Research On Process Test And Structure Optimization Of Ultrasonic Cutting Knife Based On Finite Element Model

Ultrasonic transducer has been widely applied in industry area, such as ultrasonic cleaning, ultrasonic welding, ultrasonic machining and so on. This paper designs a kind of ultrasonic cutting knife, which has a application prospect in the area of material processing and can cut rubber, ABS plastics, composite material and so on. Compared with ordinary cutting knife, ultrasonic cutting knife can cut material faster with smaller resistance, and there is not rough selvedge on incisions by the use of ultrasonic cutting knife. The whole work is aimed for improving the cutting quality and optimizing the transducer’s working performance, in which the working principle, finite element analysis, structure optimization design and experimental verification for transducer system are discussed.Firstly, the finite element model of the ultrasonic system is created, and its vibration modal and response characteristics are analyzed. The basic theory of the finite element method for the piezoelectric structure is introduced. The simulation model, which includes piezoelectric rings, font/back slab, taper horn, and blade, is established. Then working axial longitudinal mode is attained by modal analysis, and the response of transducer is analyzed by harmonic response analysis.Secondly, the structure optimization design of ultrasonic cutting system is done by ANSYS software. After preliminary design of critical dimension, the vibration nodes and harmonic frequency of ultrasonic cutting system are optimized by sensitivity analysis approach to improve its stability and working performance.Thirdly, the finite element computing results are tested by experiments. Based on optimization result, a kind of ultrasonic cutting knife is maked, and its harmonic frequency and response characteristics are tested by impedance analyzer and Laser Doppler analyzer. The result shows that mechanical property and ultrasonic property of ultrasonic cutting knife well agree with the finite element computing results.Fourthly, the experiments of ultrasonic cutting of C/C composite are carried out. By comparing ultrasonic cutting with ordinary cutting, it can be found that cutting force reduced obviously and cutting quality get much better when the axial longitudinal vibration is added to the ultrasonic cutting knife. By altering ultrasonic power, it can be found that the increase in ultrasonic power is beneficial to reduce cutting force and improve the cutting quality.All above research contexts will be helpful to understand, analyze and design the ultrasonic cutting knife.