Cylinder Head Valve Seat Machining Simulation And Optimization

Trial Cutting is the traditional method to study impact of process parameters on cutting performance. Through massive trials and statistic study of trial data, trial pattern is determined and optimal feed speed and spindle speed can be finalized. Strength of this method lies in its close ties with realities and its ability to correctly reflect live machining situations; its weakness is that it takes a long time to perform massive trial cutting in order to find appropriate cutting parameters, which in turn prolongs new product development cycle and increases costs, and the impact of random factors cannot be controlled.Based on the Automobile Engine Cutting Simulation and Process Optimization Project jointly developed by SAIC GM Wuling Automobile Company and Huazhong University of Science and Technology, this article studies the problem of poor surface quality and severe tool wear during the machining of engine head intake and exhaust valve seats. The study includes:1. Through analysis of automobile engine valve train mechanism, and in regard of SGMW engine valve seat machining process characteristics, for the problem of poor surface quality and severe tool wear during the machining of intake and exhaust vale seats, this article analyzes the major reasons for process problems and designs a problem solving method of process parameter optimization through finite element modeling. 2. Use Arm Coordinate Measuring Machine on valve seat machining tool. Perform vector scan on the tool insert and obtain the scattered points cloud image. After data processing using IMAGEWARE reverse-engineering software, set up 3D tool insert model in UG. Analyze valve seat material characteristics. Choose appropriate material constitutive model and chip separation criterion. Use self-adaptive mesh plotting technique to set up finite element model of valve seat machining in professional finite element cutting software ADVANTEDGE FEM.3. Use orthogonal experiment method to design technical scheme of finite element simulation optimization. ADVANTEDGE FEM performs simulation analysis on engine intake and exhaust valve seats machining process, comparing cutting force, cutting temperature, and trend of stress and strain with different feed speed and spindle speed. Through simulation comparison, optimal match of feed speed and spindle speed is obtained. At the same time, several groups of experiment plans are designed based on simulation results. F instruction and S instruction in the CNC programming of intake and exhaust valve seats machining are modified. Perform machining experiments on four CNC's on the line. Check surface machining quality according to measurement requirement specified by machining process and record tool life. Keep good records of experiment results. After one month of on-site experiment, the results coincide with simulation projections. Applying the optimal parameters recommended by this article to actual machining, tool life is increased by 89.3%. Tool cost is in turn greatly reduced and number of tool change has also decreased, which increases machining efficiency. Theoretical results matching experiment results proves that the method adopted by this article is correct and it also applies to other types of machining process analysis.