First of all, the core design and block processing are carried out for the model, and the block results directly affect the production effect of the core and the casting outer mold. According to the casting process and engineering experience, the following principles should be followed for product parting: 1. To ensure that the sand core can be manufactured and taken out smoothly; 2. To reduce the number of parting surface as much as possible to ensure the structure and dimensional accuracy of the product; 3. To adopt plane parting as much as possible, the simple plane parting can reduce the deformation error of curve parting surface. According to the structure of engine cylinder head, the sand core can b e divided into: (a) lower left oil channel core (b) lower right oil channel core (c) water channel sand core (d) upper oil channel core (E) inlet sand core (f) exhaust sand core.
In the rapid sand mold gravity casting, the shape of each sand core is different and the strength requirement is high. In order to make the core quality, the surface is coated with water alcohol based coating to prevent sand inclusion and other defects during the filling process. The assembly structure of sand core is shown in Figure 2-5. The lower left and right oil duct cores are located on the floor cores. The air inlet sand cores and the exhaust sand cores are positioned with the rest of the sand cores through the left and right positioning blocks of the core heads to ensure the relative position. The middle layer is the connection between the water channel sand cores and the lower oil duct sand cores to form a whole. The upper oil duct cores are positioned through three points and installed and positioned on the mold. The core bone is used as the supporting structure at the slender part of each sand core to ensure the strength.