Firstly, the sand core design and block processing of the model are carried out. At the same time, the block results directly affect the manufacturing effect of the sand core and sand mold casting outer mold. According to the sand casting process and engineering experience, it is concluded that the following principles should be followed for product parting:
- Ensure that the sand core of sand mold casting can be made and taken out smoothly;
- Reduce the number of parting surfaces as much as possible to ensure the structural and dimensional accuracy of the product;
- Plane parting shall be adopted as far as possible. Simple plane parting can reduce the deformation error of curve parting surface.
According to the structure of sand casting engine cylinder head, the sand core can be divided into: (a) lower left oil channel core (b) lower right oil channel core (c) water channel core (d) upper oil channel core (E) inlet channel core (f) exhaust channel core, as shown in the figure.
In the rapid sand mold gravity casting, the sand cores of each sand mold casting have different shapes and high strength requirements, so the shell core process is adopted. In order to improve the quality of core making, the surface is dipped with water alcohol based coating to prevent sand inclusion and other defects during mold filling. The sand core assembly structure of sand mold casting is shown in the figure. The lower left and right oil channel cores are located on the floor core. The inlet channel sand core and exhaust channel sand core are positioned through the left and right positioning blocks of the core head to ensure the relative position with other sand cores. The middle layer is the water channel sand core, which is connected with the lower oil channel sand core to form a whole. The upper oil channel core is positioned through three points and installed and positioned on the mold. The slender part of each sand mold casting sand core adopts the core bone as the supporting structure to ensure the strength.