Casting device for a vacuum die casting system, vacuum die casting system and method for operating the vacuum die casting system

Abstract

The invention relates to a casting device (01) for a vacuum pressure casting system, wherein the casting device (01) comprises a casting chamber (10) with a cylindrical surface (11) and a piston (20) movable longitudinally in the casting chamber (10) and closing off the casting chamber (10) at a first end (12), wherein the casting chamber (10) comprises a filling opening (14), wherein the casting chamber (10) comprises a sprue opening (16) at a second end (13) opposite the first end, preferably at the end face, wherein at least one suction groove (17) is arranged tangentially on the inside of the cylindrical surface (11), and wherein at least one suction opening (18) is arranged in the suction groove (17). The invention further relates to a vacuum pressure casting system comprising at least one casting device (01) and a method for operating a vacuum pressure casting system.

Description

[0001] The invention relates to a casting device for a vacuum pressure casting system, a vacuum pressure casting system comprising the casting device and a method for operating the vacuum pressure casting system.

[0002] Vacuum die-casting systems are known in the prior art in which a molten metal is injected under pressure into a die-casting tool with a cavity via a piston-operated casting chamber, while simultaneously, at the end of the die-casting tool opposite the injection point, the gas contained in the die-casting tool is evacuated from the die-casting tool by means of a low-pressure system. This prevents air inclusions in the die-casting tool and enables the production of workpieces of particularly high quality.

[0003] Another source of air inclusions is the gap between the piston and the casting chamber, which is unavoidable due to the high thermal stress. The negative pressure in the cavity draws ambient gas, known as false air, through the gap, which can cause the melt in the casting chamber to foam. To prevent gas from being trapped in the melt itself, it is known from DE 20 2010 006 752 U1 to seal the rear of the piston using a special seal. Additionally, it is known to evacuate the casting chamber using a low-pressure system. The evacuation device is located at the rear of the casting chamber. Extraction of false air, which would support the seal, can therefore only occur once the piston has passed the extraction device. This is thus of secondary importance for preventing false air from entering the chamber.

[0004] From DE 10 2010 046 041 A1, it is known to extract the false air through a gap in the piston so that it does not reach the casting chamber. The extraction is achieved through a groove located in the rear part of the piston. Therefore, the complete and effective prevention of false air ingress by extraction can only begin once the groove in the piston has passed the filling opening. Until this point, false air can enter the casting chamber through the filling opening.

[0005] German patent application DE 11 2019 003 928 T5 discloses a method for extracting false air through a longitudinally arranged groove on the top of the casting chamber during the piston's movement. Simultaneously, the casting chamber is evacuated due to the design. However, this can lead to turbulence in the casting chamber, which can also cause the melt to foam.

[0006] A disadvantage of the prior art is that the extraction of the false air can only occur at a late stage, meaning that an air pocket, which weakens the final workpiece, may already have formed in the molten metal by this time. Additionally, with the evacuation device located at the rear of the casting chamber, the evacuation opening may need to be closed as soon as the piston moves, otherwise molten metal could be forced into it. This would prevent the ingress of false air. This problem also exists with the design featuring a groove oriented longitudinally to the piston. If the molten metal solidifies in the groove, the extraction device is at least partially blocked, making it difficult to reuse the casting chamber.

[0007] There is therefore a great need for a reliably functioning, reusable, and easily cleaned casting device with a casting chamber that effectively prevents the entrapment of gas in the molten metal, particularly through the ingress of false air, for the production of high-quality workpieces and / or for quality assurance of the workpieces to be manufactured. At the same time, the casting device and the casting chamber should enable quick and easy filling with molten metal and subsequent processing in a simple and reliable manner. Furthermore, the casting device with casting chamber should be cost-effective to manufacture, durable, and individually adaptable to the workpiece being produced. The invention therefore aims to provide a casting device with a casting chamber to overcome the aforementioned difficulties.

[0008] This problem is solved in a surprisingly simple but effective way by a casting device comprising a casting chamber according to the teaching of independent claim 1, a vacuum pressure casting system comprising at least one casting device according to claim 13 and a method for operating a vacuum pressure casting system according to claim 14.

[0009] According to the invention, a casting device for a vacuum pressure casting system is proposed, wherein the casting device comprises a casting chamber with a cylindrical surface and a piston movable longitudinally into the casting chamber and closing off the casting chamber at a first end, wherein the casting chamber includes a filling opening at the first end, preferably in the cylindrical surface of the casting chamber, and wherein the casting chamber includes a sprue opening at a second end opposite the first end, preferably at the end face. The casting device is characterized in that at least one suction groove is arranged tangentially on the inside of the cylindrical surface, at least in sections, wherein at least one suction opening is arranged in the suction groove.

[0010] The basic idea of ​​the invention is that the extraction of the false air flowing laterally past the piston, caused by the cavity evacuation, can begin via the tangentially arranged extraction groove as soon as the piston's end face has completely passed through it. Due to the tangential arrangement, this occurs early, allowing extraction to begin relatively soon. This prevents turbulence in the casting chamber, as only a small amount of the gas trapped within the chamber escapes through the extraction groove. Thus, foaming of the melt caused by false air and / or turbulence is effectively prevented. This significantly improves the quality of the manufactured workpieces.Within the scope of the invention, it has been further discovered that, due to the tangential arrangement of the groove, no melt or only small amounts of melt are pressed into the groove, and this occurs at low pressure, since the piston closes the groove after only a short distance. After the piston has passed the groove, any melt remaining in the groove can easily be discharged laterally and removed from the casting chamber.

[0011] The casting chamber with its cylindrical surface serves to hold the molten metal to be introduced into a die-casting tool. Preferably, the casting chamber is essentially cylindrical, but any shape of extruded hollow body is conceivable. To enable the molten metal to be injected from the casting chamber into the die-casting tool under pressure, the casting device further includes a piston. The piston is movable from one end of the casting chamber to the other. The first and second ends of the casting chamber close off the chamber in the extrusion direction, i.e., at the end faces. For this purpose, the piston's circumferential geometry is adapted to the interior of the casting chamber, whereby a small gap between the casting chamber and the piston is unavoidable due to the thermal stress on the chamber.When the molten metal is poured into the casting chamber, the piston is initially positioned at the first end of the chamber, sealing it off. In other words, the molten metal is contained by the end face of the piston facing the casting chamber. To introduce the molten metal into the die-casting tool by means of pressure, the piston is moved from the first end to the second end of the casting chamber. The piston applies the necessary pressure to the molten metal to force it through the sprue located at the second end. Preferably, the sprue is located at the end face of the second end, allowing for the easy removal of most, and preferably all, of the molten metal from the casting chamber. This means that the movement of the piston applies pressure to the molten metal, forcing it from the casting chamber through the sprue into the die-casting tool.To introduce the molten metal into the casting chamber, it includes a filling opening.

[0012] Before the molten metal is poured, the casting chamber is filled with a gas, usually air. This gas should be removed from the casting chamber, preferably completely, before and / or during the injection of the molten metal into the die-casting tool under pressure. Simultaneously, during injection and / or injection under pressure through the sprue, turbulence of the gas and / or the ingress of gas from the surrounding environment should be prevented as much as possible, since this can lead to small gas inclusions in the molten metal, which can weaken the workpiece being produced. Gas turbulence in the casting chamber can be prevented by the gas evacuation through the die-casting tool, which begins during the injection process. This ensures that the gas already has a predetermined flow direction.Another source of air inclusions in the melt is ambient gas flowing laterally past the piston, the so-called false air, when the piston covers or passes the filling opening. To prevent the occurrence of false air, the invention provides for at least one extraction groove with at least one extraction opening to be incorporated, at least partially, into the inner surface of the casting chamber. Preferably, at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 extraction grooves, either identical or differently configured, are arranged on the inner surface of the casting chamber, at least partially. Furthermore, preferably at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100 extraction openings of the same or different design are arranged in the extraction groove(s).The extraction openings can be arranged regularly or irregularly distributed within the extraction groove(s). If at least two extraction grooves are arranged in the cylinder surface, the extraction openings can be distributed equally or differently across the extraction grooves. An extraction opening is an opening that begins on the underside and / or bottom of the extraction groove and ends on the outer surface of the cylinder surface. Through the extraction opening, the false air flowing laterally past the piston can be extracted as the piston moves along it. Preferably, the extraction groove has a width between 4 mm and 12 mm, more preferably between 5 mm and 11 mm, further preferably between 6 mm and 10 mm, and most preferably between 7 mm and 9 mm, particularly 8 mm.

[0013] Within the scope of the invention, it has been recognized as essential that the extraction groove is arranged tangentially on the inner surface of the cylinder. This tangential orientation allows the piston to close the extraction groove at an early stage. As soon as the piston closes the extraction groove, the air introduced by the cavity evacuation can be extracted without causing turbulence in the gas within the casting chamber. In the context of the invention, the term "close" means that the piston is positioned in front of the extraction groove and thereby closes it. It is understood that the closure must not be 100% airtight, as extraction and / or evacuation would otherwise be impossible, as described elsewhere. Air will only be present as long as a gas flow through the casting chamber is possible. That is, as soon as the molten metal completely or almost completely fills the casting chamber, no more air can enter.This occurs as the piston moves from the first to the second end. This reduces the volume of the casting chamber. Once this state is reached, the extraction of false air is no longer necessary.

[0014] The invention makes it possible to provide a casting device that is both durable and effectively prevents gas inclusions in the melt during pressure build-up and even during the pouring of the melt into the casting chamber, thereby significantly improving the quality of the castings produced. Furthermore, the casting chamber can be filled more quickly and efficiently with a higher throughput, resulting in substantial cost savings.

[0015] Advantageous further developments of the invention, which can be implemented individually or in combination, are presented in the dependent claims.

[0016] In a preferred embodiment of the invention, the extraction groove is arranged behind the filling opening. By arranging the extraction groove behind the filling opening, it is possible to begin extracting the false air as early as possible and to maintain this extraction for as long as possible. False air only enters the system once the piston covers the filling opening or has already passed through it. Before the piston closes the filling opening, gas from the surroundings of the casting chamber flows through the filling opening into the casting chamber, since the flow resistance here is significantly lower compared to the gap between the piston and the casting chamber wall, through which the false air flows. As described elsewhere, the extraction should be maintained for as long as possible, ideally until the melt completely fills the decreasing volume of the casting chamber.Furthermore, the arrangement behind the filling opening eliminates the problem of air extraction failing because it enters the casting chamber through the filling opening and causes turbulence. While turbulence can occur due to the partial intake of ambient gas through the filling opening towards the extraction groove, the piston is already completely in front of the filling opening at this point. Therefore, the turbulence occurs in the area of ​​the piston and not in the area of ​​the molten metal. The term "behind" refers to a longitudinal direction measured from the first end of the casting chamber.

[0017] It is conceivable that a low-pressure system and / or a vacuum pump is connected to the extraction port. Using the low-pressure system and / or the vacuum pump, extraction through the extraction groove can be carried out simply but effectively. This prevents gas inclusions in the melt caused by incoming air as completely as possible. This improves the quality of the workpieces being manufactured. The low-pressure system and / or vacuum pump can be operated until the piston has completely passed through the extraction groove. It is conceivable that the same low-pressure system and / or vacuum pump evacuates the die-casting tool and is responsible for extracting the incoming air at the extraction groove, or that a second low-pressure system and / or vacuum pump is provided for evacuating the die-casting tool.Furthermore, if more than one extraction opening is arranged in the casing surface, it is conceivable to connect all extraction openings to a low-pressure system and / or vacuum pump. Preferably, it is conceivable to connect a first extraction opening or a first part of the extraction openings to a first low-pressure system and / or vacuum pump, and a second extraction opening or a second part of the extraction openings to a second low-pressure system and / or vacuum pump. More preferably, the casting device includes a control and / or regulation device for the targeted extraction of false air through the extraction openings in one or more extraction grooves and / or for the targeted evacuation of the die-casting tool.

[0018] In a further development of the invention, it is conceivable that the extraction groove extends partially, preferably between 10° and 120°, and particularly preferably 90°, into the cylindrical surface. It has been recognized within the scope of the invention that if the extraction groove is not arranged circumferentially but is only incorporated into the upper side of the cylindrical surface, melt that has been introduced into the extraction groove during the movement of the piston can subsequently leak out laterally and / or the melt does not fill the volume of the casting chamber to such an extent that the melt reaches the extraction groove before the piston covers it. The angle over which the extraction groove extends should not be chosen to be too small, as otherwise the surface tension of the melt prevents leakage and / or the extraction of false air is not complete, but rather some of the false air escapes past the extraction groove in the lower region and into the casting chamber.However, it should not be too large, as otherwise the melt may collect at the groove end faces due to gravity and / or the ingress of melt cannot be prevented. Preferably, the groove extends over an angle of at least 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 85°, 90°, 95°, 100°, 105°, 110° or 115°. Even more preferably, the groove extends over an angle of no more than 115°, 110°, 105°, 100°, 95°, 90°, 85°, 80°, 75°, 70°, 65°, 60°, 55°, 50°, 45°, 40°, 35°, 30°, 25°, 20° or 15°.

[0019] In a further development, it is conceivable that the extraction groove is designed with a flattened end face, thus having at least one, preferably two, flattened areas. This prevents the accumulation of molten metal in the edge regions of the extraction groove. The molten metal is drawn out of the groove by gravity. Furthermore, any air that may enter the groove can be selectively extracted from the edge regions.

[0020] In a preferred embodiment, the filling opening is located in the outer surface of the cylinder in a third of the cylinder's surface adjacent to the first end. Particularly preferably, the filling opening is positioned so close to the first end that, when the piston is in the position at the first end, the end face of the piston abuts a leading edge of the filling opening. With this positioning of the filling opening, the piston closes the opening early during its movement from the first end to the second end, so that only a small amount of the gas surrounding the casting chamber can penetrate through the filling opening into the casting chamber, and the evacuation of the die-casting tool is very effective.In a further embodiment, it is conceivable that the suction groove is arranged in the first third of a section of the casing surface, with this section extending from a rear edge of the filling opening to the second end of the casting chamber. Preferably, the suction groove is arranged a maximum of 20 mm from the rear edge of the filling opening, and particularly preferably a maximum of 19 mm, 18 mm, 17 mm, 16 mm, 15 mm, 14 mm, 13 mm, 12 mm, 11 mm, 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, or 5 mm from the rear edge of the filling opening. Particularly preferably, the suction groove is arranged directly behind the filling opening, the term "directly behind" denoting the minimum safe distance to the rear edge of the filling opening. In this way, the preferred effect described above, namely that the extraction of false air can occur early and be maintained for as long as possible, can be maximized.This is particularly the case if the filling opening is located directly at the first end, as described elsewhere.

[0021] It is also conceivable that the diameter of the filling opening increases from an inner to an outer surface of the casing, and that the suction groove runs at least partially below the filling opening. In this way, the suction groove can be positioned closer to the edge of the filling opening during manufacturing. This achieves the advantages described elsewhere. Furthermore, the filling opening forms a funnel, which facilitates the filling of the melt.

[0022] In a further embodiment of the invention, it is conceivable that the extraction groove is designed with a rectangular cross-section. A rectangular cross-section is easy to manufacture. In particular, the at least one extraction opening can be easily arranged at the bottom of the rectangular cross-section.

[0023] Furthermore, it is conceivable that the extraction groove and / or the extraction opening is located on the upper side of the casting chamber. Under normal conditions, the gas in the casting chamber is less dense than the molten metal, so that the gas is displaced by the molten metal towards the upper side of the casting chamber when the molten metal is poured in. This upper-side arrangement is particularly advantageous if the upper side is formed by a section of the cylinder's surface. In other words, the piston moves essentially horizontally within the casting chamber. Air leakage occurs particularly in the area of ​​the piston that is not covered by molten metal at its end face.

[0024] In another embodiment, the casting device could include two to ten extraction grooves, arranged longitudinally one behind the other. By selectively controlling the extraction through individual grooves, the extraction time can be extended. Extraction occurs at each groove as long as it is covered by the piston. This allows the extraction of ambient air to be maintained even with short pistons until the melt completely fills the decreasing volume of the casting chamber.

[0025] Particularly preferred are the suction grooves arranged at a distance from one another, wherein the distance between adjacent suction grooves is less than the longitudinal extent of the piston, in particular equal to the longitudinal extent of the piston minus the widths of the adjacent suction grooves. This design enables the continuous maintenance of suction.

[0026] It is assumed that the definitions and / or explanations of the above-mentioned terms apply to all aspects described in this description and below, unless otherwise stated. It is understood that the explanations given regarding the method and / or the further apparatus apply in an equivalent, though not identical, manner to the casting apparatus according to the invention, and vice versa.

[0027] According to the invention, a vacuum pressure casting system is further proposed, comprising at least one casting device described elsewhere, a drive for driving the piston, at least one die-casting tool, and at least one low-pressure system and / or vacuum pump. It is conceivable that the vacuum pressure casting system comprises two or more low-pressure systems and / or vacuum pumps, one of which is connected to the die-casting tool and the other to the extraction port. This allows for the simple decoupling of the respective extraction and / or evacuation processes. Furthermore, it is conceivable that the vacuum pressure casting system comprises at least 2, 3, 4, 5, 6, 7, 8, 9, or 10 die-casting tools, the die-casting tools preferably having different cavities for producing different components. The advantages of the casting device described elsewhere can be achieved by means of the vacuum pressure casting system.

[0028] According to the invention, a method for operating a vacuum pressure casting system described elsewhere is further proposed, wherein the method comprises the following steps: a) Providing a casting device described elsewhere; and b) Pouring a molten metal through the filling opening; and c) Moving the piston from the first end to the second end of the casting chamber, extracting a gas flowing laterally along the piston, evacuating a gas located in the die-casting tool and introducing the molten metal into the die-casting tool.

[0029] By extracting the gas flowing laterally along the piston, the false air, during piston movement, the formation of gas inclusions in the melt is prevented. When the piston is subsequently moved from the first end to the second end of the casting chamber, the melt, with low or preferably gas inclusion-free gas, is injected into the die-casting tool under pressure. Evacuating the gas from the die-casting tool simultaneously prevents the formation of gas inclusions within the die-casting tool and thus in the component being manufactured. The casting chamber, which is connected to the die-casting tool via the filling opening, can also be evacuated during this process. During the extraction of the false air, gas present in the casting chamber and / or gas flowing in through the filling opening can also be extracted, either temporarily or over a longer period, without affecting the inventive method.It is preferably conceivable to begin evacuating the die-casting tool and, if applicable, the casting chamber only when the piston closes the filling opening and / or the extraction groove. Even more preferably, it is conceivable to begin extracting the false air only when the piston closes the filling opening and / or the extraction groove. Furthermore, it is conceivable to stop extracting the false air when the piston has passed the extraction groove and / or the melt completely fills the volume of the casting chamber. With the method according to the invention, workpieces of high quality can be produced quickly, easily, and effectively.

[0030] Advantageous further developments of the invention, which can be implemented individually or in combination, are presented in the dependent claims.

[0031] In a further development of the method, it is conceivable that the extraction of gas located in the casting chamber, gas flowing into the casting chamber, and / or gas flowing laterally along the piston, and / or the evacuation of gas located in the die-casting tool, takes place in step b. If the actions are provided for in step c according to the invention, they are carried out in addition to step c. Thus, it is conceivable that the actions take place exclusively in step b, exclusively in step c, or in both steps b and c. In this way, turbulence of the gas located in the casting chamber during the pouring of the melt can be prevented.

[0032] Within the scope of the invention, it is conceivable that the method comprises further steps than those explicitly described, as described elsewhere. Furthermore, it is conceivable that individual or all steps can be repeated any number of times. In addition, it is conceivable that the method can be partially or fully automated.

[0033] Further details, features, and advantages of the invention will become apparent from the following description of the preferred embodiment in conjunction with the dependent claims. The respective features can be implemented individually or in combination with one another. The invention is not limited to this embodiment. The embodiment is shown schematically in the figures. Identical reference numerals in the individual figures denote identical or functionally equivalent elements, or elements that correspond to one another with respect to their function.

[0034] Specifically, we show: Fig. 1 a sectional view through a first embodiment of a casting device according to the invention in the longitudinal direction; and Fig. 2 a sectional view through the first embodiment of the casting device according to the invention in a transverse direction; and Fig. 3 a sectional view through a second embodiment of a casting device according to the invention in the longitudinal direction; and Fig. 4 individual steps of a first embodiment of the method according to the invention; and Fig. 5 individual steps of a second embodiment of the method according to the invention.

[0035] Fig. Figure 1 shows a longitudinal sectional view through a first embodiment of a casting device 01 according to the invention. The casting device 01 comprises a cylindrical casting chamber 10, which is bounded by a cylindrical surface 11. A piston 20 is arranged at a first end 12 of the casting chamber 10. This creates a receiving space for a melt. The melt (not shown) can be introduced into the receiving space through a filling opening 14 in the cylindrical surface 11, the filling opening 14 being located on the top side of the casting chamber 10. The filling opening 14 has a rear edge 15. The diameter of the filling opening 14 increases from an inner side of the cylindrical surface 11 to an outer side of the cylindrical surface 11. This results in chamfered edges, particularly the rear edge 15.Directly behind the rear edge 15 and below the chamfered rear edge 15 of the filling opening 14, a suction groove 17 is arranged on the inside of the outer surface 11 of the upper side of the casting chamber 10. At a second end 13, the casting chamber 10 includes a sprue opening 16. The piston 20 also includes a piston rod 21, by means of which the piston 10 can be moved from the first end 12 to the second end 13, whereby the molten metal inside the casting chamber 10 is expelled through the sprue opening 16 by means of pressure.

[0036] Fig. Figure 2 shows a sectional view through the first embodiment of the casting device 01 according to the invention in the transverse direction, wherein the section is along the line shown in the Fig. The process is shown along the axis A. It is clearly visible that the extraction groove 17 is arranged on the inside of the cylindrical surface 11 of the casting device 10. Furthermore, two laterally arranged extraction openings 18 are located in the extraction groove 17. The extraction groove 17 extends over an angle of approximately 90°. The extraction groove also has flattened sections 19 at its ends. Preferably, at least one low-pressure system and / or vacuum pump (not shown) is connected to the extraction openings 18, by means of which any false air can be extracted.

[0037] Fig. Figure 3 shows a sectional view through a second embodiment of a casting device 01 according to the invention in the longitudinal direction. The second embodiment of the casting device 01 largely corresponds to the one shown in Fig. The first embodiment shown in Figure 1 is identical, so the descriptions given for it essentially also apply to the second embodiment. The second embodiment of the casting device 01 differs from the first embodiment, particularly in its significantly shorter piston 20. Due to the shorter design, the extraction time is severely limited with only one extraction groove 17, as extraction can only occur as long as the piston 20 closes the extraction groove 17. To extend the extraction time, a second extraction groove 17 is arranged in the cylindrical surface 11. The second extraction groove 17 is spaced further apart from the first extraction groove 17, with this distance, together with the respective groove widths, being less than the longitudinal extent of the piston 20. The piston 20 completely covers the second extraction groove 17 before it releases the first extraction groove 17, thus enabling continuous extraction.

[0038] Fig. Figure 4 shows individual steps of a first embodiment of the method according to the invention. The method according to the invention is carried out in a third embodiment of a casting device 01 according to the invention, which is largely the same as that shown in Fig. The first embodiment shown in Figure 1 corresponds to the first embodiment, wherein the sprue opening 16 is arranged on the front face of the top of the casting chamber 10. Fig. 4A the piston 20 is located at the first end 12 of the casting chamber 10. Step b of the inventive method is carried out, in which a melt 30 is poured into the casting chamber 10 through the filling opening 14.

[0039] In Fig. In step 4B, the piston 20 is moved from the first end 12 to the second end 13. This reduces the volume of the casting chamber 10, and the level of the melt 30 rises. The piston 20 covers the filling opening 14 and the suction groove 17, so that the extraction of a gas flowing laterally along the piston 20, the false air, and the evacuation of the gas located in a die-casting tool (not shown) begins.

[0040] In Fig. 4C, the piston 20 continues to move from the first end 12 to the second end 13. The level of the melt 30 has risen sufficiently to fill the remaining volume of the casting chamber 10 and is forced through the gate opening 16 under the pressure exerted by the piston 20. The extraction of the false air can be stopped. Preferably, the evacuation of the die-casting tool (not shown) continues.

[0041] Fig. Figure 5 shows individual steps of a first embodiment of the method according to the invention. The method according to the invention is carried out in a fourth embodiment of a casting device 01 according to the invention, which is largely the same as that shown in Figure 5. Fig. 2 corresponds to the second embodiment shown, wherein the sprue opening 16 is arranged on the front face of the top of the casting chamber 10. Fig. In step 5A, the piston 20 is moved from the first end 12 to the second end 13. This reduces the volume of the casting chamber 10, and the level of the melt 30 rises. The piston 20 covers the filling opening 14 and the first extraction groove 17, so that the extraction of false air at the first extraction groove 17 and the evacuation of the gas located in a die-casting tool (not shown) begins.

[0042] In Fig. In step 5B, the piston 20 is moved further from the first end 12 to the second end 13, and the level of the melt 30 continues to rise. The melt 30 does not yet completely fill the volume of the casting chamber 10. However, the piston 20 is designed to be short enough that the first extraction groove 17 is exposed. The piston 20 already completely covers the second extraction groove 17, allowing the air to be extracted through it. The evacuation of the gas in the die-casting tool (not shown) is maintained.

[0043] In Fig.At 5C, the piston 20 continues to move from the first end 12 to the second end 13. The level of the melt 30 has risen sufficiently to fill the remaining volume of the casting chamber 10 and is forced through the gate opening 16 under the pressure exerted by the piston 20. The extraction of the false air can be stopped. Preferably, the evacuation of the die-casting tool (not shown) continues. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 20 2010 006 752 U1

[0003] DE 10 2010 046 041 A1

[0004] DE 11 2019 003 928 T5

[0005]

Claims

[1] Casting device (01) for a vacuum pressure casting system, wherein the casting device (01) comprises a casting chamber (10) with a jacket surface (11) and a piston (20) which is movable longitudinally in the casting chamber (10) and closes the casting chamber (10) at a first end (12), wherein the casting chamber (10) comprises a filling opening (14), wherein the casting chamber (10) comprises a sprue opening (16) at a second end (13) opposite the first end, preferably at the front side, characterized by , that at least one suction groove (17) is arranged tangentially on the inside in the lateral surface (11) at least in sections, wherein at least one suction opening (18) is arranged in the suction groove (17). [2] Casting device (01) according to claim 1, characterized by that the suction groove (17) is arranged behind the filling opening (14). [3] Casting device (01) according to claim 1 or 2, characterized bythat a low-pressure system and / or a vacuum pump is connected to the suction opening (18). [4] Casting device (01) according to claim 1 or 2, characterized by that the suction groove (17) extends partially, preferably between 10° and 120°, in the lateral surface (11). [5] Casting device (01) according to claim 3, characterized by that the suction groove (17) is flattened on the front side. [6] Casting device (01) according to one of the preceding claims, characterized by that the filling opening (14) is arranged in a third of the lateral surface (11) adjoining the first end in the lateral surface (11) of the casting chamber (10). [7] Casting device (01) according to claim 6, characterized by that the suction groove (17) is arranged in a first third of a section of the lateral surface (11), wherein the section extends from a rear edge (15) of the filling opening (14) to the second end (13) of the casting chamber (10). [8] Casting device (01) according to one of the preceding claims, characterized by that the diameter of the filling opening (14) increases from an inner side to an outer side of the casing surface (11) and the suction groove (17) runs at least partially below the filling opening (14). [9] Casting device (01) according to one of the preceding claims, characterized by that the suction groove (17) is designed with a rectangular cross-section. [10] Casting device (01) according to one of the preceding claims, characterized by that the suction groove (17) and / or the suction opening (18) is arranged on an upper side of the casting chamber (10). [11] Casting device (01) according to one of the preceding claims, characterized by that the casting device (01) comprises two to ten suction grooves (17), wherein the suction grooves (17) are arranged one behind the other in the longitudinal direction. [12] Casting device (01) according to claim 11, characterized bythat the suction grooves (17) are arranged at a distance from one another, wherein the distance between adjacent suction grooves (17) is smaller than a longitudinal extent of the piston (20), in particular equal to the longitudinal extent of the piston (20) less the widths of the adjacent suction grooves (17). [13] Vacuum die casting system comprising at least one casting device (01) according to one of claims 1 to 12, a drive for driving the piston (20), at least one die casting tool and at least one low-pressure system and / or vacuum pump. [14] Method for operating a vacuum die casting system according to claim 13, comprising the following steps: a. Providing a casting device (01) according to one of claims 1 to 10; and b. Pouring a melt through the filling opening (14); and c. Moving the piston (20) from the first end (12) to the second end (13) of the casting chamber (10), sucking off a gas flowing laterally along the piston (20), evacuating a gas located in the die casting tool and introducing the melt into the die casting tool. [15] Method according to claim 14, wherein the suction of a gas located in the casting chamber (10), a gas flowing into the casting chamber (10) and / or the gas flowing laterally along the piston (20) and / or the evacuation of the gas located in the die casting tool takes place in step b.

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