Research On Method To Test Dynamic Characteristics Of Five-axis Machine Tool In Running State

As an advancing processing and manufacturing equipment,five-axis machine tools are widely used in aerospace and high-precision machining fields due to their excellent processing characteristics of complex spatial surfaces,high efficiency and high precision.Compared with the three-axis machine tool,the five axis machine tool adds two rotating axes,so the machining space of the five axis machine tool has been expanded,and which has the good characteristics of processing complex surfaces.Due to the increase of the rotary axis,the relationship between the dynamic characteristics and the working posture of the machine tool becomes more precise,which may weaken the dynamic characteristics of the five axis machine tool to a certain extent,so that the machining performance of the five axis machine tool is limited.The research on the variation law of dynamic characteristics under different positions postures and different running states in the workspace of five axis machine tool may provide guidance for the optimization and adjustment of machining parameters during machining,and it is of great significant to improve the machining accuracy of the machine tool.The current research on the dynamic characteristics of the five-axis machine tool is mainly based on the static state of the machine tool.In the actual processing process of the five-axis machine tool,the changes in some external conditions and joint surface factors will affect the changes of dynamic characteristics.In order to explore the changing laws of dynamic characteristics in line with the actual processing conditions of five-axis machine tools,based on the advantages and disadvantages of some methods commonly used in the current research on dynamic characteristics,this paper focuses on the dynamic characteristics test method under the running state of five axis machine tool.The main research contents of this paper are as follows:(1)Analysis of the influencing factors of the dynamic characteristics of the five-axis machine tool and the planning of experimental program is designed.As a multi-degree-of-freedom complex electromechanical drive control system,there are various factors that affect the dynamic characteristics.The influencing factors of the dynamic characteristics of the five-axis machine tool are analyzed with qualitatively.The model VMC0656 e five-axis machine tool is used as the research object,combined with its structural characteristics,the dynamic test program of the five-axis machine tool under static and dynamic conditions is researched and designed.(2)The establishment and verification of the five-axis machine tool dynamics test system under the running state of the five-axis machine tool.The advantages and disadvantages of various vibration exciters and various excitation signals commonly used in the current dynamic characteristics test are analyzed.The piezoelectric vibrator and fast scanning sinusoidal signal are determined as the exciter and excitation signal of the dynamic test of this subject.The dynamic test system of five axis machine tool is built independently and the feasibility of the test system was verified through repetitive tests and hammering comparison tests.(3)Dynamic test and result analysis of five axis machine tool in running state.Based on the self-built dynamic characteristic test system,the static tests excitation were carried out when the a-axis of the machine tool is at different positions and angles,and dynamic excitation tests were carried out at different operating speeds of the machine tool.The modal parameters of the frequency response function obtained under each test condition were identified,and the first four modal frequencies under each test condition were obtained.The dynamic flexibility and modal frequency of static and dynamic excitation tests were compared and analyzed,and the dynamic characteristics of five axis machine tool under different operating conditions were obtained...