Analysis of Sand Casting Process

Sand casting is a traditional casting process that uses sand as the main molding material to make molds. Sand molds are generally cast by gravity, and low-pressure casting, centrifugal casting, and other processes can also be used when there are special requirements. Sand casting has a wide adaptability, and can be used for small and large parts, simple and complex parts, single pieces, and large quantities. The molds used for sand casting used to be mostly made of wood, commonly known as wooden molds. In addition, sand molds have higher fire resistance than metal molds, so materials with higher melting points such as copper alloys and black metals are also commonly used in this process. However, sand casting also has some shortcomings: because each sand mold can only be poured once, the mold is damaged after obtaining the casting and must be reshaped, so the production efficiency of sand casting is relatively low; Due to the overall soft and porous nature of sand, the dimensional accuracy of sand castings is lower and the surface is rougher.

Casting is the process of melting metal into a liquid that meets certain requirements and pouring it into a mold. After cooling, solidification, and cleaning, it produces castings with predetermined shapes, sizes, and properties. Casting blanks, due to their near formability, achieves the goal of no mechanical processing or minimal processing, reducing costs and to some extent reducing time. Casting is one of the fundamental processes in modern manufacturing industry. After the casting is taken out of the self cooled casting mold, there are gates, risers, and metal burrs and gaps. Castings made by sand casting also adhere to sand, so they must go through a cleaning process. The equipment used for this type of work includes shot blasting machines, sprue and riser cutting machines, etc. Sand casting cleaning is a process with poor working conditions, so when choosing the molding method, it is important to consider creating convenient conditions for sand cleaning. Some castings require special post-treatment, such as heat treatment, shaping, and rust prevention, due to special requirements

Processing, rough machining, etc. Casting is a relatively economical method for rough forming, which can better demonstrate its economy for parts with complex shapes. Such as the cylinder block and cylinder head of car engines, ship propellers, and exquisite artworks. Some difficult to cut parts, such as nickel based alloy parts for gas turbines, cannot be formed without casting methods.

In addition, the adaptability range of the size and weight of the cast parts is very wide, and the types of metals are almost unrestricted; Parts not only have general mechanical properties, but also comprehensive properties such as wear resistance, corrosion resistance, and shock absorption, which cannot be achieved by other metal forming methods such as forging, rolling, welding, and punching. Therefore, the number and tonnage of defective parts produced by casting methods in the machine manufacturing industry are still the largest.