The structure of clutch flywheel casting is shown in Fig. 1. It is a typical small disc casting with diameter of 280m, height of 50m, single piece weight of 4.6kg, material of vermicular graphite cast iron Ru T300, tensile strength ≥ 300mpa, elongation ≥ 3%, vermicular rate of 60% ~ 80%, hardness of 160 ~ 200H BW. In order to ensure that the maximum unbalance of the dynamic balance of the casting is less than 10g, shrinkage defects are not allowed inside the casting, and the thickness difference between the upper and lower walls of the casting is not allowed to exceed ± 0.3mm.
The internal shrinkage of the casting and the great difference between the upper and lower wall thickness and weight of the casting result in the out of tolerance of the dynamic balance of the casting.
1) Because the inner circle of the casting is connected with other parts such as the pressure plate by thread and riveting, the local design is relatively thick, and the external plate surface is designed to be thin considering the conditions of weight reduction and heat dissipation and ventilation. If the wall thickness difference is too large, the feeding channel will not be smooth in the, It leads to a large number of shrinkage defects at the connection between the outer circle of clutch Flywheel Casting and the disk surface.
2) At present, the horizontal parting molding line is mostly used in the production of disc castings in the industry. However, in order to improve the production efficiency per unit time, customers require our company to adopt disa vertical parting molding line. The biggest difference between vertical parting molding line and horizontal parting molding line is: compared with the gate cup, the castings with different heights are subject to different gravity acceleration, so the thickness and weight of the upper and lower walls of the castings are greatly different, and the casting process is limited by molding equipment.