Of the total casting output, 60 ~ 70% of castings are produced with sand molds, and about 70% of them are produced with clay sand molds. The main reason is that sand casting is cheaper than other casting methods, simple production process and short production cycle. So castings like automobile engine cylinder block, cylinder head, crankshaft and so on are produced by clay wet sand process.
When the wet type can not meet the requirements, then consider using clay sand surface dry sand type, dry sand type or other sand type. The weight of clay wet sand casting can range from a few kilograms to dozens of kilograms, while the weight of clay dry casting can reach dozens of tons. Generally speaking, for medium and large castings, cast iron can be produced by resin self-hardening sand mold, steel casting can be produced by water glass sand mold, and castings with accurate size and smooth surface can be obtained, but the cost is higher.
Of course, sand casting production of casting accuracy, surface finish, material density and metallographic structure, mechanical properties and other aspects are often poor, so when the performance of the casting is higher, other casting methods should be used, such as investment casting, die casting, low pressure casting, etc..
Mechanical products refer to the finished products or accessories provided by machinery manufacturers to users or the market, such as cars, engines, machine tools, etc., are called mechanical products. Any mechanical product, according to the traditional habit, can be regarded as a number of components, and can be divided into different levels of sub-components up to Z basic parts unit. The production process of a product refers to the whole process of turning raw materials into finished products.
The production process of mechanical products generally includes: production and technical preparation such as process design and special process equipment design and manufacturing, production plan preparation, production materials preparation, etc.; Blank manufacturing such as casting, forging, stamping, etc.; Machining of parts, cutting, heat treatment, surface treatment, etc. Product assembly such as final assembly, partial assembly, commissioning inspection and paint, etc. Production services such as supply, transportation and storage of raw materials, purchased parts and tools.
The processing of parts includes the production of billets, as well as various mechanical processing, special processing and heat treatment of billets, so that it becomes a qualified part of the process. A few parts are processed by precision casting or precision forging chip - free machining methods. Usually the production of blank casting, forging, welding and so on. Any mechanical product is made up of several parts, assemblies and components. According to the specified technical requirements, the parts and components of the necessary coordination and connection, so that it becomes a semi-finished product or finished product process called assembly.