Sand mold casting process is a casting method in which sand is the main molding material to prepare the casting mold. Sand casting is the most traditional casting method. Due to the characteristics of sand mold casting (not limited by the shape, size, complexity and alloy types of parts, short production cycle, low cost), sand mold casting is still the most widely used casting method in casting production, especially single or small batch casting!
The basic flow of traditional sand mold casting process includes the following steps: sand preparation, mold making, core-making, molding, pouring, sand falling, grinding, inspection and other steps.
1. In the sand mixing stage, molding sand and core sand are prepared for molding. Generally, the sand mixing machine is used to mix the old drawing and an appropriate amount of clay.
2. In the mold making stage, molds and core boxes can be made according to part drawings. Generally, a single piece can be made into a plastic mold or a metal mold (commonly known as an iron mold or a steel mold) through wood mold or batch production, and a large number of castings can be made into mold plates. Now the mold is basically using the engraving machine so the production cycle is greatly shortened, mold generally needs 2~10 days.
3. Modeling (core making) stage: including modeling (mold cavity of casting formed by molding sand), core making (inner shape of casting), and mold matching (putting nixin into mold cavity and closing upper and lower sand box). Molding is the key link in casting.
4. melting stage: according to the needs of the metal into a good distribution of chemical composition, choose the appropriate melting furnace melting alloy material, forming a qualified liquid metal liquid (including qualified composition, qualified temperature). Smelting generally USES cupola or electric furnace (due to environmental requirements, cupola is now basically banned, the basic use of electric furnace).
5. Pouring stage: inject molten iron in the electric furnace into the finished mold with the molten iron ladle. Pouring molten iron needs to pay attention to the casting speed, so that the molten iron filled the entire cavity.
6. Cleaning stage: after casting and other molten metal solidification, take a hammer to remove the gate and shake off the sand of the casting, and then use the sandblasting machine to sandblast, so that the casting surface will appear very clean
7. casting processing, for some special requirements of the casting or some casting can not meet the requirements, may need simple processing. Generally, grinding wheel or polishing machine is used to remove burrs and make the casting more smooth and clean.
8. casting inspection, casting inspection is generally in the process of cleaning or processing, unqualified generally have been found out. However, some castings have individual requirements and need to be checked again.
Before shipment, reprocess. According to the requirements of different customers, we can do heat treatment, surface treatment, additional inspection, etc.
Casting aluminum alloy has good casting performance and can be made into complicated parts. No need for large additional equipment; It is widely used in aviation industry and civil industry because of its advantages of metal saving, cost reduction and time reduction. Used to manufacture beam, turbine blade, pump body, hanger, wheel hub, intake lip and engine casing. It is also used to manufacture the cylinder cover, gearbox and piston of the automobile, the casing of instrument meter and the pump body of supercharger.