Research On Flutters And Stability Of High Speed Turning Of Nickel-based Superalloy With PCBN Cutting Tools

Because of its good mechanical property, the nickel-base superalloy were wildly used inthe aerospace industry which is the representatives of strategy industry, meanwhile the poorcutting performance also brought much new challenge. In the cutting process of thenickel-base superalloy, the cutting flutter is a kind of highly unstable and complicatedmechanical vibration phenomenon which can reduce the production efficiency and machiningprecision. Especially when using cutting tools with high hardness and high brittleness such asPCBN, the blade flutter easily lead to crack. So, the principles of metal cutting, cutting fluttertheory, cutting experiment, MATLAB software are adopted to explore the rule of the influenceof cutting parameters on flutter, stability and surface quality in the process of high speedcutting nickel-based superalloy with PCBN cutting tools. Specific studies are as follows:1）The study of flutter vibration mechanics of model in cylindrical turning. The twodegrees of freedom dynamic model were established in the feeding and radial direction whichwas based on the cylindrical turning processing mechanism of vibration and flutter, thecriteria of the stability of cutting system were determined, and the limit cutting width of thecutting system were given in this paper and the influences of cutting vibration also wereanalyzed by computer simulation.2）The dynamic parameters of the machine tool cutting system were given in this paper.and the mechanical parameters(intrinsic frequency ωn, rigidity k,damping ratio) anddynamic parameters(Unit cutting force coefficientk cu,k cv) of machine tool cutting systemwere determined by using impulse technique modal test and orthogonal cutting tests methodand the limit cuttingbl imin the nickel-base superalloy were predicted; The main componentsof machine tool also use the modal test which provide the basis for determining the mainvibrating system.3） The simulation study is regeneration cutting flutter model based onMATLAB/Simulink platform. Using this platform to build two degrees of freedomregenerative model of the cylindrical turning flutter, established a method for determing theeffective cutting state based on cutting parameter. The simulation model was used to predictthe stability limit cutting depth of nickel-based superalloy to determine the primary fluttervibration direction of cutting process. According to the results of numerical simulations,explored the process parameters such as cutting speed, feed and cutting depth for regenerative effect under the action of the influence law of cylindrical turning vibration characteristics.4) Experimental study on the stability and quality of the nickel-based superalloy cutting.By the test of cutting time varying cutting deep, to test the predicted limiting cutting width ofnickel-based superalloy and determine the validity of the main vibration system choice; usinga single factor of cylindrical turning test and combining with the results of numericalsimulation to study the cutting parameters such as spindle speed, feed rate and depth ofcutting to the PCBN cutting tool’s vibration characteristics of high-speed turning ofnickel-base superalloy; under the condition of machining vibration, analyze the influence lawof process parameters on surface roughness.In conclusion, the researches in this paper provide a theoretical reference to improve thenickel-base superalloy processing performance and improve workpiece quality.