Large casting lost-foam resin sand casting process

Abstract

The invention provides a large casting lost-foam resin sand casting process which comprises steps of mould manufacturing, mould assembling, paint spraying and drying, resin sand vibration-filling, bottom-injection type semi-closed casting system applying, a casting clearing process and the like. A large casting lost-foam model is processed in a programmed and digital manner; the mould material replace rare korean pine wood with reproducible low-cost EPS foam, so that a great deal of non-renewable resources are saved; meanwhile, the processing performance and efficiency are greatly improved. A pouring system is designed with a gas exhaust channel, so that complex operations such as operation of eliminating a mould cavity lost mould by adopting methods such as combustion, and the like are avoided, limit in aspect of a metal material of a lost-foam casting process is further broken through, and therefore, the application field is wider.

Description

technical field [0001] The invention belongs to casting technology, in particular to a large casting lost foam resin sand casting technology. Background technique [0002] Lost foam casting is a new technology that my country's foundry molding has been promoting in recent years. Its process route is to use EPS macromolecule foam beads as the material, which are cured in a heating kettle and foamed in a metal mold to form a foam model with the same size and structure as the cast parts. Put it into a special sand box, fill it with dry sand, fill it with three-dimensional vibration, cover the surface of the sand, vacuumize the sand, and then pour the metal liquid to make the pattern escape by heating and gasification, and the metal liquid replaces the space of the EPS model to obtain the same shape Consistently shaped metal castings are a method of precise forming with near no margins. [0003] The lost foam casting process has many incomparable advantages over the traditiona...

AI Technical Summary

Problems solved by technology

[0004] Since the lost foam casting process is based on the metal mold foaming model and dry sand, negative pressure and three-position vibration molding, for large and small batch castings, the lost foam process is limited by the following aspects: 1. The cost of foaming metal mold production 2. The molding process equipment, no matter the sand box or the vibrating table, cannot guarantee the versatility of castings of various specifications; 3. During the pouring process, the surface area of ​​large castings is large, and when the molten metal is poured In the state where the negative pressure is destroyed, the reliability of dry sand compaction is difficult to guarantee and support the smooth filling of large and super large castings, so that the lost foam casting has been limited to the production of small batches of castings for a long time. It is difficult to apply the advantages of lost foam in the molding of large castings

Technically, lost foam casting is still limited to the replacement of lost foam space by molten metal, and there is no means of eliminating the replacement of air gap pressure. It is difficult to control the defects of castings caused by air gap pressure and foam residue.

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