Ultrasonic welding transducer is an energy conversion device, and its performance description and evaluation require many parameters.The characteristic parameters of the transducers include resonance frequency, frequency bandwidth, electromechanical coupling coefficient, electroacoustic efficiency, mechanical quality factor, impedance characteristics, frequency characteristics, directivity, transmit and receive sensitivity, etc.
Ultrasonic welding transducers have different requirements for performance parameters for different application. For example, for transmitting transducers, the transducers are required to have large output power and high energy conversion efficiency; while for receiving transducers, It requires a wide frequency band and high sensitivity and resolution of piezoceramic ring componnets. Therefore, in the specific design process of the transducer, the relevant parameters of the transducer must be rationally designed according to the specific application.
In order to determine the working state of the transducer, the welding transducer must find the state equation of its mechanical vibration system and the state equation of the circuit system. The state equation of the mechanical system of the transducer (referred to as the mechanical vibration equation) is the relationship between the force and the vibration speed of the mechanical vibration system when the transducer is in the working state, and the state equation of the circuit system (abbreviated as the circuit state equation ) Describes the vibration characteristics of the circuit system. Because the mechanical system and the circuit system of the
piezoelectric welding transducer are coupled with each other, the vibration of the mechanical system will affect the balance of the circuit, and the change of the circuit will also affect the vibration of the mechanical system.Therefore, we always use these equations to analyze, Discussing the working characteristics of the transducer. The mature and reliable device that realizes the mutual conversion of electrical energy and acoustic energy by the piezoelectric effect is called the piezoelectric transducer. The piezoelectric effect converts electrical signals into mechanical vibrations. This kind of transducer has high electro-acoustic conversion efficiency, cheap raw materials, easy production, and is not easy to aging.