DE102019219234A1 - Casting arrangement for gravity casting - Google Patents

Abstract

Casting arrangement (1) for gravity casting, in particular of aluminum components, comprising a crucible (2) for receiving melt (3), a filter device (4) with a filter for filtering the melt (3), and a metering unit (5) which is set up for removing melt (3a) filtered by the filter device (4) from the crucible (2) and for transferring and metering the filtered melt (3a) to a casting mold (6).

Description

The present invention relates to a casting assembly for gravity casting. The invention also relates to a method for gravity casting.

The disclosure document DE 10 2006 040 944 A1 shows a previously known method for pouring gravity molds.

It is an object of the present invention to provide a casting arrangement with which casting can be carried out as efficiently as possible using the gravity casting process. In particular, it should be possible to manufacture metal components as quickly, inexpensively and with high quality as possible.

The object is achieved by a casting arrangement for gravity casting with the features of claim 1. The casting arrangement is preferably designed to cast components from a metal, in particular aluminum or an aluminum alloy. In principle, the casting arrangement is suitable for any casting process based on gravity. The arrangement is preferably provided for gravity die casting and / or for tilt casting. For example, aluminum components, such as cylinder heads for internal combustion engines, in particular of vehicles, can be cast in this way.

The casting arrangement comprises a crucible, a filter device, and a metering unit. The crucible is designed to hold melt. It is preferably a container that is open at the top. For example, the crucible can be a holding furnace for holding the liquid melt warm. The filter device comprises a filter for filtering the melt.

The metering unit is set up to remove, in particular a predefined volume, of melt filtered by the filter device from the crucible. Furthermore, the metering unit is set up to transfer the removed, filtered melt to a casting mold and to feed it into the casting mold in a metered manner. In particular, the metering unit thus allows the melt to be removed in portions and then the melt removed to be metered into the casting mold.

For a particularly simple and inexpensive arrangement, the metering unit can preferably be a pouring ladle. It is also particularly advantageous if the casting arrangement further comprises a robot which is designed to handle the dosing unit; especially to enable automated casting. A mold is preferably provided as the casting mold; that is, a reusable casting mold for casting metals, the mold preferably forming a negative shape of the component to be cast.

As a result of the casting arrangement, high-quality components can thus be produced in a particularly simple and inexpensive manner. The filter device enables a filtering out or at least a reduction of oxides and impurities of the melt present in the crucible. On the one hand, this ensures a high material quality of the component to be produced, and on the other hand, this reduces wear on the casting mold, in particular a sprue system, and the metering unit, which enables a particularly long service life of the casting arrangement.

The filter device is preferably arranged inside the crucible in order to enable components to be cast in a simple and time-saving manner. In addition, a simple, flexible adaptation of the casting arrangement to different uses and / or components to be cast is thereby possible. For example, the casting arrangement can be used for casting in the most varied of molds without the need to adapt the components, since the filter device can remain in the crucible.

The casting arrangement particularly preferably further comprises a holding device which is set up to hold the filter device within the melt which is located in the crucible. That is, the filter device is immersed in the melt and is held therein by the holding device. The holding device is preferably attached to the crucible in order to hold the filter device relative to the crucible. As a result, the filter device remains within the liquid melt at all times, in particular for the duration of at least one filling of the crucible, so that it cannot solidify in or on the filter device. As a result, the filter device can be used at least as long as it is covered by the melt. Advantageously, a plurality of components can be cast with the melt of an entire filling of the crucible. In this case, the filter device can be viewed as reusable. A particularly cost-efficient casting arrangement can thus be provided with which a large number of components can be cast with little wear of the casting arrangement. With such an arrangement of the filter device within the melt, the filtered melt can preferably be removed by the metering unit directly above the filter device. Particularly preferably, the removal and metering of the melt by the metering unit can be adapted in such a way that no melt remains in the metering unit after metering, whereby, in particular, heating of the metering unit, for example to avoid solidification of residual melt in the metering unit, is dispensed with.

The holding device is preferably set up to hold the filter device within the melt as a function of a filling level of the crucible. In this case, the holding device preferably has a sensor which is set up to detect the filling level of the crucible. Alternatively, it is preferably also possible for the holding device to hold the filter device passively as a function of the fill level in the melt, for example by means of a float that floats in the melt. In particular, the holding device is set up to hold the filter device at a predefined distance below a melt pool surface. The predefined distance can be in the range of a few centimeters, for example at least 0.02 m and a maximum of 0.1 m. This ensures that the dosing unit, which is preferably introduced into the melt from above, always has "fresh" filtered melt can be removed in order to obtain a particularly high material quality for the component to be cast.

The crucible particularly preferably comprises a lid to which the holding device is attached. As a result, a particularly simple and flexible construction of the casting arrangement can be provided, since, for example, the filter device is easily accessible by lifting the cover, and is therefore easy to replace, for example. In addition, the lid means that less energy is required to keep the melt warm in the crucible. The lid preferably has a lid opening through which the dosing unit can be inserted into the crucible, which is otherwise closed by the lid. A particularly simple construction of the holding device is possible in that it advantageously has at least one rail element which is arranged in the vertical direction and in which the filter device is arranged so as to be linearly displaceable, in particular vertically. In addition, an actuating device can preferably be provided which is coupled to the filter device and which can be actuated by the dosing unit. The actuating device is preferably set up to move the filter device vertically in response to the dosing unit being immersed in the melt; in particular to ensure a predefined distance between the filter and an opening of the dosing unit through which melt can be let into the dosing unit, so that well-filtered melt can always be removed.

The holding device and the filter device advantageously divide the melt volume into a first area and a second area. The filtered melt can be located in the first area and the unfiltered melt in the second area. In other words, the first area and the second area are only in fluid connection with one another via the filter device, the holding device otherwise in particular causing a seal. The filtered melt is thus withdrawn by means of the metering unit in the first area. For example, the holding device can comprise a pipe element which is immersed in the melt, in particular essentially vertically from above. The filter device can be arranged within an opening of the tubular element immersed in the melt. For a particularly simple construction, the pipe element can be designed, for example, as a cylindrical pipe, the filter device being arranged in an opening on the end face of the cylindrical pipe. Preferably, a volume of filtered melt can be provided in the first area which is greater than a volume of a metering chamber of the metering unit in which the melt can be received. In this way, for example, melt filtered several times can be removed from the first volume, and the melt can gradually flow in through the filter device. Another advantage of such an arrangement of the holding device and the filter device, which divide the melt volume into the first area and the second area, is that, in particular due to the removal, the filter device flows through only in exactly one direction. This in particular prevents impurities from being released from the filter device.

In an alternatively preferred variant, the filter device is arranged within an opening of the dosing unit. In particular, the filter device is thus part of the metering unit. The filtered melt is preferably metered in such a way that the melt passes through the filter device in the opposite direction, based on the influence of gravity. That is to say that the opening acts both as an inlet opening and as an outlet opening in this case. Alternatively, it is also possible to provide two separate openings on the metering unit, the filter device being arranged within one of the two openings, preferably provided as an inlet opening. Thus, an alternative casting arrangement can be provided which is characterized by a particularly simple structure. In particular, in the case of a single opening, particularly good filtering of the melt can be achieved by the melt passing through the filter device twice. The dosing unit preferably further comprises a warming device. The warming device can, in particular, prevent melt from getting into the metering unit and / or for example, melt located in or on the filter device solidifies.

The filter device preferably comprises a ceramic filter, such as a foam ceramic filter, a round hole ceramic filter, or a cell ceramic filter. Such a ceramic filter can in particular have a predefined pore density, for example 787 pores per meter to 1575 pores per meter (20 PPI to 40 PPI; PPI = pores per inch). Such a ceramic filter is particularly durable and offers a high quality of filtering.

The metering unit is particularly preferably set up to remove the filtered melt from the crucible by means of negative pressure. For this purpose, the metering unit preferably comprises a negative pressure source, such as a vacuum pump. By means of the vacuum source, the filtered melt can be sucked into a metering chamber of the metering unit, for example. The dosing unit furthermore preferably comprises an opening in the dosing space which is arranged in particular on an underside of the dosing unit. The filtered melt can thus be sucked into the dosing chamber through the opening by dipping the dosing unit into the melt. The metering unit particularly preferably has a valve device which is set up to release or block the opening in the metering chamber in order to enable particularly precise removal and metering of the melt, and in particular to prevent unwanted outflow when the melt is transferred to the casting mold avoid.

• - Entnehmen von, insbesondere eines vordefinierten Volumens an, durch eine Filtervorrichtung, gefilterter Schmelze aus einem Tiegel mittels einer Dosiereinheit,
• - Überführen der gefilterten Schmelze zu einer Gießform, und
• - Dosieren der gefilterten Schmelze in die Gießform. Das Verfahren bietet somit eine einfache und kostengünstige Möglichkeit zum Schwerkraftgießen, bei dem Bauteile mit besonders hoher Qualität effizient hergestellt werden können. Insbesondere kann das Verfahren dabei ohne Umrüstung oder Anpassung der eingesetzten Werkzeuge, wie beispielsweise Gießform oder Dosiereinheit, durchgeführt werden. Wie oben beschrieben kann die Filtervorrichtung vorzugsweise innerhalb des Tiegels oder alternativ bevorzugt in oder an der Dosiereinheit vorgesehen sein. Zudem ist eine flexible Durchführung des Verfahrens, nämlich in unterschiedlichen spezifischen Ausführungen, wie beispielsweise Schwerkraft-Kokillengießen oder Kippgießen, und für unterschiedlichste Einsatzzwecke, also bei unterschiedlichsten zu gießenden Bauteilen, möglich.

Furthermore, the invention leads to a method for gravity casting, which is carried out by means of a casting arrangement described. The procedure consists of the following steps:

• - Removal of, in particular a predefined volume of, through a filter device, filtered melt from a crucible by means of a dosing unit,
• - transferring the filtered melt to a casting mold, and
• - Dosing the filtered melt into the casting mold. The method thus offers a simple and inexpensive option for gravity casting, in which components of particularly high quality can be manufactured efficiently. In particular, the method can be carried out without retooling or adapting the tools used, such as, for example, casting mold or dosing unit. As described above, the filter device can preferably be provided within the crucible or, alternatively, preferably in or on the dosing unit. In addition, the method can be carried out flexibly, namely in different specific designs, such as gravity die casting or tilt casting, and for a wide variety of uses, that is to say for a wide variety of components to be cast.

A filter device of the casting arrangement is preferably held within the melt located in the crucible by means of a holding device as a function of a filling level of the crucible. As a result, the method for gravity casting can be carried out particularly efficiently, since as a result the filter device is constantly wetted by the liquid melt while the method is being carried out, which in particular enables the use of a permanent filter. In particular, a large number of components can be cast without the need to adapt or convert the casting arrangement.

• 1 eine vereinfachte schematische Ansicht einer Gießanordnung gemäß einem ersten Ausführungsbeispiel der Erfindung,
• 2 die Gießanordnung der 1 in einer Dosierposition, und
• 3 eine vereinfachte schematische Ansicht einer Gießanordnung gemäß einem zweiten Ausführungsbeispiel der Erfindung.

The invention is explained in more detail below with the aid of exemplary embodiments. To do this, show:

• 1 a simplified schematic view of a casting arrangement according to a first embodiment of the invention,
• 2 the casting assembly of 1 in a dosing position, and
• 3rd a simplified schematic view of a casting arrangement according to a second embodiment of the invention.

The following are two exemplary embodiments of a casting arrangement 1 explained in detail. The 1 to 3rd Referenced. Identical or functionally identical components are always provided with the same reference symbols.

The casting assembly 1 the 1 is intended for gravity die casting of aluminum components. This creates a melt 3rd from liquid aluminum by means of gravity, that is, without the melt 3rd is poured with the help of (over) pressure into a casting mold 6th , which is also referred to as a permanent mold. The mold 6th has a negative shape 61 of the aluminum component to be cast.

The casting assembly 1 includes a crucible 2 in which a melt 3rd is recorded. By the crucible 2 it is a holding furnace in which the melt 3rd kept warm to remain in the liquid state. The crucible 2 has a lid 21 on which one top of the crucible 2 essentially concludes.

Inside the crucible 2 is a filter device 4th arranged with a porous ceramic filter, which the melt 3rd filters. The filter device 4th is in the melt 3rd immersed and by means of a holding device 7th within the melt 3rd held.

The holding device 7th has a tubular element 71 on, within which the filter device 4th is arranged. The pipe element 71 and the filter device 4th divide the melt volume into a first area 20a with filtered melt 3a vertically above the filter device 4th and inside the tubular element 71 and into a second area 20b with unfiltered melt 3b vertically below the filter device 4th and outside of the tubular element 71 . The filter device 4th This causes oxides and impurities from the melt 3rd be filtered out, so by pouring the filtered melt 3rd Components can be produced with particularly high material quality.

For holding the pipe element 71 has the holding device 7th also two guide rails 72 on which the item 71 in the vertical direction A. linearly movable with the lid 21 of the crucible 2 connect. This allows the holding device 7th the filter device 4th always at a predefined distance 30th to a melt pool surface 31 the melt 3rd hold. This allows the filter device 4th constantly from the liquid melt 3rd be wetted, causing a "freezing" of the filter device, that is, a solidification of the melt 3rd in or on the filter device 4th is prevented as long as there is melt 3rd in the crucible 2 is located.

About the level of the weld pool surface 31 to capture, has the holding device 7th also a level sensor 73 which is set up, the fill level, that is, a level of the molten bath surface 31 , capture.

The casting assembly also includes 1 a dosing unit 5 , which is set up, the filtered melt 3a from the crucible 2 , in detail from the first area 20a , to be found, to the casting mold 6th to transfer, and into the mold 6th to dose (cf. 2 ). The dosing unit is used for this 5 around a vacuum dosing unit, which is a vacuum source 55 having. By means of the vacuum source 55 can be a negative pressure within a dosing room 52 are generated so that the filtered melt 3a in the dosing room 52 through an opening arranged at its vertically lower end 51 sucked in when the opening 51 into the filtered melt 3a is immersed.

For handling the dosing unit 5 has the casting assembly 1 also a robot 9 on. The robot 9 the dosing unit can be inserted into the 1 move the removal position shown by the robot 9 the dosing unit 5 in the vertical direction A. at least partially through an opening 22nd of the lid 21 leads through, and at least partially into the filtered melt 3a immersed. To ensure correct positioning of the dosing unit 5 relative to the lid 21 is possible on the dosing unit 5 also a positioning device 54 provided which the dosing unit 5 relative to one of the two guide rails 72 as well as relative to the filter device 4th positioned.

In addition, the robot is 9 set up the dosing unit 5 from the removal position to one in the 2 shown dosing position in which the dosing unit 5 vertically above the mold 6th is arranged to transfer. In the dosing position, in particular by switching off the vacuum source 55 , at least part of the in the dosing room 52 filtered melt located 3a into the mold due to gravity 6th metered in.

That in the 3rd The illustrated second embodiment of the invention corresponds essentially to the first embodiment of FIG 1 and 2 with the difference that the filter device 4th not inside the crucible 2 is arranged, but within the opening 51 the dosing unit 5 . That means filtering the melt 3rd only takes place when it is sucked into the dosing chamber 52 . As a result, the filtered melt lies 3a exclusively in the dosing room 52 before, being in the crucible 2 only the unfiltered melt 3b is available. As a result, the casting arrangement offers 1 according to the second exemplary embodiment, a particularly simple and therefore inexpensive function.

List of reference symbols

1

Pouring arrangement

2

crucible

3

melt

3a

filtered melt

3b

unfiltered melt

4th

Filter device

5

Dosing unit

6th

Casting mold

7th

Holding device

9

robot

20a

first area

20b

second area

21

cover

22nd

opening

31

Melt pool surface

30th

distance

51

opening

52

Dosing room

54

Positioning device

55

Vacuum source

61

negative form

71

Tubular element

72

Guide rail

73

Level sensor

A.

vertical direction

QUOTES INCLUDED IN THE DESCRIPTION

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

Patent literature cited

• DE 102006040944 A1 [0002]

Claims (11)

Casting arrangement for gravity casting, in particular of aluminum components, comprising: - a crucible (2) for receiving melt (3), - A filter device (4) with a filter for filtering the melt (3), and - A metering unit (5) which is designed to remove melt (3a) filtered by the filter device (4) from the crucible (2) and to transfer and meter the filtered melt (3a) to a casting mold (6). Casting arrangement according to Claim 1 , wherein the filter device (4) is arranged inside the crucible (2). Casting arrangement according to Claim 2 , further comprising a holding device (7) which is set up to hold the filter device (4) within the melt (3) located in the crucible (2). Casting arrangement according to Claim 3 wherein the holding device (7) is set up to hold the filter device (4) within the melt (3) as a function of a filling level of the crucible (2). Casting arrangement according to one of the Claims 3 or 4th wherein the crucible (2) comprises a lid (21), and wherein the holding device (7) is attached to the lid (21) of the crucible (2). Casting arrangement according to one of the Claims 3 to 5 , wherein the holding device (7) and the filter device (4) divide a melt volume into a first area (20a) with filtered melt (3a) and a second area (20b) with unfiltered melt (3b). Casting arrangement according to Claim 1 , wherein the filter device (4) is arranged within an opening (51) of the metering unit (5). Casting arrangement according to one of the preceding claims, wherein the filter device (4) comprises a ceramic filter. Casting arrangement according to one of the preceding claims, wherein the metering unit (5) is set up to remove the filtered melt (3a) from the crucible (2) by means of negative pressure. A method for gravity casting, which is carried out with a casting arrangement (1) according to one of the preceding claims, comprising the steps: - Removal of melt (3a) filtered by a filter device (4) from a crucible (2) by means of a metering unit (5), - Transferring the filtered melt (3a) to a casting mold (6), and - Dosing the filtered melt (3a) into the casting mold (6). Procedure according to Claim 9 , wherein a filter device (4) is held within the melt (3) located in the crucible (2) by means of a holding device (7) as a function of a filling level of the crucible (2).

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