The vibration of centrifugal casting machine mold has always been an inevitable problem in production, and the vibration will have a certain impact on the quality of the final casting products, especially the furnace tube, which has high quality requirements, the impact of vibration can not be ignored. The vibration of the mold will lead to the uneven radial and axial wall thickness of the casting, especially when the furnace tube works under high temperature and high pressure. If the wall thickness is uneven or partially too thin, it will easily lead to the decline of local bearing capacity and lead to the tube explosion accident. In addition, the vibration of the mold in centrifugal casting process may cause the uneven distribution of chemical composition and microstructure, so people have been trying to reduce the vibration of the mold in centrifugal casting process.
Guo Xiaojun pointed out that the vibration of the vertical centrifugal casting machine was caused by the huge eccentric force when the centrifugal tools and tooling were assembled and rotated at high speed on the centrifugal casting machine, and put forward some countermeasures to reduce the eccentric distance. Zhai Shenqiu improved the structure of the small vertical centrifugal casting machine, adopted a pair of back-to-back tapered roller bearings to improve the rotation accuracy of the main shaft and reduce the vibration of the centrifugal casting machine, and improved the fastening method of the shaft parts to prevent the parts from jumping. Zhao Wenjie designed a retaining wheel structure which can modify the position and state of the cylinder to reduce the vibration of the vertical centrifugal casting machine.
For the horizontal centrifugal casting, bomsek and others, the factors that affect the vibration of the horizontal centrifugal casting machine are as follows: (1) the circular runout of the inner surface of the casting (uneven wall thickness) and the static imbalance of the mold; (2) the vibration becomes more intense during the filling process due to the uneven diffusion of the liquid metal; (3) the casting solidifies along the direction of the mold thickness There is a temperature gradient, which will cause thermal stress, leading to the deformation of the mold, and then make the vibration intensified.
Yang Yunfeng believes that the position of tugboat relative to the mold is also a factor affecting the vibration performance of the mold. To keep the mold stable when it rotates at high speed is fundamentally to require the minimum bending moment of the mold when it is at rest. Therefore, using the knowledge of material mechanics, a simple model is established to analyze the stress of the mold, and the method to minimize the bending moment of the mold is obtained Tugboat position.
In order to detect the vibration of centrifugal casting machine in real time, Shen Yi and others developed a virtual instrument system for process monitoring of large centrifugal casting machine based on LabVIEW, which improved the accuracy and visualization of monitoring important parameters of centrifugal casting process, but did not fundamentally solve the vibration problem of centrifugal casting.
In addition, the four rollers will also have a certain impact on the mold vibration. The surface roughness of the roller, the radial jump of the roller surface, the non parallel axis of the roller and the jump of the roller axis may lead to the unstable operation of the mold. At present, in the production of enterprises, it is mainly by experience to adjust the machine to control the mold vibration within a certain range.
It can be seen that the vibration of centrifugal casting machine is indeed one of the key problems in the casting field. At present, some people have put forward solutions to improve this problem, but so far, no one has established a systematic mathematical model for the vibration of centrifugal casting machine, and further discussed the vibration mechanism in detail and put forward solutions.