Aluminum alloy motor body die casting mold runner system and control method
By employing a two-stage gradient heating preheating method, spraying release agent, segmented pressure filling, and zoned temperature-controlled cooling for the die-casting mold of aluminum alloy motor bodies, the problem of coarse gate control in the die-casting production of aluminum alloy motor bodies was solved. This resulted in improved density and dimensional accuracy of the castings, reduced scrap rate, and increased production stability and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUIZHOU YONGYUE HONGLI TECHNOLOGY CO LTD
- Filing Date
- 2026-06-08
- Publication Date
- 2026-07-21
AI Technical Summary
In the current die casting production of aluminum alloy motor bodies, the gate control is rough, which leads to disordered filling and insufficient feeding. This results in defects such as uneven flow distribution in the gate, insufficient material in thin-walled ribs of the cavity, cold shuts, dense porosity in thick-walled areas, shrinkage porosity, etc. The density and dimensional accuracy cannot meet the requirements of high-end motor bodies, and the process repeatability is poor with a high scrap rate.
The mold is preheated by a two-stage gradient heating method, and a release agent is sprayed to control the flow state of the melt. The mold is filled by pressure in stages and cooled by temperature control in zones. Combined with the residual pressure of the gating, the mold is continuously fed back to accurately match the flow characteristics of the gating and the cavity. The mold is opened smoothly and the casting is ejected slowly. Impurities in the gating are cleaned, so that the temperature of the mold and the casting can be accurately controlled.
It effectively solves the problems of turbulent flow in the gating system, molten splashing, and air entrapment. The casting surface is free of cold runner marks and material shortages. It eliminates shrinkage porosity and other defects, improves the density and structural strength of the casting, reduces the scrap rate, and increases the production yield and process repeatability.
Smart Images
Figure CN122425183A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of die casting technology, and in particular to a gating system and control method for an aluminum alloy motor body die casting mold. Background Technology
[0002] Aluminum alloy motor bodies are core housing components of motors, pumps, and transmission equipment. They are characterized by complex structures, large variations in wall thickness, dense reinforcing ribs, and high assembly precision requirements, and are widely used in new energy, home appliances, and industrial automation. High-pressure die casting is the mainstream forming process for aluminum alloy motor bodies, offering advantages such as high forming efficiency, good casting consistency, and suitability for mass production.
[0003] Currently, in the die-casting production of aluminum alloy motor bodies, the gating system control process generally suffers from technical shortcomings. Most companies adopt the traditional constant-speed, constant-pressure die-casting mode, without refined control over the complex structure of the motor body and the flow characteristics of the gating system. During the filling stage, the uniform melt flow rate easily leads to problems such as excessively fast flow rate in the early stage causing air entrapment, and insufficient flow rate in the middle and later stages resulting in incomplete filling. This leads to uneven flow distribution in the gating system, material shortage and cold shuts in thin-walled rib areas of the cavity, and dense porosity in thick-walled areas. During the holding pressure stage, the constant pressure without gradient changes results in insufficient feeding pressure in the later stages of the gating system, making thick-walled shaft holes and mounting boss areas prone to shrinkage porosity and shrinkage cavities. During the cooling stage, the overall temperature is uniformly reduced without considering the gating distribution and the temperature control of different areas based on the casting wall thickness, resulting in asynchronous solidification of the casting and causing internal stress and warping deformation.
[0004] The aforementioned process issues result in a generally low yield rate in existing die casting production. The density and dimensional accuracy of the castings cannot meet the requirements for high-end motor bodies. Furthermore, the process repeatability is poor and the scrap rate is high, significantly increasing production costs. Summary of the Invention
[0005] The purpose of this invention is to provide a gating system and control method for die-casting molds of aluminum alloy motor bodies, aiming to solve the problems of crude control, disordered filling, insufficient feeding, and frequent defects in traditional die-casting gating technology.
[0006] To achieve the above objectives, in a first aspect, the present invention provides a method for controlling the gating system of an aluminum alloy motor body die-casting mold, comprising the following steps: After the mold is closed, clean the impurities and oil stains in the mold runner, cavity and venting groove. Use a two-stage gradient heating to preheat the mold and spray the release agent evenly on the runner and inner wall of the cavity. The molten aluminum alloy for die casting is melted, and after adding refining agent to remove gas and impurities, it is allowed to stand. The gas content and impurity content of the melt are controlled, and the qualified melt is transferred into the die casting machine barrel. Controlling the flow state of the melt in the runner allows the melt in the runner and cavity to initially solidify, and the residual pressure in the runner is used to continuously feed the motor body. Based on the differences in gating distribution and casting wall thickness, a three-level gradient cooling mode with zoned temperature control is adopted. Open the mold smoothly and eject the casting slowly. Clean the casting gate residue, flash and overflow residue. Clean the impurities in each level of the gating system and venting groove. Check the smoothness of the gating system and reset the mold.
[0007] The first stage of the two-stage gradient heating is heated to 180-200℃ at a heating rate of 4-6℃ / min and held for 15-20min; the second stage is heated to 220-240℃ at a heating rate of 2-3℃ / min and held for 25-30min, controlling the overall temperature difference of the mold to ≤±5℃.
[0008] Specifically, the method of controlling the flow state of the melt in the runner to initially shape the melt in the runner and cavity, and using the residual pressure in the runner to continuously compensate for the shrinkage of the motor body is as follows: Segmented speed filling is used to control the flow state of the melt in the runner, achieving stable filling. A segmented pressure control method is adopted to initially shape the melt in the runner and cavity, and to continuously feed the thick-walled area of the motor body and the shaft hole mounting position by using the residual pressure in the runner.
[0009] During the segmented filling process, the gas pressure and melt pressure signals inside the cavity are collected in real time. When the exhaust rate is lower than the set threshold, the injection speed is temporarily reduced by 0.3-0.5 m / s to extend the exhaust time.
[0010] The release agent is sprayed with a thickness of 0.08-0.12 mm and the drying time is 5-8 min.
[0011] The speed at which the casting is slowly ejected is controlled at 0.15-0.25 m / s.
[0012] In a second aspect, the present invention also provides a gating system for an aluminum alloy motor body die casting mold, which is applied to the gating control method for the aluminum alloy motor body die casting mold as described in the first aspect above.
[0013] This invention discloses a method for controlling the gating system of an aluminum alloy motor body die-casting mold. After mold closing, impurities and oil stains are cleaned from the mold gating system, cavity, and venting channels. A two-stage gradient heating method is used to preheat the mold, and a release agent is uniformly sprayed onto the inner walls of the gating system and cavity. The die-casting aluminum alloy melt is melted, and after adding a refining agent to remove gas and impurities, it is allowed to stand, controlling the gas content and impurity content of the melt. The qualified melt is then transferred to the die-casting machine barrel. The flow state of the melt in the gating system is controlled to achieve initial shaping of the melt in the gating system and cavity. The residual pressure in the gating system is used to continuously feed the motor body. Based on the gating system distribution and the difference in casting wall thickness, a three-stage gradient cooling mode is used for zoned temperature control. The mold is opened smoothly and the casting is ejected slowly. Residual material, flash, and overflow residue from the casting gate are cleaned, and residual impurities in each stage of the gating system and venting channels are cleaned. The gating system's unobstructed flow is checked, and the mold is reset. This method employs preheating and zoning. The cooling temperature control strategy enables precise and controllable temperature control of the mold and casting, solving the problem of asynchronous solidification in thick and thin areas, effectively releasing internal stress in the casting, and eliminating deformation and cracking. It adopts a three-stage graded filling control to precisely match the flow characteristics of the melt in the sprue, runner, annular runner and cavity. Low-speed venting, medium-speed uniform flow, and high-speed corner filling completely solve the problems of turbulent flow in the runner, melt splashing, and air entrapment in traditional processes. The casting surface is free of cold shuts, flow lines, and material shortage defects. It adopts a segmented variable pressure shrinkage process. The low-pressure shaping in the early stage ensures filling stability, and the high-pressure continuous shrinkage in the later stage relies on the residual pressure of the runner to accurately shrink the key areas of the thick wall of the motor body, effectively eliminating shrinkage porosity and shrinkage defects, and significantly improving the density and structural strength of the casting. Thus, it solves the problems of rough runner control, disordered filling, insufficient shrinkage, and frequent defects in traditional die casting technology. Attached Figure Description
[0014] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.
[0015] Figure 1 This is a flowchart of a method for controlling the gating system of an aluminum alloy motor body die-casting mold provided by the present invention.
[0016] Figure 2 This is a flowchart of step S3 of the method for controlling the gating system of an aluminum alloy motor body die-casting mold provided by the present invention. Detailed Implementation
[0017] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.
[0018] Please see Figures 1 to 2 In a first aspect, the present invention provides a method for controlling the gating system of an aluminum alloy motor body die-casting mold, comprising the following steps: After S1 mold is closed, clean the mold runner, cavity and venting groove for impurities and oil stains. Use two-stage gradient heating to preheat the mold and spray release agent evenly on the runner and cavity inner wall. In this embodiment of the invention, the first stage of the two-stage gradient heating is heated to 180-200℃ at a heating rate of 4-6℃ / min and held for 15-20min; the second stage is heated to 220-240℃ at a heating rate of 2-3℃ / min and held for 25-30min. The overall temperature difference of the mold is controlled to be ≤±5℃. After preheating, a release agent is evenly sprayed on the sprue and the inner wall of the cavity, and then air-dried for later use. The thickness of the release agent spray is controlled to be 0.08-0.12mm, and the air-drying time is 5-8min.
[0019] S2 melts the die-cast aluminum alloy melt, adds refining agent to remove gas and impurities, and then lets it stand to control the gas content and impurity content of the melt. The qualified melt is then transferred into the die-casting machine barrel. In this embodiment of the invention, the die-cast aluminum alloy melt is smelted at a temperature of 680-700℃, and after adding a refining agent to remove gas and impurities, it is allowed to stand for 10-15 minutes. The gas content of the melt is controlled to be ≤0.15ml / 100g and the impurity content is controlled to be ≤0.03%. The qualified melt is transferred into the die-casting machine barrel and kept at a constant temperature of 660-675℃.
[0020] S3 controls the flow state of the melt in the runner, so that the melt in the runner and cavity is initially shaped, and the residual pressure of the runner is used to continuously feed the motor body. Specific methods: S31 uses speed-segmented filling to control the flow state of the melt in the runner, achieving smooth filling; In this embodiment of the invention, a speed-segmented switching mode is adopted to precisely control the flow state of the melt in the runner and achieve stable filling. The first stage is a low-speed venting stage: the injection speed is 0.2-0.4 m / s, pushing the melt to slowly fill the sprue and runner, venting the air inside the runner. The mode is switched when the annular runner is filled to 90% volume. The second stage is a medium-speed uniform flow stage: the injection speed is increased to 1.0-1.5 m / s, the melt is evenly distributed along the annular runner, and simultaneously enters the cavity through each sector ingate, spreading and filling layer by layer. The third stage is a high-speed corner filling stage: when the cavity filling rate reaches 85%, the injection speed is increased to 2.0-2.5 m / s, quickly filling the cavity ribs and thin-walled areas in dead corners. The total filling time is controlled within 3.5-5 seconds. During the speed-segmented filling process, the air pressure and melt pressure signals inside the cavity are collected in real time. When the venting rate is lower than a set threshold, the injection speed is temporarily reduced by 0.3-0.5 m / s to extend the venting time.
[0021] S32 adopts a segmented pressure control method to initially shape the melt in the runner and cavity, and uses the residual pressure in the runner to continuously feed the thick-walled area of the motor body and the shaft hole mounting position.
[0022] In this embodiment of the invention, the pressure holding process begins immediately after filling, employing a segmented pressure control method of low-pressure shaping followed by high-pressure shrinkage compensation. The initial pressure holding pressure is 65-70 MPa, held for 3-5 seconds, to allow the melt in the runner and cavity to initially solidify. Subsequently, the pressure is increased to 75-80 MPa and held for 12-18 seconds, utilizing the residual pressure in the runner to continuously compensate for shrinkage in the thick-walled areas of the motor body and the shaft hole mounting position. Throughout the pressure holding process, the mold temperature is maintained at 210-230°C. During the pressure holding process, for the ingate area corresponding to the thick-walled structure of the motor body, the temperature of the mold's temperature control runner is locally increased by 10-15°C to slow down the solidification rate of the thick-walled area, match the aging of the runner shrinkage compensation, and eliminate local shrinkage porosity and shrinkage cavities.
[0023] S4 adopts a three-level gradient cooling mode with zoned temperature control based on the distribution of the gating system and the difference in casting wall thickness. In this embodiment of the invention, temperature is controlled in zones according to the distribution of the gating system and the difference in the wall thickness of the casting; in the first stage, the slow cooling rate is 2℃ / min, and the cooling time is 15-20min, so as to achieve synchronous solidification inside and outside the casting; in the second stage, the intermediate cooling rate is 4℃ / min, and the cooling time is 10-15min, so as to reduce the casting temperature to 120-150℃; in the third stage, the rapid air cooling temperature is reduced to below 60℃ to complete the shaping, and the temperature difference between different areas of the mold is ≤8℃ during the cooling process.
[0024] S5 smoothly opens the mold and slowly ejects the casting, cleans the casting gate residue, flash and overflow residue, cleans the residual impurities in each level of the sprue and venting groove, checks the smoothness of the sprue, and resets the mold.
[0025] In this embodiment of the invention, the ejection speed of the casting is controlled at 0.15-0.25 m / s to avoid deformation and cracking of the casting caused by high-speed ejection.
[0026] In a second aspect, the present invention also provides a gating system for an aluminum alloy motor body die casting mold, which is applied to the gating control method for the aluminum alloy motor body die casting mold as described in the first aspect above.
[0027] To better understand this technical solution, the following embodiments are provided for further explanation: Example 1
[0028] This embodiment provides a method for precise control of the gating system in an aluminum alloy motor body die-casting mold, including the following detailed steps: S1. Mold Gradient Preheating and Pretreatment: After completing the mold assembly, thoroughly clean all levels of runners, cavities, and venting channels to remove oil, scale, and residual impurities, ensuring unobstructed flow. Start the mold temperature control system with a two-stage gradient heating: the first stage heats to 190℃ at a rate of 5℃ / min and holds for 18 minutes; the second stage heats to 230℃ at a rate of 3℃ / min and holds for 28 minutes. Monitor the temperature of each area of the mold, controlling the overall temperature difference to ≤±5℃. After preheating, evenly spray a die-casting release agent (0.1mm thick) onto the runners and cavity walls using a misting method. Allow to air dry for 6 minutes before use.
[0029] S2. Aluminum Alloy Melt Purification and Temperature Control: Al-Si aluminum alloy ingots specifically designed for die casting are selected and melted in a furnace at a stable temperature of 690℃. After melting, a refining agent is added for degassing and impurity removal. The melt is then held at this temperature for 12 minutes, and the melt quality is tested to ensure a gas content ≤0.15ml / 100g and a solid impurity content ≤0.03%. The qualified melt is then transferred to the die-casting machine barrel, which is kept at a constant temperature of 670℃ to ensure stable melt flowability.
[0030] S3. Three-stage graded filling control of the gating system: Start the die casting machine and implement segmented speed filling control. First stage: Low-speed venting stage. Injection speed 0.3 m / s, the melt slowly fills the sprue and cross runner, gradually venting the air inside the runner. Switch to another operating mode when the melt fills 90% of the annular runner volume. Second stage: Medium-speed uniform flow stage. Injection speed increases to 1.2 m / s, the melt is evenly distributed along the annular runner, synchronously and uniformly flowing into the cavity through each sector-shaped ingate, spreading layer by layer along the cavity wall without turbulence or splashing. Third stage: High-speed corner filling stage. The cavity filling rate is monitored in real time. When 85% is filled, the injection speed increases to 2.2 m / s, quickly filling thin-walled dead-angle areas such as ribs and corners. The total filling time for a single cycle is controlled within 4 seconds. The venting status is monitored in real time during the filling process, and the flow rate is finely adjusted according to the air pressure signal to avoid air entrapment.
[0031] S4. Variable Pressure Holding Runner Feeding Control: The pressure holding program is initiated immediately upon completion of mold filling, applying pressure in stages. The initial holding pressure is 68MPa, maintained for 4 seconds, allowing the melt in the runner and cavity to quickly solidify and stabilize the casting contour. Subsequently, the pressure is increased to 78MPa and maintained for 15 seconds, utilizing the residual melt pressure in the runner to continuously feed the thick-walled areas such as the motor shaft hole and mounting bosses. Throughout the pressure holding process, the mold temperature is maintained at 220℃, with a localized temperature increase of 12℃ in the thick-walled runner areas to slow down the solidification rate and ensure the feeding effect.
[0032] S5. Zoned Gradient Cooling and Shaping: After pressure holding, a three-stage gradient cooling process is initiated. The first stage is slow cooling: a cooling rate of 2℃ / min, continuing for 18 minutes, allowing the surface layer and internal melt of the casting to solidify synchronously, achieving initial shaping. The second stage is intermediate cooling: the cooling rate is adjusted to 4℃ / min, cooling for 12 minutes, reducing the casting temperature to 130℃. The third stage is auxiliary air cooling, rapidly cooling to 55℃, completing the final shaping. Throughout the cooling process, the temperature difference between different areas of the mold is controlled to ≤8℃ to avoid uneven stress leading to deformation.
[0033] S6. Mold Opening, Demolding, and Sprue Reset and Cleaning: After cooling and solidification, control the die-casting machine to open the mold smoothly, ejecting the casting at a low and uniform speed of 0.2 m / s to prevent damage and deformation. Manually clean the casting gate residue, overflow waste, and burrs using grinding equipment. Thoroughly blow away residual aluminum chips and impurities from each stage of the sprue and venting channels, check the flow path for blockages, and reset the mold to begin the next die-casting cycle.
[0034] Example 2
[0035] In this embodiment, the process parameters are slightly adjusted, and the steps are the same as in Embodiment 1. The specific parameters are as follows: mold preheating final temperature 220℃, holding temperature for 30 min; melt melting temperature 680℃, barrel holding temperature 660℃; three-stage filling speeds are 0.2 m / s, 1.0 m / s, and 2.0 m / s respectively, with a total filling time of 5 s; initial holding pressure 65 MPa, holding pressure for 5 s, high pressure compensation 75 MPa, holding pressure for 18 s; final cooling temperature 58℃.
[0036] Example 3
[0037] In this embodiment, the process parameters are slightly adjusted, and the steps are the same as in Embodiment 1. The specific parameters are as follows: mold preheating final temperature 240℃, holding temperature for 25min; melt melting temperature 700℃, barrel holding temperature 675℃; three-stage filling speeds are 0.4m / s, 1.5m / s, and 2.5m / s respectively, with a total filling time of 3.5s; initial holding pressure 70MPa, holding pressure for 3s, high pressure compensation 80MPa, holding pressure for 12s; final cooling temperature 52℃.
[0038] The above-disclosed embodiments are merely preferred embodiments of the gating system and control method for die-casting molds of aluminum alloy motor bodies according to this application, and should not be construed as limiting the scope of this application. Those skilled in the art can understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of this application still fall within the scope of this application.
Claims
1. A method for controlling the gating system of an aluminum alloy motor body die-casting mold, characterized in that, Includes the following steps: After the mold is closed, clean the impurities and oil stains in the mold runner, cavity and venting groove. Use a two-stage gradient heating to preheat the mold and spray the release agent evenly on the runner and inner wall of the cavity. The molten aluminum alloy for die casting is melted, and after adding refining agent to remove gas and impurities, it is allowed to stand. The gas content and impurity content of the melt are controlled, and the qualified melt is transferred into the die casting machine barrel. Controlling the flow state of the melt in the runner allows the melt in the runner and cavity to initially solidify, and the residual pressure in the runner is used to continuously feed the motor body. Based on the differences in gating distribution and casting wall thickness, a three-level gradient cooling mode with zoned temperature control is adopted. Open the mold smoothly and eject the casting slowly. Clean the casting gate residue, flash and overflow residue. Clean the impurities in each level of the gating system and venting groove. Check the smoothness of the gating system and reset the mold.
2. The method for controlling the gating system of an aluminum alloy motor body die-casting mold as described in claim 1, characterized in that, The first stage of the two-stage gradient heating is to raise the temperature to 180-200℃ at a rate of 4-6℃ / min and hold it for 15-20min; the second stage is to raise the temperature to 220-240℃ at a rate of 2-3℃ / min and hold it for 25-30min, while controlling the overall temperature difference of the mold to ≤±5℃.
3. The method for controlling the gating system of an aluminum alloy motor body die-casting mold as described in claim 1, characterized in that, The specific method for controlling the flow state of the melt in the runner, so that the melt in the runner and cavity is initially shaped, and using the residual pressure in the runner to continuously compensate for the shrinkage of the motor body is as follows: Segmented speed filling is used to control the flow state of the melt in the runner, achieving stable filling. A segmented pressure control method is adopted to initially shape the melt in the runner and cavity, and to continuously feed the thick-walled area of the motor body and the shaft hole mounting position by using the residual pressure in the runner.
4. The method for controlling the gating system of an aluminum alloy motor body die-casting mold as described in claim 3, characterized in that, During the segmented filling process, the gas pressure and melt pressure signals inside the cavity are collected in real time. When the exhaust rate is lower than the set threshold, the injection speed is temporarily reduced by 0.3-0.5 m / s, and the exhaust time is extended.
5. The method for controlling the gating system of an aluminum alloy motor body die-casting mold as described in claim 1, characterized in that, The thickness of the release agent spray is controlled at 0.08-0.12 mm, and the air drying time is 5-8 minutes.
6. The method for controlling the gating system of an aluminum alloy motor body die-casting mold as described in claim 1, characterized in that, The ejection speed of the casting is controlled at 0.15-0.25 m / s.
7. A gating system for an aluminum alloy motor body die-casting mold, applied to the gating control method for an aluminum alloy motor body die-casting mold as described in any one of claims 1-6.