WO2025227143A1

WO2025227143A1 - Ultrasonic spray system for high pressure die casting assembly

Info

Publication number: WO2025227143A1
Application number: PCT/US2025/026629
Authority: WO
Inventors: Randy S. BEALS; Owen M. ZELINA; Xiaoping NIU
Original assignee: MAGNA INTERNATIONAL Inc; Magna International Inc
Current assignee: MAGNA INTERNATIONAL Inc; Magna International Inc
Priority date: 2024-04-26
Filing date: 2025-04-28
Publication date: 2025-10-30
Anticipated expiration: 2026-10-26

Abstract

A high pressure die casting assembly includes a die component presenting a die surface, and a die spray system having at least one spray nozzle oriented towards the die surface. The at least one spray nozzle defines a respective orifice for receiving a liquid release agent composition. The at least one spray nozzle is an ultrasonic spray nozzle configured to introduce an ultrasonic vibration to the liquid release agent composition for generating and applying a fine mist of atomized release agent droplets to the die surface.

Description

ULTRASONIC SPRAY SYSTEM FOR HIGH PRESSURE DIE CASTING ASSEMBLY

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This PCT International Patent Application claims the benefit of U.S. Provisional Patent Application Serial No. 63/639,502, filed April 26, 2024, the contents of which are incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0002] The present disclosure relates generally to a high pressure die casting assembly, and more specifically to a die spray system for applying a liquid release agent composition to a die surface of a die component.

2. Related Art

[0003] The section provides a general summary of background information and the comments and examples provided in this section are not necessarily prior art to the present disclosure.

[0004] High pressure die casting (HPDC) is a manufacturing method for forming parts in which a molten metal is forced at high speeds and pressures into a die cavity defined collectively by a stationary die component and a moving die component. A die spray system is commonly used to apply a liquid release agent composition to a die surface of the stationary die component and/or the moving die component prior to introduction of the molten metal into the die cavity to prevent the resultant formed part from sticking and soldering to the respective die surface, namely by creating a release film between the die surface and the resultant formed part. The sprayed liquid release agent composition can also help to control a temperature of the die surface, and lubricate any moving parts, such as slides and ejector pins.

[0005] Die spray systems include a plurality of spray nozzles for generating and directing a spray of the liquid release agent composition towards the die surface. For example, Figures 2-3 illustrate a prior art micro-spray nozzle (Figure 2) for generating and directing a spray of microspray droplets (Figure 3) of the liquid release agent composition towards the die surface, and Figures 4-5 illustrate a prior art water-free lubricant (“WFL”) spray nozzle (Figure 4) for generating and directing a spray of WFL droplets (Figure 5) of just the release agent towards the die surface. However, the nozzles in these prior art die spray systems create large droplet sizes (See Figure 8) which cause issues with thermal management and increase HPDC cycle time. The prior art micro-spray and WFL nozzles are also very small (e.g., having an orifice diameter of under 1mm), and thus tend to get clogged by the large micro-spray and WFL droplets, leading to production and maintenance issues.

[0006] Accordingly, there remains a continuing need for improved die spray systems which are more efficient, and provide an improved application process.

SUMMARY OF THE INVENTION

[0007] This section provides a general summary of the disclosure and is not intended to be a comprehensive disclosure of its full scope, aspects, objectives, and/or all of its features.

[0008] The subject disclosure is generally related to a die spray system for a high pressure die casting assembly which includes at least one spray nozzle oriented towards a die surface of a die component and defining a respective orifice for receiving a liquid release agent composition. The at least one spray nozzle is an ultrasonic spray nozzle configured to introduce an ultrasonic vibration to the liquid release agent composition for generating and applying a fine mist of atomized release agent droplets to the die surface. The atomization used by the ultrasonic spray nozzle creates a uniform distribution of significantly smaller sized droplets (e.g., 6 micron in diameter) than achievable by the prior art spray nozzles. (See Figure 8, illustrating a comparison of the atomized droplets relative to the prior art micro-spray and WFL droplets). This smaller droplet size advantageously provides for a larger coverage area of the die surface with the fine mist of atomized release agent droplets, and thus a more efficient die spray. The smaller droplet size also provides for a higher amount of cooling on the die surface, without any overspray, and even a shorter spray time. Additionally the ultrasonic spray nozzle provides for better overall equipment effectiveness (OEE), improved tooling thermal management, and lube adhesion on the die surface. Further areas of applicability will become apparent from the description provided herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Other aspects of the present disclosure will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

[0010] Figure l is a perspective view of a high pressure die casting assembly illustrating a die spray system including a plurality of ultrasonic spray nozzles for generating and applying a fine mist of atomized release agent droplets to a die surface of a die component;

[0011] Figure 2 is a cross-sectional view of a prior art micro-spray nozzle for use in a prior art die spray system to apply micro-spray droplets of release agent to the die surface;

[0012] Figure 3 is a cross-sectional view of a micro-spray droplet produced by the microspray nozzle; [0013] Figure 4 is a cross-sectional view of a prior art water-free lubricant (“WFL”) spray nozzle for use in a prior art die spray system to apply WFL droplets of release agent to the die surface;

[0014] Figure 5 is a cross-sectional view of a WFL droplet produced by the WFL spray nozzle;

[0015] Figure 6 is a perspective side view of the ultrasonic spray nozzle for use in the die spray system;

[0016] Figure 7 is a cross-sectional view of the atomized ultrasonic droplet produced by the ultrasonic spray nozzle; and

[0017] Figure 8 illustrates a significantly smaller cross-sectional shape of the atomized release agent droplet as compared to the micro-spray droplet and the WFL droplet.

DETAILED DESCRIPTION OF THE ENABLING EMBODIMENTS

[0018] Example embodiments will now be described more fully with reference to the accompanying drawings. The example embodiments are provided so that this disclosure will be thorough and fully convey the scope to those skilled in the art. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. Numerous specific details are set forth such as examples of specific components, devices, mechanisms, assemblies, and methods to provide a thorough understanding of various 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. With this in mind, the present disclosure is generally directed to an improved die spray system for a high pressure die casting assembly having at least one ultrasonic spray nozzle. [0019] As illustrated in Figure 1, a high pressure die casting assembly 10 includes at least one die component 12 configured as either a moving die component or a stationary die component. The die component 12 presents a die surface 14 that defines a die cavity 16. A die spray system 18 is disposed adjacent the die component 12 and includes a plurality of spray nozzles 20 oriented towards the die surface 14 of the die component 12 for applying a liquid spray of release agent composition to the die surface 14 of the die component 12 prior to introduction of the molten metal into the die cavity 16. The liquid release agent composition 21 received by the spray nozzles 20 can be comprised of release agent alone, or a mixture of the release agent with water. In accordance with the subject disclosure, at least one of the plurality of spray nozzles 20 is configured as an ultrasonic spray nozzle 20 configured to introduce an ultrasonic vibration to the liquid release agent composition 21 for generating a fine mist 22 of atomized droplets 23 (See Figure 7) via ultrasonic vibrations applied to the liquid release agent composition 21. In a preferred arrangement, more than one, and even all of the plurality of spray nozzles 20 are configured as an ultrasonic spray nozzle 20.

[0020] As illustrated in Figure 6, the ultrasonic spray nozzle 20 includes a housing 24 which defines a die spray inlet or orifice 26 for receiving and passing the liquid release agent composition 21 through a center of the ultrasonic spray nozzle 20. The die spray inlet 26 has a diameter being greater than 1 mm, and thus larger than inlets/orifices of the prior art micro-spray and WFL nozzles. Accordingly, as will be appreciated in view of the following more detailed disclosure, the fine mist 22 does not result in clogging of the ultrasonic spray nozzle 20, and thus leads to improved efficiency and significantly less maintenance issues, as compared to the prior art micro-spray and WFL nozzles. The ultrasonic spray nozzle 20 includes an ultrasonic generator 28 disposed within the housing 24 and in communication with the die spray inlet 26 to provide the mechanical energy for applying the ultrasonic vibrations to the liquid release agent composition 21 and generating the fine mist 22 of atomized release agent droplets 23. Put another way, the ultrasonic spray nozzle 20 converts high frequency sound waves into mechanical energy that is transferred into the liquid release agent composition 21 (i.e., the release agent alone or a mixture of release agent and water). The ultrasonic spray nozzle 20 uses high frequency vibrations on the nozzle tip 30 that create capillary waves in the liquid release agent composition 21. Once the amplitude of the capillary waves reaches a critical height (resonance frequency due to power level by the ultrasonic generator 28), the liquid release agent composition 21 becomes too tall to support themselves and thus fall off the tip of each wave resulting in atomization. In other words, as the liquid release agent composition 21 exits the nozzle tip 30 of the ultrasonic spray nozzle 20, it is broken into a fine mist 22 of uniformly sized, atomized droplets 23 as a result of the ultrasonic vibrations applied by the ultrasonic generator 28.

[0021] The ultrasonic generator 28 operates at a specific resonant frequency, which dictates the median size of the atomized ultrasonic droplet 23 down to approximately six microns, and thus significantly smaller than the droplets generated by the prior art nozzles (See Figure 8). As best illustrated in Figure 1, the high pressure die casting assembly 10 includes at least one air shaping device 32 disposed adjacent the ultrasonic spray nozzles 20 to entrain and direct the fine mist 22 towards the die surface 14. This allows precise control of the fine mist 22 into fine lines, conical patterns, or wide flat fan shapes. In a preferred arrangement, the at least one air shaping device 32 is a low velocity air shaping device for entraining and directing the fine mist 22 towards the die surface 14 within a low velocity volume of air. Thus, the soft, low velocity spray of fine mist 22 produced by the ultrasonic spray nozzle 20 allows for very high precision and uniform deposition on the die surface 14. [0022] In accordance with the aforementioned disclosure, a method of applying the liquid release agent composition 21 to the die surface 14 of the die component 12 begins by orienting at least one ultrasonic spray nozzle 20 towards the die surface 14 of the die component 12. The method proceeds by introducing the liquid release agent composition 21 to the orifice 26 defined by the at least one ultrasonic spray nozzle 20, and then introducing an ultrasonic vibration to the liquid release agent composition 21 for generating and applying a fine mist 22 of atomized release agent droplets 23 to the die surface 14. The method includes disposing at least one air shaping device 32, preferably a low velocity air shaping device, adjacent to the at least one ultrasonic spray nozzle 20 to entrain and direct the fine mist 22 of atomized release agent droplets 23 towards said die surface 14 within a low velocity volume of air.

[0023] Obviously, many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims.

Claims

CLAIMS What is claimed is:

1. A high pressure die casting assembly comprising: a die component presenting a die surface; a die spray system including at least one spray nozzle oriented towards the die surface and defining a respective orifice for receiving a liquid release agent composition; and said at least one spray nozzle being an ultrasonic spray nozzle configured to introduce an ultrasonic vibration to the liquid release agent composition for generating and applying a fine mist of atomized release agent droplets to said die surface.

2. The high pressure die casting assembly as set forth in Claim 1, wherein said die spray system includes a plurality of spray nozzles, and at least two of said plurality of spray nozzles being ultrasonic spray nozzles.

3. The high pressure die casting assembly as set forth in Claim 1, further comprising at least one air shaping device disposed adjacent said at least one ultrasonic spray nozzle to entrain and direct said fine mist of atomized release agent droplets towards said die surface.

4. The high pressure die casting assembly as set forth in Claim 3, wherein said at least one air shaping device is a low velocity air shaping device.

5. The high pressure die casting assembly as set forth in Claim 1, wherein said fine mist of atomized release agent droplets having a median size of approximately six microns.

6. The high pressure die casting assembly as set forth in Claim 1, wherein said at least one ultrasonic spray nozzle includes a housing defining an orifice for receiving said liquid release agent composition, and said orifice having a diameter being greater than 1 mm.

7. The high pressure die casting assembly as set forth in Claim 6, wherein said at least one ultrasonic spray nozzle includes an ultrasonic generator disposed within said housing and in communication with said orifice to introduce said ultrasonic vibrations to said liquid release agent composition.

8. The high pressure die casting assembly as set forth in Claim 1, wherein said die component is a stationary die component.

9. The high pressure die casting assembly as set forth in Claim 1, wherein said die component is a moving die component.

10. A method of applying a liquid release agent composition to a die surface of a die component, the method comprising: orienting at least one ultrasonic spray nozzle towards the die surface of the die component; introducing a liquid release agent composition to an orifice defined by the at least one ultrasonic spray nozzle; and introducing an ultrasonic vibration to the liquid release agent composition for generating and applying a fine mist of atomized release agent droplets to the die surface.

11. The method as set forth in Claim 10, wherein the fine mist of atomized release agent droplets having a median size of approximately six microns.

12. The method as set forth in Claim 11, further comprising: disposing at least one air shaping device adjacent to the at least one spray nozzle; and entraining and directing the fine mist of atomized release agent droplets to the die surface via a volume of air introduced by the at least one air shaping device.

13. The method as set forth in Claim 12, wherein the at least one air shaping device is a low velocity air shaping device.

14. The method as set forth in Claim 11, wherein the orifice of the at least one ultrasonic nozzle having a diameter being greater than 1 mm.

15. The method as set forth in Claim 11 , wherein the at least one ultrasonic spray nozzle includes an ultrasonic generator disposed in communication with the orifice to introduce the ultrasonic vibrations to the liquid release agent composition.