Apparatus and process for casting metal components

Abstract

The invention relates to a device (2) for casting a metal component, in particular an aluminum component, in particular a low-pressure die casting, comprising: at least one die cavity (4) formed by at least one at least partially surrounded cavity wall (6); the invention relates to an apparatus (2) for filling at least one mold cavity with molten metal, comprising a system of gates, runners and / or flow gates defining at least one runner for filling the at least one mold cavity with molten metal, the apparatus (2) further comprising at least one riser insert (14) for being arranged at least partially within the at least one riser cavity (12) of the at least one riser (8), the at least one riser insert (14) comprises at least one insert cavity (16) to at least partially receive molten metal from the at least one mold cavity (4), and the at least one insert cavity (16) is at least partially surrounded by a riser insert wall (18), the at least one riser insert (14) being configured to at least partially slow solidification of the molten metal received by the at least one insert cavity (16). The invention also relates to a process for casting a metal part, in particular an aluminum part, in a mould, in particular a low-pressure die casting.

Description

Technical Field

[0001] The present invention relates to an apparatus for casting metal components, the casting being in particular low-pressure die casting, and the metal components being in particular aluminium components. The apparatus comprises: at least one die cavity formed by at least one at least partially surrounding cavity wall; and a system of sprues, runners and / or ingates defining at least one flow path for filling the at least one die cavity with molten metal. The present invention also relates to a process for casting metal components in a mould, the casting being in particular low-pressure die casting, and the metal components being in particular aluminium components, wherein the casting process is carried out in particular by means of the aforementioned apparatus. Background Art

[0002] In the casting industry, it is known that filling a die cavity with molten metal to form a high-quality cast metal component requires precise execution of all sequential steps of the casting process so that the molten metal solidifies properly and results in a cast component having the desired mechanical properties and being substantially free of surface defects, inclusions of other materials and gases, and having geometric dimensional integrity.

[0003] Many factors affect the quality of the cast component. For example, for cast components of complex geometry and thin-wall form, the molten metal must be superheated to obtain good fluidity, which ensures that the die cavity is completely filled. However, the higher the temperature of the molten metal, the longer the time required to cool and solidify the cast component.

[0004] In the casting industry, it is a widespread practice to fill the mould with liquid metal from the bottom upwards. The purpose of this measure is to ensure that the molten metal flows into the mould in a non-turbulent and quiescent flow manner so that the molten metal does not entrain any air or other gases that could form voids in the cast component.

[0005] For this purpose, in common practice, a system of sprues, runners and ingates is provided which allows the molten metal placed in a ladle to be poured into the channel system of the mould so that the molten metal fills the die cavity for forming the corresponding cast component and enters a riser arranged above the top horizontal plane of the cast component. The liquid metal present in the riser can provide the amount of metal required to fill the gaps or voids that may form due to the volume shrinkage involved in the solidification of the molten metal.

[0006] Unfortunately, the commonly used risers may not provide their thermal centre in the middle of the riser during the solidification of the molten metal, but rather immediately above the surface of the casting. This can lead to shrinkage occurring at the riser neck during the solidification of the molten metal, which is also visible in the cast metal component after the riser has been removed.

[0007] In addition, due to the thermal design of the commonly used risers, an additional amount of molten metal is typically used in the casting process because it is necessary to ensure that the molten metal in the riser solidifies substantially after the molten metal in the mold cavity has solidified, and that there is sufficient molten metal in the riser during the casting process.

[0008] To improve the thermal performance of the commonly used risers, it is known to enhance the adiabatic properties of the risers by applying a brush-coated coating. However, the coating typically does not have a long lifespan, which may lead to downtime of the casting equipment due to coating repair. In addition, the coating application temperature may be lower than the operating temperature of the casting process, which may impede the effective application of the coating. SUMMARY OF THE INVENTION

[0009] Accordingly, the problem faced by the present invention is how to provide such an apparatus and process for casting metal components that fully improves the mechanical properties of the cast components and also reduces the amount of material required.

[0010] According to a first aspect of the present invention, there is disclosed an apparatus for casting metal components, the casting being in particular low-pressure die casting, and the metal components being in particular aluminum components. The apparatus comprises: at least one mold cavity formed by at least one at least partially surrounding mold cavity wall; a system of gates, runners, and / or ingates defining at least one flow path for filling at least one mold cavity with molten metal; at least one riser insert for at least partially disposing inside at least one riser cavity of at least one riser, wherein the at least one riser insert includes at least one (riser) insert cavity for at least partially receiving molten metal from at least one mold cavity, and the at least one insert cavity is at least partially surrounded by a riser insert wall, wherein the at least one riser insert is configured to at least partially slow down the solidification of the molten metal received by the at least one insert cavity.

[0011] According to a second aspect of the present invention, there is disclosed a process for casting metal components in a mold, the casting being in particular low-pressure die casting, and the metal components being in particular aluminum components, wherein the casting process is in particular carried out by the aforementioned apparatus. The process comprises: forming at least one mold cavity by at least one at least partially surrounding cavity wall, filling at least one mold cavity with molten metal via at least one flow path defined by a system of gates, runners, and / or ingates, disposing at least one riser insert at least partially inside at least one riser cavity of at least one riser, wherein the at least one riser insert includes at least one (riser) insert cavity for at least partially receiving molten metal from at least one mold cavity, and the at least one insert cavity is at least partially surrounded by a riser insert wall, thereby at least partially slowing down the solidification of the molten metal received by the at least one insert cavity during the casting process.

[0012] By providing at least one riser insert, the casting process and / or equipment can be adjusted in a structurally convenient manner for the metal part to be cast. By at least partially slowing down the solidification of the molten metal received in at least one insert cavity of the at least one riser insert, the feeding effectivity, process stability and / or reliability of the casting process can be improved. In particular, less material can be used while still being able to provide a cast metal part with sufficient mechanical properties by reducing surface defects of inclusions of other materials or gases.

[0013] The casting process used can in particular be die casting or low-pressure die casting (LPDC). Accordingly, the equipment can be a low-pressure die casting equipment or a part of a low-pressure die casting equipment, and the mold used can be a die-casting mold suitable for low-pressure die casting. In particular, at least one cavity mold can be filled with liquid metal from the bottom upwards. This allows the molten metal flow to enter the mold in a non-turbulent and static flow manner, such that entrainment of air or other gases that may form voids in the cast part can be reduced or substantially prevented.

[0014] Accordingly, the term metal part is understood to cover the state from molten metal to fully solidified metal in the mold. Preferably, the metal can be aluminum or an aluminum alloy.

[0015] The process can in particular be carried out by means of equipment according to the invention.

[0016] In particular, at least one riser insert is configured such that the temperature of the molten metal received in at least one insert cavity is significantly higher than the temperature of the molten metal in at least one mold cavity. The temperature of the molten metal received in at least one insert cavity is preferably the average temperature of the molten metal in at least one insert cavity. The temperature of the molten metal in at least one mold cavity is preferably the average temperature of the molten metal in at least one mold cavity. In particular, the riser insert is configured such that the molten metal received in at least one riser insert cavity solidifies substantially only after the molten metal in at least one mold cavity has solidified. Thus, it can be ensured that the riser and / or the riser insert includes molten metal that can flow into the mold cavity to prevent shrinkage during solidification in the cast metal part.

[0017] According to an exemplary aspect of all aspects of the present invention, at least one riser insert wall has a thickness of less than 5 cm, particularly less than 3 cm, preferably less than 1.5 cm. By providing a riser insert wall with a relatively thin wall, the riser insert wall can be rapidly heated, particularly faster than at least one cavity wall of the mold cavity, such that only a small amount of heat of the molten metal disposed in at least one riser insert cavity needs to be transferred to heat at least one riser insert wall. This can allow the solidification of the molten metal received by at least one insert cavity to be slowed down in a convenient manner. The thickness of at least one riser insert wall can vary along an extension of at least one riser insert wall. The thickness of at least one riser insert wall can be the thickness of the thinnest region of at least one riser insert wall or the thickness of the thickest region of at least one riser insert wall. Preferably, the thickness of at least one riser insert wall is the average thickness of at least one riser insert wall, particularly if the thickness of at least one riser insert wall varies along its extension.

[0018] According to an exemplary aspect of all aspects of the present invention, at least one riser includes at least one heat insulation device for insulating the molten metal received by at least one insert cavity. By providing at least one heat insulation device, heat transfer from the molten metal disposed in at least one riser cavity can be further reduced, thereby allowing the solidification of the metal disposed in at least one riser cavity to be slowed down. This can, for example, enable the use of less molten metal during the casting process and also allow the liquid metal to flow from the riser insert cavity into the mold cavity during the casting process.

[0019] According to another exemplary aspect of all aspects of the present invention, at least one heat insulation device includes at least one air gap disposed between the riser insert wall of the riser insert and the riser wall of at least one riser. This can allow for low-cost insulation of the molten metal disposed in at least one riser insert cavity and thus enable the solidification of the molten metal inside at least one riser cavity to be slowed down. Preferably, at least one air gap can generally surround, preferably generally annularly surround or enclose at least one riser insert.

[0020] According to an exemplary aspect of all aspects of the present invention, at least one thermal insulation device includes a fibrous material (wool material), in particular rock wool, stone wool, glass wool, and / or a combination thereof, and / or a ceramic thermal insulation material. This can allow at least partial prevention of thermal convection and thermal radiation of the molten metal disposed inside at least one riser insert cavity, and thus enables effective slowing of the solidification of the molten metal disposed inside at least one riser insert cavity, particularly as compared to the solidification of the molten metal inside the mold cavity. Preferably, the fibrous material can at least partially surround at least one riser insert. Preferably, the fibrous material is at least partially disposed in at least one air gap located between the riser insert wall of the riser insert and the riser wall of at least one riser. The at least one thermal insulation device may also include a ceramic thermal insulation material, wherein preferably, at least one riser insert wall includes or is made of a ceramic thermal insulation material. Such a ceramic material may be beneficial for the thermal radiation of at least one riser insert.

[0021] According to an exemplary aspect of all aspects of the present invention, there is provided at least one heating insert for at least partially heating the molten metal received by at least one insert cavity, and the at least one heating insert is preferably at least partially disposed inside at least one riser cavity and / or at least partially disposed inside at least one protective element. By using at least one heating insert, heat can be introduced from the outside into the molten metal disposed inside at least one riser cavity. In particular, it can be ensured that the molten metal disposed inside at least one riser insert cavity has a higher temperature than the molten metal disposed inside at least one mold cavity. Therefore, it can be ensured in a structurally beneficial manner that the metal in at least one riser insert cavity substantially solidifies only after the metal disposed in the mold cavity has solidified. This allows the cast metal part to have favorable mechanical properties. The at least one heating insert is preferably disposed close to and / or at least partially inside at least one riser cavity so as to sufficiently heat the (molten) metal disposed inside at least one riser insert cavity. Preferably, the at least one heating insert is at least partially disposed inside at least one protective element, particularly at least partially disposed inside a protective tube, so as to allow sufficient thermal radiation to enter the direction of at least one riser insert cavity.

[0022] According to an exemplary aspect of all aspects of the present invention, at least one heating insert is configured as at least one burner and / or at least one electric heating cartridge. This allows effective heating of the metal disposed inside at least one riser insert cavity. The at least one heating insert may also be configured as an induction heating element. Therefore, not only can the material of at least one riser insert, particularly a steel material, be effectively heated, but also the molten metal disposed inside at least one riser insert, particularly molten aluminum, can be directly heated.

[0023] According to an exemplary aspect of all aspects of the present invention, the device further comprises at least one sensor device for monitoring at least one heating insert, in particular for measuring the thermal radiation of at least one heating insert. The at least one sensor device can be, for example, at least one thermocouple. Thereby, it can be ensured that the at least one heating insert radiates a sufficient amount of heat so that the metal in at least one riser insert cavity can solidify substantially after the metal in the mold cavity has solidified. The at least one sensor device can particularly be arranged near the at least one riser insert. Preferably, the at least one sensor device is fixed to and / or inserted into the center and / or centering device of the at least one heating insert.

[0024] According to an exemplary aspect of all aspects of the present invention, at least one holding element is at least partially arranged between the at least one riser insert and the at least one heating insert, and the at least one holding element is preferably at least partially arranged within the riser cavity. Preferably, the at least one holding element is heated via the at least one heating insert so that the holding insert transfers heat to the at least one riser insert cavity and the (molten) metal arranged in the at least one riser insert cavity. This allows for reliable and uniform heat transfer of the heat generated by the at least one heating insert. Alternatively, the at least one riser and / or the at least one riser insert can be directly heated by the at least one heating insert, which can provide energy-efficient heating of the (molten) metal arranged inside the at least one riser insert cavity.

[0025] According to an exemplary aspect of all aspects of the present invention, the at least one riser insert comprises centering means, in particular centering pins, for aligning and / or fixing the at least one riser insert within the at least one riser cavity. This allows for effective alignment and / or reliable fixation of the at least one riser insert. Preferably, the centering means is integrally formed with the at least one riser insert, wherein the centering means preferably extends in an outward direction of the at least one riser insert. Preferably, the extension of the centering means does not constitute the thickness of the at least one riser wall insert.

[0026] According to an exemplary aspect of all aspects of the present invention, the at least one riser insert comprises at least one vent hole for venting the metal received by the at least one insert cavity. In particular during low-pressure die casting, reliable venting is required to ensure a sufficiently good quality of the metal casting part. Preferably, the at least one vent hole is arranged at a substantially distal end of the at least one riser insert relative to the end of the at least one riser insert corresponding to the at least one mold cavity. The at least one vent hole can comprise a substantially circular cross-section. A vent insert can be arranged inside the at least one vent hole, wherein the vent insert can comprise a plurality of vent slits.

[0027] According to an exemplary aspect of all aspects of the present invention, at least one riser insert is in fluid connection with at least one riser neck of at least one riser for receiving molten metal at least partially from at least one mold cavity.

[0028] The present invention is particularly applicable to casting cast components for internal combustion engines, such as cylinder blocks and cylinder heads made of light metal alloys, in particular aluminum alloys. The present invention can also be applicable to casting cast components for structural components, for electric machines, etc.

[0029] The exemplary embodiments described in this specification are also intended to disclose, for each aspect and in all combinations with each other. In particular, a method or process step is also intended to disclose the corresponding apparatus for performing the method or process step. Similarly, an apparatus for performing a certain method or process step is also intended to disclose the corresponding method or process step. Description of the Drawings

[0030] Further advantageous exemplary embodiments of the present invention are indicated by the following detailed description of a plurality of practical examples of the present invention, in particular in conjunction with the drawings.

[0031] However, the drawings attached to this application are only for illustrative purposes and not for determining the scope of protection of the present invention. The drawings are only intended to be examples reflecting the general concept of the present invention. In particular, the features shown in the drawings should not be considered as essential components of the present invention in any way.

[0032] The present invention will be described in more detail below with reference to the drawings.

[0033] Figure 1 A schematic detail view of an exemplary embodiment of an apparatus for casting a metal component is shown in a sectional perspective manner. Detailed Description of the Invention

[0034] Figure 1 A schematic detail view of a first embodiment of an apparatus 2 for casting a metal component is disclosed in a sectional perspective manner. The apparatus 2 includes a mold cavity 4 formed by a cavity wall 6. Figure 1 Only a part of the mold cavity 4 is shown. Additionally, the apparatus 2 includes two risers 8, where the risers 8 are in fluid connection with the mold cavity 4 via respective riser necks 10.

[0035] In the inner riser cavities 12 of two risers 8, riser inserts 14 are respectively arranged, wherein each riser insert 14 is formed with an (insert) cavity 16 for receiving molten metal from the mold cavity 4 and / or supplying molten metal to the mold cavity 4. The riser insert cavities 16 are surrounded by riser insert walls 18. The riser insert walls 18 preferably have a thickness of less than 3 cm, preferably less than 1.5 cm, wherein the centering pins 20 integrally formed with the riser insert walls 18 do not constitute the thickness of the riser insert walls 18. Therefore, without considering the lateral extensions of the centering pins 20, the riser walls 18 have a thickness of less than 3 cm, preferably less than 1.5 cm. Through the centering pins 20, the riser inserts 14 are aligned and fixed within the riser cavities 12. A sensor device (not shown) for monitoring the heating insert 28 can be fixed to the centering pins 20.

[0036] An insulating device 22 is arranged between the riser 8 and the riser insert 14 for insulating the molten metal received by the riser insert cavity 16. The insulating device 22 is formed as an air gap 24 that annularly surrounds the riser insert 14 and is arranged between the riser insert wall 18 and the riser wall 26 of the riser 8.

[0037] Furthermore, a heating insert 28 is arranged inside a protection element 30 for distributing heat towards the riser insert cavity 16 during the casting process. Thus, the solidification of the molten metal inside the riser insert cavity can be slowed down, and thus a sufficient flow of molten metal from the riser insert cavity 16 to the mold cavity 4 can be provided.

[0038] Retention elements 32 and 33 (in particular a retention plate 32 and a retention ring 33) are arranged between the riser insert 14 and the heating insert 28. The retention plate 32 and the retention ring 33 include openings such that the heat radiated by the heating insert 28 can be directly radiated to the riser insert 14. The retention elements 32 and 33 are arranged within the riser cavity 12.

[0039] The riser insert 14 includes exhaust holes 34 for exhausting the metal received by at least one riser insert cavity 16 respectively, wherein the exhaust holes 34 are arranged at the distal ends of the riser necks 10. An exhaust insert 36 including a plurality of exhaust slits is arranged inside the exhaust holes 34.

[0040] The riser insert 14 is in fluid connection with the riser necks 10 of the risers 8 for receiving at least part of the molten metal from at least one mold cavity 4.

[0041] The exemplary embodiments / aspects of the invention described in this specification are intended to be understood as being disclosed individually and in all combinations with each other. In particular, unless explicitly stated to the contrary, even the description of the features included in the embodiments is not intended to be understood as implying that the feature is essential or necessary for the function of the embodiment. The order of the process steps described in this specification is not mandatory; alternative orders of the process steps can be contemplated. The process steps can be implemented in various ways, for example, it can be contemplated to implement the process steps in an implementation manner of software (through program instructions), hardware, or a combination of both.

[0042] Terms used in patent claims, such as "comprising", "having", "including", "containing", etc. do not exclude additional elements or steps. The phrases "at least in part" or "substantially" cover both the cases of "part" and "entirely". The phrase "and / or" is intended to be understood as disclosing both alternatives and combinations, so "A and / or B" means "(A) or (B) or (A and B)". In the context of this specification, the plural forms of entities, persons, etc. mean multiple entities, persons, etc. The use of the indefinite article does not exclude the plural. A single device can perform the functions of multiple units or devices described in the claims. The reference numerals indicated in the patent claims should not be considered as a limitation on the devices and steps employed.

Claims

1. An apparatus for casting metal components, the casting being in particular low-pressure die casting, and the metal components being in particular aluminum components, the apparatus comprising: - at least one mold cavity (4) formed by at least one at least partially surrounding cavity wall (6), - a system of gates, runners and / or ingates defining at least one flow path for filling the at least one mold cavity with molten metal, characterized in that - the apparatus (2) further comprises at least one riser insert (14) for at least partially arranging in at least one riser cavity (12) of at least one riser (8), wherein the at least one riser insert (14) comprises at least one insert cavity (16) for at least partially receiving molten metal from the at least one mold cavity (4), and at least one of the insert cavities (16) is at least partially surrounded by a riser insert wall (18), - wherein the at least one riser insert (14) is configured to at least partially slow down the solidification of the molten metal received by the at least one insert cavity (16).

2. The apparatus according to claim 1, characterized in that - the at least one riser insert wall (18) has a thickness of less than 5 cm, in particular less than 3 cm, preferably less than 1.5 cm.

3. The apparatus according to claim 1 or 2, characterized in that - the at least one riser (8) comprises at least one heat insulation device (22) for insulating the molten metal received by the at least one insert cavity (16).

4. The apparatus according to claim 3, characterized in that - the at least one heat insulation device (22) comprises at least one air gap arranged between the riser insert wall (18) and the riser wall (26) of the at least one riser (8).

5. The apparatus according to claim 3 or 4, characterized in that - the at least one heat insulation device (22) comprises a fibrous material, in particular rock wool, asbestos, glass wool and / or a combination thereof, and / or a ceramic heat insulation material.

6. The apparatus according to any one of claims 1 to 5, characterized in that - the apparatus (2) further comprises at least one heating insert (28) for at least partially heating the molten metal received by the at least one insert cavity (16), and - the at least one heating insert (28) is preferably at least partially arranged inside the at least one riser cavity (12) and / or at least partially arranged inside at least one protective element (30).

7. The apparatus according to claim 6, characterized in that - the at least one heating insert (28) is configured as at least one burner, at least one electric heating cartridge and / or at least one induction heating element.

8. The apparatus according to any one of claims 6 or 7, characterized in that - at least one holding element (32, 33) is at least partially arranged between the at least one riser insert (14) and the at least one heating insert (28), and - The at least one holding element (32, 33) is preferably at least partially arranged within the riser cavity (12).

9. The apparatus according to any one of claims 1 to 8, characterized in that - the at least one riser insert (14) comprises centering means (20), in particular centering pins, for aligning and / or fixing the at least one riser insert (14) within the at least one riser cavity (12).

10. The apparatus according to any one of claims 1 to 9, characterized in that - the at least one riser insert (14) comprises at least one vent hole (34) for venting the metal received by the at least one insert cavity (16).

11. The apparatus according to any one of claims 1 to 10, characterized in that - the at least one riser insert (14) is in fluid connection with at least one riser neck (10) for receiving molten metal at least partially from the at least one mold cavity (4).

12. A process for casting a metal component in a mold, the casting being in particular low-pressure die casting and the metal component being in particular an aluminum component, wherein the process for casting is in particular carried out by means of the apparatus according to any one of claims 1 to 11 and the process comprises: - forming at least one mold cavity by means of at least one at least partially surrounding cavity wall, - filling the at least one mold cavity with molten metal by means of at least one runner defined by a system of gates, runners and / or ingates, - arranging at least one riser insert at least partially within at least one riser cavity of at least one riser, wherein the at least one riser insert comprises at least one insert cavity for receiving molten metal at least partially from the at least one mold cavity and at least one of the insert cavities is at least partially surrounded by a riser insert wall, - at least partially slowing down the solidification of the molten metal received by the at least one insert cavity during the casting process.

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