| As the key parts of large-pitch equipment such as CNC gantry mobile vertical milling machine,when turning large-pitch threaded parts in production,due to the characteristics of long cutting stroke,high accuracy of starting point position,long cutting edge and large-pitch,the processing mode of low speed,large feed and large cutting depth is often adopted.The sudden change of cutting load often leads to the sharp increase of cutting force and the aggravation of tool vibration and wear,which seriously affects the service life of the tool and the quality of threaded parts,and can not complete the high-efficiency and high-quality machining of large-pitch threaded parts.This paper takes the conflict between tool life and cutting efficiency under large pitch thread vibration as the starting point to optimize the parameters.The specific research content is as follows:Firstly,the structural parameters of machine tool,workpiece and tool and the axial cutting technology of large pitch-thread are determined.The dynamic and static finite element simulation software under vibration is studied.The influence of different cutting parameters on the dynamic and static finite element simulation software is analyzed from the angle of cutting force,cutting temperature and tool deformation under the vibration of large pitch thread,and the simulation accuracy is verified by the large pitch thread turning experiment.Based on the cutting force and cutting temperature,the orthogonal simulation experiment of large pitch thread cutting tool is designed,and the mathematical model of cutting force and cutting temperature is established by DEFORM finite element simulation data.Secondly,the tool life experiments were conducted to analyze the tool wear morphology and evolution by ultra-deep field microscopy and scanning electron microscopy.In order to establish the tool vibration wear model,the intermediate variable cutting force was introduced,and the instantaneous cutting force model and the cutting force and tool wear model under vibration were established respectively,and the effectiveness of the model was verified by experiments.Through the vibration wear model and the relationship equation of the surface roughness of the threaded part,acquiring mutations tool wear amount of cutting force and vibration signal features corresponding to the calculated value corresponding to the amount of tool wear when machining high quality can not be satisfied,it is determined standard threaded tool change,and establish the tool life prediction model.Third,through the established life model and material removal rate equation,the tool life and cutting efficiency changes under different cutting parameters are analyzed,and the law of equal life efficiency changes is studied;the workpiece surface roughness mathematical model is established,and the cutting parameters are determined based on the artificial bee colony algorithm.Optimization,with the best objective function as the optimization objective,to obtain the optimal cutting parameter combination of large-pitch thread tools.Finally,the evaluation criteria of tool life and cutting efficiency are determined,and the process of stable tool life and cutting efficiency for large pitch screw thread is proposed.The optimal combination of cutting parameters is verified from tool life and cutting efficiency,tool wear and cutting force,vibration and surface roughness respectively,which can realize high-efficiency and highquality machining.Through the research on tool life and cutting efficiency,this article can effectively resolve the conflict between the two and realize high-quality processing,which has important guiding significance for improving the quality of heavy equipment products in my country. |
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