Research On Reliability Optimization Method Of Milling Process Parameters Of Ball-End Milling Cutter

As a kind of high precision and high efficiency machining method,the ball end milling cutter is widely used in the fields of mould,automobile,aerospace and other industries.Studying the milling force and the tool deflection error can provide a reliable theoretical basis for formulating rational machining process before processing.At the same time,the rational selection of milling parameters is of great practical significance to improve the production efficiency and reduce the processing cost.In this paper,the double-edged ball end milling cutter machining the rigid workpiece at the same height was taken as the research object,considering the influence of random factors,the reliability of machining precision,the reliability sensitivity and the reliability optimization of ball end milling process parameters were researched,based on the model of milling force and the tool deflection error.The specific work is as follows:(1)The method for modeling the force and the tool deflection error of ball milling was researched.On this basis,considering the influence of randomness of milling parameters on the metal cutting,a method was put forward for predicting the probability distribution of the milling force and the tool deflection error based on the Monte Carlo simulation method.Compared with the deterministic calculation method,the prediction results matched the actual situation better.The influence of milling parameters on milling force and tool deflection error was studied based on the deterministic computation model of the milling force and the tool deflection error.It laid the theoretical foundation for reasonable selection of milling parameters to improve machining precision and machining quality in the actual processing.(2)BP neural network was used to fit the approximate function expression between the tool deflection error and the milling parameters.The reliability and reliability sensitivity of ball end milling cutter were calculated by the improved first-order two-moment method and the Monte Carlo simulation method was used to verify its correctness.Through the analysis of the reliability sensitivity results,the influence of milling parameters on the milling precision was obtained which could provide a theoretical basis for the design of milling parameters in order to improve the milling precision.(3)The highest productivity,the lowest processing cost and the minimum milling force were taken as the objective function respectively.Limitations on the milling parameters from the requirements of the machine tool,the workpiece quality and the reliability of the milling precision were taken as the constraint conditions.The reliability optimization model of milling parameters for ball end milling cutter was established,and the model was solved by GlobalSearch,a function in MATLAB.Considering the above three objective functions and weighing thier importance,multi-objective optimization of milling parameters for ball end milling cutter was carried out by the linear weighted combination method to achieve the best comprehensive economic benefits.