The process of removing the precision casting from the mold, removing the excess parts outside the body, and polishing the inner and outer surfaces of the casting.
Core removal and surface cleaning:
Divided into two types of dry method and wet method. Dry cleaning is the use of mechanical equipment to clean up castings. The equipment used is simple, the production efficiency is high, it has greater adaptability to different types of castings and has the advantages of not only removing the core but also effectively cleaning the surface. The disadvantage is that the equipment is often flying with dust, noise, and environmental pollution. There is no dust in wet cleaning, but the surface of castings is easy to rust due to the use of water as a medium. A large amount of sewage and cemented sand were generated during the operation, which brought about problems such as sand and water regeneration and sludge treatment.
The dry and wet cleaning methods commonly used in production are:
①Roller cleaning. Put the casting and star iron together into the round drum. When the drum rotates, the internal and external sand of the casting is removed by the impact and friction between the casting, star iron and waste sand, and the surface of the casting is polished. At the same time, the flash is also partially removed. glitch. This type of equipment is suitable for cleaning small and medium-sized castings with simple shapes and thick walls.
② Shot blasting. Use the impact force of high-speed steel shot, iron shot and abrasive flow to remove the core and sticky sand and polish the surface of the casting. In addition, commonly used shot blasting equipment also includes shot blasting tables and shot blasting chambers. The shot blasting machinery used for continuous production includes chain plate type shot blasting drum, continuous shot blasting cleaning table, hanging continuous shot blasting cleaning chamber, etc. The operation and maintenance cost of such equipment is relatively high.
③ Hydraulic sand cleaning. The high-pressure water is shot from the spray gun to the casting to be processed through the pipeline, and the core and casting sand are removed by the kinetic energy of the water flow and the scouring effect. Hydraulic sand cleaning is usually provided with an open cleaning room composed of steel and steel plates. A rotary table is installed at the bottom. The spray gun is installed on the side wall. It can move up and down and rotate, so that the high-pressure water jet can be directed to any part except the bottom of the casting. Sometimes in order to improve the efficiency of removing the sticky sand on the surface of the precision castings, abrasives such as quartz sand are introduced at the appropriate position of the spray gun to obtain a high-speed water sand flow. This method is generally called water sand cleaning.
④ Clear sand with water burst. After the casting mold is cast, the casting is cooled to the specified temperature, and the box is immediately immersed in the pool. The water penetrates into the casting mold through all the gaps and contacts with the high-temperature metal to rapidly vaporize and explode. The shock wave can basically remove the sand attached to the inside and outside of the casting. The water explosion sand cleaning method has the advantages of short operation time and high efficiency, and is widely used in the Chinese steel casting workshop. It is generally used to process simple steel castings with a carbon content of less than 0.35%.