1. The role of casting  other materials production  processing technology

The manufacturing industry has undergone tremendous changes in the past two decades,  these changes will continue. In view of the fierce market competition around the world, a new generation of advanced manufacturing technologies such as casting, forging,  welding will emerge with new products  processing techniques. To deal with the market economy system  participate in global market competition, we must especially improve the basic  applied research of material production  processing science  technology. Only by adopting new material production  processing technology can we obtain the structure  performance of high-quality product workpieces  spare parts. Such high-performance materials include traditional materials  new materials.

However, compared with developed countries, there is still a certain gap in the technology of my country's foundry industry. For example, the annual output of castings in my country has exceeded 10 million tons, ranking second in the world. However, the high-quality casting (product quality) in my country is only 18%,  the accurate forming casting (output value) represented by investment casting is only 2%; while the United States is 40%  13% respectively. In addition, compared with developed countries, the average product quality of castings in our country exceeds that of overseas by 10%-20%; labor efficiency is 5-8 times lower  energy consumption is 2 times higher. Another example is the average wall thickness of automobile cylinder castings in my country is still 5.5-6.0mm, while in developed countries it is only 3.5-4.5mm  thinner.

2. The advanced casting process of the 21st century

Casting technology is an interdisciplinary industry of manufacturing  material science  technology. "New manufacturing process  equipment"  "Modeling  simulation" are two of the ten key technologies in the new manufacturing plan. In addition, in the book "Processing  Manufacturing Ushering in the Challenges of 2020", the United States also regards "waste-free production  processing  new material processing technology"  "modeling  simulation" as core technologies that should be prioritized for funding. Whether in my country  overseas, the correct understanding of the development trend of the casting process is consistent, that is, the new accurate forming casting process (NetShapeCasting)  multidisciplinary simulation will be the two primary research areas.

The so-called "waste-free production  processing" new casting process means that no waste is formed during the production  processing;  the formed waste is used as raw materials during the entire production  manufacturing process,  will  be formed in the next step Waste. In view of reducing waste, pollution  energy consumption,  benefiting the natural environment, "waste-free production  processing" will become a vital technology widely promoted.

In order to better cast more precise, stronger, lighter,  more economical machine parts, accurate forming  casting technology will be one of the primary choices for waste-free production  processing. For example, the overall new automotive research goal (PNGV) in the United States The goal is to reduce fuel consumption per 100km to 3L in 2003. A 10% reduction in vehicle weight can increase efficiency by 7%  reduce pollution by 10%. In order to better achieve this overall goal, the product quality requirements of the car body  frame must be reduced by 50%,  the power  transmission system must be reduced by 10%.

In recent years, many accurate forming  casting processes have been developed. For example, Cosworth precision casting (using high-precision zirconium sand molds  casting with electromagnetic pumps), lost foam casting  pressure precision casting will be the three main types of thin-walled, high-quality aluminum alloy cylinder castings in the automotive industry. Precision casting method. Many scientific studies predict that lost foam casting is "the new precision casting technology of tomorrow".

In addition, the single-crystal superalloy blades of turbines produced by directional solidification-investment casting are also the embodiment of the accurate forming casting process in aerospace.

3 Simulation of forming casting process

Simulation  simulation of shape casting process based on professional knowledge will be another key research area. Simulation can ensure the product quality of spare parts, optimize the whole process design, reduce the research  development cycle,  then generate economic benefits for the precision casting industry. High performance, high fidelity  high efficiency will be the overall goal of simulation. The use of computer simulation for the whole process of precision casting can increase the material production rate by 25%, save product costs by 30%,  reduce the development cycle by 40%. At this stage, numerical simulation on the macro scale of castings has been applied in engineering projects,  there are already some commercialized software such as MAGMA, PROCAST, FT-STAR, etc. at home  abroad. The simulation analysis  microscopic simulation ( mm, μm to nm scale) of the stress field are new research hot topics in recent years.

The scientific research  R&D in the simulation  simulation of raw material production  processing is the priority of the Ministry of Science  Technology  the Natural Science Foundation of China to fund new projects. In recent years, great progress has been made in these aspects. For example, my country has now developed an FDM/FEM integrated system for thermal stress analysis during the entire solidification process. The system software couples thermal simulations based on the finite difference method  the finite element method. Stress simulation. In order to scientifically study the stress changes of molded castings, predict thermal cracking  residual stress, the [H]-[H|N]-[N|S] rheological model can be used in the quasi-solid phase region,  the solid phase after solidification can be used thermally. -Elastic-plastic model.

4 Commodity  process design under networked concurrent engineering

The modern processing  manufacturing industry is facing fierce competition all over the world, the sales market changes rapidly,  the products are more complex. This requires the processing  manufacturing industry to reduce the production cycle,  the speed  efficiency of developing new products are the core ideas of its economic survival. Therefore, Concurrent Engineering (CE) has become a systematic software method for the integrated design of the whole process of goods  technology (including molding, production, processing,  related auxiliary links). The purpose of concurrent engineering projects is to improve product quality, reduce product costs, reduce the time for products to enter the sales market,  meet user requirements. The American Advanced Metal Material Production  Processing Engineering Project Research Center put forward the idea of "effective commodity  whole process design", which is also the core idea of concurrent engineering. Using this method to simulate  optimize the design of the whole process of precision casting can ensure the quality of casting products.

In recent years, with funding  the National Science  Technology Commission, Tsinghua University has conducted an in-depth analysis of the numerical simulation system software for the entire casting process in a parallel environment. For example, by using the CAE system to simulate a typical magnesium alloy shell casting, its quality is obvious Improve,  the development of new products has been carried out smoothly.

Integrating with intelligent manufacturing, virtual factory, network manufacturing, casting  other raw material forming production process simulation will become a very effective tool for the whole process design of new products in the manufacturing industry. To meet the requirements of different customers  product designs

Requirement, Beijing Tsinghua University is researching network-based intelligent casting system software. For example, Ford Company transmits the data of automobile castings designed by IDEAS/CAD software to Beijing via the Internet,  both parties use STL format as the online platform. After the macroscopic  microscopic simulation of castings by Tsinghua University in Beijing, the results are fed back to Ford for further evaluation. Therefore, the networked remote intelligent casting processing system software will be a new advanced casting technology in the 21st century.

5 Conclusion

(1) The processing technology of casting, forging, welding  other raw materials plays an important role in the development of the national economy. Facing the fierce market competition in the market, the emergence of new casting processes will result in brand-new products  technologies.

(2) The whole process of "waste-free processing" new production  manufacturing reduces waste, environmental pollution  energy consumption. It is an important processing technology in the future,  accurate forming  casting technology will be an ideal choice among them.

(3) High performance, high fidelity,  high efficiency will be the direction of effort for knowledge-based casting process simulation.

(4) The speed  efficiency of new product research  development are the key to global processing  manufacturing market competition. Concurrent engineering is a systematic software method for the integrated design of the whole process (such as casting) of the product  its related processing technology.

(5) Networking  intelligence are the trends of the whole process design of foundry products  processing technology in the 21st century.