Vibration Of Cutting Tool For Turning Large Pitch Thread And Its Suppression Measures Machining

Large pitch threaded parts are the key parts in heavy equipment to provide power transmission and realize motion function.In the process of high-efficiency machining of large pitch thread,the vibration of cutting tool is intensified due to the large feed rate,and the high-quality machining of long stroke of large pitch thread surface cannot be completed.In this paper,the tool vibration in the process of turning large pitch thread is studied,and the suppression measures are put forward to ensure the tool life and the processing quality of thread parts.The specific research contents are as followsFirstly,the excitation effect of the process system on the tool vibration is studied,and the composition of the process system is analyzed.The vibration frequency response of the substructure divided by the tool feed system is coupled by the response coupling method,and the vibration equation of the tool tip point of the feed system is obtained.The process system is tested in the air,and the effective value of the vibration acceleration signal under different working conditions of the process system is obtained FFT frequency-domain and time-domain analysis,the influence of process system on tool vibration is obtained,which provides a theoretical basis for the subsequent tool vibration suppression measures.Secondly,the influence of cutting force on tool vibration is studied.Based on the structural characteristics of the rigid material of the cutting tool,it is simplified as a cantilever structure,and the vibration displacement of the cutting tool is obtained.Combined with the parameters of the left and right cutting layers in turning,the instantaneous cutting force model based on the vibration of the cutting tool is established.The single factor experiment of cutting parameters in turning large pitch thread is carried out,and the influence of the cutting parameters on the cutting force is obtained.The wavelet packet analysis is carried out by using MATLAB software,and the results are summarized According to the experimental data,the instantaneous cutting force model is modified and verified.Based on the instantaneous cutting force model and multiple linear regression analysis method,the relationship equation between the instantaneous cutting force and tool vibration of large pitch thread is established.Thirdly,based on the study of the influence of tool vibration excitation,the tool vibration suppression measures are proposed.Aiming at the excitation effect of the process system on the tool vibration,SolidWorks is used to carry out the threedimensional modeling of each subsystem of the process system,and then the modal analysis module in ANSYS is used to carry out the modal analysis,and the natural frequency of each subsystem of the process system is obtained.Finally,the resonance interval is obtained by combining with the frequency of each subsystem obtained from the air operation test of the process system to prevent resonance The cutting parameters are optimized by using the experimental data combined with the response surface method;a cooling and damping tool bar is designed to suppress the tool vibration through the cooling unit and damping unit in the damping tool bar.Finally,based on the proposed tool vibration suppression measures,the comparative experiment of turning large pitch thread is carried out,and the accuracy of the optimized parameters is verified by comparing the effective values of cutting force and vibration acceleration of the tool under different cutting parameters;the effectiveness of the vibration reduction tool bar is verified by comparing the effective values of cutting force and vibration acceleration of the vibration reduction tool bar and ordinary tool bar.In this paper,through the analysis and research of tool vibration and suppression measures,the tool wear in the process of large pitch thread processing is reduced,and the surface quality of machined workpiece is improved,which provides technical support for enterprises to process large thread with high quality.