Cutting Behavior And Design Method Of Cutting Tool In Layered Turning Large Pitch Thread

As the key processing parts of heavy-duty press,large pitch thread plays the role of transmitting torque and accuracy,which left and right thread surfaces should have high accuracy consistency and high reliability.When turning large pitch thread with tool left and right cutting edges,the contact relationship of toolworkpiece and tool cutting behavior between left and right cutting edges are different.And the differences lead the forming process of left and right thread surfaces into different states,which directly affects the machining quality and consistency of left and right thread surfaces.The process method of turning large pitch thread directly determines the cutting behavior of tool left and right cutting edges.Therefore,through the study of radial and axial layered cutting methods effected on the quality of the machined surface,the processing technology design method of semi finish machining and finish machining are proposed in this paper.And the cutting experiment is done to obtain the feasible process parameter domain of finish machining tool for turning large pitch thread,which provides the basis for further research on the cutting behavior and the design method of cutting tool in finishing process of turning large pitch thread.In order to reveal the difference and influencing factors of cutting behavior between left and right cutting edges which in the process of turning large pitch external thread,the contact relationship of cutting tool and workpiece in turning large pitch thread with tool left and right cutting edges is studied,and the force models of cutting tool with left and right cutting edges are established.Through the analysis of tool cutting deformation and friction behavior,the difference experiment of cutting behavior of tool left and right cutting edges is carried out.The results show that,when cutting with tool left and right cutting edges,the combined action of tool-workpiece contact relationship,shear deformation and load constraints,lead the forming process of left and right thread surface to be obviously different.According to the difference of cutting tool force when alternating turning large pitch external thread with tool left and right cutting edges,the difference of the transient cutting force which under the action of vibration between tool left and right cutting edges is analyzed.The axial layered cutting mode with tool left and right cutting edges is used to do the experiment of turning large pitch thread.According to the experiment,the tool vibration characteristics in the forming process of left and right thread surfaces are achieved.Transient cutting motion trajectory and cutting attitude of tool left and right cutting edges are studied.Then the transient cutting force model is established.The technology evaluation and design method of turning large pitch external thread is proposed,and the process verification experiment is done.The tool design method of cutting large pitch thread is proposed which put the transient cutting force in the machining process of left and right thread surfaces,wear width of tool left and right flank,the consistency of machining surface topography and machining accuracy between left and right thread surfaces as goals.Using this method,a new cutting tool is designed and the cutting experiment is done.The experimental results are achieved with the existing results.The comparison result shows that,the cutting behavior of tool left and right cutting edges have been effectively controlled by using this design method.This paper provides an effective design method to improve the machined surface quality consistency of left and right thread surfaces.