EPC is known as “casting technology in the 21st century”. The process is made of expandable polystyrene beads and a foam model with a closed cell structure, similar to that of castings. It is embedded in fillers and makes the packing compact and has a certain molding strength. The high temperature molten metal vaporizes the foam model, and the gas spills through the sand gap. Finally, the metal liquid is replaced with the foam model, and the casting is obtained.
Compared with conventional sand casting, EPC has the following advantages:
(1) There is no need to mold.
(2) The surface quality of the casting is high, so the machining amount can be reduced or even no machining is required.
(3) Skillfully no external mold, no assembly of sand core, reducing the labor intensity of workers.
(4) Without lower core, the inner cavity of the casting can be directly cast with W.
(5) Dry sand molding, reduce cost.
(6) Less working procedures, lower cost of workers, simple steps are also conducive to the production of mechanical automation.
(7) Dry sand can be recycled easily after injection.
The lost foam was invented by H.F. Shroyer in 1958 in the United States, and improved by the Japanese in the early 1970s. In the early 1980s, the British cast steel research and Business Association (scraa) combined the two methods to study EPC successfully, and named it replica method, also known as gasified pattern casting method. In 1982, Ford Motor Company built a set of EPC intermediate test device with an annual output of 25000 lead alloy intake manifolds in Essex plant, which was successful. Then in 1984, it spent 11 million US dollars to establish a high-level automatic production of 100000 square meters, 180 type / hour production capacity and 1 million aluminum alloy intake manifolds per year Line. In 1991, Fiat Italia built the largest EPC workshop in Europe at that time in Turin with an annual output of 5000-15000 tons of iron castings, 60-120 type / hour, with a very high degree of automation, and only 22 people in the whole workshop.
After a long time of EPC technology accumulation, some developed countries in Europe and the United States have been able to produce large quantities of EPC Castings in combination with the efforts of some key domestic automobile enterprises. Some products of lost touch foundry enterprises in Europe and America.
Under the influence of foreign enterprises, EPC, a new foundry technology, has been introduced into China, and some independent production lines have been developed gradually. The research of EPC process in China started later than that in developed countries, and only in 1970 did we produce castings using EPC process. With the acceleration of the industrialization of the country, as an important branch of foundry, lost foam casting (EPC) has been greatly developed because of its many advantages. There are more and more research units and universities of EPC in China, and more and more enterprises using EPC production. These units and enterprises have accumulated technology over the years, which provides good theoretical support for the foundry industry in China, especially for the EPC industry.
With years of development, China’s EPC industry has made great progress, but compared with developed countries, there is still a big gap. For example, the same type of castings can be produced at home or abroad, but the precision and quality of castings are not enough to replace foreign products. Most of the domestic manufacturers using EPC to produce castings are still exploring and improving. In the face of some complex key parts, the lost foam casting enterprises in China have been able to compete with foreign enterprises. It can be seen that China’s EPC technology can not completely replace foreign castings for the time being, but this is a stage of development. China has started in the aspect of EPC. In the next stage, it is to study and solve the technical barriers of EPC abroad and produce castings with international competitiveness at home.
