WO2022112611A1

WO2022112611A1 - Mold, apparatus and method for low pressure casting

Info

Publication number: WO2022112611A1
Application number: PCT/EP2021/083634
Authority: WO
Inventors: Ernesto BILOTTA; Michael NÜNLIST; Felix Schäfer; Lothar Hartmann; Constantin KEMMER
Original assignee: Kurtz Gmbh & Co. Kg
Priority date: 2020-11-30
Filing date: 2021-11-30
Publication date: 2022-06-02
Also published as: EP4251347A1

Abstract

The invention relates to a mold for low pressure casting. Said mold comprises a base part, a cover part, the base part and the cover part delimiting a mold space, and a riser pipe connection opening into the mold space, and wherein a region in which the base part and the cover part contact each other in a closed state forms a contact area. The mold is characterized in that a venting groove is formed in the contact area, said venting groove being communicatively connected to the mold space and to a venting opening.

Description

Mould, device and method for low-pressure pouring

The present invention relates to a mold, a device and a method for low-pressure casting.

Low-pressure casting is an industrial casting process for the production of castings.

A molten metal, in particular aluminium, but also magnesium, copper, iron and/or steel, is pressed from below into a mold cavity of a casting mold, usually a chill mold (permanent mold), or a sand mold or an investment casting mold (shell mould) by means of at least one riser pipe. A corresponding upward movement of the liquid metal against the force of gravity usually takes place by subjecting the melt to gas pressure (gas pressure principle).

A corresponding device for low-pressure casting comprises a furnace chamber, in which a crucible is located, and a heating device for heating a melt held in the crucible. Furthermore, the furnace chamber can be charged with a gas, with a riser tube being arranged in the crucible in such a way that after the furnace chamber has been charged with a gas, e.g. compressed air, the melt is pressed via a riser tube into a mostly two-part mold (movable upper part, fixed lower part). is, and wherein a mold cavity of the mold is filled by the rising melt. The mold may include a plunger and air operated closures.

By subjecting the melt to gas pressure, it rises up the riser pipe into the mold cavity of the casting mold. After the mold has been completely filled, the gas pressure is maintained in order to ensure replenishment to compensate for volume deficits (cavities) during the transition from the liquid to the solid state. Directional solidification from top to bottom is desirable in order to achieve the best possible casting design and/or cross-sectional gradations. This technique favors a dense and pore-free casting. When designing the mold, care must be taken to ensure that the molten metal fills all areas of the mold before solidification begins in the thin-walled, non-gated areas. In order to prevent the development of volume deficits, the formation of cavities, it is usually necessary to delay solidification in certain areas of the casting either through insulation or to accelerate it through cooling pins. After cooling, the mold is opened and the cast part is removed.

Low-pressure casting systems offer a wide range of applications. From small parts weighing only a few kg to entire housings weighing 260 kg and more as a cast iron, there is a wide range from Fligh-Tech prototype individual parts to large-scale applications.

DE 199 36 973 A1 discloses a device for low-pressure casting of metals. This comprises a pouring furnace with a filling chamber and a riser pipe, which can be connected at the end via a pouring nozzle successively to casting mold boxes having flea spaces.

DE 10 2008 051 998 A1 discloses a casting process in which liquid casting material is transported from a low-pressure furnace and the low pressure via a pouring column against the force of gravity to a cast body in a casting container. It is provided here that the low pressure in the low-pressure furnace is lowered after the end of the casting to such an extent that at least part of the still liquid casting material still in the pouring column flows back into the low-pressure furnace.

DE 10 2004 050 781 A1 discloses a low-pressure full mold casting process in which controlled filling of the mold is to be made possible, with the liquid metal being transported in the region of a connection opening of a mold container through a connection piece having low thermal conductivity. As a result, a directional solidification from bottom to top and a fine-grained structure of the master should be achieved.

Furthermore, it is known to form a mold for low-pressure casting with at least one ventilation channel, which opens into the mold space by means of a slot nozzle (or also a point nozzle) inserted into the channel. The slits of the slit die are designed so narrowly that only air but not melt can pass through. If the melt is still very fluid when it comes into contact with the slot die, melt can penetrate the slot die and clog it. The slot nozzle must then be removed from the mold and cleaned or replaced with a new slot nozzle. The object of the present invention is to provide a mold and a device for low-pressure casting and a corresponding method with which castings can be produced reliably and with high quality.

Another object of the present invention is to provide a mold and a device for low-pressure casting and a corresponding method that is easy to handle and safe to operate.

One or more of these objects are solved by the features of independent claims 1, 8, 15 and 16. Advantageous configurations are specified in the dependent claims.

According to a first aspect of the present invention, a mold for low-pressure casting is provided. This mold comprises a base part, a cover part, with the base part and the cover part delimiting a mold space, and a riser pipe connection opening into the mold space, and a region in which the base part and the cover part contact each other in a closed state forms a contact surface. The mold is characterized in that a venting groove is formed in the contact surface, which is connected to the mold space and to a venting opening in a communicating manner.

In particular, a contact surface in the base part, which is referred to below as the base part contact surface, and a contact surface in the cover part, which is referred to below as the cover part contact area, are formed.

The vent groove, which is communicatively connected to the mold cavity and the vent opening, allows the mold cavity to be vented during low-pressure casting. In this way, the formation of pores and air pockets in the cast part are avoided.

During casting, melt penetrates into the vent groove in the area of the contact surface and runs dead. This means that it solidifies into a sprue before the melt reaches the vent opening and can clog it.

In the areas in which no ventilation groove is formed, the cover part and the base part contact each other in such a way that as little melt as possible penetrates or only so little melt penetrates that a casting lug not belonging to the cast part occurs. the Contact surfaces are thus outside of the mold space. Such a casting flag can later be removed from the cast part without leaving any residue.

Since the venting groove is formed in the contact surface, the venting groove is completely uncovered when the mold is opened or when the cover part is separated from the base part and the mold space is removed from the mold associated therewith. The ventilation groove is easily accessible in this state and excess metal can be removed safely and reliably without much effort or the sprue can be separated from the cast part. As a result, the ventilation groove can be cleaned extremely easily and completely.

The vent groove may be formed in a base part contacting surface of the base part or in a lid part contacting surface of the lid part. The ventilation groove is preferably approximately semicircular in cross section. The ventilation groove can be closed in a lateral outward direction by a wall of the base part or the cover part.

Thus, the vent groove can be provided either in the base part or in the lid part.

A vent groove according to the present invention provides a free passage from the mold cavity to the vent opening. This means that the ventilation groove is free of components and/or structures that are inserted into or connected to the ventilation groove.

In conventional molds with ventilation openings, slot or point nozzles are provided at the mouth of the mold space. No such components, such as slot or point nozzles, and/or other structures are arranged in the present ventilation groove.

It is also possible for a ventilation groove section to be provided in the base part and a ventilation groove section in the cover part, so that the ventilation groove sections lie directly on top of one another in the closed state and form an approximately circular cross-section channel for ventilation.

Instead of being in the form of a half circle, the cross section of the venting groove can also be in the form of a segment of a circle or also polygonal, provided this results in an easy-to-clean structure without edges or flinter cuts.

The ventilation groove can also be designed in a wavy manner in its longitudinal direction, in order to lengthen the path of the melt, similar to a labyrinth seal. The riser pipe connection is designed to connect the mold via a riser pipe to a crucible of a device for low-pressure casting in such a way that the mold space can be filled with a melt using a low-pressure casting process.

The venting groove can extend outwards from the mold space approximately in the lateral, in particular approximately in the horizontal direction, with the mold having one or more side walls, and with preferably four side walls being provided, and with one venting groove being provided for each side wall, each is connected to a vent opening formed in the lid part.

The base portion contact surface and also the vent groove may also be inclined laterally outward from the mold cavity at a predetermined angle with respect to the florizontal. It is preferably provided here that the base part contact surface and thus the ventilation groove is designed to rise outwards from the mold space in the lateral direction. The same applies to an arrangement of the ventilation groove in the cover part contact area and/or in the base part contact area.

Irrespective of the formation of corresponding side walls or side wall sections of the mold, the ventilation grooves are formed in an upper region of the mold in the vertical direction. This means that a ventilation groove is arranged with its mouth to the mold space approximately in a vertically upper area of the mold, with this area increasing from approximately over 75% or 80% or 85% or 90% or 95% to % of a total height of the mold space of the mold in the vertical direction upwards.

The further up the mouth of the ventilation grooves to the mold space in the mold are arranged, the less melt can enter, since the melt has already cooled down a little by the time it reaches the upper area of the mold and solidification has already begun.

The ventilation groove can preferably have a width of at least 0.05 mm or at least 0.1 mm to 0.5 mm or 0.6 mm and preferably 0.2 mm and a depth of at least 0.05 or at least 0.1 mm to 0.5 mm or 0.6 mm and preferably 0.2 mm. In the case of a ventilation groove with an approximately semicircular cross section, this then has a radius of at least 0.05 mm to 0.3 mm and preferably of approximately 0.1 mm. In the case of a semi-circular cross section, the ventilation groove can also have a diameter of at least 0.05 mm to 0.3 mm and preferably of approximately 0.05 mm. The vent opening may form an elongate tubular channel extending through the lid portion of the mould.

With one ventilation groove per side wall, more efficient ventilation of the mold is possible. This also enables the melt to be evenly vented.

According to a particularly advantageous embodiment, the one or more ventilation openings can be connected to a common pump device via connections or lines, and the pump device is designed to apply an overpressure and/or an underpressure to the mold space.

Each ventilation opening is thus connected to the pump device via a respective connection. As a result, only one pump device is necessary in order to apply an overpressure or underpressure to the mold space. In addition, a simpler change from positive to negative pressure within the mold is possible with a pump device.

The pump device can be used to apply a predetermined negative and/or positive pressure to the melt during the filling process.

For example, at the beginning of the filling of the mold, the melt can be subjected to excess pressure. The resulting back pressure causes the melt to be compressed and compressed and/or recompressed (squeezing), so that air trapped in the melt is pressed out of the melt.

By means of the pump device, the air can be sucked out of the mold by applying the negative pressure at the end of the filling process. This prevents the formation of air pockets and the formation of pores in the melt. Safe and reliable venting of the mold (cavity) space is thus possible.

By applying a negative pressure, it is also possible to fill the mold space more quickly.

A negative pressure and/or a positive pressure can be applied to the mold space alone or in combination with one another.

A combination of positive pressure at the beginning of the filling process and negative pressure at the end of the filling process ensures efficient removal of trapped air in the melt and efficient suction of air from the mold. This prevents that air pockets remain in the melt and it is achieved that there are no air pockets, defects or pores in the finished cast part. This significantly increases the quality of the cast parts produced.

A functional section can be formed on an inner jacket wall of the mold that delimits the mold space and extends approximately in the vertical direction, the functional section having functional elements extending in the vertical direction and/or in the horizontal direction, and the functional elements having corrugated, meandering - or are designed in a zigzag shape and form secondary venting grooves that open into the venting grooves, and wherein the functional section is formed in the vertical direction at the top of the mold and extends approximately over at least 25% or at least 33% or at least 50% of a total height of the mold space extends in the vertical direction.

Alternatively, it could also be provided that the ventilation grooves extend essentially over the entire height of the mold. However, it is more expedient for the secondary ventilation grooves to be arranged as shown above in an upper region in the vertical direction, since the air is driven forward by the melt and is compressed upwards.

The provision of functional elements in the inner jacket wall of the mold that delimits the mold space helps to prevent the formation of air inclusions in the melt when the mold is being filled. Furthermore, the functional elements are also filled with melt during the filling process, which ensures that the actual mold is completely filled and defects are avoided.

The functional elements are arranged in the mold space in such a way that the additional cast-on elements on the actual cast part have no influence on the subsequent function of the cast part.

The functional elements can in particular be designed as zigzag or wave-like secondary ventilation grooves which extend essentially in the vertical direction.

The secondary ventilation grooves can have a width of approximately at least 0.1 mm or 0.2 mm or 0.3 mm or 0.5 mm or a width of approximately at least 0.05 mm or 0.1 mm or 0.15 mm and 0.25 mm, respectively. In addition, the secondary ventilation grooves a depth of approximately at least 0.1 mm or 0.2 mm or 0.3 mm or 0.5 mm or a depth of approximately at least 0.05 mm or 0.1 mm or 0, 15 mm or 0.25 mm.

The base part can have a bottom wall and one or more, in particular four, side walls that delimit the mold space, the side walls being displaceable laterally outwards in particular to open the mold space, and guide elements preferably being provided for guiding the side walls, or that the Lid part has a top wall and at least one or more sections of the side walls.

The bottom wall preferably forms a stationary base plate of the mold, in which the at least one riser pipe connection is formed. The cover part preferably forms a movable upper plate of the mould.

The base part can have a square bottom wall and four side walls which delimit the mold space, the side walls being displaceable in the lateral direction outwards in particular to open the mold space. Due to the movable side walls, the finished cast part can be easily removed from the mold.

A use of movable side walls is possible here in a simple manner, since low-pressure casting places fewer demands on the mold in terms of tightness.

The guide elements can be designed as lateral sections of columns which are integrally formed on the bottom wall and extend in the vertical direction

Alternatively, it is possible that at least one or more sections of the side walls or entire side walls are attached to the cover part. Accordingly, the base part is then designed as a plate. If only sections of the side walls are attached to the cover part, corresponding further sections of the side wall are formed on the base part. In this embodiment, the ventilation groove is formed, for example, in a contact surface or a base part contact surface and/or a cover part contact surface between two sections of the respective side walls.

The side parts that release the mold can thus also be arranged on the cover part. The mold space is opened according to the same principle. Corresponding guide elements can also be provided. It can also be the case that there is a division, ie slides can be arranged at the bottom and/or at the top in the vertical direction. The cover part can have a plunger element or a plunger that can be arranged in the mold space, the plunger element preferably being designed to be displaceable in the vertical direction and a displacement being approximately up to 5 mm or more. A corresponding shift also depends on the size and design of a stamp. The ventilation groove can also be provided on the contact surface formed by the plunger element with the base part.

The stamping element arranged in the cover part can be displaced in the vertical direction and is designed to delimit the mold space. The stamp element serves to exert additional pressure (pressing down or squeezing) on the melt within the mold as soon as the mold is completely filled with melt. Air is pressed out of the melt again by pressing it down accordingly and, if necessary, the melt is reliably pressed into all areas of the mold, which increases the quality of the finished cast part.

The stamp element can be displaceable in the vertical direction by means of a stamp displacement device.

According to a second aspect of the present invention, a mold for low-pressure casting is provided. This mold comprises a base part, a cover part, the base part and the cover part delimiting a mold space, and the cover part having a cover and a stamping element, the stamping element being arranged on the side of the cover facing the mold space, so that it delimits part of the mold space , and a riser pipe connection opening into the mold space. The mold is characterized in that the base part and the stamping element in a closed state have at least one area in which they contact each other and form a contact surface, with a ventilation device being formed at least partially in the contact surface, which communicates with the mold space and with a vent opening defined by a channel portion extending upwardly through a corresponding opening in the lid part, the channel portion projecting somewhat at an upper side of the lid part.

The base part and the plunger element are so close together in the area of the contact surface that no melt can penetrate between them, but still far enough away from one another that they do not cause any frictional contact. Such a frictional connection would lead to damage to the base part and the stamping element. If some melt penetrates into the area of the contact surface, it will quickly run dead due to the small amount and form a casting lug.

The stamp element is generally also referred to as the upper stamp, which is firmly connected to the cover of the cover part and is moved together with it. When the mold is closed, the cover part is moved onto the base part and the upper punch is simultaneously introduced into the mold space. The shape and size of the upper punch defines the area of the mold cavity that is filled with melt. The upper punch thus has a significant influence on the shape of the later cast part.

The venting device, which is communicatively connected to the mold space and to the vent opening, enables the mold space to be vented during low-pressure casting. In this way, the formation of pores and air inclusions in the later cast part are avoided.

The ventilation device is formed in an area of the contact surface of the base part and the stamping element, which is completely exposed when the mold is opened or when the cover part with the stamping element is separated from the base part and the mold cavity is demoulded. The ventilation device is easily accessible in this state and excess metal can be removed safely and reliably without much effort or the sprue can be separated from the cast part. This allows extremely simple and also complete cleaning of the ventilation device.

The venting device can be arranged adjacent to the cover of the cover part and can extend approximately in vertical directions, with the venting device being formed at least in regions in a stamp venting section in an approximately radially circumferential casing wall of the stamp element, i.e. on its radial outside.

The stamp ventilation section of the stamp element refers to the section of the jacket wall of the stamp element that contacts a section of an approximately radially circumferential inner wall of the base part, the stamp ventilation section of the stamp element and this section of the base part forming the contact surface.

In the context of the present invention, adjacent to the cover of the cover part means that the venting device is formed in the area of the cover part in an upper area of the plunger element in the vertical direction. This area extends in the vertical direction approximately over at least 10% or at least 20% or at least 30% of a total height of the mold cavity of the mold. The channel section can be formed in one piece on the plunger element.

By providing such a channel section, which extends upwards through the lid of the lid part like a snorkel, the ventilation opening can be formed on the stamp element and the stamp element can be moved in relation to the lid of the lid part during use, so that there is also a small gap between the plunger element and the cover of the cover part is bridged with the channel section.

The venting device can have one or preferably several venting channels extending in the vertical direction and/or in the horizontal direction, the venting channels preferably having an approximately semicircular and/or rectangular cross section and/or the venting channels having a wave, meandering or zigzag shape are and wherein the vent channels open into the vent opening.

The shape of the ventilation channels can be adapted according to the shape of the stamp ventilation section of the stamp element.

The venting channels are primarily designed to direct air that flows in the direction of the venting channels when the mold is being filled with melt to the venting opening as effectively as possible. This means that the ventilation ducts are free of components and/or structures that are inserted into or connected to the ventilation ducts.

The venting device can be designed as a single venting section that runs completely radially around the stamp venting section of the stamp element or as a plurality of venting sections that run radially around the stamp venting section of the stamp element in sections, with the venting device preferably comprising a plurality of venting sections that each have a plurality of venting channels, and the venting channels of each venting section are in a vertical position Direction and / or extend in the horizontal direction and wherein the venting channels of each venting section are connected to at least one vent opening.

Consequently, one or more ventilation openings can be provided per ventilation section of the ventilation device. Depending on the shape of the plunger element, it can be useful to form the venting device only in sections. This reduces the area that needs to be cleaned after the casting is demoulded.

The venting device preferably has at least one

Stamp venting section, which is arranged distributed in the circumferential direction on the radial outside of the stamping element, wherein in particular each stamp venting section has at least one first venting channel and at least one second venting channel which is connected to the first venting channel and wherein the first venting channel is in particular essentially perpendicular to the second venting channel is arranged. In an advantageous embodiment of the invention, a plurality of stamp venting sections are arranged evenly distributed over the circumference of the radial outside of the stamp element.

The at least one first venting channel of the stamp venting section can be connected to the mold space and in particular exit from the mold space at the end face of the stamp element. As a result, the air in the mold cavity displaced by the hot melt during the casting process can be discharged from the mold cavity via the first ventilation channel. Each stamp venting section preferably has a plurality of first venting channels which can be arranged parallel to one another.

The at least one second venting channel can be arranged essentially perpendicularly to the first venting channel, in particular horizontally, most preferably with a directional component in the circumferential direction of the radial outside of the plunger element. The stamp venting section preferably has precisely one second venting channel which is connected to at least two, in particular to all of the first, venting channels of the stamp venting section. In this embodiment, the plunger venting section with its several first venting channels and the one second venting channel is designed like a comb. In this way, hot air that rises from the mold space into the, in particular, multiple first ventilation ducts can be directed into a single second ventilation duct, collected there and discharged from there, which is expressed in a structurally simple configuration. Most preferably, a single stamp venting section is provided, which is arranged over the entire circumference of the radial outside of the stamp element and has a plurality of first and precisely one second venting channel.

One or more ventilation openings can be provided per ventilation section of the stamp ventilation section of the ventilation device. The at least one ventilation opening can be an approximately tubular channel which is formed in the stamp element.

The at least one ventilation opening is preferably provided in the area of the transition from the plunger element to the cover of the cover part.

In the context of the present invention, provision is made for air to flow out of the mold space first into the venting channels of the venting device. Since the ventilation ducts open into the ventilation opening, the air flows into the ventilation opening and can be discharged from there to the environment.

Furthermore, several ventilation openings can be provided on the radially encircling stamp vent processing section of the stamp element. Thus, a more efficient and more even venting of the mold is possible. This also ensures that the melt is evenly vented.

The vent opening may comprise a first vent opening section and a second vent opening section, the first vent opening section being connected to the second vent opening section, the first vent opening section extending from the venting device into the stamping element in an approximately horizontal direction, and the second vent opening section extending in an approximately vertical direction Direction to the first vent opening section and extends through the plunger element and the lid of the lid part to a terminal.

Each vent opening is preferably connected, in particular to its first vent opening section, to a punch vent section, in particular to its second vent channel, in order to conduct hot air flowing through the punch vent section from the mold space via the vent opening to the outside environment.

The at least one ventilation opening is preferably delimited at least in sections by at least one essentially vertical channel section of the plunger element which is in particular designed in one piece, the channel section preferably reaching through the cover in an opening and in particular protruding vertically from the cover. In this arrangement, in particular, the second vent opening section of the vent opening is encased by the channel section of the plunger element extending through the opening in the cover part.

The one or more ventilation openings can be connected to a common pump device via the connections, the pump device being designed to apply an overpressure and/or an underpressure to the mold space.

A device according to the invention for low-pressure casting with one of the molds explained above comprises a heating device for heating a melting pot, wherein the melting pot is designed to hold melt, and wherein the melting pot is connected via a riser pipe to a riser pipe connection of the mold, a gas pressure application device to heat the melt to be applied in the crucible with a gas pressure such that the melt can be fed from the crucible via the riser of the mold.

The crucible and the heating device are preferably part of a corresponding furnace.

The crucible can also be a crucible furnace or a brick furnace.

Furthermore, a method according to the invention for low-pressure casting with a device explained above is provided, comprising the following steps,

Filling a mold space of a mold with melt,

Application of a negative pressure to the mold space by means of a pump device, the negative pressure preferably being applied when a volume of the mold space is approximately at least 50% or at least 65% or at least 80% filled with melt.

The negative pressure can also be applied when the mold space is approximately filled with melt in the vertical direction to a level of at least 50% or at least 65% or at least 80%. The volume roughly corresponds to the amount of displaced air anyway. The method outlined above can additionally and/or alternatively include in particular the further step

Application of a counter-pressure to the melt by means of the pump device, the counter-pressure preferably being applied at the beginning of the filling of the mold cavity until the volume of the mold cavity is approximately at least 50% or at least 65% or at least 80% or at least 90% up to is 100% filled.

The counter-pressure can be applied at the beginning of the filling of the mold space when the mold space is filled in the vertical direction to at least 50% or at least 65% or at least 80% or at least 90% up to 100% .

The advantages described above with reference to the mold and the device for low-pressure casting apply analogously to the method for low-pressure casting according to the invention.

Other objects, features and advantages of the present invention will become apparent from the detailed description and exemplary embodiment illustrated in the accompanying drawings. These show in:

FIG. 1 shows a schematic, laterally sectioned illustration of a mold for low-pressure casting according to the invention with a detailed view according to a first aspect of the present invention,

FIG. 2 shows a schematic top view of the mold according to the invention, sectioned along the line AA,

FIG. 3 shows a schematic, laterally sectioned representation of a device according to the invention for low-pressure casting,

Figure 4 is a schematic, laterally sectioned representation of a mold for

Low pressure casting according to a second aspect of the present invention,

FIG. 5 shows a stamp element of the mold according to FIG. 4 in a perspective view and

FIG. 6 shows a partial area of the stamp element according to FIG. 5 in a longitudinal section through a ventilation opening of the stamp element. A mold 1 for low-pressure casting according to a first aspect of the present invention is described in more detail below by way of example using an exemplary embodiment (FIG. 1).

The mold 1 according to the invention comprises a base part 2 and a cover part 3. The base part 2 and the cover part 3 delimit a mold space (mold cavity) 4.

According to this exemplary embodiment, the mold space 4 is approximately circular in a plan view from above or in a horizontal cross section. However, any other shape designed according to the cast part to be produced can also be provided.

According to this exemplary embodiment, an outer horizontal cross section of the mold 1 is approximately rectangular, in particular square. A circular cross-section, for example, can also be provided here.

The base part 2 has a bottom wall 5 which forms a base plate of the mold 1 . A riser pipe connection 6 for connection to a riser pipe 25 of a crucible 23 of a device 21 for low-pressure casting is provided in the bottom wall 5 . The base part 2 is designed as a fixed lower part of the mold 1.

Columns 7 extending in the vertical direction 8 and having an approximately cuboid cross-section are integrally formed at corners of the bottom wall 5 . In the area between the columns 7, the mold space 4 delimiting side walls 9 are arranged.

The side walls 9 extending approximately in the vertical direction 8 are designed to be displaceable in the lateral direction 10 in order to open the mold space 4 . The side walls 9 can be displaced manually or by means of an automated side wall displacement device 27 .

In the area between the columns 7 and the side walls 9 and/or the bottom wall 5 and/or the cover part 3, guide elements (not shown) are provided which cause the side wall 9 to be guided along a predetermined path.

The guidance of the side wall 9 can be designed, for example, in that at least one protruding profile rail is arranged on the columns 7 in the region of the side walls 9, with the side walls 9 being designed correspondingly Have hollow rails. The profile rails are open on one side and are preferably designed with a latching means. The open side of the profile rails points away from the mold space 4 . The profile rails can be designed, for example, as a T-profile or as other suitable guide or fitting connections.

The side walls 9 can each be pushed between two columns 7 in such a way that the side walls 9 delimit the mold space 4 in the lateral direction 10 .

The side walls 9 each have a functional section 12 on an inner wall 11 facing the mold space 4 . The functional sections 12 are formed in the vertical direction 8 in an upper area in the side walls 9 and extend approximately over at least 25% or at least 33% or at least 50% of a height of the mold cavity 4 in the vertical direction 8.

The functional sections 12 preferably have functional elements extending in the vertical direction 8 . The functional elements are preferably designed in a zigzag shape and form secondary ventilation grooves 31 . The secondary venting grooves 31 each open into a venting groove 13. Furthermore, the secondary venting grooves 31 can also be straight, meandering or wavy.

Furthermore, the secondary ventilation grooves 31 have a width of approximately at least 0.1 mm or 0.2 mm or 0.3 mm or 0.5 mm or a width of approximately at least 0.05 mm or 0.1 mm mm or 0.15 mm or 0.25 mm. A depth of the secondary ventilation grooves 31 is approximately at least 0.1 mm or 0.2 mm or 0.3 mm or 0.5 mm or approximately at least 0.05 mm or 0.1 mm or 0. 15 mm or 0.25 mm.

Additionally and/or alternatively, the ventilation grooves 13 can also extend, at least in sections, in the horizontal direction or, if necessary, can also be designed as elevations or as ventilation structures.

The cover part 3 (upper plate mold) is approximately plate-shaped. The base part 2 is designed as a movable upper part of the mold 1.

In the cover part 3 there is a plunger element (piston, plunger) 20 designed to be displaceable in the vertical direction 8 . The plunger element 20 delimits the mold space 4 and can be provided for (re)compacting (squeezing) the melt 24 . The stamp element 20 can be displaceable by means of a stamp displacement device 29 of an ejector device 30 . Furthermore, a displacement of the stamping element 20 in the vertical direction 8 of approximately up to 5 mm can also be provided during and/or after the filling of the mold space 4 in order to recompact the melt 24 and give a cast part its final shape.

In the closed state, the base part 2 and the cover part 3 each form a contact surface 14 in an area in which the side walls 9 and the cover part 3 contact one another.

The contact area 15 of the base part 2 is referred to below as the base part contact area 15 and the contact area 16 of the cover part 3 is referred to as the cover part contact area 16 below.

One ventilation groove 13 extending outwards in the lateral direction 10 is introduced into the base part contact surfaces 15 on each side. The ventilation grooves 13 are formed approximately centrally in the base part contact surfaces 15 .

In addition, the ventilation grooves 13 are designed to be open towards the mold space 4 and are closed outwards in the lateral direction 10 by a corresponding section of a side wall 9 of the mold 1 .

The ventilation grooves 13 are approximately semicircular in cross section in such a way that they are exposed when the mold 1 or base part 2 and cover part 3 are in an open state.

In the cover part 3 , in the region of a lateral end region of the ventilation grooves 13 , ventilation openings 17 are provided which extend approximately in the vertical direction 8 . In the closed state of base part 2 and cover part 3, the ventilation grooves 13 thus open into one of the ventilation openings 17 and form a communicating passage from outside the mold 1 into the mold space 4.

The ventilation openings 17 are approximately circular through-channels in cross section, which are arranged approximately orthogonally to the ventilation grooves 13 .

The ventilation openings 17 are connected to a common pump device 19 outside the cover part 3 via a respective connection 18 . The pump device 19 is designed to apply an overpressure and/or underpressure to the mold space 4 . The ventilation grooves 13 can be designed in a wavy manner in their longitudinal direction in a top view and/or in a side view in order to lengthen the path up to the ventilation opening 17 . This ensures that melt that enters the vent groove will "drain" and form an easily removable sprue on the casting.

In the following, an apparatus 21 for low-pressure casting according to a first aspect of the present invention, which comprises the mold 1 described above, will be explained by way of example.

The device 21 comprises, in addition to the mold 1, a furnace 22 and a gas pressure application device 26 (gas pressure principle).

The furnace 22 has a crucible 23, a riser 25 and a heater. The crucible 23 can be heated by the heating device and is designed for heating and holding a melt 24 .

The riser pipe 25 is provided for connecting the crucible 23 to the mold 1 via the riser pipe connection 6 of the mold. by means of

Gas pressure application device 26 is the stored in the crucible 23 melt 24 via the riser 25 from below or in the vertical direction 8 upwards in the mold space 4 of the mold 1 can be transferred.

The gas pressure application device 26 is thus designed to apply a gas pressure to the melt 24 in such a way that the melt 24 is pressed via the riser pipe 25 against the force of gravity into the mold space 4 of the mold 1 .

The device 21 also includes a vertical displacement device 28 and a stamp displacement device 29 which are part of the ejector device 30 . The ejector device 30 includes corresponding guide cylinders for vertical guidance and an ejector plate (not shown) with an ejector cylinder (not shown).

The vertical displacement device 28, the stamp displacement device 29 and the side wall displacement device 27 are preferably designed as piston/cylinder units. The vertical movement device 28 is designed to move the movable cover part 3 in the vertical direction 8 with respect to the base part 2 in order to open or close the mold space 4 .

The ram movement device 29 is designed to move the ram element 20 of the cover part 3 in the vertical direction 8 into the mold cavity 4 and, if necessary, also to enable the melt 24 to be re-pressed in the mold cavity 4 .

The side wall moving device 27 is designed to move the side walls 9 between the columns 7 in the lateral direction 10 in order to open and close the mold space 4 .

In addition, the device 21 comprises a process-controlled pressure control device 31 for the pump device 19 and a process-controlled pressure control device 31 for the gas pressure application device 26.

All components of the device can be controlled with a corresponding control device.

In particular, the stamping element 20 is provided for repressing (squeezing). However, this squeezing can also be effected by an additional stamp (not shown) or directly by the cover part or by elements formed thereon.

In the following, a method for low-pressure casting according to a first aspect of the present invention using the device 21 shown above is explained by way of example.

The side walls 9 of the base part 2 are arranged between the columns 7 by means of the side wall displacement device 27 in such a way that the side walls 9 delimit the mold space 4 in the lateral direction 10 .

The mold 1 is in the closed state.

The ventilation openings 17 of the cover part 2 are connected to the pump device 19 via the connections 18 which are designed as compressed air lines.

The mold 1 is connected to the crucible 23 of the furnace 22 via the riser pipe connection 6 and the riser pipe 25 . The furnace 22 heats the crucible 23 and the melt 24 arranged therein, so that liquid melt 24 is kept available in the crucible 23 .

Gas pressure is applied to the liquid melt 24 in the crucible 23 by means of the gas pressure application device 26 in such a way that the melt 24 is pressed via the riser tube 25 against gravity in the vertical direction 8 upwards into the mold space 4 of the mold 1 .

The mold space 4 is charged with melt 24 from the crucible 23 .

As soon as the melt 24 enters the mold space 4 of the mold 1 , an overpressure is applied to the mold space 4 by means of the pump device 19 . The overpressure must not exceed the gas pressure of the gas pressure application device 26 . The overpressure in the mold space 4 ensures that the melt 24 has to overcome a resistance when the mold space 4 is filled or that an air cushion is formed in the mold space so that the melt is distributed more evenly in the mold space 4 and, if necessary, is slightly compressed.

When the mold cavity 4 is approximately 70% to 75% filled with melt 24, the melt 24 is no longer subjected to excess pressure.

A negative pressure of approximately 120 mbar to 20 mbar or up to 10 mbar is now applied to the mold space 4 of the mold 1 by means of the pump device 19 . The negative pressure must not be too high and must not apply too early, since otherwise parts of the melt 24 will be torn off. The negative pressure ensures that the air that is in the mold space 4 and is pushed in front of the melt 24 is sucked out.

The air is discharged from the mold space 4 via the secondary venting grooves 31 , the venting grooves 13 and the venting openings 17 , the connections 18 and the pump device 19 . This largely ensures that the mold space 4 is completely filled with melt 24 at the end of filling and that there are no air pockets and/or pores within the melt 24 .

The functional elements of the functional sections 12, which are designed as secondary ventilation grooves in the vertically upper area of the side walls 9 and which open into the ventilation grooves 13, ensure that the air is discharged even more efficiently. If the mold space 4 is completely filled with melt 24, the stamp element 20 of the lid part 3 is pressed onto the melt 24 by means of the stamp displacement device 29 in order to recompact it. The melt 24 is thus compressed and any residual air is removed or pressed out of the melt 24 . The cast part is given its final shape.

This condition is maintained until the melt 24 is solidified. By removing the finished cast part from the mold, by opening the cover part 3 and the side walls 9 and the associated opening of the mold 1, the venting grooves 13 are exposed and can then easily be freed from melt residues or sprues that are in the venting grooves 13 forming can be easily separated from the casting.

In the exemplary embodiment explained above, a plunger element 20 is arranged on the cover part 3 . Within the scope of the invention, the cover part 3 can be designed in several parts, in particular with a central, vertically movable part and a stationary peripheral part. The central part can then serve as a plunger element 20 for compressing the melt.

A mold 1 with the ventilation and the stamping element 20 is particularly advantageous for the production of cast parts which have radially outwardly extending rod-shaped or spoke-shaped sections, such as vehicle wheels. With such complex shapes, there is a high risk that the mold space 4 will not be completely filled with melt 24 in the low-pressure casting process. The combination of active venting and compression by means of the stamp element 20 ensures that elongated channels in the mold space 4 are also completely filled with melt 24 .

In particular, castings such as wheel rims (vehicle wheel rims) or wheel carriers can be produced with the present invention. In principle, however, a large number of castings can be produced using the present invention. Accordingly, the mold space 4 can be adapted to other component geometries in almost any way.

A mold 1 for low pressure casting according to a second aspect of the present invention will be described below (Figs. 4-6). Identical parts have the same reference numbers as in the previous exemplary embodiment. In addition, the above explanations apply equally to the parts of the other exemplary embodiment. This mold 1 differs from the mold 1 according to the first aspect of the present invention in that a ventilation device 34 is provided in a region in which the base part 2 and the stamping element 20 contact each other in a closed state and form a contact surface 33 .

The mold 1 comprises the base part 2 and the cover part 3. The base part 2 and the cover part 3 delimit the mold space 4.

In the plan view from above or in horizontal cross section, the mold space 4 is approximately circular. However, any other shape designed according to the cast part to be produced can also be provided.

The outer horizontal cross section of the mold 1 is approximately rectangular, in particular square. A circular cross section can also be provided here.

The cover part 3 has a cover 35 and the stamping element 20 arranged on the side of the cover 35 facing towards the mold space 4 . The stamp element 20 is approximately cylindrical. The stamp element 20 can be displaced by means of the stamp displacement device 29 of the ejector device 30 . The ejector device 30 can be a piston/cylinder unit.

Furthermore, the base part 2 has the bottom wall 5 which forms the base plate of the mold 1 . A riser pipe connection 6 for connection to a riser pipe 25 of a crucible 23 of a device 21 for low-pressure casting is provided in the bottom wall 5 . The base part 2 is designed as a fixed lower part of the mold 1.

Side walls 9 that extend in the vertical direction 8 and delimit the mold space 4 are arranged on the base part 2 .

If the stamping element 20 is arranged in the closed state in the mold space 4, the resulting mold space 4 is a space between the stamping element 20 and the side walls 9 or between the stamping element 20 and the bottom wall 5.

In the closed state, the base part 2 and the plunger element 20 have an area in which a section of an approximately radially circumferential casing wall 36 of the plunger element 20, i.e. a section on its radial outside, and a section of the approximately radially circumferential inner wall 11 of the base part 2 contact each other and form the contact surface 33 . This area is formed adjacent to the cover 35 of the cover part 3 in an upper area of the mold 1 in the vertical direction 8 .

In this area, the section of the casing wall 36 of the stamp element 20 forms a stamp venting section 37 in which the venting device 34 is provided at least in certain areas.

The venting device 34 has at least three or at least four or at least five radially circumferential venting sections, which are preferably arranged at equal distances from one another in the stamp venting section 37 .

For example, five to ten vertical ventilation ducts are provided in each ventilation section, all of which open into a horizontal ventilation duct. Preferably, the ventilation channels are approximately semicircular in cross section.

In addition, each of these horizontally running ventilation channels is connected to at least one ventilation opening 38 .

According to FIG. 5, the stamp element 20 has only a single stamp venting section 37, it being possible for several stamp venting sections 37 to be provided on the radial outside 36 of the stamp element 20 within the scope of the invention. The stamp ventilation section 37 is connected as a ventilation device 34 in a communicating manner to the mold space 4 and to at least one ventilation opening 38 .

The stamp venting section 37 of the stamp element 20 has a plurality of first venting channels 37a, which are aligned essentially vertically, are distributed evenly over the lateral surface 36 of the stamping element 20 in the circumferential direction and are designed as grooves, all of which flow into a single second venting channel 37b, running horizontally, in particular in the circumferential direction Stamp venting section 37 open, wherein the second venting channel 37b is designed as a groove. The first ventilation channels 37a are each arranged perpendicular to the second ventilation channel 37b. Preferably, the venting channels 37a, 37b are approximately semicircular in cross section.

The horizontally running second venting channel 37b is connected to a plurality of venting openings 38 which are distributed evenly over the circumference of the plunger element 20 . The design of the ventilation opening 38 according to FIGS. 4 and 6 will be discussed below, with each ventilation opening 38 in FIG. 5 being designed analogously thereto.

The ventilation opening 38 according to Figures 4 and 6 comprises a first ventilation opening section 39 and a second ventilation opening section 40. The first ventilation opening section 39 extends approximately in the horizontal direction from the ventilation device 34 into the stamp element 20.

The second vent opening portion 40 is connected to the first vent opening portion

39 and runs approximately in the vertical direction 8 to the first vent opening section 39. The second vent opening section 40 extends through the plunger element 20 and through an opening 41 in the cover 34 of the cover part 3 to the connection 18 and is connected to a channel section 42 of the plunger element 20 limited. The channel section 42 thus represents a kind of "snorkel" which delimits the ventilation opening 38 and extends through the cover 34 .

The channel portion 42 of the plunger member 2 and the second vent portion

40 of the ventilation opening 38 protrude slightly at the top of the cover part 3.

The connection 18 is connected to a pump device 19 which is designed to apply an overpressure and/or underpressure to the mold space 4 .

The stamp vent section 37 of the stamp element 20 is preferably a wall section running parallel to the florizontal.

The stamp ventilation section 36 of the stamp element 20 extends approximately over at least 10% or at least 20% or at least 30% of the fleas of the mold space 4 in the vertical direction 8.

According to the first aspect of the present invention and the second aspect of the present invention, it can be provided to provide a mold 1 in which a vent groove 13 is formed in a contact surface 14 between a base part 2 and a cover part 3, and in addition in a Area in which the base part 2 and a plunger element 20 contact each other in a closed state and form a contact surface 33, a venting device 34 is provided. A low-pressure casting method according to the embodiment of the second aspect of the present invention will be explained below.

The mold 1 is in the closed state.

The ventilation openings 38 are connected to the pump device 19 via the connections 18 which are designed as compressed air lines.

The mold 1 is connected to the crucible 23 of the furnace 22 via the riser pipe connection 6 and the at least one riser pipe 25 .

The furnace 22 heats the crucible 23 and the melt 24 arranged therein, so that liquid melt 24 is kept available in the crucible 23 .

Gas pressure is applied to the liquid melt 24 in the crucible 23 by means of the gas pressure application device 26 in such a way that the melt 24 is pressed via the riser pipe 25 counter to gravity in the vertical direction 8 upwards into the mold space 4 of the mold 1 .

The mold space 4 is charged with melt 24 from the crucible 23 .

A negative pressure of approximately 120 mbar to 20 mbar or up to 10 mbar is now applied to the mold space 4 of the mold 1 by means of the pump device 19 . The negative pressure must not be too high and must not apply too early, since otherwise parts of the melt 24 will be torn off. The negative pressure ensures that the air that is in the mold space 4 and is pushed in front of the melt 24 is sucked out. The air is discharged from the mold space 4 via the ventilation device 34 , the ventilation openings 38 , the connections 18 and the pump device 19 . This largely ensures that the mold space 4 is completely filled with melt 24 at the end of filling and that there are no air cushions and/or pores within the melt 24 .

The vertical and horizontal ventilation channels or the first and second ventilation channels 37a, 37b of the ventilation device 34, which are formed in the stamp ventilation section 37 of the stamp element 20 and which open into the ventilation opening 38, ensure that the air is discharged even more efficiently.

If the mold space 4 is completely filled with melt 24, the stamp element 20 of the lid part 3 is pressed onto the melt 24 by means of the stamp displacement device 29 in order to recompact it. The melt 24 is thus compressed and any residual air is removed or pressed out of the melt 24 . The cast part is given its final shape.

Since the second vent opening section 40 of the vent opening 38 is encased by the channel section 42 of the plunger element 2, which also extends through the opening 41 of the cover 35 of the cover part 3, there is also a small gap between the plunger element 2 and the cover 35 of the cover part 3 bridged by the channel section 42 when the plunger element 2 is moved with respect to the cover 35 of the cover part 3 .

This condition is maintained until the melt 24 is solidified. By removing the finished cast part from the mold, by opening the cover 35 of the cover part 3 and the side walls 9 and the associated opening of the mold 1 and the lowering of the plunger element 20, the venting device 34 is exposed and can then be easily freed from melt residues or removed. Sprues that form in the venting channels of the venting device 34 can be easily separated from the cast part.

All method steps according to the first aspect of the present invention can be provided additionally or optionally. For example, the method steps according to the first aspect and the second aspect of the present invention can be combined with one another, if appropriate. The same applies to combinations of the technical features of the molds 1 according to the first and the second aspect of the present invention. The technical features of the present invention can be summarized as follows, by way of example:

The mold for low-pressure casting comprises a base part, a cover part, with the base part and the cover part delimiting a mold space, and a riser pipe connection opening into the mold space. In a closed state, the base part and the cover part have at least one area in which they contact each other and form a contact surface, with a ventilation device being formed at least partially in the contact surface, which is connected in a communicating manner to the mold space and to at least one ventilation opening.

The cover part has a cover and a plunger element, the plunger element being arranged on the side of the cover facing the mold space so that it delimits part of the mold space and the plunger element having the ventilation device on its radial outside.

The ventilation device has one or preferably several ventilation ducts extending in the vertical direction and/or in the horizontal direction, the ventilation ducts preferably having an approximately semicircular and/or rectangular cross section and/or the ventilation ducts having a corrugated, meandering or zigzag shape are. The ventilation channels communicate at least indirectly with the ventilation opening.

The ventilation device has at least one stamp ventilation section, which is arranged distributed in the circumferential direction on the radial outside of the stamp element, with each stamp ventilation section having at least one first ventilation channel and at least one second ventilation channel, which is connected to the first ventilation channel. In particular, the first ventilation channel is arranged essentially perpendicular to the second ventilation channel.

The at least one vent includes a first vent portion and a second vent portion, wherein the first

Vent opening portion is connected to the second vent opening portion. The first ventilation opening section extends from the ventilation device in an approximately horizontal direction into the plunger element. The second vent opening section runs approximately in a vertical direction to the first vent opening section and extends through the plunger element and the lid of the lid part to at least one port. The at least one ventilation opening is delimited at least in sections by at least one channel section of the plunger element which is in particular formed in one piece and is essentially vertically aligned, the channel section preferably reaching through the cover in an opening and in particular protruding vertically from the cover.

The one or more ventilation openings are connected to a common pump device via the connections, the pump device being designed to apply an overpressure and/or an underpressure to the mold space.

The venting device of the contact surface is designed as a venting groove which is connected in a communicating manner to the mold space and to the venting opening.

The vent groove extends outwardly from the mold space in an approximately lateral direction, the vent groove being formed in a base part contact surface of the base part and/or in a lid part contact surface of the lid part. The ventilation groove is preferably approximately semicircular in cross-section and closed outwards in the lateral direction.

The mold has one or more side walls, with four side walls preferably being provided. One ventilation groove is provided per side wall and each ventilation groove is connected to a ventilation opening formed in the cover part.

A functional section is formed on an inner wall of the mold that delimits the mold space and extends approximately in the vertical direction, the functional section having functional elements that extend in the vertical direction and/or in the horizontal direction. The functional elements are designed in waves, meanders or zigzags and form secondary venting grooves that open into the venting grooves, with the functional section being formed in the vertical direction at the top of the mold and extending approximately by at least 50% or at least 33% or at least 25% of a fleas of the mold space in the vertical direction.

The base part has a bottom wall and one or more, in particular four, side walls that delimit the mold space, the side walls being displaceable in the lateral direction outwards to open the mold space. Or the cover part has a top wall and at least one or more sections of Side walls or the side walls, with guide elements being provided for guiding the side walls.

The cover part has the plunger element which can be arranged in the mold space, the plunger element preferably being designed to be displaceable in the vertical direction and a displacement amounting to approximately 5 mm.

The device for low-pressure casting with a mold described above comprises a heating device for heating a crucible, the crucible being designed to store melt and the crucible being connected to a riser pipe connection of the mold via a riser pipe. The device also includes a gas pressure application device in order to apply gas pressure to the melt in the crucible in such a way that the melt can be supplied from the crucible to the mold via the riser pipe.

The method for low-pressure casting, in particular with a device described above, comprises the following steps: filling a mold space of a mold with melt and applying a vacuum to the mold space by means of a pump device, the vacuum preferably being applied when the mold space is approximately at least 50 % or at least 65% or at least 80% is filled.

The method includes the further step that at the beginning of the filling of the mold space, the melt is subjected to a back pressure by means of the pump device until the mold space is approximately at least 50% or at least 65% or at least 80% full.

The features listed above as examples can be used individually or in any combination.

reference list

24 melt

I mold 25 riser 2 base part 2 gas pressurization device

3 cover part I 30 27 side wall moving device

4 mold space 28 vertical traversing device

5 bottom wall 29 stamp traversing device

6 riser pipe connection 30 ejector device 7 column 31 pressure control device

8 vertical direction 35 32 secondary vent grooves

9 side wall 33 contact surface

10 lateral direction 34 vent

II inner wall 35 cover 12 functional section 36 jacket wall

13 Vent Groove 40 37 Stamp Vent Section

14 contact surface 37a first vent channel

15 base part contact surface 37b second vent passage

16 cover part contact surface 38 vent opening 17 channel-like vent opening 39 first

45 vent opening section

18 connection

40 second

19 pump device vent portion

20 stamp element 41 opening

21 device

42 channel section 22 furnace

23 Crucible

Claims

patent claims

1. Mold (1) for low-pressure casting, comprising a base part (2), a cover part (3), the base part (2) and the cover part (3) delimiting a mold space (4) and one opening into the mold space (4). Riser pipe connection (6), and wherein an area in which the base part (2) and the cover part (3) contact each other in a closed state forms a contact surface (14), characterized in that in the contact surface (14) a ventilation groove ( 13) which is communicatively connected to the mold space (4) and to a vent opening (17).

2. Mold (1) according to claim 1, characterized in that the venting groove (13) extends outwards from the mold space (4) approximately in the lateral direction (10), and wherein the venting groove (13) is in a base part contact surface (15) of the base part (2) and/or in a cover part contact surface (16) of the cover part (3), the venting groove (13) preferably having an approximately semicircular cross section and being closed outwards in the lateral direction (10).

3. Mold (1) according to claim 1 or 2, characterized in that the mold (1) has one or more side walls (9), four side walls (9) preferably being provided, and one ventilation groove ( 13) is provided, and wherein each ventilation groove (13) is connected to a ventilation opening (17) formed in the cover part (3).

4. mold (1) according to any one of claims 1 to 3, characterized in that that the one or more ventilation openings (17) are connected to a common pump device (19) via connections (18), and wherein the pump device (19) is designed to apply an overpressure and/or an underpressure to the mold space (4).

5. Mold (1) according to one of claims 1 to 4, characterized in that on an inner wall (11) of the mold (1) delimiting the mold space (4) and extending approximately in the vertical direction (8), a functional section (12) is formed, wherein the functional section (12) has functional elements extending in the vertical direction and/or in the horizontal direction, and the functional elements are designed in a wave, meander or zigzag shape and form secondary venting grooves (32) which are inserted into the venting grooves ( 13), wherein the functional section (12) is formed in the vertical direction (8) at the top of the mold (1) and extends approximately over at least 50% or at least 33% or at least 25% of a fleas of the mold space (4) extends in the vertical direction (8).

6. Mold (1) according to one of Claims 1 to 5, characterized in that the base part (2) has a bottom wall (5) and one or more, in particular four, side walls (9) which delimit the mold space (4), wherein the side walls (9) can be displaced outwards in the lateral direction (10) to open the mold space (4), or that the cover part (3) has a top wall and at least one or more sections of the side walls (9) or the side walls (9) has, and wherein guide elements are provided for guiding the side walls (9).

7. Chill mold (1) according to one of claims 1 to 6, characterized in that the cover part (3) has a stamp element (20) which can be arranged in the mold space (4), the stamp element (20) preferably being displaceable in the vertical direction (8). is formed and a displacement is about 5mm.

8. Mold (1) for low-pressure casting, in particular according to claim 1, comprising a base part (2), a cover part (3), wherein the base part (2) and the cover part (3) define a mold space (4) and wherein the lid part (3) has a lid (35) and a stamp element (20), the stamp element (20) being arranged on the side of the lid (35) pointing towards the mold space (4), so that it fills part of the mold space (4 ) delimited, and a riser pipe connection (6) opening into the mold space (4), characterized in that the base part (2) and the stamp element (20) in a closed state have at least one region in which they contact one another and a contact surface ( 33), wherein a ventilation device (34) is formed at least partially in the contact surface (33) and is connected in a communicating manner to the mold space (4) and to a ventilation opening (38) which extends upwards through a corresponding opening ( 41) in the cover (35) of the cover part (3) extending channel section (42), the channel section (42) protruding slightly at an upper side of the cover (35) of the cover part (3).

9. Mold (1) according to claim 8, characterized in that the ventilation device (34) is arranged adjacent to the cover (35) of the cover part (3) and extends approximately in the vertical direction (8), the ventilation device (34) is formed at least in regions in a stamp venting section (37) in an approximately radially circumferential casing wall (36) of the stamp element (20).

10. Mold (1) according to claim 8 or 9, characterized in that the channel section (42) is formed in one piece on the stamp element (20).

11. Mold (1) according to one of claims 8 to 10, characterized in that the ventilation device (34) has one or preferably several ventilation channels extending in the vertical direction and/or in the horizontal direction, the ventilation channels preferably being approximately semicircular in cross section and/or are rectangular in shape and/or wherein the ventilation channels are in the form of waves, meanders or zigzags and the ventilation channels open into the ventilation opening (38).

12. mold (1) according to any one of claims 9 to 11, characterized in that the venting device (34) is designed as a single venting section running completely radially around the stamp venting section (37) of the stamp element (20) or as a plurality of venting sections section by section running radially around the stamp venting section (37) of the stamp element (20), the venting device (34 ) preferably comprises a plurality of ventilation sections, each having a plurality of ventilation channels, and the ventilation channels of each ventilation section extend in the vertical direction and/or in the horizontal direction, and the ventilation channels of each ventilation section are connected to at least one ventilation opening (38).

13. Mold (1) according to one of claims 8 to 12, characterized in that the vent opening (38) comprises a first vent opening section (39) and a second vent opening section (40), the first vent opening section (39) being connected to the second

Vent opening section (40) is connected, wherein the first vent opening section (39) of the

Venting device (34) approximately in the horizontal direction in the plunger element

(20), and wherein the second vent opening section (40) runs approximately in the vertical direction to the first vent opening section (39) and through the plunger element (20) and the cover (35) of the cover part (3) to a connection (18 ) extends.

14. Mold (1) according to one of Claims 8 to 13, characterized in that the one or more ventilation openings (38) are connected to a common pump device (19) via the connections (18), and the pump device (19) for Applying an overpressure and / or a vacuum to the mold space (4) is formed.

15. Device (21) for low-pressure casting with a permanent mold (1) according to one of claims 1 to 7 and/or one of claims 8 to 14, comprising a heating device (22) for heating a crucible (23), the crucible ( 23) is designed for holding melt (24) and wherein the Crucible (23) is connected via a riser pipe (25) to a riser pipe connection (6) of the mold (1), and a gas pressure application device (26) in order to apply a gas pressure to the melt (24) in the crucible (23) in such a way that that the melt (24) from the crucible (23) via the riser (25) of the mold (1) can be fed.

16. A method for low-pressure casting, in particular with a device (21) according to claim 15, comprising the following steps, filling a mold space (4) of a mold (1) with melt (24) and

Application of a negative pressure to the mold space (4) by means of a pump device (19), the negative pressure preferably being applied when the mold space (4) is approximately at least 50% or at least 65% or at least 80% full. 17. Method for low-pressure casting, in particular according to claim 15, comprising the further step that at the beginning of the filling of the mold space (4), the melt (24) is subjected to a counter-pressure by means of the pump device (19) until the mold space (4) in is about at least 50% or at least 65% or at least 80% filled.