The principle of the casting method choose
1. Used sand precision casting. According to statistics, China or international, in the production of all castings, 60 to 70% of the casting sand production, of which about 70% is clay sand production. The main reason is sand casting and low cost compared to other casting methods, the production process is simple, short production cycle. So, like a car engine cylinder block, cylinder head, crankshaft castings with green sand process are produced. Consider the use of clay, sand dry sand, dry sand or other sand when wet type can not meet the requirements. Green sand mold castings weight from a few kilograms up to several tens of kilograms, dry clay production castings weighing dozens of tons. In general, large castings, iron castings with resin from the hard sand steel casting water glass sand production, you can get the precise size, smooth surface of the casting, but the cost is higher. Of course, the accuracy of the sand casting production of castings, surface finish, material density and microstructure, mechanical properties, etc., is often poor, so should be used when casting these higher performance requirements, other casting methods, such as casting (lost wax) casting, die casting, low pressure casting and so on.
2. Low pressure die casting, die casting, centrifugal casting, casting method, expensive equipment and tooling for mass production. Horizontal or vertical flaskless high-pressure molding machine production line can be used for small castings, real style and high production efficiency, the area is also less; in pieces the choice of a variety of high-pressure molding machine production line box, gas impact molding line, in order to adapt to fast, high-precision molding production line requirements, making the core method can be selected: efficient cold box, hot box and shell core coremaking. Moderate quantities of large castings can consider the application of the resin from the hard sand molding and core making.
The single-piece, small-batch production of heavy castings, hand molding is still important, hand shape is more flexible to adapt to a variety of complex requirements, does not require a lot of technology and equipment. Water glass sand, the VRH law water glass sand, organic ester water glass from the hard sand, dry clay, resin since the hard sand and cement sand, etc. can be applied; single production of heavy castings pit modeling method is low cost, put into operation fast. Styling products for mass production, or long-term production of multi-box style, and the hack box modeling method is more appropriate, although the mold, started to invest in the sand box, but can be compensated from saving modeling time, improve product quality.
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