Stability Test Of Liquid Nitrogen Cryogenic Titanium Alloy Ti5553 During Cutting Process

Ti5553 titanium alloy is a metastable phase near beta titanium alloy,with high strength,high toughness,high permeability and low segregation and other advantages,has won high praise in the world,and won the world's most advanced,high strength and high toughness titanium alloy material(as compared to the Ti-1023,improve the strength of 15%),can replace the Ti-1023 titanium alloy is widely used in aircraft and aircraft parts in frame structure.Ti5553 is prone to generate speed sensitivity,flutter and continuous chip during the turning process.The production process has the characteristics of large cutting force,large vibration amplitude and high vibration frequency,which can easily cause system resonance and cause potential safety hazards in the process.Because of the difficulty in processing of Ti5553,low temperature liquid nitrogen cooling has gradually replaced the conventional cooling process for its excellent cooling performance and good implementation.It plays an increasingly important role in the field of metal processing.Liquid nitrogen cryogenic cutting can greatly reduce cutting temperature,reduce tool wear and improve surface integrity of workpiece,so as to improve machining efficiency on the premise of ensuring machining quality.Therefore,this paper focuses on the theoretical and Experimental Research on the stability of titanium alloy Ti5553 liquid nitrogen cryogenic cutting process,and further studies the flutter suppression device of liquid nitrogen low-temperature turning.Finally,the stability model and flutter suppression device are tested and verified.The main contents are as follows:For the flexible workpiece cryogenic machining process,considering the precise blade edge geometry and regeneration effect,establish the dynamic model of turning stability,and the Chebyshev collocation method based on the coefficient of variation of cutting angle and cutting edge discrete principal cutting force model,to solve the time domain to achieve dynamic equation.According to the cutting vibration characteristics of flexible workpiece machining in the low temperature of liquid nitrogen,were selected,electrorheological materials,electrorheological fluids composite materials and magnetostrictive actuator as brake chatter control,establish the structure of cutting chatter suppression based on function principle of the flutter suppression theory and simulation analysis in depth,and gives the cutting chatter suppression structure function condition.The dynamic stable domain signal threshold and the machining stability model based on the acquisition,respectively,application of intelligent electrorheological fluids composite structure and magnetostrictive brake design of three kinds of cutting chatter suppression structure of electrorheological fluid technology,intelligence,in-depth theoretical analysis on inhibition of chatter suppression structure flutter,and put forward the conditions and the corresponding improvement measures of the flutter suppression device.By modal test,the kinetic parameters of liquid nitrogen acquisition turning system to obtain the stability limit of turning;the cutting force and vibration signal feature extraction in the turning process,the accuracy and the accuracy of the prediction model by using the method of parameter verification verification of stability of turning process;in addition,the dynamic characteristics of external vibration experiment of the cutting system of electric field.The three kinds of turning chatter suppression structure is applied to the slender shaft machining process,workpiece by changing the overhang length and the electric field strength and other factors,the influence of parameters on flutter suppression,the vibration suppression effect to verify the flutter suppression device.