Development history of coated sand
Cofilm sand was invented by Dr Cronin, Germany, during World War II, and the process of mixing powder thermosetting phenolic resin with the original sand machinery and curing when heating.After developed into thermoplastic phenolic resin and latent curing agent (urotropine) and lubricant through a certain film coated sand, when the surface of the sand resin melt, in the decomposition of the methyl, molten resin from linear structure quickly into not molten body structure, so that the coated sand curing molding.
China's coating sand technology began in the mid-1950s and was once stopped in the 1960s.In the 1980s, due to the rapid development of the automobile industry and the need of mechanical products export, higher requirements for the quality of castings, thus promoting the rapid development of coated sand production and application technology .In 1986, Jinan Casting and Forging Technology Research Institute first developed a new coating sand production technology, and the amount of resin added decreased from 6~10% in the early 1980s to 3~4%, close to the international advanced level in the same period.In the early 1990s, coated sand factories all over the country developed rapidly, and new products and new technologies continued to emerge. In the 21st century, the annual sales of coated sand industry in China has reached more than 900,000 tons, widely used in the production of automobile cylinder block, cylinder head, intake manifold, various pipe fittings, pump bodies and other complex castings.
Since 1977, due to the vigorous development of China's machinery, electronics, light industry, instrument, transportation and other industrial departments, the demand for casting mold is more and more in quantity, the quality requirement is getting higher and higher, and the supply period is getting shorter and shorter.
High production efficiency: high machine productivity, such as domestic J 3 horizontal cold air die cast aluminum 600~700 times every eight hours; die cast aluminum life, one die cast aluminum, die cast aluminum clock alloy, life can reach hundreds of thousands of times, even millions of times; easy to realize mechanization and automation.