Aluminum alloy tire mold multi-gradient temperature control forming method based on low-pressure precision casting

Abstract

The invention discloses an aluminum alloy tire mold multi-gradient temperature control forming method based on low-pressure precision casting, and particularly relates to the technical field of tire mold temperature control forming, and the method comprises the steps of S1, mold temperature control module division and structure construction, S2, temperature monitoring system deployment and optimization, S3, precise temperature regulation and control and pressure linkage in the mold filling stage, and S4, temperature control and temperature control. S4, staged gradient cooling and composite temperature control are conducted in the solidification stage; S5, a dynamic pressure adjusting strategy is conducted in the forming process; and S6, a molten metal flow field is optimized, and defects are prevented. According to the invention, through division of independent temperature control modules of the mold, precise temperature monitoring, implementation of multi-gradient temperature control and pressure linkage adjustment in mold filling and solidification stages, and combination of flow field optimization and intelligent monitoring, casting defects are effectively reduced, the quality of the mold is improved, the service life of the mold is prolonged, energy consumption is reduced, and high-quality and low-energy-consumption aluminum alloy tire mold forming is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature control for tire mold forming, and more specifically, to a multi-gradient temperature control forming method for aluminum alloy tire molds based on low-pressure precision casting. Background Art

[0002] In the current industrial manufacturing field, aluminum alloy is widely used in the manufacture of tire molds due to its characteristics of low density, high specific strength, and good thermal conductivity. The low-pressure precision casting technology has become one of the mainstream processes for the production of aluminum alloy tire molds because it can effectively improve the internal quality of castings and reduce porosity and shrinkage defects.

[0003] However, there are still many technical bottlenecks in the traditional low-pressure precision casting process for aluminum alloy tire molds. For example: 1. Most existing mold temperature control systems adopt single-zone or simple dual-zone temperature control modes, which are difficult to meet the different temperature requirements of various parts under the complex structure of the mold. During the filling and solidification processes of the gate area, bead area, and tread area, the sensitivities and requirements for temperature changes are different. The traditional uniform temperature control method is prone to uneven metal liquid flow, resulting in shrinkage porosity and shrinkage cavity defects in parts such as the bead, reducing the forming accuracy and service life of the mold; 2. Temperature and pressure control are independent of each other and cannot be dynamically coordinated and adjusted according to the actual production conditions. During the filling stage, when the temperature of the metal liquid drops and its fluidity becomes poor, the pressure cannot respond and adjust in time, easily resulting in incomplete filling. During the solidification stage, the temperature gradient change is not effectively correlated with the crystallization pressure, making it difficult to achieve an ideal feeding effect and affecting the density of the internal structure of the casting; 3. The means of controlling the metal liquid flow field are limited, and the design of cooling channels mostly relies on experience, unable to accurately predict and optimize the metal liquid flow path, easily forming turbulent flow areas, resulting in local overheating or uneven cooling, and further exacerbating the generation of casting defects.

[0004] In view of the above situation, the present invention provides a multi-gradient temperature control forming method for aluminum alloy tire molds based on low-pressure precision casting. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides a multi-gradient temperature control forming method for aluminum alloy tire molds based on low-pressure precision casting to solve the problems raised in the above background art.

[0006] To achieve the above object, the present invention provides the following technical solution: A multi-gradient temperature control forming method for aluminum alloy tire molds based on low-pressure precision casting, comprising the following steps: S1. Division and Structure Construction of Mold Temperature Control Module: The cavity of the aluminum alloy tire mold is divided into three independent temperature control modules, namely the gate area, the bead area, and the tread area. Embedded heating wires and spiral cooling channels are respectively installed in each module, and the cooling channels adopt a variable cross-section design; S2. Deployment and Optimization of Temperature Monitoring System: Distributed thermocouples are deployed on the cavity surface, inside the core, and at the outlet of the cooling channels to collect temperature data in real time. The spacing of the thermocouples is optimized according to the thermal stress distribution; S3. Precise Temperature Control and Pressure Linkage during Filling Stage: During the filling stage, the temperature of the gate area is maintained at 720 ± 10 °C, and a temperature gradient of 20 - 30 °C is formed in the bead area and the tread area through pulsed cooling. The temperature at the filling front is monitored in real time. When the temperature is lower than 680 °C, local heating compensation is automatically started; S4. Stepwise Gradient Cooling and Composite Temperature Control during Solidification Stage: During the solidification stage, stepwise gradient cooling is adopted. In the first stage of 0 - 5 minutes, the cooling rate of the bead area is increased to 15 °C / min, and the tread area is maintained at 5 °C / min to form a radial temperature gradient of 40 - 50 °C. In the second stage of 5 - 15 minutes, the cooling rate of the gate area is reduced to 2 °C / min, and feeding is realized by delaying solidification through reverse heating. At the same time, phase change materials are introduced to assist in temperature control, and the phase change materials absorb or release heat in the range of 58 °C and 20 °C; S5. Dynamic Pressure Regulation Strategy during Forming Process: The filling pressure is linked with the temperature gradient for adjustment. When the temperature of the bead area is lower than 650 °C, the filling pressure is automatically increased to 80 kPa. During the solidification stage, the pressure is dynamically adjusted with the temperature gradient. For every 10 °C increase in the temperature gradient, the crystallization pressure is synchronously increased by 50 kPa; S6. Optimization of Metal Liquid Flow Field and Defect Prevention: The simulated annealing algorithm is used to predict the flow path of the metal liquid. Turbulent flow areas are eliminated by adjusting the layout of the cooling channels, and diversion grooves are set at the bead parts prone to shrinkage porosity.

[0007] Preferably, in step S1, the power adjustment range of the embedded heating wire at the gate area is 500 - 2000 W, which is used to precisely control the temperature of the gate area.

[0008] Preferably, in step S1, the variable cross-section diameter range of the spiral cooling channel at the bead area is 2 - 5 mm, and the variable cross-section diameter range of the spiral cooling channel at the tread area is 1 - 3 mm. Gradient cooling is achieved by adjusting the flow rate of the cooling medium.

[0009] Preferably, in step S2, the measurement accuracy of the distributed thermocouple is ±1 °C, which can accurately collect temperature data in real time.

[0010] Preferably, in step S3, the flow rate range of the cooling water for pulsed cooling is 3 - 8 L / min, and the interval time is 20 - 40 s.

[0011] Preferably, in step S4, the power of the reverse heating is 300 - 800W to delay the solidification of the gate area.

[0012] Preferably, in step S4, the phase change material is a paraffin - polyethylene glycol composite phase change material, and its filling ratio in the mold is 10 - 30%.

[0013] Preferably, in step S6, the number of iterations of the simulated annealing algorithm is 100 - 500 times to optimize the flow path of the molten metal.

[0014] Preferably, in step S6, the depth of the diversion groove is 1 - 3mm and the width is 3 - 8mm, which is set at a specific position in the bead area to guide the directional solidification of the molten metal.

[0015] Preferably, the entire molding process is intelligently monitored and self - learned through a fuzzy PID controller, and the temperature control parameters are automatically optimized according to historical data.

[0016] Technical effects and advantages of the present invention: 1. Through the multi - gradient temperature control molding method of the present invention, including precise temperature control, reasonable cooling strategy, and dynamic adjustment of pressure, it can effectively guide the flow and solidification of the molten metal, reduce the defects of shrinkage porosity and shrinkage cavity, improve the density and internal quality of the casting, and thus enhance the overall performance and service life of the aluminum alloy tire mold.

[0017] 2. The simulated annealing algorithm of the present invention is used to predict the flow path of the molten metal. Combined with the adjustment of the cooling channel layout and the setting of the diversion groove, it optimizes the flow field distribution of the molten metal, eliminates the turbulent flow area, and makes the filling process more stable and orderly. At the same time, the intelligent monitoring and self - learning functions of the fuzzy PID controller can automatically optimize the temperature control parameters according to real - time data and historical data, realizing the automation and intelligence of the production process, and improving production efficiency and product consistency; 3. The molding method of the present invention can reduce the rejection rate caused by process defects, reduce the waste of raw materials and energy. In addition, intelligent temperature control and process optimization help to shorten the production cycle, improve production efficiency, thus reducing production costs and enhancing the market competitiveness of products. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the overall flow chart of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention provides a multi - gradient temperature control molding method for an aluminum alloy tire mold based on low - pressure precision casting, including the following steps: S1. Division and Structure Construction of the Mold Temperature Control Module: The cavity of the aluminum alloy tire mold is divided into three independent temperature control modules: the gate area, the bead area, and the tread area. Embedded heating wires and spiral cooling channels are respectively installed in each module. The cooling channel adopts a variable cross-section design. The power adjustment range of the embedded heating wire at the gate area is 500 - 2000W, which is used to precisely control the temperature of the gate area. The variable cross-section diameter range of the spiral cooling channel at the bead area is 2 - 5mm, and the variable cross-section diameter range of the spiral cooling channel at the tread area is 1 - 3mm. Gradient cooling is achieved by adjusting the flow rate of the cooling medium. Specifically, in this step, based on the different temperature requirements of different parts of the aluminum alloy tire mold during the casting process, the cavity is divided into three independent temperature control modules: the gate area, the bead area, and the tread area. Embedded heating wires and spiral cooling channels are respectively set in each module, and the temperature of the module is adjusted by using the heating wire and the cooling channel. The heating wire at the gate area precisely controls the temperature through a power adjustment of 500 - 2000W to meet the temperature requirements for the inflow of the molten metal. The cooling channels in the bead area and the tread area, with variable cross-section diameters of 2 - 5mm and 1 - 3mm respectively, cooperate with the adjustment of the cooling medium flow rate to achieve different cooling rates, forming the required temperature gradient, so as to ensure that the temperatures of all parts of the aluminum alloy tire mold meet the process requirements during the casting process and improve the quality of the casting.

[0020] S2. Deployment and Optimization of the Temperature Monitoring System: Distributed thermocouples are deployed on the surface of the cavity, inside the core, and at the outlet of the cooling channel to collect temperature data in real time. The spacing of the thermocouples is optimized according to the thermal stress distribution. The measurement accuracy of the distributed thermocouples is ±1°C, which can accurately collect temperature data in real time. Specifically, in this step, considering that there are differences in the thermal stress distribution of different parts of the aluminum alloy tire mold during the casting process and the temperature change has a significant impact on the quality of the casting, distributed thermocouples are deployed on the surface of the cavity, inside the core, and at the outlet of the cooling channel. The spacing of the thermocouples is optimized according to the thermal stress distribution, and more are arranged densely at the thermal stress concentration areas, so that the thermocouples can fully cover the key temperature monitoring points. Utilizing its high-precision measurement ability of ±1°C, it collects temperature data of each part in real time and accurately, providing a reliable basis for subsequent precise regulation of the temperature of each module of the mold according to the temperature situation, ensuring that the temperature during the casting process is within a reasonable range and guaranteeing the quality of the casting.

[0021] S3. Precise Temperature Regulation and Pressure Linkage during the Filling Stage: During the filling stage, the temperature of the gate area is maintained at 720 ± 10°C. A temperature gradient of 20 - 30°C is formed in the bead area and the tread area through pulsed cooling. The temperature at the filling front is monitored in real time. When the temperature is lower than 680°C, local heating compensation is automatically started. The cooling water flow rate range for pulsed cooling is 3 - 8L / min, and the interval time is 20 - 40s. Specifically, in this step, during the filling stage, based on the functions of various parts of the aluminum alloy tire mold and the flow characteristics of the molten metal, differential temperature control is implemented for different regions. The gate area is maintained at 720 ± 10 °C to provide a suitable temperature environment for the smooth inflow of the molten metal and ensure its good fluidity. The bead area and the tread area adopt pulsed cooling (cooling water flow rate: 3 - 8 L / min, interval: 20 - 40 s) to form a temperature gradient of 20 - 30 °C, which promotes the orderly filling of the molten metal and initially establishes a temperature field. At the same time, the temperature at the filling front is monitored in real time. When it is lower than 680 °C, local heating compensation is automatically started to prevent the molten metal from having poor fluidity due to too low temperature, ensuring complete and smooth filling and meeting the strict requirements of the aluminum alloy tire mold forming process for the temperature during the filling stage.

[0022] S4. Stepwise gradient cooling and composite temperature control during the solidification stage. During the solidification stage, stepwise gradient cooling is adopted. In the first stage of 0 - 5 min, the cooling rate of the bead area is increased to 15 °C / min, and the tread area is maintained at 5 °C / min, forming a radial temperature gradient of 40 - 50 °C. In the second stage of 5 - 15 min, the cooling rate of the gate area is reduced to 2 °C / min, and reverse heating is used to delay solidification for feeding. At the same time, phase change materials are introduced to assist in temperature control. The phase change materials absorb or release heat in the range of 58 °C to 20 °C, and the power of reverse heating is 300 - 800 W for delaying the solidification of the gate area. The phase change materials are paraffin - polyethylene glycol composite phase change materials, and their filling ratio in the mold is 10 - 30%. Specifically, in this step, during the solidification stage of the aluminum alloy tire mold, in order to obtain good casting quality, according to the solidification requirements of different regions of the mold, a stepwise gradient cooling strategy is implemented: In the first stage of 0 - 5 min, the cooling rate of the bead area is rapidly increased to 15 °C / min, and the tread area is maintained at a relatively low cooling rate of 5 °C / min, forming a radial temperature gradient of 40 - 50 °C, which can promote the preferential solidification of the bead area, lay the foundation for the subsequent solidification process, facilitate the directional solidification of the molten metal, and reduce the defects of shrinkage porosity and shrinkage cavity. In the second stage of 5 - 15 min, the cooling rate of the gate area is reduced to 2 °C / min, and reverse heating with a power of 300 - 800 W is used to delay the solidification of the gate area, aiming to use the extended liquid state time of the molten metal in the gate area to achieve feeding for other parts and ensure the overall density of the casting. Meanwhile, a paraffin-polyethylene glycol composite phase change material with a filling ratio of 10-30% is introduced. This phase change material absorbs or releases heat in the temperature range of 58°C to 20°C, can buffer the temperature change in the mold, stabilize the local temperature field, further optimize the temperature distribution during solidification, reduce casting defects caused by excessive temperature fluctuations, and thus improve the quality and performance of the aluminum alloy tire mold casting.

[0023] S5. Dynamic pressure regulation strategy during the molding process. The filling pressure and temperature gradient are linked for regulation. When the temperature in the bead area is lower than 650°C, the filling pressure is automatically increased to 80 kPa. During the solidification stage, the pressure is dynamically adjusted with the temperature gradient. For every 10°C increase in the temperature gradient, the crystallization pressure is synchronously increased by 50 kPa. Specifically, in this step, during the molding process of the aluminum alloy tire mold, the interaction relationship between the two key factors of pressure and temperature is fully considered, and dynamic regulation is carried out for the filling and solidification stages: During the filling stage, when the temperature in the bead area is lower than 650°C, it indicates that the fluidity of the molten metal in this area may deteriorate due to the temperature decrease. At this time, the filling pressure is automatically increased to 80 kPa. By increasing the pressure, the fluidity of the molten metal is enhanced, enabling it to smoothly fill the mold cavity, ensuring the integrity and quality of filling, and avoiding defects such as incomplete filling caused by too low temperature. In the solidification stage, the temperature gradient reflects the difference in solidification rates at different parts of the mold. With the change of the temperature gradient, the crystallization pressure is dynamically adjusted accordingly, that is, for every 10°C increase in the temperature gradient, the crystallization pressure is synchronously increased by 50 kPa. The purpose of this is to provide appropriate pressure conditions for the solidification of the molten metal according to different solidification situations, promote the feeding process, make the casting more dense during solidification, reduce the generation of shrinkage porosity and shrinkage cavity defects, and thus improve the quality and performance of the aluminum alloy tire mold casting, ensuring that the molding process meets the process requirements.

[0024] S6. Optimization of the molten metal flow field and defect prevention. The simulated annealing algorithm is used to predict the flow path of the molten metal. The turbulent flow area is eliminated by adjusting the layout of the cooling channels, and a diversion groove is set at the bead part where shrinkage porosity is likely to occur. The number of iterations of the simulated annealing algorithm is 100-500 times to optimize the flow path of the molten metal. The depth of the diversion groove is 1-3 mm, and the width is 3-8 mm. It is set at a specific position in the bead part to guide the directional solidification of the molten metal. Specifically, in this step, the flow and solidification processes of the molten metal in the aluminum alloy tire mold casting are comprehensively optimized by algorithm simulation, channel layout adjustment and structural design: Using the simulated annealing algorithm, in 100-500 iterations, the physical properties of the molten metal and the factors of the mold structure are fully considered to simulate the flow of the molten metal under different conditions, so as to predict a more reasonable flow path. According to the simulated flow path, the cooling channel layout is adjusted in a targeted manner, the temperature field distribution around the molten metal is changed, and then its flow state is optimized, the possible turbulent area is eliminated, and the smooth flow of the molten metal is ensured. A guide groove with a depth of 1-3mm and a width of 3-8mm is set in the tire bead area where shrinkage is prone to occur. Its special structure is used to guide the molten metal to solidify in a specific direction, reduce shrinkage defects, and improve the quality of castings.

[0025] The entire molding process is intelligently monitored and self-learned through a fuzzy PID controller, which automatically optimizes temperature control parameters based on historical data; During the entire molding process of the aluminum alloy tire mold, the fuzzy PID controller is used to intelligently control key parameters such as temperature. The fuzzy PID controller can collect and analyze various parameter data such as temperature and pressure in real time. At the same time, combined with historical production data, the fuzzy logic and PID control algorithm are used to evaluate the current temperature control parameters. Based on the evaluation results, the controller continuously adjusts and optimizes the temperature control parameters such as heating wire power and cooling medium flow through the self-learning function. It can dynamically make the temperature control more accurate according to different production conditions and mold states, thereby ensuring that the aluminum alloy tire mold is always in the best temperature environment during the entire molding process, improving molding quality and production efficiency, and reducing product defects caused by improper temperature control.

[0026] In summary, the present application provides a multi-gradient temperature control molding method for an aluminum alloy tire mold based on low-pressure precision casting. In specific operation, the aluminum alloy tire mold cavity is divided into three independent temperature control modules, namely, the gate area, the bead area and the pattern area, and the embedded heating wire, the variable-section spiral cooling channel and the distributed high-precision thermocouple are used to realize accurate monitoring and basic control of the mold temperature. During the filling stage, a temperature gradient is formed by constant temperature in the gate area and pulse cooling in the tire bead and pattern areas, and the filling pressure is adjusted in conjunction to ensure smooth filling of the molten metal. The solidification stage uses segmented gradient cooling, combined with reverse heating, phase change material auxiliary temperature control and dynamic adjustment of pressure with temperature gradient to ensure shrinkage compensation and internal quality of castings; At the same time, the simulated annealing algorithm is used to optimize the flow path of the molten metal, and guide grooves are set to guide directional solidification. Finally, the fuzzy PID controller intelligently monitors and self-learns to optimize the temperature control parameters. All links work together to achieve high-quality multi-gradient temperature control molding of aluminum alloy tire molds.

[0027] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A multi-gradient temperature control molding method for aluminum alloy tire mold based on low-pressure precision casting, characterized by: The following steps are involved: S1. Divide the mold temperature control module and structure. Divide the mold cavity of the aluminum alloy tire mold into three independent temperature control modules: the gate area, the bead area, and the tread area. Each module has an embedded heating wire and a spiral cooling channel. The cooling channel adopts a variable cross-section design. S2. Deployment and optimization of the temperature monitoring system. Distributed thermocouples are deployed on the cavity surface, inside the core, and at the cooling channel outlet to collect temperature data in real time. The spacing of the thermocouples is optimized according to the thermal stress distribution. S3. Precise temperature control and pressure linkage during the filling stage. During the filling stage, the gate area temperature is maintained at 720±10℃, and the bead area and the pattern area form a 20-30℃ temperature gradient through pulse cooling. The filling front temperature is monitored in real time. When the temperature is lower than 680℃, local heating compensation is automatically started; S4, segmented gradient cooling and composite temperature control during the solidification stage. In the solidification stage, segmented gradient cooling is adopted. In the first stage of 0-5min, the cooling rate of the bead area is increased to 15℃ / min, and the pattern area is maintained at 5℃ / min, forming a radial temperature gradient of 40-50℃. In the second stage of 5-15min, the cooling rate of the gate area is reduced to 2℃ / min, and reverse heating is used to delay solidification to achieve shrinkage compensation. At the same time, phase change materials are introduced to assist in temperature control. The phase change materials absorb or release heat in the range of 58℃ and 20℃; S5. Dynamic pressure adjustment strategy during molding process. The filling pressure is linked to the temperature gradient. When the temperature of the tire bead area is lower than 650°C, the filling pressure is automatically increased to 80kPa. The pressure in the solidification stage is dynamically adjusted with the temperature gradient. For every 10°C increase in the temperature gradient, the crystallization pressure is simultaneously increased by 50kPa. S6. Optimization of the metal liquid flow field and prevention of defects. The simulated annealing algorithm is used to predict the metal liquid flow path, the turbulent area is eliminated by adjusting the cooling channel layout, and guide grooves are set in the tire bead area that is prone to shrinkage.

2. The multi-gradient temperature control molding method of aluminum alloy tire mold based on low-pressure precision casting according to claim 1 is characterized in that: In step S1, the power adjustment range of the embedded heating wire at the gate area is 500-2000W, which is used to accurately control the temperature of the gate area.

3. The multi-gradient temperature control molding method of aluminum alloy tire mold based on low-pressure precision casting according to claim 1 is characterized in that: In step S1, the variable cross-sectional diameter range of the spiral cooling channel in the tire bead area is 2-5 mm, and the variable cross-sectional diameter range of the spiral cooling channel in the pattern area is 1-3 mm, and gradient cooling is achieved by adjusting the flow rate of the cooling medium.

4. The multi-gradient temperature control molding method of aluminum alloy tire mold based on low-pressure precision casting according to claim 1 is characterized in that: In step S2, the measurement accuracy of the distributed thermocouple is ±1°C, which can accurately collect temperature data in real time.

5. The multi-gradient temperature control molding method of aluminum alloy tire mold based on low-pressure precision casting according to claim 1 is characterized in that: In step S3, the cooling water flow rate of the pulse cooling is in the range of 3-8 L / min, and the interval time is 20-40 s.

6. The multi-gradient temperature control molding method of aluminum alloy tire mold based on low-pressure precision casting according to claim 1 is characterized in that: In step S4, the power of the reverse heating is 300-800W, which is used to delay the solidification of the gate area.

7. The multi-gradient temperature control molding method of aluminum alloy tire mold based on low-pressure precision casting according to claim 1 is characterized in that: In step S4, the phase change material is a paraffin-polyethylene glycol composite phase change material, and its filling ratio in the mold is 10-30%.

8. The multi-gradient temperature control molding method of aluminum alloy tire mold based on low-pressure precision casting according to claim 1 is characterized in that: In step S6, the number of iterations of the simulated annealing algorithm is 100-500 to optimize the flow path of the molten metal.

9. The multi-gradient temperature control molding method of aluminum alloy tire mold based on low-pressure precision casting according to claim 1, characterized in that: In step S6, the guide groove has a depth of 1-3 mm and a width of 3-8 mm, and is arranged at a specific position of the tire bead to guide the directional solidification of the molten metal.

10. The multi-gradient temperature control molding method of aluminum alloy tire mold based on low-pressure precision casting according to claim 1, characterized in that: The entire molding process is intelligently monitored and self-learned through a fuzzy PID controller, which automatically optimizes temperature control parameters based on historical data.

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