Method for pouring molten aluminum

Abstract

A pour vessel and pour spot for providing molten metal, typically aluminum, to a shot sleeve of a die casting machine is provided. During the process, in response to a pour start signal, the pour spout pivots though a pour hole of the shot sleeve, and the shot vessel rotates to pour the molten metal into the pour spout and thus into the shot sleeve. After some of the molten metal enters the shot sleeve, the process includes raising the shot vessel and pour spot while pouring additional molten metal into the shot sleeve. Due to the design and movement of the curved or spiral pour spout, reduced erosion of the shot sleeve as well as a more laminar flow, more even distribution of the molten metal, and reduced mixing of air and the molten metal in the shot sleeve is achieved.

Description

METHOD FOR POURING MOLTEN ALUMINUMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This PCT International Patent Application claims the benefit of and priority to U.S. Provisional Patent Application Serial No. 63 / 533,367, filed August 18, 2023, titled “Method For Pouring Molten Aluminum,” the entire disclosure of which is hereby incorporated by reference in its entirety.BACKGROUND OF THE INVENTION1. Field of the Invention

[0002] The present invention relates to a pour spout for providing molten metal to a shot sleeve, for example a shot sleeve of a high pressure die casting machine, a die casting system including the pour spout, and a method of die casting a metal part using the pour spout.2. Related Art

[0003] This section provides background information related to the present disclosure which is not necessarily prior art.

[0004] Die casting can be used to form metal parts, such as metal parts for vehicles. Aluminum and aluminum alloys are often formed into parts by high pressure die casting. During the die casting process, molten metal is poured into a shot sleeve and then injected into a die cavity to be formed. A ladle or other device typically provides the molten metal to the shot sleeve. The molten metal enters through a pour hole of the shot sleeve, and a plunger presses the molten metal from the shot sleeve into the die cavity.

[0005] It has been found that, over time, a portion of the shot sleeve bushing located under the pour hole can become eroded by the molten metal. For example, typically when casting parts from aluminum, 12 kg of molten aluminum may be poured through the pour hole in only 7 seconds.However, when manufacturing giga castings, up to 220kg of aluminum needs to be poured in only 10 seconds. Due to the amount of molten metal being poured in a short amount of time, air can mix with the molten metal, which can impact the mechanical properties of the cast part. However, slower pouring can cause a loss of heat, which is also undesirable as it can lower elongation and impact mechanical properties. Thus, improvements to the die casting process are desired.SUMMARY

[0006] This section provides a general summary of the disclosure and is not to be interpreted as a complete and comprehensive listing of all of the objects, aspects, features and advantages associated with the present disclosure.

[0007] One aspect of the subject disclosure provides a pour spout for providing molten metal to a shot sleeve, the shot sleeve conveying the molten metal to a die casting machine. The pour spout has a curved, preferably spiral, shape and is capable of providing for reduced erosion of the shot sleeve as well as a more laminar flow, more even distribution of the molten metal, and reduced mixing of air and the molten metal in the shot sleeve.

[0008] An assembly for conveying molten metal to a die casting machine is also provided. The assembly comprises a shot sleeve having a passage extending from a first end to a second end for conveying the molten metal toward the die casting machine. The shot sleeve also has a pour hole located between the first end and the second end for receiving the molten metal. A pour spout extends through the pour hole for providing the molten metal into the passage of the shot sleeve, and the pour spout has a curved, preferably spiral, shape. The pour spout is designed to provide the required quantity of molten metal in the specified time, while reducing the amount of air mixed into the molten metal.

[0009] A method for die casting metal is also provided. The method includes conveying molten metal through a pour spout and into a shot sleeve. The pour spout extends through a pour hole of the shot sleeve, the shot sleeve conveys the molten metal to a die casting machine, and the pour spout has a curved, preferably spiral, shape.

[0010] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The drawings described herein are for illustrative purposes only of selected embodiments and are not intended to limit the scope of the present disclosure. The inventive concepts associated with the present disclosure will be more readily understood by reference to the following description in combination with the accompanying drawings wherein:

[0012] Figure 1 illustrates a conventional die casting machine including a ladle pouring the molten metal into the shot sleeve;

[0013] Figure 2 is a perspective view of a conventional die casting machine which show the molten metal in a cavity of the shot sleeve; and

[0014] Figures 3A-3C illustrates a die casting machine including a shot vessel and pour spout according to example embodiments.DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

[0015] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments are only provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, andmethods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well- known device structures, and well-known technologies are not described in detail.

[0016] One aspect of the subject disclosure provides a die casting assembly 10, for example a high pressure die casting assembly, or a high pressure vacuum die casting assembly, which can be used to cast parts from molten metal 12, for example parts formed of aluminum or an aluminum alloy. However, the disclosure could related to other types of die casting assemblies. Examples of conventional pressure die casting assemblies are shown in Figures 1 and 2. The die casting assembly includes a shot sleeve 14 with a pour hole 16 for receiving the molten metal 12. The shot sleeve 14 can also be referred to as a shot sleeve bushing. According to this conventional assembly, a ladle 18 is used to pour the molten metal 11 through the pour hole 16, and a plunger 20 presses the molten metal 12 through the shot sleeve 14 and into a die cavity to form the part.

[0017] According to the present disclosure, an improved method of providing the molten metal 12 to the shot sleeve 14 is provided. Instead of pouring the molten metal 12 directly from the ladle 18 or other device into the shot sleeve 14, a pour spout 22 typically having a curved, preferably spiral, shape is used to convey the molten metal 12 from a shot vessel or doser 24 and into the shot sleeve 14. An example of the pour spout 22 and shot vessel 24 is shown in Figures 3A-3C. The pour spout 22 can have various different shapes and cross-sections to achieve the desired flow of the molten metal 12. The pour spout is formed of metal, ceramic, or another type of material which has been used to form a ladle. In addition, the shot vessel 24 could be replaced by a typical dosing feeder or other fdling means if desired.

[0018] As shown in the Figures, the shot vessel 24 receives the molten metal 12 and is able to rotate to pour the molten metal 12 into the pour spout 22. A holding furnace is typically used to provide the molten metal 12 during the casting process. The shot vessel 24 and pour spout 22 begin outside of the shot sleeve 14. When a press of the die casting machine closes, and in response to a pour start signal, the pour spout 22 pivots and extends though the pour hole 16 and into a cavity of the shot sleeve 14. The shot vessel 24 rotates and pours the molten metal into the pour spout 22 and thus into the shot sleeve 14. After some of the molten metal enters the shot sleeve 14, the shot vessel 24 and pour spout 22 are raised upward relative to the pour hole 16 so that additional molten metal 12 is poured into a pool and spread around the shot sleeve 14. The upward movement can also help to reduce splashing and mixing of air with the molten metal 12. The motion of the pour spout 22 and the shot vessel 24 is programmable and thus could move in other manners and directions.

[0019] During the pouring step, the molten metal 12 does not concentrate in a single spot in the cavity of the shot sleeve 14, thus reducing erosion. In other words, the motion of the pour spout 22 spreads the heat sink from the molten metal 12 over a larger area. The pour spout 22 also provides for a more laminar flow, rather than turbulent, of the molten metal 12 into the shot sleeve 14. Thus, less air mixes with the molten metal 12 during the pouring step. Also, at the end of the pouring step, the higher temperature molten metal 12 from the shot vessel 24 mixes into the cooler molten metal 12 located at the ends of the shot sleeve 14, which improves mechanical properties of the finished cast part. According to preferred embodiments, the amount of molten aluminum poured into the shot sleeve is at least 1.21 liters per second, or up to 220 kg in 10 seconds.

[0020] In addition to the shot vessel 24 and pour spout 22, the die casting assembly can also include a larger pour hole 16, or a pour hole 16 having an updated design, compared toconventional pour holes. The pour hole 16 in the shot sleeve 14 is designed to allow for the desired movement of the pour spout 22.

[0021] Another aspect of the disclosure provides a method for die casting a metal part using the shot vessel 24 and pour spout 22 of the present disclosure. The method includes providing the molten metal 12 from a holding furnace to the shot vessel 24, and then pouring the molten metal 12 from the shot vessel 24 to the pour spout 22. In response to a pour start signal, the pour spout 22 pivots though the pour hole 16 and into the shot sleeve 14, and the shot vessel 24 rotates to pour the molten metal 12 into the shot sleeve 14. After some of the molten metal 12 enters the shot sleeve 14, the method includes raising the shot vessel 24 and pour spout 22 while pouring additional molten metal 12 into the shot sleeve 14.

[0022] As discussed above, the system and method of the present disclosure provides for reduced erosion of the shot sleeve 14 as well as a more laminar flow, more even distribution of the molten metal 11, and reduced mixing of air and the molten metal 12 in the shot sleeve 14.

[0023] More specifically, the system and method reduces the amount of air mixed into the molten aluminum or other metal during the step of filling the shot sleeve 14 by providing a laminar flow of the material. This reduces the potential for porosity in the final casting.

[0024] The system and method also improves the thermal diffusion within the shot sleeve 14 after filling, reducing the potential for molten aluminum or other metal cooling at the far end of the shot sleeve 14.

[0025] This system and method provides for faster pouring of large quantities of aluminum or other metal, such as in giga castings. Typical high pressure die castings are approximately 12 kg to 20 kg, while giga castings can be 200 kg and greater.

[0026] Further, this system and method reduces the molten aluminum or other metal heat saturation on a localized area of the shot sleeve bushing 14. By providing a larger landing area for the molten aluminum or other metal, the wear of the shot sleeve 14 is greatly reduced, thus reducing maintenance costs and machine downtime for repairs of the shot sleeve 14.

[0027] It should be appreciated that the foregoing description of the embodiments has been provided for purposes of illustration. In other words, the subject disclosure it is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varies in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of disclosure.

Claims

CLAIMSWhat Is Claimed Is:

1. A pour spout for providing molten metal to a shot sleeve, the shot sleeve conveying the molten metal to a die casting machine, wherein a curved shape of the pour spout provides for a laminar flow of the molten metal.

2. The pour spout of claim 1, wherein the pour spout has a spiral shape.

3. The pour spout of claim 1, wherein the pour spout is formed of ceramic or metal.

4. The pour spout of claim 1, wherein the motion of the pour spout is programmable.

5. A pouring system for providing molten metal to a shot sleeve, the pouring system including the pour spout of claim 1.

6. An assembly for conveying molten metal to a die casting machine, comprising: a shot sleeve having a passage extending from a first end to a second end for conveying the molten metal toward the die casting machine, the shot sleeve having a pour hole located between the first end and the second end for receiving the molten metal,a pour spout extending through the pour hole for providing the molten metal to the passage of the shot sleeve, and the pour spout having a curved shape.

7. The assembly according to claim 6, wherein the curved shape is a spiral8. The assembly according to claim 6 including a shot vessel for containing the molten metal and pouring the molten metal into the pour spout and the shot sleeve, the shot vessel being rotatable and movable toward and away from the shot sleeve.

9. The assembly of claim 6, wherein the pour spout is movable into and out of the passage of the shot sleeve.

10. The assembly of claim 6, wherein the die casting machine is a high pressure vacuum die casting machine.

11. The assembly of claim 6 including a holding furnace for containing the molten metal and pouring the molten metal into the shot vessel.

12. The assembly of claim 6, wherein the molten metal is aluminum or an aluminum alloy.

13. The assembly of claim 6, wherein the pour spout is formed of ceramic or metal.

14. A method for die casting metal, comprising the steps of: conveying molten metal through a pour spout and into a shot sleeve, wherein the pour spout extends through a pour hole of the shot sleeve, the shot sleeve conveys the molten metal to a die casting machine, and the pour spout has a curved shape.

15. The method of claim 14, wherein the curved shape is a spiral.

16. The method of claim 14, wherein the pour spout pivots through the pour hole and into a passage of the shot sleeve before a pour start signal, and pouring the molten metal from a shot vessel into the pour spout in response to the pour start signal.

17. The method of claim 16 including moving the shot vessel and the pour spout outward relative to the shot sleeve after pouring some of the molten metal into the shot sleeve.

18. The method of claim 14, wherein the molten metal is aluminum or an aluminum alloy.

19. The method of claim 14, wherein the shot sleeve conveys the molten metal to a high pressure die casting machine.

20. The method of claim 14, wherein the pour spout is formed of ceramic or metal.

Images