layer 17 in order to reduce heat loss during the casting process. If the insulating layer 17 of the casting furnace 2 is made sufficiently, it is conceivable that the casting furnace 2 does not have a separate heater. Conversely, this means that separate heating is provided on the casting furnace 2 in order to ensure adequate temperature control of the molten metal 22. In particular, it is conceivable that the casting furnace is additionally heated externally with every second or third casting. The heating takes place in particular while the casting furnace 2 is arranged in the casting mold station 5. In particular, a connection for heating, in particular for electrical heating, can be provided at the casting mold station 5. The connection for electrical heating is designed in particular in such a way that the casting furnace 2 is automatic is coupled to the connection when it is in the arrangement for filling the mold 9. In addition, an air connection (not shown) is provided for the air supply. A line for connection to a central air supply can be provided at the air connection. In this case, the control of the filling pressure in the casting furnace 2 is part of the furnace unit, that is to say of the casting furnace 2. It is also possible to provide a regulated air supply via the air connection. In this case, the control of the casting furnace 2 is carried out in a stationary manner.

The inner container 16 can be closed in a pressure-tight manner with a lid 18 on an upper side. The cover 18 is insulated from the outside on an inside. The casting furnace 2 has a pressure-tight connection line, not shown, to the outside in order to be able to increase the pressure atmosphere above the melt. The cover 18 has a cover opening 19, which can in particular be arranged centrally on the cover 18. When converting an existing device, an adapter may be required in order to compensate for a lateral offset of a riser pipe 24 and / or an adapter housing 25. This makes it possible to use an existing casting furnace immediately. There is no need to replace the casting furnace. A removal tube 20 is guided into the inner container 16 through the cover opening 19. The extraction tube 20 can be pressed into the interior of the inner container 16 against a spring force of a shaft compensator 21. By means of the spring force of the shaft compensator 21, the separation point between the extraction pipe 20 and the riser pipe 24 can be connected in a pressure-tight manner. The extraction pipe 20 is also referred to as a furnace riser pipe. For improved sealing, additional sealing elements, which are not shown, can be used in the area of the separation point. The wave compensator 21 simplifies the changing of casting furnaces 2. In principle, it is also possible to use a riser pipe arrangement known from the prior art, in which the riser pipe 24 is fixedly fixed to the cover 18. In this embodiment, the tightness is guaranteed by the fact that the casting furnace 2 is pressed with the casting mold 9 and additional sealing elements are used.

The inner container 16 is filled with a molten metal, in particular with molten aluminum 22. The casting furnace 2, in particular the extraction pipe 20, is connected to the casting mold 9 via an adapter unit 23. According to the exemplary embodiment shown, the adapter unit 23 has a riser pipe 24, which is arranged essentially concentrically to the extraction pipe 20, as a connecting line. With the riser 24, an adapter housing 25 is connected, the one Has housing longitudinal axis 26. A piston 27 is arranged in the adapter housing 25.

The riser pipe 24 has a substantially L-shaped flow channel which extends vertically upward as an extension of the extraction pipe 20 and has a 90 ° bend at an upper end of the riser pipe 24. A flow channel formed in the adapter housing 25 is also essentially L-shaped. The two flow channels in the riser pipe 24 and in the adapter housing 25 enable a fluid connection between the casting furnace 2 and the casting mold 9. The flow channels are connected to one another in such a way that the fluid connection is essentially S-shaped.

The transition from the riser pipe 24 to the adapter housing 25 is conical. This ensures that the molten metal 22 flows back completely and in particular independently from the riser pipe 24 into the casting furnace 2 during venting.

The following is based on the Figures 3 to 7 the structure of the adapter unit 23 is explained in more detail. According to the embodiment shown, adapter housing 25 and riser pipe 24 are designed as separate, independent components. It is also conceivable to design the adapter housing 25 in one piece with the riser pipe 24. In particular, it is conceivable to produce a one-piece component from ceramic material. This can simplify production. The separate design according to the exemplary embodiment shown has the advantage that different materials can be used. This makes it possible, in particular, to select the materials for the riser pipe 24 and the adapter housing 25 that meet the requirements.

A piston 27 can be displaced along the longitudinal axis 26 of the housing. The piston 27 is rotatable about the housing longitudinal axis 26 in the adapter housing 25. A melt reservoir 28 is provided in the adapter housing 25 and faces the casting mold 9. The melt reservoir 28 is designed as a substantially frustoconical recess. Melt can be stored in this recess during the filling of the casting mold 9. The melt reservoir 28 ensures that sufficient metal melt 22 is available for reprinting. The adapter housing 25 has a transverse bore 29 which enables the melt reservoir 28 to be connected to the fluid channel in the riser pipe 24. The cross hole 29 is in Fig. 3 shown. The adapter housing 25 also has a vent hole 51. The The ventilation bore 51 is arranged along the housing longitudinal axis 26 essentially at the same height as the transverse bore 29. In relation to an angle of rotation about the housing longitudinal axis 26, the transverse bore 29 and the ventilation opening 51 are arranged at a distance from one another. Typically, the transverse bore 29 and the venting opening 51 are not in fluid connection with one another through the piston 27, which is arranged in the adapter housing 25, in particular during the filling of the casting mold 9.

Concentric to the transverse bore 29, a flow-favorable recess is made in the piston 27 as a continuation of the fluid channel. The streamlined recess has the effect that turbulence in the molten metal 22 when filling the casting mold 9 is avoided.

An opening 30, which faces the melt channel in the riser pipe 24, is arranged on an outside of the piston 27. The opening 30 is in particular in Fig. 3 , 5 and 6 recognizable. The opening 30 enables air and / or gas to be fed into the riser pipe 24. The opening 30 serves to ventilate the fluid connection between the piston 27 and the casting furnace 2.

The opening 30 is designed as a groove-shaped recess of the piston 27 on an outer cylinder jacket surface. The groove-shaped depression extends along the outer cylindrical surface of the piston 27 along an angle of rotation range based on a longitudinal axis of the piston 27. The angle of rotation range is approximately 90 ° according to the exemplary embodiment shown. It is essential that the angle of rotation range is large enough that the opening 30 can serve as an air connection channel. In particular, the opening 30 is designed like a blind hole. This means that the opening 30 is not a through opening and, in particular, there is no connection between the melt reservoir 28 and the riser pipe 24 through the opening 30. The opening 30 and the transverse bore 29 are arranged at a distance from one another on an outer side of the piston 27 along an angle of rotation about the housing longitudinal axis 26.

The piston 27 is connected to a drive unit, not shown, which enables the piston 27 to be displaced along a pushing-down direction 31, i.e. along the longitudinal housing axis 26, or a rotation about the longitudinal housing axis 26 independently of one another or in combination with one another.

In a lower section facing away from the casting mold 9, the piston 27 has a cooling bore 32. The cooling bore 32 serves to supply or flow through the lower piston section with a coolant. The cooling bore 32 can also be used to heat the piston 27 or to control the temperature in some other way.

The following is based on Figures 1 to 7 a method for casting metal, in particular aluminum, explained in more detail. First of all, aluminum is provided as molten metal 22 in the first casting furnace 2. The casting furnace 2 is under the to be filled, according to Fig. 1 The casting mold 9 arranged on the left is positioned and coupled by means of the adapter unit 23. The coupling takes place in that the riser pipe 24 is placed on an end flange of the extraction pipe 20. As soon as the casting furnace 2 is connected to the casting mold 9 in a pressure-tight manner, the interior of the casting furnace 2 is subjected to pressure. As a result of the application of pressure, the molten metal 22 rises via the extraction pipe 20, the riser pipe 24 and the adapter housing 25 into the casting mold 9. An arrangement of the adapter unit 23 for filling the casting mold 9 is shown in FIG Fig. 2 and 3 shown. How it looks in particular Fig. 3 results, the piston 27 is arranged at a distance from the transverse bore 29 during the filling of the casting mold 9 with the opening 30. In particular, the transverse bore 29 is separated from the vent opening 51 in a fluid-tight manner. There is no fluid connection between the transverse bore 29 and the ventilation opening 51 while the casting mold 9 is being filled.

After the casting mold 9 has been completely filled with molten metal 22, the piston 27 is rotated about the longitudinal axis 26 of the housing. The melting reservoir 28 is separated from the transverse bore 29 by the rotation. There is then no continuous fluid connection. The fluid connection is interrupted. This arrangement is in Fig. 4 shown.

It is also conceivable that the casting mold 9 is not completely filled with molten metal 22. In this case, the casting mold 9 is filled by axially displacing the piston 27 along the housing longitudinal axis 26, in particular by pressing metal melt 22 from the melt reservoir 28 into the not completely filled casting mold 9.

Because the fluid connection is interrupted by rotating the cylindrical piston, this method step is isobaric. Additional pressurization of the Metal melt 22 in the melt reservoir 28 and in particular in the casting mold 9 does not take place. In the in Fig. 4 There is no direct fluid connection between the casting furnace 2 and the casting mold 9, in particular not via the molten metal 22. Due to the pipette effect, the molten metal initially remains in the riser 24 even if the fluid connection is interrupted, although the casting furnace 9 is vented.

By further turning the piston 27 about the housing longitudinal axis 26, the opening 30 is exposed. This means that by rotating the piston 27, the groove-shaped recess 30 enables a fluid connection between the transverse bore 29 and the vent opening 51. As a result, the fluid connection is ventilated from an end of the riser pipe 24 facing away from the casting furnace 2. For reasons of presentation, in Fig. 6 the molten metal in the adapter housing 25 is not shown and the piston 27 is shown partially in section. An air supply opening in the adapter housing 25 is used to ventilate the riser pipe 24. In relation to the transverse bore 29, the air supply opening is arranged at an angle of rotation of approximately 10 ° to 30 ° around the longitudinal axis 26 of the housing. The air supply opening (not shown) corresponds to the opening 30, which is designed in particular as an external groove in the piston 24. The molten metal 22 can automatically flow back into the casting furnace 2 from the riser pipe 24 as a result of gravity. The casting furnace 2 can be separated from the casting mold 9. In particular, the casting furnace 2 is separated from the casting mold 9 while the melt 22 in the casting mold 9 is still liquid. The casting furnace 2 can be thermally and mechanically decoupled from the casting mold 9 by means of the adapter unit.

The melt can be pushed down in the casting mold 9 by means of an axial displacement along the pushing-down direction 31 of the piston 27.

The casting furnace 2 is decoupled after the casting mold 9 has been filled in the casting mold station 5 shown on the left and after the fluid connection has been vented, and is arranged below the casting mold 9 of the casting mold station 5 shown on the right by means of the roller conveyor 3. The casting mold 9 is then closed and connected to the casting furnace 2 for filling. The connection is made in an uncomplicated manner via the adapter unit 23. The casting mold 9 is closed and the casting furnace 2 is displaced independently of one another.

A linear change between the two casting mold stations 5 takes place until the in the The molten metal stored in the first casting furnace 2 can no longer be processed, for example due to the passage of time, and / or the molten metal 22 has been used up. In this case, the first casting furnace 2 is conveyed via the roller conveyor devices 3, 13 for refilling and the second casting furnace 14 is conveyed under one of the casting mold stations 5 along the transverse conveying direction 15 for further operation of the device 1.

The device 1 enables uninterrupted operation. The downtimes are minimized and, in particular, excluded. An optimal quality of the molten metal 22 is guaranteed.

In Fig. 8 a further embodiment of a device is shown, wherein several casting mold stations 5, six according to the embodiment shown, are arranged on a rotary indexing table 33 in the form of a casting carousel. The rotary indexing table 33 can be rotated about a vertical axis of rotation 34 in such a way that a casting mold 9 to be filled in a casting mold station 5 can be arranged above the casting furnace 2 located in a casting position. The relative displacement between the casting mold 9 and the casting furnace 2 takes place in particular by rotating the rotary indexing table about the vertical axis of rotation 34 by an angular amount of 60 °. As soon as the casting furnace 2 located in the casting position has been emptied, uninterrupted operation of the device 35 by the second casting furnace 14 can be ensured.

It is conceivable that the casting furnace 2 is arranged on a rotary indexing table 33 and the casting mold stations 5 are arranged statically.

The casting furnaces 2, 14 are exchanged in the device 35 in the exemplary embodiment according to FIG Fig. 8 analogous to the first embodiment with the roller conveyor devices 3, 13. It is alternatively possible to provide other conveyor devices that enable linear and / or rotary conveying of the casting furnaces 2, 14. Continuous conveyors, rail-bound systems and / or driverless transport systems are also possible. In particular, a combination of several of these systems is also possible.

In Fig. 9 a further embodiment of a device is shown, wherein the mold stations 5 are designed as a series system. The main difference compared to the first embodiment consists in that four mold stations 5 are arranged side by side in a row.

In principle, it is conceivable that the casting furnace 2 is designed to be static and a relative displacement takes place by transporting the casting molds 9. It is essential that a cyclical process is provided, which means that a filling sequence is determined by a filling direction 37 for the device 36 in Fig. 9 is given. This means that the filling molds 9 as shown in FIG Fig. 9 be filled from left to right. If the in Fig. 9 The casting mold 9 shown on the right is filled, a new filling cycle begins with the in Fig. 9 The casting mold 9 of the casting mold station 5 shown on the left, however, is also possible after the filling of the in Fig. 9 The casting mold 9 shown on the right, the casting furnace 2 is transported to the adjacent casting mold 9. In this case, the filling direction 37 is oriented from right to left. In principle, it is therefore conceivable that the filling direction 37 can be oriented in both directions along the roller conveyor device 3.

A second casting furnace 14 is also provided here in order to ensure an uninterrupted process.

The casting furnace is exchanged during the cooling phase, so that it is ensured that the casting mold 9 is essentially always at operating temperature and unintentional cooling does not take place. After the last casting mold 9 has been filled, the casting furnace 2 can be conveyed back to the first casting station 5 and then used for the further filling of casting molds 9. In particular, the second casting furnace 14 is only used when the first casting furnace 2 has been emptied.

In Fig. 10 a further embodiment of a device 38 is shown. The device 38 corresponds essentially to the device 36 in FIG Fig. 9 , a total of eight casting mold stations 5 are provided. The first casting furnace 2 sequentially fills the casting molds 9 of the casting molding stations 5, which are arranged in a row. If the first casting furnace 2 has reached the end of the row along the filling direction 37, that is, according to FIG Fig. 10 has reached the mold station 5 shown on the right, a new mold cycle is started by moving the second casting furnace 14 from the waiting position on the roller conveyor 13 to the first mold station 5, which is shown in FIG Fig. 10 Left is shown, is transported along the transverse conveying direction 15. Correspondingly, the first casting furnace 2 is transported back from the roller conveyor 3 along the transverse conveying direction 15 to the roller conveyor 13 and positioned against the filling direction 37 on the roller conveyor 13 back into the waiting position in front of the first casting mold station 5. With the device 38 it is also possible for the first casting furnace 2 and the second casting furnace 14 to be used simultaneously on the roller conveyor 3 for filling casting molds 9. The casting furnaces 2, 14 are operated at a certain distance from one another, which can be defined in terms of time or geometry. The number of casting mold stations 5 that are located at this distance depends in particular on the cycle time of the cast part. In addition, a third casting furnace 39 and a fourth casting furnace 40 are provided. The third and the fourth casting furnace 39, 40 are made ready for casting and are ready as soon as the first casting furnace 2 and / or the second casting furnace 14 are emptied.

In Fig. 11 a further embodiment of a device 41 is shown in which several, in particular two first casting furnaces 2 are used in parallel for filling casting molds. Correspondingly, two second casting furnaces 14 are provided in waiting position and two third casting furnaces 39 are provided for the exchange. Depending on the capacity of the casting furnace, the weight of the casting and the cycle time for filling the casting mold 9, the number of casting mold stations 5 and / or casting furnaces 2 can be determined.

The method according to the invention is suitable for different types of casting frames, in particular the design of the casting frame is irrelevant for the application of the method according to the invention. In particular, it is irrelevant whether the core pulls of the casting frame are mounted on a base plate, are designed to be suspended from columns or move up and down as quill pulls with the movable platen. The type of displaceability of the casting furnace is also irrelevant for carrying out the method according to the invention. It is conceivable to use roller conveyors or rail-bound and / or driverless transport systems. The design of the mold for producing the cast part is also irrelevant for the method according to the invention. Brick foundry furnaces, which are tempered by ceiling heating elements, can be used. It is also possible to use crucible furnaces which are heated by means of meander elements. Highly insulating casting furnaces are also conceivable, which are heated, for example, by means of immersion heaters. In particular, these are according to the invention The method and the device according to the invention are not limited to the specific exemplary embodiments in which, for example, a portal is designed as a casting frame, the changing of casting furnaces via roller conveyors, a wheel mold as a mold, and the casting furnace as an insulating furnace.

Claims (15)

1. Process for casting metal comprising the process steps of

   - providing metal melt (22) in a casting furnace (2),

   - filling the metal melt (22) from the casting furnace (2) into a casting mold (9),

   - actively interrupting a fluid connection between the casting furnace (2) and the casting mold (9) by a rotation of a piston (27) around a longitudinal housing axis (26) in an adapter housing (25),

   - venting the casting furnace (2),

   - actively aerating the fluid connection.
2. Process according to claim 1, characterized by pressing the metal melt (22) into the casting mold (9) by means of an adapter unit (23), in particular after the interruption of the fluid connection, wherein the holding pressure in particular is performed by an axial displacement of a piston (27) in an adapter housing (25), wherein in particular an active cooling of the adapter unit (23) is intended, in particular during and/or after the pressing.
3. Process according to any one of the preceding claims, characterized by bunching a plurality of casting molds (9) and rotating the bunched casting molds under active feeding pressure, wherein the axis of rotation in particular is oriented horizontally.
4. Process according to any one of the preceding claims, characterized by a maximal filling pressure in the casting furnace (2) for filling the metal melt (22) into the casting mold (9), wherein the maximal filling pressure is lower than 0.5 bar.
5. Process according to any one of the preceding claims, characterized by demolding a cast piece from the casting mold (9), in particular by means of the adapter unit. (23).
6. Process according to any one of the preceding claims, characterized in that the interruption of the fluid connection takes place in an isobaric manner, in particular as an isobaric cutting off of the melt by a rotation of a piston (27) in an adapter housing (25).
7. Process according to any one of the preceding claims, characterized by a separation of the casting furnace (2) from the casting mold (9), in particular a separation of a connecting line (24) from the casting furnace (2), in particular after a thermal decoupling of the casting furnace (2) from the casting mold (9).
8. Process according to any one of the preceding claims, characterized by providing further metal melt for subsequent casting cycles during the solidification phase of the casting cycle, in particular by replacing the at least partially emptied casting furnace (2) with a filled casting furnace (2) and/or by refilling the at least partially emptied casting furnace (2) with metal melt (22).
9. Process according to any one of the preceding claims, characterized by an opening (30) arranged along the fluid connection towards the casting furnace (2) in a spaced manner, which in particular is released for aerating the fluid connection actively, wherein for actively aerating in particular a storage volume in the form of a pressurized gas, in particular an inert gas, is fed through the opening (30) to the fluid connection.
10. Process according to any one of the preceding claims, characterized by connecting the casting furnace (2) with at least one second casting mold (9) after separating the first casting mold (9), in particular during the cooling of the metal melt (22) in the first casting mold (9).
11. Adapter unit (23) for decoupling a casting furnace (2) from a casting mold (9) with an adapter housing (25) having a longitudinal housing axis (26),
    characterized by

    - a piston (27) which is rotatably drivable around the longitudinal housing axis (26),

    - a melt reservoir (28) arranged in the adapter housing (25) and facing the casting mold (9),

    - a cross hole (29) of the adapter housing (25), which allows for a connection of the melt reservoir (28) with a fluid channel in a riser (24)

    such that by a rotation of the piston (27) around the longitudinal housing axis (26) the melt reservoir (28) can be separated from the cross hole (29) and the fluid connection can be interrupted.
12. Adapter unit according to claim 11, characterized in that the piston (27) has an opening (30) for actively aerating a connecting line (24) which can be connected with the adapter housing (25).
13. Device for casting metal comprising

    - a casting furnace (2) for providing metal melt (22),

    - at least one casting mold (9),

    - at least one adapter unit (23) according to claim 11 or 12.
14. Device according to claim 13, characterized by a plurality of casting molds (9), in particular arranged in a grid-like manner or concentrically, wherein in particular at least one second casting furnace (14) is intended for providing metal melt when the first casting furnace (2) is emptied.
15. Device according to claim 13 or 14, characterized in that the adapter unit (23) and/or the connecting line (24) are made of ceramic material, wherein the adapter housing (25) and the connecting line (24) in particular are construed in one piece.

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