Research On Cutting Vibration Transmission Path Of NC Turret Based On Energy Flow

Numerical control(NC)turret is a key functional part of computerized numerical control(CNC)lathe,its reliability directly affects the availability of the whole machine.In the actual operation process,the vibration and noise problems of NC turret are common,and the occurrence of faults is often accompanied by changes in their vibration response.Studying the vibration characteristics and the vibration energy transmission of NC turret is of great significance to the condition monitoring,fault diagnosis and reliability improvement of NC turret.In this paper,the research object is the domestic AK36*** NC turret.And the finite element energy flow and transmission path analysis methods are used to study the vibration characteristics and transmission path of the NC turret under cutting conditions by a combination of theoretical derivation,simulation and experimental verification.Specific research work is as follows:1.Analysis of NC turret working principle and failure mode.According to the structural characteristics of the NC turret,the working principle of the NC turret is analyzed in detail,and the structure and functional characteristics of the research object in this article are clarified.And the NC turret is divided into five subsystems.Through FMECA,10 typical failure modes of NC turret are obtained,and the typical failure modes are prioritized for risk.It is indicated that the chainring faults are more dangerous to NC turret.2.Harmonic response analysis of NC turret finite element model.Firstly,the finite element model of NC turret was established,and the key technologies of the NC turret finite element model processing were studied: model simplification,meshing,processing of joint surfaces,material assignment,definition of boundary conditions and loading of dynamic cutting forces;Then,the solution and analysis of the harmonic response analysis of the NC turret were performed by ABAQUS.The response of the NC turret to dynamic cutting forces was obtained.Finally,the simulation result data was extracted from the post-processing module of the harmonic response analysis.It provides basic simulation data for subsequent research on energy flow and transfer path.3.Research on vibration energy flow of NC turret based on finite element analysis.Based on energy flow theory and the data of simulation results,the two-dimensional and three-dimensional energy flow vector diagram of the NC turret shell are respectively drawn,which intuitively shows the flow direction and size distribution of the vibration energy on the shell.Combining the turret structure,we analyzed the cause of the vibration energy transmission path on the turret shell.Based on the theoretical formula of two-dimensional shell energy flow,combining the knowledge of the crossspectral density of the signals,the experimental energy flow calculation formula was derived.A dynamic cutting force simulation test bench similar to the simulation was set up in the laboratory,and the energy flow test was designed and completed.By comparing the simulation and test results,the correctness of the theoretical analysis and simulation results was verified.4.Research on Cutting Vibration Transmission Path of NC Tool Post Based on Energy flow.The finite element simulation of the NC turret chainring poor toothing fault is completed.And the energy flow vector diagram of the NC turret failure status is drawn.By comparing and analyzing the energy flow vector diagrams of the health status and failure status of the NC turret,three abnormal vibration energy regions on the NC turret shell were determined in this typical failure mode.On the basis of the energy method,the calculation method of transmission path contribution rate and distribution rate is deduced.And we analyzed and planed the cutting vibration energy transmission path of the NC turret.Nine measurement points were selected in the vibration energy abnormal area of the shell,and the above-mentioned distribution ratio calculation method was used to obtain the energy flow distribution ratios of different fault locations on the chainring to each measurement point.According to the calculation results,we have selected the measuring points that can accurately distinguish the fault location as the sensitive measuring points for this typical fault mode.