(1) What is the lost foam casting process: the lost foam casting process is called full mold casting and vaporization mold manufacturing. It was invented by American shilol and patented in 1958. At the beginning, the process was used for the production of Arts and crafts castings. In the late 1950s, West Germany first used the lost foam casting process for the production of industrial castings. Since then, the casting industries all over the world have competed to study and research The dry sand method without binder is issued, which makes the process enter a new full mold casting period characterized by physical modeling. It is characterized by dry sand molding without binder, high frequency and low amplitude vibration compaction, and there is no need to take out the shape after molding. When pouring, foam plastics are decomposed under the action of metal. After being decomposed, the space position of the foam plastic is replaced by the metal liquid. After solidification, the metal is the desired casting.
(2) the characteristics of lost foam casting process: first, the foam plastics need not be completed in the whole process of production, and can be produced by block making and then glued into the required shape. The mold does not need to take off the mold, and can produce complex castings which can not be produced by traditional casting method. Of course, the dimension precision and surface finish of the casting are directly proportional to the manufacturing accuracy of the foam plastic parts, and have reached the trend of stabilization. The fixed investment casting greatly reduces the machining amount of the blank. The second is to optimize and simplify the process. There is no sand core, no parting, no mold lifting and box closing, no sand mixing for sand treatment, simple and convenient sand dropping, and can effectively eliminate the defects of EPC caused by water, binder and additives. Thirdly, it is easy to realize automatic and mechanized production. The recovery rate of used sand can reach more than 90%, the energy consumption cost saving rate is about 15%, and the casting cost can be reduced by about 30%. Thanks to the large-scale simplification of production processes, the simplification of equipment and the reduction of labor and material costs, it can effectively save a lot of money for enterprises.
(3) The research direction of EPC process: the first is the research on EPC model materials and molding technology. EPC is the production process of casting by making molten liquid metal replace plastic model. Therefore, pattern material and molding quality directly affect the quality of casting products. Therefore, the material requirements of EPC model are less gas generation, low density and low cost Strength can resist molding sand pressure and deformation caused by external forces. At present, the disadvantage of EPS material used in EPC is that when it is used in the production of cast steel and cast iron castings, it is easy to have defects such as surface wrinkle and surface carburization, and EPS mold is easy to be damaged in the production process due to its low density. Foreign EPMMA can effectively solve the carburization of steel castings, but the price is expensive. There is a lack of research in this field in China. EPS particles are imported from abroad, and there is no manufacturer of EPS in China. This requires workers in related fields and research institutions in related industries to develop high-quality pattern materials, so as to better improve the production quality of patterns.
The second is to study new casting materials: different from the traditional process, EPC is to coat the coating on the pattern and bury it in the sand for pouring after it is dry. Therefore, the requirement for the coating is to ensure high strength and good air permeability, so as to make the gas overflow quickly. In addition, the coating also controls the flow speed of liquid metal, The appropriate pressure between liquid metal and vaporization film is maintained, so the requirements for coatings exceed the coatings required by traditional cavity casting. There is still a lot of work to be done to develop high-quality coatings. Thirdly, the research on EPC in dry sand: EPC process has brought a complete change to the molding process. It enlarges its application scope and brings convenience to automatic and mechanized mass production. In terms of dry sand vibration, Japan and the United States are in the forefront of the world. There are still deficiencies in this aspect in China, and we need to strengthen research.