Research On Dynamic Performance Of Marine Compound NC Machine Tool

Inevitably, there are damage and loss parts in ship navigation, so it is very important to guarantee ship normal working in a long-term. In order to realize the supportability requirements of the ship equipments, it is important to make a marine compound NC machine tool to adapt to the typical parts machining;so the machine tool is created to meet the technical requirements of structural lightweight, operational reliability, seakeeping, salt-fog corrosion resistance, fast flexible processing and low cost. To study the structural stability and processing performance of the machine tool in the ship environment, this paper studies structural modal analysis, seakeeping and machining dynamics.The main contents and conclusions are as follows:(1) This paper presented macro-micro vibration coupled numerical model according to the structural characteristics of the marine tool; then the six-order natural modes were achieved by the FEM(Finite Element Method) numerical analysis and experimental modal method. The results show that the numerical model and FEM model are able to explain the natural dynamic performance of the machine tool; furthermore, it shows that calculation method is suitable for the modal calculation process, which is based on the similar test modal shapes and FEM modes to calculate the static stiffness and damping ratio of viscous damping system.(2) To study the effect of extreme wave loads on the machine tool structural seakeeping features, the transient analysis, PSD(Power Spectral Density analysis) and harmonic response analysis were used. The results show that the maximum slamming stress is located in the column guide-slider, and the minimum safety factors are safe under extreme wave load. Moreover, the extreme PSD slamming wave load has a greater influence on the machine structure. In addition, the harmonic response of the machine tool shows that the structural is safe under extreme sway acceleration wave loads.(3) Due to the vibration environmental characteristics affected by the wave loads, the fatigue analysis and reducing vibration method were used to study the machine tool structural features. The results show that the machine tool has extreme fatigue safety performance. Furthermore, to enhance the machine tool structural performance against wave loads, this paper proposes a quick-locking secondary support system in the column center.(4) To study the dynamic performance in the machine tool processing, this paper studied the effect of maximum working wave load on the machine tool, and the results indicate that the machine tool has 0.01 mm machining accuracy. Based on the data, numerical analysis and experimental analysis are used to study the machining dynamic characteristics. Then it studied the cutting dynamic performance of the machine tool in the affordable remanufactured coating cutting process, and it presented two-step process. Moreover, three factors and three levels of Response Surface Methodology and Regression Analysis were used to obtain the numerical models of cutting force and coating bond strength influenced by the machine tool. Furthermore, because the residual stress is mainly affected by the cutting force, the orthogonal test and regression analysis are used to achieve the coating bond strength numerical mode.