Stability And Tool Reliability Research On The Milling Process

Manufacturing, as the national economic’ foundation, is a traditional field, has been developed for many years, accumulated a lot of technology and experience. But with the development of the society and technology, the manufacturing industry which plays a vital role in every walk of life, is facing serious challenges, and developing towards the direction of automation, precision, informatization and intelligence. Milling is one of the most important cutting technologies in advanced manufacturing technology. With the quick development of advanced manufacturing technology, higher demand of machining reliability and stability are requested. Chatter and tool failure during the cutting process are undesirable phenomenon because they are the limiting factors for the productivity, accuracy, quality of machining and they lead the system of milling to instability and unreliability.The problems that stability of milling system and reliability of cutting tool are studied by the method optimizing the parameters of the milling system and increasing the lifetime of the cutting tool in this project. First of all, based on a dynamic model of end milling processes, the generation and development of end milling chatter are analyzed; the stability lobes verified by the experiments are estimated by ZOA (zero-order-analysis), using the parameters form the modal experiment and cutting force coefficients identification experiment. In order to research the principle of metal cutting, a finite element model is built deals with multi-steps modeling strategy. Cutting forces, chip morphology and chip flow direction as well as cutting temperature are obtained, and a tool wear subroutine is used to calculate amount of tool wear, the analysis of the effect of cutting parameters on tool wear is discussed according to the orthogonal test method. Found that cutting depth and feeding speed on tool wear effect significantly. It has laid a base for material process parameter optimization, tool selection optimization and technics programming. Secondly, based on the discussion of the acoustic emission energy, metal cutting parameters, tool wear, AE technology is applied in tool condition monitoring. In processing the AE signal, the analysis tool of time and frequency-wavelet package is adopted, in order to confirm the characteristics of time and frequency in strange points of the signal. The milling cutter’s state on-line monitoring system has been designed, based on these characteristics. A cutting tool reliability evaluation method is established, using the Logistic regression model, using the average force and the wavelet energy of acoustic emission in the tool service life test.A systematic analysis about the stability and reliability of milling system issues is researched in this project. The method and measure for enhancing the reliability of the system are stated, and a serial of cutting tests was performed to validate the results, the conclusions have been found in good agreement with experiments.