Design Of Vibration Damping Tool For Turning Large Pitch Thread

Large pitch screw assembly is the key component of large-scale equipment,which transfers power and movement displacement for mechanical equipment,and plays an important role in the production equipment of enterprises.In the process of cutting,because of the large amount of feed and the violent vibration of the processing system,the sudden change of the cutting load results in the violent vibration of the cutting tool,which cannot complete the long stroke and highquality processing of the large pitch thread surface and becomes the bottleneck restricting high processing efficiency”.Therefore,how to suppress the cutting vibration and improve the surface quality of the workpiece will become the primary task of the machining research of the large pitch screw assembly.This paper starts from the angle of tool structure design,designs and develops the vibration damping tool which is suitable for turning the workpiece with large pitch thread,and applies it to the actual machining process.Through the cutting experiment,it is verified that the designed vibration damping tool can effectively suppress the cutting vibration and ensure the accuracy requirements of the workpiece design.Firstly,the structure of the blade is designed,and the influence of the geometric parameters of the blade,the structural parameters of the blade and the cutting parameters on the cutting force,the cutting heat and the deformation of the tool are analyzed by the finite element simulation.Based on the genetic algorithm,the multi-objective parameter optimization model is established,and the geometric parameters,the structural parameters of the blade and the cutting parameters are optimized,and finally the turning of the large pitch thread is completed The design and development of cemented carbide blade and the determination of its matching cutting parameters.Secondly,the structure and internal damping of the vibration damping tool bar are designed.Through the theoretical design and analysis of the vibration damping cavity,the influence law of the cavity size on the deflection of the tool bar is obtained.Through the finite element simulation,the variation law of the harmonic response vibration amplitude of the cavity with different structure size is analyzed,and the optimal cavity structure size suitable for the processing conditions of this paper is obtained.The large pitch thread reduction is established Based on the model,the optimal elastic coefficient,stiffness coefficient and damping coefficient are determined.Finally,the rationality of the design of the tool bar is verified by the comparison simulation experiment of the harmonic response vibration amplitude,and the design of the tool bar is completed.Thirdly,the paper analyzes the safety of screws in the connection mode of blade and cutter bar,estimates the range of bolt pre tightening force through theoretical derivation,and compares and analyzes several state changes of screws under different pre tightening forces by using finite element simulation,and determines the best pre tightening force under the cutting conditions described in this paper;uses finite element simulation to several states of screws under different eccentricity Through the comparison and analysis of the variation,the best eccentricity e value under the cutting conditions mentioned in this paper is determined.Finally,the safety of the screw is verified by simulation to ensure that the blade is clamped properly.Finally,a reasonable turning experiment scheme is designed,and the blades with different parameters are used for experiments to compare the cutting force,vibration acceleration signal and the change of blade structure in the time domain,so as to verify the rationality of the selection of the structural parameters of the blade and the geometric parameters of the tool;the solid tool bar and the designed vibration damping tool bar are used for experiments to compare the cutting force and vibration acceleration signal in the time domain And the structure change of the cutting edge verifies the damping effect of the cutter bar.The vibration damping tool designed in this paper can effectively suppress the cutting vibration in the process of turning the large pitch thread workpiece,which is of great practical significance to improve the manufacturing accuracy and product quality of heavy equipment in China.