Cleaning scope and method of precision castings

The process of taking the precision casting out of the mold, removing excess parts other than the body, and polishing the inner and outer surfaces of the casting.

Coring and Surface Cleaning:

        Divided into two categories: dry method and wet method. Dry cleaning is the use of mechanical equipment to clean castings. The equipment used is simple, the production efficiency is high, the adaptability to different types of castings is large, and the advantages of being able to remove the core and effectively clean the surface. The disadvantage is that the equipment is often dusty, noisy and pollutes the environment during operation. There is no dust in wet cleaning, but because water is used as the medium, the surface of the casting is easy to rust. A large amount of sewage and cemented sand are produced during the operation, which brings problems such as sand and water regeneration and sludge treatment.

Dry and wet cleaning methods commonly used in production are:

①Roller cleaning. Put the castings and star iron together into the circular drum. When the drum rotates, rely on the impact and friction between the castings, star iron and waste sand to remove the sand inside and outside the casting, polish the surface of the casting, and also partially remove the flash glitch. This type of equipment is suitable for cleaning small and medium-sized castings with simple shapes and thick walls.

②Shot blasting. Use the impact force of high-speed moving steel shots, iron shots, and abrasive flow to remove cores, sticky sand, and polish the surface of castings. In addition, commonly used shot blasting equipment includes shot blasting tables and shot blasting rooms. The shot blasting machines used for continuous production include chain plate type shot blasting drum, continuous shot blasting cleaning table, suspended continuous production shot blasting cleaning room, etc. The operation and maintenance costs of such equipment are relatively high.

③Hydraulic sand cleaning. The high-pressure water is injected through the pipeline from the nozzle of the spray gun to the casting to be processed, and the core and casting sticky sand are removed by the kinetic energy and scouring effect of the water flow. Hydraulic sand cleaning is usually equipped with an open cleaning room made of steel and steel plates, with a rotary table at the bottom, and a spray gun installed on the side wall, which can move up and down and rotate, so that high-pressure water can be sprayed on any part except the bottom surface of the casting. Sometimes in order to improve the efficiency of removing sticky sand on the surface of precision castings, abrasives such as quartz sand are introduced into the appropriate position of the spray gun to obtain high-speed water and sand flow. This method is generally called water sand cleaning.

④Water blasting to clean the sand. After the casting mold is poured, when the casting is cooled to the specified temperature, the box is opened, and it is immediately immersed in the water pool. The water penetrates into the mold through all the gaps and contacts with the high-temperature metal to quickly vaporize and explode. The shock wave can basically remove the sand attached to the inside and outside of the casting. The water blasting sand cleaning method has the advantages of short operation time and high efficiency, and has been widely used in Chinese steel casting workshops. It is generally used to process steel castings with a carbon content of less than 0.35% and a relatively simple shape.