The process of removing precision castings from the mold, removing excess parts outside the body, and polishing the inner and outer surfaces of the castings.

Core removal and surface cleaning:

It is 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, has high production efficiency, has great adaptability to different types of castings, and has the advantages of both core removal and effective surface cleaning. The disadvantage is that during equipment operation, dust often flies, noise is high, and the environment is polluted. Wet cleaning does not produce dust, but due to the use of water as a medium, the surface of castings is prone to rusting. A large amount of sewage and cement sand are generated during the homework process, which brings problems such as sand and water regeneration and sludge treatment.

The commonly used dry and wet cleaning methods in production include:

① Drum cleaning. Put the casting and star iron together into a circular drum. When the drum rotates, it relies on the impact and friction between the casting, star iron, and waste sand to remove the sand inside and outside the casting, polish the surface of the casting, and partially remove burrs. This type of equipment is suitable for cleaning small and medium-sized castings with simpler shapes and thicker walls.

② Shot blasting cleaning. Utilize the impact force of high-speed steel shot, iron shot, and abrasive flow to remove the core and sand sticking, and polish the surface of the casting. In addition, commonly used shot blasting cleaning equipment includes a shot blasting cleaning table and a shot blasting cleaning room. The shot blasting cleaning machinery used for continuous production includes chain plate shot blasting drum, continuous shot blasting cleaning table, hanging continuous production shot blasting cleaning room, etc. The operation and maintenance costs of such equipment are relatively high.

③ Hydraulic sand cleaning. Inject high-pressure water through the pipeline from the nozzle towards the processed casting, and rely on the kinetic energy and scouring effect of the water flow to remove the core and casting sand sticking. Hydraulic sand cleaning usually has an open cleaning chamber composed of steel and steel plates, with a rotating workbench at the bottom and a spray gun installed on the side wall. It can move up and down and rotate, allowing high-pressure water to be directed towards any part except the bottom of the casting. Sometimes, in order to improve the efficiency of removing sand sticking on the surface of precision castings, abrasive materials such as quartz sand are introduced into the appropriate position of the spray gun to obtain high-speed water sand flow. This method is generally referred to as water sand cleaning.

④ Water explosion to clear sand. After pouring the mold, when the casting cools to the specified temperature, the box is opened and immediately immersed in a water pool. Water seeps into the mold through all gaps and rapidly vaporizes and explodes in contact with high-temperature metal. 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 is widely used in Chinese steel casting workshops. Generally used to handle steel castings with a carbon content below 0.35% and simpler shapes.