High-speed Cutting Parameter Optimization For Marine Diesel Engine Cylinder Head Under The Condition Of Stability And Low Stress

In recent years, with the development of manufacturing technology, the application of high-speed cutting technology is more and more extensive. How to achieve high-speed milling of marine diesel engine cylinder head has also been put on the agenda. Due to the immaturity of the domestic high-speed machining technology, high-speed machining technology of marine diesel engine cylinder head has not been effective utilized and promotion. There are many problems in the process of high-speed machining, and cutting chatter is the most prominent. When cutting chatter occurs, the machined surface will be leaved a lot of chatter marks that seriously affect the quality of processed products. At the same time, high feed processing can easily cause stress concentration. Excessive stress can lead to considerable deformation, which seriously affects the quality of product. The difficulties of the high-speed machining technology of cylinder head lead the parameters that are used in the actual process of cylinder head are too conservative. In order to solve technical difficulties in the high-speed machining of marine diesel engine cylinder head, this paper studies high-speed machining mechanism of marine diesel engine cylinder head, stability prediction, low cutting stress and cutting parameters optimization based on the research status of high-speed processing technology. The main contents are as follows:(1) Based on the research status of cylinder head high-speed machining, this paper analyzes chip formation mechanism and the formation mechanism of the high-speed processing residual stress that is as a theoretical basis for high-speed cutting finite element analysis of cylinder head. And this paper establishes dynamics model of high-speed milling system of cylinder head that provides a mathematical model to predict the stability of the high-speed milling of cylinder head.(2) In order to predict stability of high-speed milling of cylinder head, based on the theory of high-speed milling stability, and using chatter stable frequency domain methods, this paper draws the stability limit diagram of high-speed milling of cylinder head. Then, combined with the milling force model and the stability limit diagram of the process simulation, this paper analysis on the influence of different parameters on the cutting tool vibration displacement and verifies the reliability of the stability limit diagram.(3) For the problem that the processing stress of cylinder head is too high with high-speed and high-feed, the effects of different machining factors on the high-speed cutting surface cutting stress of marine diesel engine cylinder head are studied. Simplified the process of the high-speed milling of cylinder head and established 2-D high-speed cutting finite element model of marine diesel engine cylinder head, this paper explores the variation of surface cutting stress of cylinder head under the different cutting speed, cutting depth and tool angle.(4) In order to improve the processing efficiency of the cylinder head, according to the characteristic of the marine diesel engine cylinder head high-speed machining process, and combining with processing system performance parameters and stable low-stress processing requirements, this paper completes the constraints setting, and uses Particle Swarm Optimization to achieve the cylinder head high-speed cutting parameter optimization.