1. Introduction
Casting is one of the most important manufacturing processes, which has a wide range of applications in various industries. However, the traditional casting process often involves a lot of trial and error, resulting in long production cycles, high costs, and difficulties in ensuring casting quality. With the development of computer technology, virtual simulation technology has been increasingly applied in the casting field, providing a new way to optimize the casting process and improve casting quality.
1.1 The Significance of Casting Virtual Simulation Technology
Virtual simulation technology allows designers to predict potential defects in castings before actual pouring, enabling them to optimize the existing process and ensure casting quality. It also shortens the casting process design cycle, accelerates the casting manufacturing speed, and significantly improves casting quality. Moreover, it raises higher requirements for the quality of casting technicians, demanding them to have a solid professional foundation and strong innovation awareness, and be able to master and develop new processes and technologies.
1.2 Current Application Status of Casting Virtual Simulation Technology
In foreign countries, virtual simulation technology has been widely used in the casting industry. In China, as the world’s largest casting country, this technology is also being vigorously promoted and applied. However, currently, most domestic relevant higher education institutions only offer CAD/CAM courses, and few schools have introduced casting virtual simulation courses.
2. Casting Virtual Simulation Software
There are several casting virtual simulation software available in the market, each with its own unique features and functions. In this section, we will introduce some of the commonly used software and their main capabilities.
2.1 MAGMA Software
MAGMA software is a widely used casting virtual simulation software. It takes the numerical simulation technology of the casting filling and solidification process as the core to analyze the casting process. It can complete the entire process of casting filling flow for various casting alloys under various casting methods, calculate results such as temperature field, liquid pressure, gas pressure, flow velocity, gas content, and the flow of each runner, simulate the gas generation situation of the sand core, predict the internal gas pressure of the sand core, predict the risk areas of pore defects, and calculate the volume shrinkage during the solidification and cooling process.
2.2 Other Software
In addition to MAGMA software, there are other casting virtual simulation software such as AnyCasting, ProCAST, etc. These software also have their own advantages and can be used for different casting simulation requirements. For example, AnyCasting is known for its user-friendly interface and powerful simulation capabilities for fluid flow and heat transfer. ProCAST has excellent performance in simulating complex geometries and multicomponent systems.
3. Process Implementation of Casting Virtual Simulation Technology
In this section, we will take the example of a training center’s casting laboratory to introduce the process implementation of casting virtual simulation technology.
3.1 Introduction of the Training Center’s Casting Laboratory
The training center’s casting laboratory introduced casting virtual simulation technology in 2018 to reform the engineering practice. While emphasizing practical hands-on operations, it also focuses on cultivating students’ simulation skills. MAGMA software is mainly used as a simulation platform.
3.2 Simulation Process and Results Analysis
The simulation process using MAGMA software involves several steps. First, a three-dimensional model of the casting is established using a three-dimensional modeling software such as SolidWorks. Then, the casting virtual simulation software is used to simulate the pouring and solidification process of the casting. Through the analysis of the simulation results, various common casting defects such as shrinkage holes and porosity can be predicted. The simulation results have a good effect on improving and optimizing the process, reducing the scrap rate, increasing the process yield, shortening the production cycle, reducing the manufacturing cost, and reducing the dependence of technicians on experience and maintaining the stability of the process design.
4. Case Analysis of Casting Virtual Simulation Technology
In this section, we will analyze the application of casting virtual simulation technology in sand casting and lost foam casting through specific cases.
4.1 Sand Casting Case
4.1.1 Process Introduction
Sand casting is a casting method that produces castings in a sand mold. In this case, the connection plate is taken as an example. First, a three-dimensional design of the connection plate pattern is carried out, and then the MAGMA simulation software is used to simulate the casting. The simulation results are analyzed and verified. If there are defects, the casting process parameters or the design of the gating system are adjusted. If there are no defects, the casting is carried out through sand casting using a mold, and the casting and the simulation results are compared.
4.1.2 Simulation and Experimental Results
According to the two-dimensional drawing, a three-dimensional drawing is drawn. Through the MAGMA software geometry processing interface, material matching and sorting are carried out with the geometry. The selected pouring material is AISI7Mg – sand, and the pouring time is 6s. Boundary conditions such as the gate position and vent holes are added, and the grid is divided using the finite difference method for simulation pouring. The simulation results show that there are no problems. Then, sand casting is carried out. The casting quality has the following characteristics: there is a tendency of slag inclusion and pores on the small end face, and the quality of the large end face and the outer circular face is better. The casting is compared with the simulation results, and it is found that the results are relatively consistent.
4.2 Lost Foam Casting Case
4.2.1 Process Introduction
Lost foam casting is a new casting method in which a foam model similar to the casting size and shape is brushed with refractory paint and dried, buried in dry quartz sand for vibration molding, and poured under negative pressure. The model is gasified, and the liquid metal occupies the model position to form a casting after solidification and cooling. In this case, a gearbox is taken as an example. Virtual simulation is carried out before the pre-foaming of polystyrene beads, and then the casting is obtained through a series of processes such as pre-foaming of polystyrene beads, plate bonding, paint brushing and drying, sand filling, vibration, vacuum extraction, pouring of liquid metal, and sand dropping.
4.2.2 Simulation and Experimental Results
The simulation results are compared with the casting, and it is found that the final casting surface has serious sand sticking and a few pinholes. The reason is analyzed to be a problem with the paint. The paint used is a water-based paint with long drying time, poor suspension and coating properties. A resin-based quick-drying paint with better suspension and coating properties is selected, and the polystyrene foam model is brushed twice with a brush to ensure uniformity. Through actual casting verification, it is found that it is indeed a problem in the paint link.
5. Comparison and Evaluation of Different Casting Methods with Virtual Simulation Technology
In this section, we will compare and evaluate different casting methods (sand casting and lost foam casting) using virtual simulation technology from different aspects.
5.1 Comparison of Casting Defects
5.1.1 Sand Casting Defects
In sand casting, common defects include slag inclusion, pores, shrinkage holes, and porosity. Through virtual simulation technology, these defects can be predicted and optimized. For example, in the case of the connection plate in sand casting, the tendency of slag inclusion and pores on the small end face was predicted, and appropriate measures could be taken to improve the casting quality.
5.1.2 Lost Foam Casting Defects
In lost foam casting, common defects include sand sticking, pinholes, and deformation. Virtual simulation technology can also help predict and address these defects. For example, in the case of the gearbox in lost foam casting, the problem of sand sticking was predicted due to the paint problem, and a new paint was selected to solve the problem.
5.2 Comparison of Process Complexity
5.2.1 Sand Casting Process Complexity
The sand casting process involves steps such as mold making, pouring system design, and sand preparation. Although it has a certain degree of complexity, it is a relatively mature process with established procedures and techniques. Virtual simulation technology can further optimize the process and reduce the complexity of trial and error.
5.2.1 Lost Foam Casting Process Complexity
The lost foam casting process is more complex, involving steps such as foam model making, paint application, sand filling under vibration and vacuum, and pouring under negative pressure. Virtual simulation technology is more crucial in this process to predict potential problems and ensure the success of the casting.
5.3 Comparison of Applicability
5.3.1 Sand Casting Applicability
Sand casting is widely applicable to a variety of casting alloys and has a large production scale. It is suitable for producing castings with relatively simple shapes and structures. Virtual simulation technology can improve the quality and efficiency of sand casting production.
5.3.2 Lost Foam Casting Applicability
Lost foam casting is suitable for producing complex-shaped castings, especially those with internal cavities or complex geometries. It can achieve better casting quality for such castings with the help of virtual simulation technology.
6. The Role of Virtual Simulation Technology in Casting Process Optimization
Virtual simulation technology plays a crucial role in optimizing the casting process. In this section, we will discuss its role from different aspects.
6.1 Optimization of Pouring System
The pouring system is an important part of the casting process. Virtual simulation technology can simulate the flow of liquid metal in the pouring system, predict potential problems such as air entrainment and slag inclusion, and optimize the design of the pouring system. For example, in the sand casting case of the connection plate, the design of the pouring system was optimized to ensure the quality of the casting.
6.2 Optimization of Mold Design
Mold design also affects the quality of the casting. Virtual simulation technology can predict the stress and deformation of the mold during the casting process, optimize the design of the mold, and ensure its durability and stability. In the lost foam casting case of the gearbox, the mold design was optimized to prevent deformation of the foam model during…
Complexity | Applicability | Role in Optimization |
|—|—|—|—|
| Sand Casting | Slag inclusion, pores, shrinkage holes, porosity | Moderate complexity with established procedures | Widely applicable to various alloys and simple shapes | Optimization of pouring system, mold design, and casting parameters |
| Lost Foam Casting | Sand sticking, pinholes, deformation | More complex process | Suitable for complex-shaped castings | Optimization of mold design, addressing paint-related issues, and casting parameters |
6. The Role of Virtual Simulation Technology in Casting Process Optimization
6.1 Optimization of Pouring System
The pouring system design significantly influences the quality of castings. Virtual simulation technology enables the prediction of liquid metal flow behavior within the pouring system. By analyzing factors such as flow velocity, pressure distribution, and potential air entrainment or slag inclusion, designers can optimize the pouring system design. For instance, in the sand casting example of the connection plate, the simulation results guided the adjustment of the pouring system’s parameters. This included determining the optimal gate position, size, and the number and layout of runners to ensure a smooth and defect-free filling process of the mold cavity.
6.2 Optimization of Mold Design
Mold design is crucial for achieving high-quality castings. Virtual simulation technology can predict the stress and deformation that the mold may experience during the casting process. This allows for the optimization of the mold’s geometry, thickness, and material selection to ensure its durability and stability. In the lost foam casting case of the gearbox, the simulation helped in identifying potential areas of deformation in the foam model during the casting process. Based on these insights, the mold design was modified to provide better support and prevent deformation, thereby ensuring the integrity of the final casting.
6.3 Optimization of Casting Parameters
Casting parameters such as pouring temperature, pouring speed, and cooling rate have a direct impact on the quality of the casting. Virtual simulation technology can simulate the influence of these parameters on the casting process. By varying these parameters in the simulation and observing the resulting effects on the casting’s microstructure, mechanical properties, and defect formation, optimal values can be determined. In both the sand casting and lost foam casting cases presented, the casting parameters were adjusted according to the simulation results to achieve better casting quality. For example, in sand casting, the pouring temperature was optimized to ensure proper fluidity of the molten metal and to minimize the formation of defects such as shrinkage holes.
7. Challenges and Future Directions of Casting Virtual Simulation Technology
7.1 Challenges
7.1.1 Accuracy of Simulation Results
The accuracy of simulation results is a critical factor for the successful application of virtual simulation technology in casting. However, due to the complex nature of the casting process, which involves multiple physical phenomena such as fluid flow, heat transfer, and solidification, achieving highly accurate simulations can be challenging. Additionally, the limitations of the simulation software, including simplifications in physical models and numerical algorithms, can lead to inaccuracies in the results. To overcome this challenge, continuous research and development efforts are required to improve the simulation software’s capabilities. This involves incorporating more detailed and accurate physical models, enhancing numerical calculation methods, and validating the simulation results against experimental data.
7.1.2 Integration with Actual Production
Another significant challenge is the seamless integration of virtual simulation technology with actual production processes. While simulation results can provide valuable guidance for production, there are often differences between the simulated and actual scenarios. These differences can arise due to factors such as variations in raw materials, equipment performance, and operator skills. To address this issue, closer collaboration between the design and production departments is essential. This includes establishing clear communication channels, sharing data and knowledge, and jointly developing strategies to ensure that the simulation results are effectively translated into practical production improvements.
7.2 Future Directions
7.2.1 Improvement of Simulation Software
To enhance the accuracy and reliability of virtual simulation technology, future efforts should focus on improving the simulation software. This can be achieved by incorporating advanced numerical algorithms and physical models. For example, more accurate models for fluid flow, heat transfer, and solidification can be integrated to better represent the real casting process. Additionally, the software’s user interface can be enhanced to make it more intuitive and user-friendly, enabling designers and engineers to more easily interact with the simulation tool and interpret the results.
7.2.2 Expansion of Application Areas
In addition to its current applications in traditional casting methods, virtual simulation technology has the potential to be extended to other emerging casting technologies and applications. For example, with the increasing interest in additive manufacturing of castings, virtual simulation can be used to predict the behavior of the molten material during the deposition process and optimize the build parameters. Similarly, for micro-casting processes, where the size and precision requirements are extremely high, simulation technology can help in understanding the unique challenges and optimizing the process to achieve high-quality micro-castings.
7.2.3 Integration with Industry 4.0
As the manufacturing industry moves towards Industry 4.0, virtual simulation technology can play a crucial role in integrating with other advanced manufacturing technologies. By combining with the Internet of Things (IoT), big data analytics, and artificial intelligence (AI), casting production can become more intelligent and efficient. For example, IoT sensors can be used to collect real-time data from the casting process, which can be fed into the simulation software for more accurate predictions. Big data analytics can help in analyzing large volumes of simulation and production data to identify patterns and trends, enabling better process optimization. AI can be used to automate certain aspects of the simulation process, such as parameter optimization and defect prediction, further enhancing the efficiency and effectiveness of the technology.
8. Conclusion
In summary, casting virtual simulation technology has emerged as a vital tool in the casting industry. It offers numerous benefits in terms of predicting casting defects, optimizing the casting process, and enhancing casting quality. Through detailed case studies of sand casting and lost foam casting, we have demonstrated the practical applications and effectiveness of this technology. However, it also faces challenges related to simulation accuracy and integration with actual production. Looking ahead, the future of casting virtual simulation technology lies in continuous improvement of the simulation software, expansion of application areas, and integration with Industry 4.0. These developments will not only enhance the performance of the technology but also contribute to the transformation of China from a casting large country to a casting strong country, enabling the casting industry to achieve higher levels of productivity, quality, and competitiveness.