Die-casting mold filling process simulation method based on injection punch motion state analysis

Abstract

The invention discloses a die casting and mold filling process simulation method based on injection punch motion state analysis. The method comprises the following steps: establishing a simulation model of an injection hydraulic system of a die casting machine; hydraulic simulation analysis is conducted on the simulation model, the die-casting action is completed, and a die-casting punch motion curve is obtained; performing die-casting mold filling process analog simulation based on the injection punch motion curve; and analyzing a die-casting mold filling result, and visualizing the result. According to the method, the actual motion state of the injection punch is obtained by establishing the simulation model of the injection hydraulic system of the die-casting machine, selecting parameters, simulating dynamic parameters and simulating actual working conditions, then die-casting analysis is carried out on the basis of motion analysis of the injection punch, and the die-casting action is completed; and the actual mold filling process can be better reflected, and influence factors are clear, so that the die casting with better quality and performance is obtained.

Description

Technical Field

[0001] The invention relates to a die-casting filling technology, and in particular to a die-casting filling process simulation method based on the motion state analysis of an injection punch. Background Art

[0002] As a major part of the die casting process, the filling process has a very important impact on the final quality of the casting. Die casting filling is the process of using a punch to force the molten metal into a complex metal mold. It includes three stages: low-speed injection, high-speed injection and pressurization. All three stages require strict control of different process parameters and working conditions to ensure that the final product can meet the design requirements. Simulation has become an important means of process design and quality control.

[0003] Chinese patent CN108846223A discloses a method for simulating the die-casting process of an aluminum alloy cylinder body, comprising the following steps: (1) design of the cylinder body pressure casting process: including the design of the pouring overflow system, the exhaust system, the cooling system, and the die-casting process parameters; (2) solid three-dimensional modeling and preprocessing: using three-dimensional modeling software to perform three-dimensional solid modeling on the casting, pouring overflow system, the exhaust system, the cooling system, the movable mold and the fixed mold insert, and the core, and then converting them into STL format and importing them into the casting simulation analysis software, so that each entity is given a corresponding name attribute after importing, and tracking particles and cooling curve control points are set according to requirements; (3) network division: the movable mold and the fixed mold insert material adopts standard network division; the cylinder body casting adopts primary network subdivision because of its complex shape and structure and the thin-walled area; the feed, runner, and slag bag all adopt primary grid subdivision; the inner gate and the overflow port adopt secondary grid subdivision; (4) simulation calculation: input material parameters, initial conditions, boundary conditions, and process parameters, and use the simulation casting software to calculate the simulation result parameters.

[0004] The gate pressure and speed are the main process parameters. The existing technologies all use the designed pressure and speed curves as the input conditions for simulation. In fact, the gate pressure and speed are controlled by the motion state of the punch. Especially when switching between the three stages of low-speed injection, high-speed injection and pressurization, the movement of the punch is affected by the hydraulic system, friction, inertia, and resistance of the molten metal, and the flow state of the gate becomes very complicated. The existing technology does not take into account the influence of the motion state of the injection punch on the die-casting filling process and the final result during the die-casting filling simulation, which easily leads to a large error between the simulation results and the actual die-casting production process. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for simulating the die-casting filling process based on the analysis of the motion state of the injection punch.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A die casting filling process simulation method based on the analysis of the motion state of the injection punch comprises the following steps:

[0008] S1. Establish a simulation model of the injection hydraulic system of the die-casting machine;

[0009] S2, performing hydraulic simulation analysis on the simulation model, completing the die-casting action, and obtaining a die-casting punch motion curve;

[0010] S3, simulating the die casting filling process based on the motion curve of the injection punch;

[0011] S4. Analyze the die casting filling results and visualize the results.

[0012] As a preferred solution of the present invention, the process of establishing the simulation model of the injection hydraulic system in step S1 includes the following steps:

[0013] S11, Modeling stage: First, in the sketch mode of the hydraulic simulation software, select appropriate components and establish a system model according to the simulation requirements; then, complete the model construction by connecting components and setting parameters; only when all models are connected can we enter the sub-model selection stage;

[0014] S12, sub-model selection interface: manual sub-model selection is used for key components, and system recommended sub-model is used for non-critical components;

[0015] S13, parameter mode setting: according to the actual situation, detailed parameter setting is performed for the selected components and sub-models;

[0016] S14. Calculation parameter setting: When setting the calculation parameters, the size of the data text is controlled by adjusting the output time and the calculation time.

[0017] As a preferred solution of the present invention, the simulation model of step S2 performs hydraulic simulation analysis, including setting the simulation parameters of the hydraulic oil of the die-casting machine and the parameters of the hydraulic power energy device; the setting of the simulation parameters of the hydraulic oil of the die-casting machine includes density, bulk elastic modulus, and viscosity; the parameter setting of the hydraulic power energy device includes motor parameter setting, hydraulic pump parameter setting, accumulator parameter setting, and hydraulic cylinder parameter setting.

[0018] As a preferred solution of the present invention, the simulation model of step S2 performs hydraulic simulation analysis to complete one cycle of the die-casting action, and obtains the die-casting punch motion curve of the model and the performance parameter changes of other components in the model. The obtained die-casting punch motion curve includes the curve of the speed, displacement and acceleration of the injection punch changing with time.

[0019] As a preferred solution of the present invention, step S3 performs die casting filling process simulation, and the process is as follows:

[0020] S31, Meshing: Import the pre-modeled die castings and the designed casting system, then perform entity settings, mold settings, solution domain settings, meshing, and check the mesh information;

[0021] S32, basic process: task setting, material setting, initial and boundary conditions, heat conduction model, gate conditions, gravity setting;

[0022] S33, optional module: select different models. The optional module contains a pressure chamber model option, which includes the size of the pressure chamber and the injection residue; the melt and the alloy selection in the loading, the melt weight and the casting temperature.

[0023] As a preferred solution of the present invention, step S3 performs simulation of the die casting filling process, and defines the die casting punch motion curve as the motion state of the injection punch in the die casting filling simulation software.

[0024] As a preferred solution of the present invention, step S3 performs a die-casting filling process simulation. According to the die-casting filling process simulation requirements, the required instruments and appropriate solution conditions are set, and the simulation is run after the file is saved.

[0025] As a preferred solution of the present invention, the result visualization of step S4 is to establish the connection between the die-casting filling process and the motion state of the punch through the die-casting filling process and result analysis; by changing the motion state of the punch, its influence on the die-casting filling process is studied, and the influence of its friction force, inertia force, and resistance of the metal liquid on the movement of the punch can be expanded to analyze.

[0026] The technical effect of the present invention is: the present invention obtains the actual motion state of the injection punch by establishing a simulation model of the die-casting machine injection hydraulic system, parameter selection, dynamic parameter simulation, and actual working condition simulation, and then performs die-casting analysis based on the injection punch motion analysis and completes the die-casting action. Compared with the setting of ideal parameters in the die-casting filling simulation process, the present invention can better reflect the actual filling process and clarify the influencing factors to obtain die-casting parts with better quality and performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart of the die casting filling process simulation based on the analysis of the motion state of the injection punch;

[0028] Figure 2 It is a type of gasoline engine case casting produced by the process obtained by theoretical curve simulation;

[0029] Figure 3 The invention relates to a gasoline engine case casting produced by the process of the invention. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with specific implementation modes.

[0031] A simulation method for die casting filling process based on the motion state analysis of the injection punch, the process is as follows Figure 1 As shown, the method comprises the following steps:

[0032] S1. Establish a simulation model of the injection hydraulic system of the die-casting machine;

[0033] S2. Perform hydraulic simulation analysis on the simulation model, complete the die-casting action, and obtain the die-casting punch motion curve;

[0034] S3, simulating the die casting filling process based on the motion curve of the injection punch;

[0035] S4. Analyze the die casting filling results and visualize the results.

[0036] The simulation model establishment process of the injection hydraulic system in step S1 includes the following steps:

[0037] S11, modeling stage: First, in the sketch mode of hydraulic simulation software (such as Ames im), select appropriate components according to simulation requirements and establish a system model. This includes selecting appropriate components from the library, dragging the model in the model library to the drawing interface, and connecting the modules with wires. Then, the model is built by connecting components and setting parameters. The background of the connected module will turn white, and the background of the unconnected model will turn red. Only when all models are connected can we proceed to the next stage (sub-model selection stage). The connection between models requires mutual parameter matching before they can be connected. If the parameters do not match, they cannot be connected.

[0038] S12, sub-model selection interface: For key components, the sub-model is manually selected, and for non-important components, the sub-model recommended by the hydraulic software system is used.

[0039] S13. Parameter mode setting: There are three basic methods for detailed parameter setting of the selected components and sub-models according to the actual situation:

[0040] ① Directly click on the component or pipeline to set the parameters: If the parameters of the component can be changed, a dialog box will pop up, and the parameter value can be directly modified in this dialog box.

[0041] ② Load parameter settings from file: Parameter settings can be loaded from external files. This method is suitable for batch modification or importing existing parameter settings.

[0042] ③Copy the parameters of one component or pipeline and assign them to another component or pipeline: By copying and pasting, users can quickly apply the parameters of one component to another component, which is suitable for situations where parameter settings need to be quickly copied.

[0043] S14. Calculation parameter setting: When setting the calculation parameters, the size of the data text is controlled within 2 GB by adjusting the output time and the calculation time.

[0044] The simulation model of step S2 performs hydraulic simulation analysis. When using hydraulic simulation software to analyze the entire injection hydraulic system, due to the large number of components involved in the hydraulic circuit, the relevant parameters are complicated. In order to quickly find the main parameters that affect the system performance, it is necessary to first divide the entire system into several subsystems for separate research and then integrate them. This includes the setting of the simulation parameters of the hydraulic oil of the die-casting machine and the parameter setting of the hydraulic power energy device; the setting of the simulation parameters of the hydraulic oil of the die-casting machine includes density, bulk elastic modulus, and viscosity; the parameter setting of the hydraulic power energy device includes the setting of motor parameters, hydraulic pump parameters, accumulator parameters, and hydraulic cylinder parameters.

[0045] When the simulation model performs hydraulic simulation analysis, it completes one cycle of die-casting action, obtains the die-casting punch motion curve in the model and the performance parameter changes of other components, with the focus on obtaining the die-casting punch motion curve. The obtained die-casting punch motion curve includes the curves of the velocity, displacement, and acceleration of the die-casting punch changing with time.

[0046] One cycle of die casting includes three stages: (1) Slow injection stage: The die casting process requires that in the slow injection stage, the injection punch moves forward slowly, seals the metal liquid gate on the pressure chamber, and pushes the metal liquid to flow smoothly to the inner gate in the pressure chamber, in order to slowly discharge the air in the pressure chamber. Usually for aluminum alloy casting, the slow injection speed range is required to be 0.2m / s-0.30m / s. The factor that mainly affects the slow injection speed is the flow rate through the cartridge valve. By adjusting its flow rate, the purpose of controlling the slow injection speed can be achieved, so the speed response characteristics of the hydraulic cylinder should be analyzed. (2) Fast injection stage: For the fast injection circuit with oil supplied by the accumulator and the pump at the same time, the fast injection speed can be controlled by changing the flow rate through the two-way flow cartridge valve. After selecting the appropriate sub-model for each component, setting the parameters and running the simulation, the speed characteristic curve of the fast injection process at different flow rates can be obtained. (3) Boosting stage: In order to ensure that the casting can obtain a denser metallographic structure and good mechanical properties, the boosting system of the die casting machine must have good boosting performance, and its main indicators include boosting final pressure, pressure building time, pressure shock wave, etc. The parameters that affect the boosting pressure mainly include the diameter of the piston and piston rod, the mass of the boosting piston, and the stroke of the boosting piston.

[0047] Step S3 performs die casting filling process simulation, and the process is as follows:

[0048] S31. Meshing: Import the pre-modeled die castings and the designed casting system into the die casting filling software, and then perform entity settings, mold settings, solution domain settings, meshing, and check the mesh information.

[0049] S32. Basic process: task setting, material setting, initial and boundary conditions, heat conduction model, gate conditions, gravity setting.

[0050] S33, optional module: select different models. The optional module contains the pressure chamber model option, which includes the size of the pressure chamber and the injection residue; the alloy selection in the melt and loading, the melt weight and the casting temperature.

[0051] During the simulation of die casting filling process, the die casting punch motion curve is defined as the motion state of the injection punch in the die casting filling simulation software. In the die casting filling simulation software (such as Anycasting), the motion state of the injection punch is customized, and the speed and position curve of the injection punch is drawn in it by using the advanced injection speed setting option to customize the punch motion state. According to the simulation requirements of the die casting filling process, set the instruments to be selected and the appropriate solution conditions, and run the simulation after saving the file.

[0052] The result visualization of step S4 is to establish the connection between the die casting filling process and the punch motion state through the die casting filling process and result analysis. By changing the punch motion state, its influence on the die casting filling process is studied, and the influence of friction, inertia, and resistance of molten metal on the punch motion can be expanded and analyzed.

[0053] The present invention can combine the die-casting equipment with the die-casting process, and the mutual analysis between the two replaces the individual research. By establishing a simulation model of the die-casting machine injection hydraulic system, parameter selection, dynamic parameter simulation, and actual working condition simulation, the actual motion state of the injection punch is obtained; the die-casting filling process is simulated based on the motion analysis of the injection punch; and the die-casting equipment is combined with the die-casting process.

[0054] Compared with the setting of ideal parameters of the die-casting filling simulation process, the present invention can better reflect the actual filling process, clarify the influencing factors, and obtain a die-casting with fewer holes and inclusion defects in the casting. Figure 2 It was a type of gasoline engine case casting that was originally produced using a process simulated by a theoretical curve. Due to inappropriate switching time between low speed and high speed, cold shut occurred on a large number of castings. Figure 3A gasoline engine case casting of a certain type is produced by the process obtained by the invention, the process control is more precise, and the cold shut defect disappears.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A die casting filling process simulation method based on the analysis of the motion state of the injection punch, characterized in that: The method comprises the following steps: S1. Establish a simulation model of the injection hydraulic system of the die-casting machine; S2, performing hydraulic simulation analysis on the simulation model, completing the die-casting action, and obtaining a die-casting punch motion curve; S3, simulating the die casting filling process based on the motion curve of the injection punch; S4. Analyze the die casting filling results and visualize the results.

2. The die casting filling process simulation method based on the analysis of the motion state of the injection punch according to claim 1 is characterized in that: The simulation model establishment process of the injection hydraulic system in step S1 includes the following steps: S11, Modeling stage: First, in the sketch mode of the hydraulic simulation software, select appropriate components and establish a system model according to the simulation requirements; then, complete the model construction by connecting components and setting parameters; only when all models are connected can we enter the sub-model selection stage; S12, sub-model selection interface: manual sub-model selection is used for key components, and system recommended sub-model is used for non-critical components; S13, parameter mode setting: according to the actual situation, detailed parameter setting is performed for the selected components and sub-models; S14. Calculation parameter setting: When setting the calculation parameters, the size of the data text is controlled by adjusting the output time and the calculation time.

3. The die casting filling process simulation method based on the analysis of the motion state of the injection punch according to claim 1 is characterized in that: The simulation model of step S2 performs hydraulic simulation analysis, including setting of simulation parameters of hydraulic oil of the die casting machine and setting of parameters of the hydraulic power energy device; The settings of the die-casting machine hydraulic oil simulation parameters include density, bulk elastic modulus, and viscosity; The parameter settings of the hydraulic power energy device include motor parameter settings, hydraulic pump parameter settings, accumulator parameter settings, and hydraulic cylinder parameter settings.

4. The die casting filling process simulation method based on the analysis of the motion state of the injection punch according to claim 1 is characterized in that: The simulation model of step S2 performs hydraulic simulation analysis to complete one cycle of the die-casting action, and obtains the die-casting punch motion curve and the performance parameter changes of other components in the model. The obtained die-casting punch motion curve includes the curve of the speed, displacement, and acceleration of the die-casting punch changing with time.

5. The die casting filling process simulation method based on the analysis of the motion state of the injection punch according to claim 1 is characterized in that: Step S3 performs die casting filling process simulation, and the process is as follows: S31, Meshing: Import the pre-modeled die castings and the designed casting system, then perform entity settings, mold settings, solution domain settings, meshing, and check the mesh information; S32, basic process: task setting, material setting, initial and boundary conditions, heat conduction model, gate conditions, gravity setting; S33, optional module: select different models. The optional module contains a pressure chamber model option, which includes the size of the pressure chamber and the injection residue; the melt and the alloy selection in the loading, the melt weight and the casting temperature.

6. The die casting filling process simulation method based on the analysis of the motion state of the injection punch according to claim 4 is characterized in that: In step S3, the die casting filling process is simulated, and the die casting punch motion curve is defined as the motion state of the injection punch in the die casting filling simulation software.

7. The die casting filling process simulation method based on the analysis of the motion state of the injection punch according to claim 1 is characterized in that: Step S3 performs die casting filling process simulation. According to the die casting filling process simulation requirements, the required instruments and appropriate solution conditions are set, and the simulation is run after the file is saved.

8. The die casting filling process simulation method based on the analysis of the motion state of the injection punch according to claim 1 is characterized in that: The result visualization of step S4 is to establish the connection between the die-casting filling process and the punch motion state through the die-casting filling process and result analysis; by changing the punch motion state, its influence on the die-casting filling process is studied, and the influence of friction, inertia, and resistance of the metal liquid on the punch motion can be expanded to analyze.

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