Design And Research Of On-line Self-sensing Tool Holder For Ultrasonic Cutting Force Of Honeycomb Core Material

Honeycomb core material is widely used in aerospace,high-speed rail and ship fields due to its excellent characteristics.As a typical anisotropic difficult-to-machine material,compared with traditional processing methods,ultrasonic vibration assisted cutting can effectively reduce the cutting force in the process,reduce tool wear and improve the surface quality of the processed parts.Cutting force is one of the most important parameters in the ultrasonic machining process of honeycomb core material.Scholars at home and abroad judge the smooth degree of machining operation by its real-time changes.How to accurately collect the cutting force signal online is also an important research content.In this paper,aiming at the detection of ultrasonic cutting force on the ultrasonic tool holder of honeycomb core,the design and research of online self-sensing ultrasonic tool holder for ultrasonic cutting force of honeycomb core are carried out from the parameters of cutting force signal and the structural characteristics of ultrasonic machining system.The research work and results are as follows :1.Ultrasonic tool holder cutting force online detection sensing unit design.The structural characteristics of each part of ultrasonic machining system are analyzed.The force range and vibration frequency of cutting force are obtained by analyzing the actual cutting process of ultrasonic machining.The force condition of ultrasonic tool holder is analyzed by finite element simulation,and the selection range of detection point is determined.Based on the theory of piezoelectric effect,two kinds of cutting force sensing schemes are designed.By comparing the advantages and disadvantages of the schemes,the cutting force sensing scheme based on piezoelectric three-dimensional force sensor is selected as the research content of this paper.By analyzing the structural design requirements of the ultrasonic tool holder,the design parameters are obtained.According to the sensor design theory,the structure of the sensing unit : piezoelectric quartz wafer and crystal shell is designed,and the pre-tightening mode and connector of the sensing unit are determined and designed.2.Structure design and optimization of ultrasonic tool holder.The parameters Correlation module in ANSYS Workbench is used to design and optimize the structure of ultrasonic tool holder,and the optimized parameters of ultrasonic tool holder are obtained.Impedance analysis and amplitude test experiments were carried out on the optimized ultrasonic toolholder to verify that the performance of the ultrasonic toolholder meets the design requirements.3.Research on static and dynamic calibration method of ultrasonic cutting force online self-sensing tool holder.By analyzing and studying the static and dynamic calibration principles of the sensor,the static and dynamic calibration methods of the cutting force self-sensing system are determined.The static and dynamic calibration test benches are designed and built respectively.After the calibration experiment,the static and dynamic performance parameters of the cutting force self-sensing system are obtained by analyzing the obtained calibration experimental data.4.Online self-sensing system design and experimental research of cutting force.The cutting force self-sensing hardware system and the software system based on LabVIEW are designed.The software system includes zero drift compensation module,acquisition card driver module,data storage module,data optimization module and data analysis module.In order to verify the performance of the cutting force self-sensing system in this paper,a cutting comparison test with the ultrasonic machining three-way dynamometer was designed.By analyzing the frequency and amplitude of the cutting force,the static and dynamic performance of the cutting force self-sensing system was verified.