A method of die casting an integrated vehicle body rear floor
By using CAE fluid simulation and system-linked die casting methods, the problems of incomplete filling and uneven cooling of the floor after one-piece die casting were solved, achieving stable production with high density and high yield, and reducing production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DONGFENG ELECTRONICS TECH
- Filing Date
- 2026-04-30
- Publication Date
- 2026-06-09
AI Technical Summary
In the existing technology, the integral die-cast floor has defects such as incomplete filling, uneven cooling, easy generation of porosity and shrinkage, which affect the mechanical properties of the component and the yield.
A die-casting mold with a temperature zone control system, a vacuum exhaust system, and a multi-stage gating system was designed using CAE fluid simulation software. The molten metal filling was controlled in stages, from low speed to high speed to pressurization, and the flow path design was optimized by combining zoned temperature fields and pressure holding cooling.
It significantly improved the density and mechanical property consistency of castings, reduced defects such as porosity and oxide inclusions, increased the yield, and achieved stable production with high quality and high efficiency, while reducing production costs.
Smart Images
Figure CN122164881A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of automotive component die casting technology, and in particular to a die casting method for an integrated rear floor of a vehicle body. Background Technology
[0002] The rear floor is an important component of the vehicle body, comprising the rear wheel arches, the crossbeams connecting the rear wheel arches, and the rear longitudinal beams. In related technologies, the various components of the rear floor are primarily connected by welding.
[0003] To further improve the overall strength of the rear floor and simplify its manufacturing process, a one-piece die-casting process can be used. This involves designing a rear floor die-casting mold and injecting molding material into it to achieve the one-piece die-cast rear floor.
[0004] With the development of integrated die casting technology, although integral die casting structural parts have been applied, in large and complex structures such as rear floor, there are still defects such as incomplete filling, uneven cooling, easy generation of porosity and shrinkage, which affect the mechanical properties of the components and the yield. Summary of the Invention
[0005] This application provides a die-casting method for an integrated rear floor of a vehicle body, in order to solve the problems in related technologies where large and complex structures such as integrated die-cast rear floors still have defects such as incomplete filling, uneven cooling, and easy generation of porosity and shrinkage, which affect the mechanical properties and yield of the components.
[0006] This application provides a die-casting method for an integrated rear floor of a vehicle body, the method comprising: Based on the product's 3D model, CAE fluid simulation software was used to simulate and analyze the filling process, solidification process, and temperature field. Based on the analysis results, a die-casting mold including a mold temperature zone control system, a vacuum exhaust system and a multi-stage gating system was designed and manufactured. Before filling, the mold temperature zone control system is activated to actively heat and keep the material flow end and thin-walled areas warm, while cooling the ingate area and thick-walled areas. Start the vacuum exhaust system connected to the die-casting mold. The vacuum exhaust system draws the gas in the cavity of the die-casting mold to the set pressure threshold. A ladle-type quantitative feeding device is used to draw a predetermined amount of molten metal from the melting furnace and transfer it to the injection chamber; The injection chamber uses a phased sequence of low speed-high speed-pressurization to control the molten metal to fill the cavity of the die-casting mold; During the final pressing stage, the pressure is maintained until the gate solidifies, while the mold temperature zone control system strengthens cooling of thick areas and moderately heats thin-walled areas. After the product cools to below the solidus line, the mold is opened, and the ejection mechanism ejects the formed integrated rear floor of the vehicle body.
[0007] The die-casting method described in this application combines a vacuum exhaust system with a laminar flow optimized gating system and a slag overflow system, which greatly reduces defects such as porosity and oxide inclusions in the castings. The injection chamber employs a multi-stage injection process with low speed, high speed, and pressurization, coupled with end-stage pressurization. During the cooling stage, the synergistic effect of zoned temperature fields and pressure holding effectively eliminates shrinkage porosity and shrinkage cavities, significantly improving the density and mechanical property consistency of the castings, thereby significantly increasing the yield.
[0008] The directional temperature gradient field of the mold temperature zone control system guides the molten metal to achieve sequential filling and directional solidification, solving problems such as incomplete filling and cold shuts in large parts. The optimized flow path design of the multi-stage gating system ensures that the molten metal can be filled to all corners of the cavity synchronously and smoothly, especially for thin-walled and complex feature areas, ensuring the integrity of the structure and the clarity of the outline.
[0009] Furthermore, the traditional die-casting process, which relies on manual experience, is transformed into a precise and controllable process based on CAE simulation, data feedback, and system linkage. The mold temperature zone control and the precise management of the injection process in stages make the entire process highly resistant to interference, have good repeatability, and stable product quality, making it suitable for large-scale industrial production.
[0010] This application reduces subsequent inspection, rework, and scrap disposal costs through closed-loop control of process parameters and proactive defect prevention, thereby achieving high-quality, high-efficiency, and stable production, and reducing overall production costs.
[0011] In some embodiments: the mold temperature zone control system includes heating or cooling pipes machined inside the die-casting mold, and is connected to an external oil mold temperature controller, water mold temperature controller or high-pressure spot cooler, with the medium being mold temperature oil or water; The mold temperature zone control system actively heats and maintains the mold temperature at approximately 200±5°C at the end of the metal flow and in the thin-walled area. The mold temperature zone control system enhances cooling of the ingate area and wall thickness area, controlling the mold temperature at approximately 150±5°C.
[0012] In some embodiments: before the injection chamber begins to operate, the vacuum exhaust system connected to the die-casting mold cavity and vacuum valve is activated to pump the absolute pressure of the gas in the cavity to ≤100mbar.
[0013] In some embodiments: the molten metal is C611 aluminum alloy melted and refined in a melting furnace, the melting furnace controls the temperature of the molten metal at 720±10°C, and then transfers it to the machine-side heat preservation furnace via a transfer bag; A ladle-type quantitative feeding device is used to precisely draw 105 kg of molten aluminum alloy from the holding furnace and pour it smoothly into the injection chamber.
[0014] In some embodiments, the injection chamber employs a phased sequence of low speed-high speed-pressurization to control the filling of the die-casting mold cavity with molten metal, specifically including: The injection chamber injection program is started, and the injection punch moves according to the preset curve: First stage: The injection punch advances slowly at a speed of 0.15-0.5 m / s, smoothly breaking through the molten metal surface in the injection chamber and expelling the air from the injection chamber; Second stage: When the molten metal reaches the ingate, the speed of the injection punch is instantly increased to 6m / s for high-speed filling so that the molten metal fills the entire cavity before it begins to solidify. The third stage: When the filling degree reaches 98%~99%, the die-casting machine instantly establishes a boost pressure of 45MPa and maintains this pressure to compensate for the solidification shrinkage of the molten metal.
[0015] In some embodiments: after the third stage, the pressure holding stage begins, and the die casting machine maintains a pressure of 45MPa for 18±3 seconds until the gate is completely solidified. The mold temperature zone control system works continuously, providing powerful cooling to thick areas and heating thin-walled areas to maintain the set temperature, thus achieving coordinated cooling.
[0016] In some embodiments: after the total holding and cooling time exceeds 25 seconds, the die casting machine opens the die casting mold and the ejection mechanism of the die casting machine is activated to eject the formed integrated rear floor casting of the vehicle body. The extracted integrated rear floor casting is trimmed, polished, and inspected before being stored in the warehouse.
[0017] In some embodiments, the flow path of the multi-stage gating system includes a main gating system, a fan-shaped crossflow system, and an acceleration gating gate.
[0018] In some embodiments, the method further includes calculating the clamping force and the appropriate equipment tonnage based on the maximum projected area of the product, and is equipped with a ladle-type quantitative feeding device, a melting furnace, a slag bag overflow system, and a multi-stage injection control system.
[0019] In some embodiments, the CAE fluid simulation software is MAGMA.
[0020] The beneficial effects of the technical solution provided in this application include: This application provides a die-casting method for an integrated rear floor of a vehicle body. The die-casting method first uses a CAE fluid simulation software based on a three-dimensional product model to simulate and analyze the filling process, solidification process, and temperature field. Based on the analysis results, a die-casting mold is designed and manufactured, including a mold temperature zone control system, a vacuum exhaust system, and a multi-stage gating system. Before filling, the mold temperature zone control system is activated to actively heat and maintain the material flow end and thin-walled areas, while cooling the ingate area and thick-walled areas. The vacuum exhaust system connected to the die-casting mold is activated to extract gas from the mold cavity to a set pressure threshold. Based on the flow resistance of the molten metal during the filling process, the flow path of the multi-stage gating system is optimized to ensure that the molten metal fills the cavity in a laminar flow state. A ladle-type quantitative feeding device is used to draw a predetermined amount of molten metal from the melting furnace and transfer it to the injection chamber. The injection chamber uses a phased sequence of low speed-high speed-pressurization to control the molten metal to fill the cavity of the die-casting mold. During the final pressing stage, the pressure is maintained until the gate solidifies, while the mold temperature zoning control system strengthens the cooling of thick areas and moderately heats thin-walled areas. After the product cools below the solidus line, the mold is opened, and the ejector mechanism ejects the formed integrated rear floor of the car body.
[0021] Therefore, the die-casting method of this application, by combining a vacuum exhaust system with a laminar flow optimized gating system, greatly reduces defects such as porosity and oxide inclusions in castings. The injection chamber employs a multi-stage injection process with low-speed, high-speed, and pressurization, coupled with end-stage pressurization. During the cooling stage, the synergistic effect of zoned temperature fields and pressure holding effectively eliminates shrinkage porosity and shrinkage cavities, significantly improving the density and mechanical property consistency of castings, thereby significantly increasing the yield. The mold temperature zoned control system guides the molten metal to achieve sequential filling and directional solidification through a directional temperature gradient field, solving problems such as incomplete filling and cold shuts in large parts. The optimized flow path design of the multi-stage gating system ensures that the molten metal can synchronously and smoothly fill all corners of the cavity, especially for thin-walled and complex feature areas, ensuring structural integrity and contour clarity.
[0022] Furthermore, the traditional die-casting process, which relies on manual experience, is transformed into a precise and controllable process based on CAE simulation, data feedback, and system linkage. Zoned mold temperature control and precise phased management of the injection process result in a highly resistant to interference, excellent repeatability, and stable product quality, making it suitable for large-scale industrial production. Closed-loop control of process parameters and proactive defect prevention reduce subsequent inspection, rework, and scrap disposal costs, achieving high-quality, high-efficiency, and stable production, thereby lowering overall production costs. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a flowchart illustrating the method of an embodiment of this application; Figure 2 This is a simulation analysis diagram of the CAE simulation filling process in the embodiments of this application; Figure 3 This is a simulation analysis diagram of the solidification process in CAE simulation of an embodiment of this application; Figure 4 This is a simulation analysis diagram of temperature field control in CAE simulation of an embodiment of this application. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0026] This application provides a die-casting method for an integrated rear floor of a vehicle body, which can solve the problems in related technologies where large and complex structures such as integrated die-cast rear floors still have defects such as incomplete filling, uneven cooling, easy generation of porosity and shrinkage, which affect the mechanical properties and yield of the components.
[0027] See Figures 1 to 4 As shown in the figure, this application provides a die-casting method for an integrated rear floor of a vehicle body, the method comprising: S101. Based on the product's 3D model, use CAE fluid simulation software (such as MAGMA mold flow analysis software) to simulate and analyze the filling process, solidification process, and temperature field (see...). Figures 2 to 4 (As shown).
[0028] S102. Based on the analysis results, design and manufacture a die-casting mold including a mold temperature zone control system, a vacuum exhaust system and a multi-stage gating system. The die-casting mold is made of high-quality H13 hot work die steel and is subjected to surface nitriding treatment.
[0029] S103. Before filling, activate the mold temperature zone control system to actively heat and keep warm the end of the material flow and the thin-walled area, and cool the ingate area and the thick-walled area, so as to establish a directional temperature gradient field before filling and guide the molten metal to fill and solidify in a directional manner.
[0030] S104. Start the vacuum exhaust system connected to the die-casting mold. The vacuum exhaust system draws the gas in the cavity of the die-casting mold to the set pressure threshold. After the air in the cavity of the die-casting mold is drawn by the vacuum exhaust system, a negative pressure environment is formed, which can effectively reduce the porosity defects caused by air entrapment in the cavity.
[0031] S105. A ladle-type quantitative feeding device is used to draw a predetermined amount of molten metal from the melting furnace and transfer it to the injection chamber. The ladle-type quantitative feeding device ensures that the volume of molten metal is accurate and consistent for each die casting, and ensures accurate supply of molten metal each time.
[0032] S106. The injection chamber adopts a phased sequence of low speed-high speed-pressurization to control the molten metal to fill the cavity of the die-casting mold. The phased sequence of low speed-high speed-pressurization in the injection chamber makes the internal structure of the casting dense, effectively eliminating shrinkage porosity and shrinkage cavities, and greatly improving the density and mechanical property consistency of the casting.
[0033] S107. During the final pressing stage, maintain the pressure until the gate solidifies. At the same time, the mold temperature zone control system executes a differentiated cooling strategy to strengthen the cooling of thick areas and moderately heat the thin-walled areas, so as to control the overall cooling rate of the component and reduce internal stress and deformation.
[0034] S108. After the product cools to below the solidus line, the mold is opened, and the ejection mechanism ejects the formed integrated rear floor of the vehicle body.
[0035] The die-casting method of this application combines a vacuum exhaust system with a laminar flow optimized multi-stage gating system, which greatly reduces defects such as porosity and oxide inclusions in the castings. The injection chamber adopts a multi-stage injection process of low speed-high speed-pressurization combined with end pressurization, and in the cooling stage, the synergistic effect of zoned temperature fields and pressure holding effectively eliminates shrinkage porosity and shrinkage cavities, greatly improving the density and mechanical property consistency of the castings, thereby significantly increasing the yield.
[0036] The directional temperature gradient field of the mold temperature zone control system guides the molten metal to achieve sequential filling and directional solidification, solving problems such as incomplete filling and cold shuts in large parts. The optimized flow path design of the multi-stage gating system ensures that the molten metal can be filled to all corners of the cavity synchronously and smoothly, especially for thin-walled and complex feature areas, ensuring the integrity of the structure and the clarity of the outline.
[0037] Furthermore, the traditional die-casting process, which relies on manual experience, is transformed into a precise and controllable process based on CAE simulation, data feedback, and system linkage. Zoned mold temperature control and precise phased management of the injection process result in a highly resistant to interference, excellent repeatability, and stable product quality, making it suitable for large-scale industrial production. Closed-loop control of process parameters and proactive defect prevention reduce subsequent inspection, rework, and scrap disposal costs, achieving high-quality, high-efficiency, and stable production, thereby lowering overall production costs.
[0038] In some alternative embodiments: see Figure 4 As shown in the illustration, this application provides a die-casting method for an integrated rear floor of a vehicle body. The method includes a mold temperature zoning control system comprising heating or cooling pipes machined within the die-casting mold, connected externally to an oil mold temperature controller, a water mold temperature controller, or a high-pressure spot cooler, with the medium being mold temperature oil or water. The mold temperature zoning control system actively heats and maintains the mold temperature at approximately 200±5°C at the end of the metal flow and in the thin-walled region. The system also provides enhanced cooling to the ingate region and the thick-walled region, controlling their mold temperature at approximately 150±5°C. This process continuously establishes a stable and directional temperature gradient field within the die-casting mold.
[0039] In some alternative embodiments: This application provides a die-casting method for an integrated rear floor of a vehicle body. In this method, approximately 2 seconds before the injection chamber begins operation, a vacuum exhaust system connected to the die-casting mold cavity and vacuum valve is activated, reducing the absolute pressure of the gas inside the cavity to ≤100 mbar within 1.5 seconds. This establishes a vacuum environment in the die-casting mold cavity, reducing the amount of residual gas inside the cavity, effectively eliminating gas resistance, allowing the molten metal to smoothly fill thin-walled areas, and significantly reducing the incidence of porosity defects.
[0040] In some alternative embodiments: This application provides a die-casting method for an integrated rear floor of a vehicle body. In this method, the clamping force and suitable equipment tonnage are calculated based on the maximum projected area of the product. A large vacuum die-casting machine with a clamping force of 10000T is selected, and it is equipped with a ladle-type quantitative feeding device, a melting furnace, a slag overflow system, and a multi-stage injection control system. The flow path of the multi-stage gating system includes a main runner, a fan-shaped crossflow channel, and an acceleration gate, ensuring that the molten metal fills the cavity smoothly, synchronously, and in a laminar flow state.
[0041] The molten metal is C611 aluminum alloy, which is melted and refined in a melting furnace. The melting furnace controls the temperature of the molten metal at 720±10°C, and then it is transferred to the machine-side holding furnace via a transfer bag. Using a ladle-type quantitative feeding device, 105 kg of molten aluminum alloy is precisely drawn from the holding furnace and poured smoothly into the injection chamber.
[0042] In some optional embodiments: This application provides a die-casting method for an integrated rear floor of a vehicle body. In this method, the injection chamber uses a phased sequence of low speed-high speed-pressurization to control the molten metal to fill the cavity of the die-casting mold. Specifically, this includes starting the injection chamber injection program, and the injection punch moving according to a preset curve. First stage (low speed): The injection plunger advances slowly at a speed of 0.15-0.5 m / s, smoothly breaking through the molten metal surface in the injection chamber and expelling the air from the injection chamber.
[0043] Second stage (high speed): When the molten metal reaches the ingate, the speed of the injection punch is instantly increased to 6m / s for high-speed filling, so that the molten metal fills the entire cavity before it begins to solidify.
[0044] The third stage (pressure boosting): When the filling degree reaches 98%~99%, the die casting machine instantly establishes a pressure boosting pressure of 45MPa, and maintains this pressure to compensate for the solidification shrinkage of the molten metal, making the internal structure of the casting denser and shrinking.
[0045] After the third stage, the pressure holding stage begins, where the die-casting machine maintains a pressure of 45 MPa for 18 ± 3 seconds until the gate is completely solidified.
[0046] The mold temperature zone control system works continuously, providing powerful cooling to thick areas and heating thin-walled areas to maintain the set temperature, achieving coordinated cooling and thus balancing the cooling rate of the entire component, reducing thermal stress and deformation.
[0047] After the total holding and cooling time exceeds 25 seconds, the die-casting machine opens the die-casting mold and the ejection mechanism of the die-casting machine is activated to eject the formed integrated rear floor casting of the vehicle body. After the integrated rear floor casting of the vehicle body is removed, it is trimmed and polished. After inspection and flaw detection, the internal quality of the product meets the standards (such as X-ray inspection showing a porosity level of ≤2). The mechanical properties and dimensional accuracy meet the design requirements before it is put into storage.
[0048] Working principle This application provides a die-casting method for an integrated rear floor of a vehicle body. The die-casting method first uses a CAE fluid simulation software based on a three-dimensional product model to simulate and analyze the filling process, solidification process, and temperature field. Based on the analysis results, a die-casting mold is designed and manufactured, including a mold temperature zone control system, a vacuum exhaust system, and a multi-stage gating system. Before filling, the mold temperature zone control system is activated to actively heat and maintain the material flow end and thin-walled areas, while cooling the ingate area and thick-walled areas. The vacuum exhaust system connected to the die-casting mold is activated to extract gas from the mold cavity to a set pressure threshold. Based on the flow resistance of the molten metal during the filling process, the flow path of the multi-stage gating system is optimized to ensure that the molten metal fills the cavity in a laminar flow state. A ladle-type quantitative feeding device is used to draw a predetermined amount of molten metal from the melting furnace and transfer it to the injection chamber. The injection chamber uses a phased sequence of low speed-high speed-pressurization to control the molten metal to fill the cavity of the die-casting mold. During the final pressing stage, the pressure is maintained until the gate solidifies, while the mold temperature zoning control system strengthens the cooling of thick areas and moderately heats thin-walled areas. After the product cools below the solidus line, the mold is opened, and the ejector mechanism ejects the formed integrated rear floor of the car body.
[0049] Therefore, the die-casting method of this application, by combining a vacuum exhaust system with a laminar flow optimized gating system, greatly reduces defects such as porosity and oxide inclusions in castings. The injection chamber employs a multi-stage injection process with low-speed, high-speed, and pressurization, coupled with end-stage pressurization. During the cooling stage, the synergistic effect of zoned temperature fields and pressure holding effectively eliminates shrinkage porosity and shrinkage cavities, significantly improving the density and mechanical property consistency of castings, thereby significantly increasing the yield. The mold temperature zoned control system guides the molten metal to achieve sequential filling and directional solidification through a directional temperature gradient field, solving problems such as incomplete filling and cold shuts in large parts. The optimized flow path design of the multi-stage gating system ensures that the molten metal can synchronously and smoothly fill all corners of the cavity, especially for thin-walled and complex feature areas, ensuring structural integrity and contour clarity.
[0050] Furthermore, the traditional die-casting process, which relies on manual experience, is transformed into a precise and controllable process based on CAE simulation, data feedback, and system linkage. Zoned mold temperature control and precise phased management of the injection process result in a highly resistant to interference, excellent repeatability, and stable product quality, making it suitable for large-scale industrial production. Closed-loop control of process parameters and proactive defect prevention reduce subsequent inspection, rework, and scrap disposal costs, achieving high-quality, high-efficiency, and stable production, thereby lowering overall production costs.
[0051] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.
[0052] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0053] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A die-casting method for an integrated rear floor of a vehicle body, characterized in that, The method includes: Based on the product's 3D model, CAE fluid simulation software was used to simulate and analyze the filling process, solidification process, and temperature field. Based on the analysis results, a die-casting mold including a mold temperature zone control system, a vacuum exhaust system and a multi-stage gating system was designed and manufactured. Before filling, the mold temperature zone control system is activated to actively heat and keep the material flow end and thin-walled areas warm, while cooling the ingate area and thick-walled areas. Start the vacuum exhaust system connected to the die-casting mold. The vacuum exhaust system draws the gas in the cavity of the die-casting mold to the set pressure threshold. A ladle-type quantitative feeding device is used to draw a predetermined amount of molten metal from the melting furnace and transfer it to the injection chamber; The injection chamber uses a phased sequence of low speed-high speed-pressurization to control the molten metal to fill the cavity of the die-casting mold; During the final pressing stage, the pressure is maintained until the gate solidifies, while the mold temperature zone control system strengthens cooling of thick areas and moderately heats thin-walled areas. After the product cools to below the solidus line, the mold is opened, and the ejection mechanism ejects the formed integrated rear floor of the vehicle body.
2. The die-casting method for an integrated rear floor of a vehicle body as described in claim 1, characterized in that: The mold temperature zone control system includes heating or cooling pipes machined inside the die-casting mold, and is connected to an external oil mold temperature controller, water mold temperature controller or high-pressure spot cooler, with the medium being mold temperature oil or water; The mold temperature zone control system actively heats and maintains the mold temperature at approximately 200±5°C at the end of the metal flow and in the thin-walled area. The mold temperature zone control system enhances cooling of the ingate area and wall thickness area, controlling the mold temperature at approximately 150±5°C.
3. The die-casting method for an integrated rear floor of a vehicle body as described in claim 1, characterized in that: Before the injection chamber begins operation, the vacuum exhaust system connected to the die-casting mold cavity and vacuum valve is activated to reduce the absolute pressure of the gas in the cavity to ≤100mbar.
4. The die-casting method for an integrated rear floor of a vehicle body as described in claim 1, characterized in that: The molten metal is C611 aluminum alloy melted and refined in a melting furnace. The melting furnace controls the temperature of the molten metal at 720±10°C, and then it is transferred to the machine-side heat preservation furnace via a transfer bag. A ladle-type quantitative feeding device is used to precisely draw 105 kg of molten aluminum alloy from the holding furnace and pour it smoothly into the injection chamber.
5. The die-casting method for an integrated rear floor of a vehicle body as described in claim 1, characterized in that, The injection chamber employs a phased sequence of low speed-high speed-pressurization to control the filling of the die-casting mold cavity with molten metal, specifically including: The injection chamber injection program is started, and the injection punch moves according to the preset curve: First stage: The injection punch advances slowly at a speed of 0.15-0.5 m / s, smoothly breaking through the molten metal surface in the injection chamber and expelling the air from the injection chamber; Second stage: When the molten metal reaches the ingate, the speed of the injection punch is instantly increased to 6m / s for high-speed filling so that the molten metal fills the entire cavity before it begins to solidify. The third stage: When the filling degree reaches 98%~99%, the die-casting machine instantly establishes a boost pressure of 45MPa and maintains this pressure to compensate for the solidification shrinkage of the molten metal.
6. The die-casting method for an integrated rear floor of a vehicle body as described in claim 5, characterized in that: After the third stage, the pressure holding stage begins, where the die casting machine maintains a pressure of 45MPa for 18±3 seconds until the gate is completely solidified. The mold temperature zone control system works continuously, providing powerful cooling to thick areas and heating thin-walled areas to maintain the set temperature, thus achieving coordinated cooling.
7. The die-casting method for an integrated rear floor of a vehicle body as described in claim 6, characterized in that: After the total holding and cooling time exceeds 25 seconds, the die-casting machine opens the die-casting mold and the ejection mechanism of the die-casting machine is activated to eject the formed integrated rear floor casting of the vehicle body. The extracted integrated rear floor casting is trimmed, polished, and inspected before being stored in the warehouse.
8. The die-casting method for an integrated rear floor of a vehicle body as described in claim 1, characterized in that: The flow path of the multi-stage gating system includes a main gating runner, a fan-shaped cross runner, and an acceleration gating gate.
9. The die-casting method for an integrated rear floor of a vehicle body as described in claim 1, characterized in that: The method also includes calculating the clamping force and the appropriate equipment tonnage based on the maximum projected area of the product, and is equipped with a ladle-type quantitative feeding device, a melting furnace, a slag bag overflow system, and a multi-stage injection control system.
10. The die-casting method for an integrated rear floor of a vehicle body as described in claim 1, characterized in that: The CAE fluid simulation software is MAGMA.