Study Of The Instantaneous Cutting Force Prediction Of The Machining Process Of Large Pitch Thread Machining

High feed,as one of the important means of high efficient cutting,is widely used in the processing of key components of large equipment.However,the cutting speed of small pitch process is unreasonable with high feed speed,which also leads to a large increase in cutting force.Besides,the turning tool may vibrates violently during machining because of the long axial-length of workpiece and the poor rigidity.And it is impossible to guarantee processing quality of large pitch thread long journey of high-quality,because Cutting load mutation and Strong vibration would lead to Tool wear,worn,Degradation of Service performance.The instantaneous cutting force is important indicators to the impact of the workpiece surface quality and processing performance.The research on the instantaneous cutting force in the existing large pitch only reflects the influence of the cutting parameters on the cutting force and can not reveal the instantaneous variation of the cutting force with the cutting parameters as the processing progresses.The thesis considered the machine tool system in the paper,and the actual processing of the vibration large pitch thread is divided into the machine tool feed system vibration and the vibration under the influence of theoretical cutting force.Therefore,the paper deeply studies the prediction of left and right instantaneous cutting forces in the process of large-pitch threading.First,the processing system of large pitch thread were divided into several substructures,and the thesis would determine the machine tool-the feed system joint surface that affects the tip of tool vibration.The sub-structure is coupled by response coupling method,and finally the thesis gets the effect of the self-structure of the machine to the tool vibration when the machine is idling or not cutting.Secondly,based on the deform simulation software,the left and right instantaneous cutting forces with different axial removal of the large pitch thread during finishing were obtained.The left and right instantaneous cutting forces are fitted functionally by MATLAB software.the thesis obtained the left and right cutting force equations of a large pitch thread in the finishing process.Thirdly,by using the method of the cantilever beam model and the theoritical theory,the instantaneous vibration of the left and right cutting threads with large pitch thread under theoretical instantaneous cutting force can be obtained.By analyzing the parameters model of the left and right cutting layers,the thesis would obtain changing cutting parameters of tool.And finally the thesis established the left and right instantaneous cutting force equation of large pitch thread in the actual finishing process。Finally,in order to verify the accuracy of the left and right instantaneous cutting forces methods established in this thesis,the precision machining experiments of different materials,different pitch and different diameter of screw were carried.Taking two set of cutting parameters as an example,we would obtained instantaneous cutting force data are compared with the predicted instantaneous cutting force data.The result of the comparison shows that the established numerical values of the left and right instantaneous cutting force values are small and have a good consistency with the experimental ones.Thus verifying the methods validity of the established instantaneous cutting force.After analyzing and studying the instantaneous cutting force during machining,this thesis provides the basis for the research on the surface quality and tool wear of the large pitch thread workpiece,and provides the guidance for the theoretical processing.