Casting is a metal melting into meet certain requirements of the liquid is poured into the mold, after cooling solidification, men get a predetermined shape, size and properties of the casting process.Precision casting blank for almost forming, and achieve the goal of free machining or a small amount of processing to reduce the cost and to a certain extent, reduce the time. Casting is one of the foundation of modern manufacturing technology.High production flexibility and strong adaptability. Both can be used in mass production, is also applicable to small batch and single production.To sum up, precision casting with a small investment scale, large production capacity, low production cost, the advantages of complex product process simplification, investment, fast effect. Thus in competition with the rest of the process and the means of production in a favorable position, a bright future.Fine casting dimension precision, surface roughness value, the dimension precision of casting can reach level 4, 6, the surface roughness of 0.4-3.2 mu m, can greatly reduce the casting machining allowance, and can realize WuYuLiang manufacture, reduce the production cost.Casting machinery industry and set up the completed "car casting blank elaboration efficient modelling and clean up the complete set of technology and equipment", "block efficient continuous line of development and research the shotblast cleaning" is a great success, in 1999 completed the national research high levels of air impact molding line project success.