A die casting method for improving the performance of a die casting by using vibration

Abstract

The application discloses a die casting method for improving the performance of a die casting by vibration, which applies vibration to a die casting cavity during die casting, and is characterized in that, during the process of filling the die casting cavity with metal melt and / or the solidification process, a vibration along the axis direction of a ejector pin is directly applied to the metal melt filled into the die casting cavity by the ejector pin vertically abutting against the surface of the die casting cavity until the metal melt is solidified and cooled to be taken out. The application can improve the filling performance of the melt, improve the solidification structure and performance of the die casting, reduce the residual stress in the die casting, and thus improve the quality of the die casting, and is especially suitable for use in the production of cast products which need to strengthen the performance of the local position structure of the cast.

Description

Technical Field

[0001] This invention relates to the field of metal melt die casting technology, and in particular to a die casting method that utilizes vibration to improve the performance of die castings. Background Technology

[0002] Pressure casting is a precision metal casting method, often shortened to die casting. During die casting, molten metal fills the die casting cavity under high pressure through a die casting pipe. The resulting die casting not only has good surface quality and dense structure, but also boasts a short production cycle and high efficiency, making it widely used in automotive parts production; for example, Tesla car bodies are integrally die-cast. However, the mechanical properties of die castings are often not high, mainly due to the following reasons: 1) Pre-crystallization in the pressure chamber: In conventional cold chamber die casting, molten metal is poured into a pressure chamber separate from the furnace, and then subjected to slow and fast injection to enter the mold cavity, completing filling and solidification. The molten metal undergoes nucleation and crystallization in the pressure chamber, a process known as pre-crystallization. These pre-crystallized grains have a long time to grow, eventually becoming coarse grains, reducing the mechanical properties of the die casting. 2) Gas entrapment: One of the key characteristics of die casting is high-speed filling. During the rapid injection stage, the molten metal enters the mold cavity at an extremely high filling speed, causing the gas inside the cavity to be unable to escape completely. This gas becomes trapped within the molten metal, leading to gas-induced defects and adversely affecting the mechanical properties of the die casting. Furthermore, for large, complex, thin-walled die castings, filling is difficult, easily resulting in problems such as cold shuts and insufficient filling.

[0003] Patent CN115722635A addresses the above issues with its die-casting method utilizing ultrasonic molten metal treatment. While this method achieves degassing, slag removal, and grain refinement to some extent, improving the microstructure of die-cast parts and enhancing their mechanical, heat-treatment, and weldability, several problems remain: 1) The ultrasonic probe does not directly act on the molten metal within the die-casting mold cavity, but rather on the molten metal in the crucible and pouring ladle. Due to the presence of air within the die-casting mold cavity, the degassing, slag removal, and grain refinement effects are not significant; 2) The use of piezoelectric ceramic ultrasonic probes at high temperatures results in a short lifespan and imposes high equipment requirements.

[0004] Furthermore, patent CN109604553B discloses a device for eliminating the condensation layer in the pressure chamber of a die-casting machine using ultrasonic treatment. This device heats the pressure chamber with circulating high-temperature hot oil, increasing the fluidity of the molten metal; indirect ultrasonic vibration acts on the molten metal, refining the grains on one hand and heating the molten metal on the other. To a certain extent, this solves the problem of cold shuts caused by reduced melt fluidity under quenching and refines the grains. However, some problems remain: 1) The high-temperature hot oil only circulates within the pressure chamber; when the molten metal enters the metal mold cavity, quenching still occurs, reducing the effectiveness of eliminating the condensation layer; 2) Indirect ultrasonic vibration results in significant energy loss at the interface between the high-temperature hot oil and the pressure chamber wall, leading to cavitation effects and poor heating of the molten metal; 3) Ultrasonic vibration is high-frequency and low-amplitude, limiting its effect on the molten metal.

[0005] In addition, patents such as CN201620452461.7 (Improved Die Casting Mold) and CN201310622359.8 (A Vibration Device for Die Casting Mold) can all influence die casting through vibration, thereby improving die casting quality. However, in existing technologies, vibration is generally applied to the entire die casting mold and cavity through the action of the mold itself, which cannot achieve targeted reinforcement of weak areas that require localized strengthening. Therefore, the effect of improving casting quality is limited. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide a die casting method that can improve the performance of die castings by utilizing vibration to improve the performance of die castings, so as to improve the die casting effect for local weak areas that need to be strengthened.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A die-casting method for improving the performance of die-cast parts by utilizing vibration. The method applies vibration to the die-casting cavity during die casting. The method is characterized in that, during the process of molten metal filling the cavity and / or solidification, a push rod perpendicular to the surface of the cavity is used to directly apply vibration along the axis of the push rod to the molten metal filling the cavity until the molten metal solidifies and is cooled and removed from the mold.

[0008] In this way, the present method uses an ejector pin to directly apply vibration to the molten metal filling the mold cavity. This allows the vibration to act more directly on the molten metal, improving its filling performance and preventing cavitation in areas where filling is poor. Simultaneously, the vibration effectively breaks up dendrites, refines grains, reduces residual stress inside the die casting, and improves casting quality. Furthermore, compared to existing conventional techniques, this invention can achieve highly targeted quality enhancement of specific areas within the casting as needed.

[0009] Furthermore, the vibration is applied to locations with weak die-casting properties. These locations include, but are not limited to, areas with irregular structures (leading to poor molten filling), areas with reduced thickness or width (causing premature solidification of the molten metal), areas requiring higher local strength, and areas where pre-installed embedded reinforcing members are added to the die-cast product. This allows for more targeted vibration reinforcement of specific locations. When targeting locations with pre-installed embedded reinforcing members, the ejector pin can directly abut against the embedded reinforcing member and apply vibration to it, ensuring the fluidity of the surrounding molten metal and the grain refinement reinforcement effect, thus better guaranteeing the bonding strength between the embedded reinforcing member and the die-cast part. Die-cast parts can strengthen their local structures by incorporating embedded reinforcing members, or they can be used as connectors to facilitate easier connection with other components.

[0010] Furthermore, a pneumatic method is used to control the vibration applied by the ejector pin. This allows for better concentration of kinetic energy onto the ejector pin to apply vibration to the cavity, resulting in better local performance improvement.

[0011] Furthermore, after die casting is completed, the ejector pin continues to push forward to demold the die-cast product. In this way, the ejector pin serves as both a vibration-inducing component and a demolding component, simplifying the mold structure and making it easy to modify existing mold structures.

[0012] Furthermore, this method is implemented using a die-casting mold device, which includes a matching fixed mold and a moving mold. After the fixed mold and the moving mold are closed, a cavity is formed between them. The closing surfaces of the fixed mold and the moving mold are also provided with a sprue and a sprue gate. The device also includes an ejector rod vibration device installed on the moving mold or the fixed mold. The ejector rod vibration device includes an ejector rod that is vertically positioned facing the cavity surface and a vibration device located at the rear end of the ejector rod.

[0013] In this way, during die casting, the mold can directly apply vibration to the molten metal filling the cavity via ejector pins. This breaks down and refines the gas and oxide film entrained during die casting, distributing them evenly throughout the melt. This avoids structural defects, improves the filling performance of the molten metal, refines the grain size, and enhances the quality of die casting. Because the vibration of the mold cavity is applied via ejector pins, ejector pins and vibration devices can be specifically installed at locations requiring localized reinforcement, facilitating the enhancement of specific areas in the casting.

[0014] Furthermore, the front end of the push rod is provided with an abutment whose width increases along the circumferential direction.

[0015] In this way, increasing the contact area between the front end of the push rod and the molten metal allows for better application of vibration to the molten metal, while avoiding the situation where the solidified layer on the surface of the molten metal is punctured due to an insufficient contact area, thus affecting the surface quality of the casting product.

[0016] Furthermore, the vibration device includes an inflation chamber located at the rear of the push rod. A piston that is slidably fitted into the inflation chamber is provided at the rear end of the push rod. A return spring abuts between the front end of the inflation chamber and the front end surface of the piston. An air inlet pipe is also provided at the rear end of the inflation chamber behind the piston. An air outlet pipe is also provided on the inner wall of the inflation chamber. When the return spring is not compressed, the air outlet pipe is located in front of the piston. When the return spring is compressed to the point where the piston is located at the air outlet pipe position, the front end face of the push rod (the front side of the abutment joint) abuts against the mold cavity surface.

[0017] In this way, when the vibration device is working, it controls the intake of air through the inlet pipe, increasing the air pressure in the inflation chamber and pushing the piston forward. The return spring is compressed. When the piston moves to the outlet pipe position, the abutment is located on the mold cavity surface. At this time, the ejector rod abuts against the molten surface in the cavity through the abutment. If the piston continues to move forward, it will connect the outlet pipe and the inflation chamber to release air. After the inflation chamber is depressurized, the piston retracts under the action of the return spring, and the outlet pipe is immediately closed, causing the gas pressure in the inflation chamber to increase again, pushing the piston again and exposing the outlet pipe to release air. This achieves repeated axial vibration of the ejector rod, and the vibration is transmitted to the molten material in the mold cavity, thus improving the die-casting quality. After die-casting, when demolding, the outlet pipe is closed first, and the inlet pipe is used to inject air to eject the die-cast product. Therefore, the above-mentioned vibration device is integrated into the ejection mechanism, which allows the ejector rod to not only realize the normal ejection function of the product, but also serve as a vibration transmission device to improve the die-casting quality.

[0018] Furthermore, an air outlet is provided between the air outlet pipe and the inner wall of the inflation chamber. The air outlet is a groove formed by the inward indentation along the inner wall of the inflation chamber.

[0019] In this way, the vent ensures that venting occurs evenly throughout the entire circumference, guaranteeing the uniformity of vibration, preventing polarization, and extending the lifespan of the device. Secondly, this structure significantly increases the venting area and improves venting efficiency, allowing the vent to be exposed only a very small distance axially to complete venting, ensuring that vibration remains within a small amplitude range and preventing excessive amplitude from damaging the product's surface quality.

[0020] Furthermore, the abutment is matched and set in a mounting groove on the mold cavity surface; the push rod is set in two sections, and a slidable sleeve structure is provided between the front half and the rear half. When the return spring is not stressed, the distance from the piston position to the air outlet position is the sliding fit stroke distance of the sleeve.

[0021] In this way, the above structure allows the piston to push forward and compress the return spring after the inflation chamber begins to inflate. When the piston reaches the outlet pipe position, the front and rear halves of the ejector rod have just completed the sliding engagement stroke of the sleeve structure. At this point, the front and rear halves of the ejector rod are in contact and can apply force to the abutment. Under the repeated deflation of the outlet pipe, the piston vibrates and acts on the mold cavity surface through the ejector rod and the abutment. This recessed design limits the abutment when the ejector rod retracts, ensuring that its front surface is always on the mold cavity surface (and forms part of the mold cavity surface), preventing damage to the cavity surface from the abutment's back-and-forth movement. The ejector rod is designed as a telescopic structure, with a telescopic stroke equal to the piston stroke. During operation, the piston provides sufficient compression force to the return spring by traveling a certain distance. This ensures that the vibration generated when the piston reaches the outlet pipe position has a high frequency, giving the vibration a stronger disturbance effect on the molten metal, more efficiently breaking dendrites, and resulting in higher fluidity of the molten metal. The broken dendrites become new crystallization nuclei, further refining the metal grain structure. This ensures that vibration improves the performance of die-cast products.

[0022] Furthermore, the push rod has a section of elastic material. This elastic material section, when compressed, better provides space for the push rod to withstand pressure, allowing it to generate outward vibration more effectively. This ensures that the output vibration has room for adjustment and control, thus better guaranteeing the vibration effect.

[0023] Furthermore, a threaded section is provided on the push rod at the front end of the piston, and an adjusting sleeve is screwed onto the threaded section. The rear end of the return spring abuts against the adjusting sleeve. In this way, the axial position of the piston on the push rod can be adjusted by rotating the adjusting sleeve, and thus the starting position of the piston can be adjusted by the action of the return spring. In effect, the distance from the starting position of the piston to the position of the exhaust pipe is adjusted. This distance affects the strength of the return spring when the piston reaches the position of the exhaust pipe, and thus affects the frequency of vibration. The greater the strength of the return spring, the higher the vibration frequency and the faster the vibration.

[0024] Furthermore, a pressure control valve is installed on the intake pipe, and a flow control valve is installed on the exhaust pipe.

[0025] In this way, the air pressure control valve can regulate the amount of air pressure input through the intake pipe, thereby regulating the vibration intensity. Simultaneously, the flow control valve can regulate the amount of air released through the outlet pipe, thus regulating the vibration amplitude.

[0026] Furthermore, the ejector pin vibration devices are installed in multiple locations within the mold cavity where die-casting performance is weak. As mentioned earlier, these weak locations include, but are not limited to, locations with irregular structures (leading to poor molten material filling), locations with reduced thickness or width (leading to premature solidification of the molten material), locations where the product requires higher local strength, and locations where pre-installed embedded reinforcing components are added to the die-cast product. In practice, the distribution, size, shape, and number of ejector pin vibration devices can be adjusted according to the specific structure of the mold cavity and the performance requirements of the product, thereby better achieving targeted vibration reinforcement effects at specific locations.

[0027] Compared with existing technologies, this invention has the following advantages: 1. By directly using the ejector rod of the die-casting mold as a vibration device, the performance of the die-casting parts can be improved without changing the original mold structure. 2. By directly using the vibratory ejector rod as a pneumatic ejector rod, the die-casting parts are ejected by air pressure, greatly simplifying the structure of the die-casting machine and improving production efficiency. 3. The vibration acts directly on the molten metal in the mold cavity, avoiding energy loss in the propagation medium and at the interface between the medium and the molten metal, which not only improves the efficiency of improving the microstructure but also greatly improves the performance of the die-casting parts. 4. The vibratory ejector rod is a pneumatic vibratory ejector rod, which, compared with traditional piezoelectric ceramic ultrasonic vibration probes, has strong high-temperature resistance, high operational reliability, large amplitude, and high energy input to the molten metal. 5. Using a pneumatic vibratory ejector rod, the high-pressure gas provides energy for the ejector rod vibration and cools the ejector rod during the flow process, improving the service life of the vibration device. 6. The vibration frequency can be adjusted by the high-pressure gas flow rate, achieving both ultrasonic vibration frequency and a frequency resonating with the molten metal; the vibration amplitude can be adjusted by the gas pressure, allowing for free adjustment under different working conditions. 7. The amplitude and frequency of the vibrating ejector pin can be adjusted according to the shape, size, and position of the mold cavity, fully utilizing the regulating effect of vibration on the solidification process. 8. The vibrating ejector pins are distributed within the mold cavity in the traditional ejector pin position, avoiding areas with high surface quality requirements and ensuring uniform distribution, which is beneficial for the homogenization of the molten metal composition during solidification.

[0028] In summary, this invention can improve the filling performance of molten metal by utilizing vibration, improve the solidification structure and properties of die castings, and reduce the residual stress inside die castings, thereby improving the quality of die castings. It is especially suitable for use in the production of casting products that require reinforcement of the structural properties of local parts of the casting. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a die-casting mold device according to an embodiment of the present invention.

[0030] Figure 2 for Figure 1A schematic diagram of the cavity surface of the moving mold.

[0031] Figure 3 for Figure 1 A cross-sectional view of the bottom of the inner cavity of the moving mold, used to show the structure of the air inlet and outlet pipes.

[0032] Figure 4 for Figure 1 A schematic diagram of the structure of a single-rod vibration device. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to specific embodiments.

[0034] Example: A die casting method for improving the performance of die castings using vibration. This method applies vibration to the die casting cavity during die casting. The feature is that, during the process of molten metal filling the cavity and / or solidification, for the weak points in die casting performance, a push rod perpendicular to the cavity surface is used to directly apply vibration along the axis of the push rod to the molten metal filling the cavity until the molten metal solidifies and cools before the part is removed.

[0035] In this way, the present method uses an ejector pin to directly apply vibration to the molten metal filling the mold cavity. This allows the vibration to act more directly on the molten metal, improving its filling performance and preventing cavitation in areas where filling is poor. Simultaneously, the vibration effectively breaks up dendrites, refines grains, reduces residual stress inside the die casting, and improves casting quality. Furthermore, compared to existing conventional techniques, this invention can achieve highly targeted quality enhancement of specific areas within the casting as needed.

[0036] The weak points in die casting performance include, but are not limited to, locations with irregular structures (leading to poor molten filling), locations with reduced thickness or width (leading to premature solidification of the molten metal), locations requiring higher local strength, and locations with pre-installed embedded reinforcing members. This allows for better targeted vibration reinforcement of specific locations. When targeting locations with pre-installed embedded reinforcing members, the ejector pin can directly abut against the embedded reinforcing member and apply vibration, ensuring the fluidity of the surrounding molten metal and the grain refinement effect, thus better guaranteeing the bonding strength between the embedded reinforcing member and the die casting. Die castings can strengthen their local structures by incorporating embedded reinforcing members, or use them as connectors to facilitate easier connection with other components.

[0037] In this method, pneumatic control is used to apply vibration to the ejector pin. This allows for better concentration of kinetic energy onto the ejector pin to apply vibration to the cavity, resulting in better local performance improvement.

[0038] After die casting is completed, the ejector pin continues to push forward to demold the die-cast product. In this way, the ejector pin serves as both a vibration-inducing component and a demolding component, simplifying the mold structure and making it easy to modify existing mold structures.

[0039] Specifically, this method is implemented using a die-casting mold device, which is described in [reference needed]. Figure 1-4 The system includes a matching fixed mold 1 and a moving mold 2, which form a cavity 3 after mold closing. The mold closing surfaces of the fixed mold 1 and the moving mold are also provided with a sprue 4 and a sprue gate 5. It also includes an ejector pin vibration device mounted on the moving mold 2 (or the fixed mold). The ejector pin vibration device includes an ejector pin 6 perpendicularly facing the cavity surface, and a vibration device located at the rear end of the ejector pin 6. See also... Figure 3 In this embodiment, the cavity is a cavity containing multiple irregularly shaped components.

[0040] In this way, during die casting, the mold can directly apply vibration to the molten metal filling the cavity via ejector pins. This breaks down and refines the gas and oxide film entrained during die casting, distributing them evenly throughout the melt. This avoids structural defects, improves the filling performance of the molten metal, refines the grain size, and enhances the quality of die casting. Because the vibration of the mold cavity is applied via ejector pins, ejector pins and vibration devices can be specifically installed at locations requiring localized reinforcement, facilitating the enhancement of specific areas in the casting.

[0041] The front end of the push rod 6 is provided with an abutment 7 whose width increases along the circumferential direction.

[0042] In this way, increasing the contact area between the front end of the push rod 6 and the molten metal can better apply vibration to the molten metal, while avoiding the situation where the solidified layer on the surface of the molten metal is punctured due to the low contact area, which would affect the surface quality of the casting product.

[0043] The vibration device includes an inflation chamber 8 located at the rear of the push rod 6. A piston 9 is slidably fitted into the inflation chamber at the rear end of the push rod. A return spring 10 abuts between the front end of the inflation chamber and the front end surface of the piston. An air inlet pipe 11 is also provided at the rear end of the inflation chamber behind the piston. An air outlet pipe 12 is also provided on the inner wall of the inflation chamber. When the return spring 10 is not compressed, the air outlet pipe 12 is located in front of the piston 9. When the return spring is compressed to the point where the piston is located at the air outlet pipe position, the front end face of the push rod (the front side of the abutment joint) abuts against the mold cavity surface.

[0044] In this way, when the vibration device is working, it controls the intake of air through the inlet pipe, increasing the air pressure in the inflation chamber and pushing the piston forward. The return spring is compressed. When the piston moves to the outlet pipe position, the abutment is located on the mold cavity surface. At this time, the ejector rod abuts against the molten surface in the cavity through the abutment. If the piston continues to move forward, it will connect the outlet pipe and the inflation chamber to release air. After the inflation chamber is depressurized, the piston retracts under the action of the return spring, and the outlet pipe is immediately closed, causing the gas pressure in the inflation chamber to increase again, pushing the piston again and exposing the outlet pipe to release air. This achieves repeated axial vibration of the ejector rod, and the vibration is transmitted to the molten material in the mold cavity, thus improving the die-casting quality. After die-casting, when demolding, the outlet pipe is closed first, and the inlet pipe is used to inject air to eject the die-cast product. Therefore, the above-mentioned vibration device is integrated into the ejection mechanism, which allows the ejector rod to not only realize the normal ejection function of the product, but also serve as a vibration transmission device to improve the die-casting quality.

[0045] Among them, an air outlet 13 is provided between the air outlet pipe 12 and the inner wall of the inflation chamber. The air outlet 13 is a groove formed by the inward concavity of the inner wall of the inflation chamber.

[0046] In this way, the vent outlet ensures that the venting is uniformly distributed throughout the entire circumference, guaranteeing the uniformity of vibration, preventing polarization, and extending the service life of the device. Secondly, this structure greatly increases the venting area and improves venting efficiency, allowing the vent outlet to be exposed only a very small distance axially to complete the venting, ensuring that the vibration is within a very small amplitude range and preventing excessive amplitude from damaging the surface quality of the product.

[0047] The abutment 7 is matched and set in a mounting groove on the mold cavity surface; the push rod 6 is set in two sections, and a slidable sleeve structure 14 is provided between the front half and the rear half. When the return spring is not stressed, the distance from the piston position to the air outlet position is the sleeve sliding fit stroke distance.

[0048] In this way, the above structure allows the piston to push forward and compress the return spring after the inflation chamber begins to inflate. When the piston reaches the outlet pipe position, the front and rear halves of the ejector rod have just completed the sliding engagement stroke of the sleeve structure. At this point, the front and rear halves of the ejector rod are in contact and can apply force to the abutment. Under the repeated deflation of the outlet pipe, the piston vibrates and acts on the mold cavity surface through the ejector rod and the abutment. This recessed design limits the abutment when the ejector rod retracts, ensuring that its front surface is always on the mold cavity surface (and forms part of the mold cavity surface), preventing damage to the cavity surface from the abutment's back-and-forth movement. The ejector rod is designed as a telescopic structure, with a telescopic stroke equal to the piston stroke. During operation, the piston provides sufficient compression force to the return spring by traveling a certain distance. This ensures that the vibration generated when the piston reaches the outlet pipe position has a high frequency, giving the vibration a stronger disturbance effect on the molten metal, more efficiently breaking dendrites, and resulting in higher fluidity of the molten metal. The broken dendrites become new crystallization nuclei, further refining the metal grain structure. This ensures that vibration improves the performance of die-cast products.

[0049] The push rod 6 has an elastic material section 15. By compressing this elastic material section, more space is provided for the push rod to be compressed, allowing it to generate outward vibration more effectively. This ensures that the output vibration has room for adjustment and control, and better guarantees the vibration effect.

[0050] The piston's front end, the push rod 6, has a threaded section. An adjusting sleeve 16 is screwed onto this threaded section, and the rear end of the return spring abuts against the adjusting sleeve 16. This allows adjustment of the axial position of the piston on the push rod by rotating the adjusting sleeve, which in turn adjusts the piston's initial position through the action of the return spring. This effectively adjusts the distance from the piston's initial position to the outlet pipe position. This distance affects the force of the return spring when the piston reaches the outlet pipe position, thus affecting the vibration frequency. A greater return spring force results in a higher vibration frequency and faster vibration.

[0051] The air inlet pipe 11 is equipped with a pressure control valve 17, and the air outlet pipe 12 is equipped with a flow control valve 18.

[0052] In this way, the air pressure control valve can regulate the amount of air pressure input through the intake pipe, thereby regulating the vibration intensity. Simultaneously, the flow control valve can regulate the amount of air released through the outlet pipe, thus regulating the vibration amplitude.

[0053] The ejector pin vibration devices are installed in multiple locations within the mold cavity where die-casting performance is weak. As mentioned earlier, these weak locations include, but are not limited to, locations with irregular structures (leading to poor molten material filling), locations with reduced thickness or width (causing premature solidification of the molten material), locations where the product requires higher local strength, and locations where pre-installed embedded reinforcing components are added to the die-cast product. In practice, the distribution, size, shape, and number of ejector pin vibration devices can be adjusted according to the specific structure of the mold cavity and the performance requirements of the product, thereby better achieving targeted vibration reinforcement effects at specific locations.

[0054] In addition, during implementation, the moving mold is connected to the die-casting machine via bolts. The fixed mold surface is provided with a cavity corresponding to the parting surface of the die-cast part, and the fixed mold is fixed to one side of the die-casting machine via bolts. Half of the ingate cavity is provided below both the moving mold and the fixed mold. When the moving mold and the fixed mold are closed, a complete ingate is formed, which connects the pressure chamber of the die-casting machine to the ingate of the mold. During implementation, the moving mold is composed of multiple connected parts, facilitating the installation of the internal ejector vibration device.

[0055] To further verify the effectiveness of the invention, the applicant conducted a die-casting test using the aforementioned mold device. Molten 7075 aluminum alloy was directly fed into the mold cavity through the pressure chamber of the die-casting machine for filling. The ejector vibration device was not activated during the die-casting process. After die-casting, the ejector rod was used to propel the die-casting part forward, resulting in a control example. Then, the same molten aluminum alloy was used for die-casting again. During die-casting, the air compressor connected to the air inlet pipe was turned on. By controlling the gas flow rate, the ejector rod vibration frequency was controlled to be the natural frequency of the 7075 aluminum alloy melt, 2000Hz, completing the die-casting filling process during vibration. After filling, vibration continued for 10 seconds, then the air compressor was turned off, and the ejector rod stopped vibrating. After 20 seconds, the moving mold moved backward, and the ejector rod propped the die-casting part forward.

[0056] Experimental Results: Compared with the control example, the experimental examples showed a significant improvement in mechanical properties. Cutting open test samples of different thicknesses revealed that with increasing thickness of the stepped-filled samples, the grain size and porosity distribution did not change significantly, and no obvious structural defects were found. Comparing the flow-filled samples, the experimental group showed complete filling, while the control group, although also fully filled, exhibited severe defects at the ends. The results of these examples demonstrate that the die-cast parts obtained using the device of this invention exhibit superior performance.

Claims

1. A die-casting method for improving the performance of die-cast parts by utilizing vibration, wherein vibration is applied to the die-casting cavity during die-casting, characterized in that, During die casting, during the process of molten metal filling the mold cavity and / or solidification, a push rod perpendicular to the surface of the mold cavity is used to directly apply vibration along the axis of the push rod to the molten metal filling the mold cavity until the molten metal solidifies and cools before the part is removed. The vibration is applied by the push rod using a pneumatic method; The method is implemented by a die-casting mold device, which includes a matching fixed mold and a moving mold. After the fixed mold and the moving mold are closed, a cavity is formed between them. The mold closing surfaces of the fixed mold and the moving mold are also provided with a sprue and a sprue gate. The device also includes an ejector rod vibration device installed on the moving mold or the fixed mold. The ejector rod vibration device includes an ejector rod that is perpendicular to the cavity surface and a vibration device that is provided at the rear end of the ejector rod. The vibration device includes an air chamber located at the rear of the push rod. A piston that can be slidably fitted into the air chamber is provided at the rear end of the push rod. A return spring abuts between the front end of the air chamber and the front end surface of the piston. An air inlet pipe communicating with the air chamber is also provided at the rear end of the air chamber behind the piston. An air outlet pipe communicating with the air chamber is also provided on the inner wall of the air chamber. When the return spring is not compressed, the air outlet pipe is located in front of the piston. When the return spring is compressed to the point where the piston is located at the position of the air outlet pipe, the front end face of the push rod abuts against the mold cavity surface. An air outlet is also provided between the air outlet pipe and the inner wall of the inflation chamber. The air outlet is a groove formed by the inward concavity of the inner wall of the inflation chamber. The ejector rod has an abutment with a circumferentially wider end. The abutment is fitted into a mounting groove on the mold cavity surface. The ejector rod is divided into two sections, with a slidably fitted sleeve structure between the front and rear sections. When the return spring is not under stress, the distance from the piston position to the vent pipe position is the sliding fit stroke distance of the sleeve. This allows the piston to push forward and compress the return spring after the inflation chamber begins to inflate. When the piston reaches the vent pipe position, the front and rear sections of the ejector rod have just completed the slidably fitted stroke of the sleeve structure. At this point, the front and rear sections of the ejector rod come into contact and apply force to the abutment. The mounting groove limits the position of the abutment when the ejector rod retracts, ensuring that its front end surface is always on the mold cavity surface and forms part of the mold cavity surface. After die casting is completed, the ejector pin continues to push forward to demold the die-cast product.

2. The die-casting method for improving the performance of die-cast parts by utilizing vibration as described in claim 1, characterized in that, The vibration is applied at locations where the die-casting performance is weak. These locations include those with irregular structures, those with reduced thickness or width, those where the product requires higher local strength, and those where pre-set embedded reinforcing members are added to the die-cast product.

3. The die-casting method for improving the performance of die-cast parts by utilizing vibration as described in claim 1, characterized in that, The push rod has a section of elastic material; The piston front end push rod is also provided with a threaded section, and an adjusting sleeve is screwed into the threaded section. The rear end of the return spring abuts against the adjusting sleeve. A pressure control valve is installed on the air inlet pipe, and a flow control valve is installed on the air outlet pipe. Multiple ejector vibration devices are installed at locations in the mold cavity where die-casting performance is weak.

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