Large-size Rectangular Vibrating Body Ultrasound Coupled Vibration

Plastic has the properties of slight mass, smaller friction resistance and extreme small conductivity of electricity and heat, so its use is increasing year by year. Currently, most plastic products are mould, and its size and structure is constrained by mould. In order to improve economic efficiency, connect various parts are often welded together. The traditional method of welding has many shortcomings such as pollution of environment, lower efficiency, and high-intensity of labour, while ultrasonic plastic welding is the better method, and its development may enforce the usage of plastic in industry.Because the shape and size of welding pieces is different, the ultrasonic welding tool of large size should be developed. For the impact of crosswise vibration, the amplitude distribution of radiation surface is not uniform, which will cause lack or excess of welding. So the amplitude distribution of radiation surface should be taken into account. Therefore, it is important to research of distribution of the radiation surface of large size tool.Slotting is a method to control the large-size vibration amplitude of distribution. At present, the research of slotting location and size is limited to traditional methods or finite element method, so we need to further explore ultrasonic welding tool of large size, so as to discover the law of controlling the amplitude of welding tool and establish a correct theory.This paper consists of the following aspects:(1) Because of the effect of crosswise vibration, the frequency and amplitude distribution of radiation surface of longitudinal vibration tool are changed. Based on the apparent flexibility modules, the impact of crosswise size on the frequency is analyzed. The theory results are compared to the finite element analysis results, which shows that flexibility modules theory and finite element simulation in dealing with large-size body vibration is the same; the amplitude uniformity varies with the size of crosswise dimensions and shows attenuation of cyclical change, which is helpful us to understand and use the tools of large size vibration..(2)Slotting may help to improve the amplitude uniform of radiation surface of large size tool. The slotted tools are analyzed by finite element software. The laws of frequency and amplitude ratio are obtained. The results show that the broad, length and space between two slots affect on the frequency and amplitude. Otherwise, if the slots are distributed illogically, the amplitude distribution of radiation surface may be more asymmetry. The frequency decreases to the increase of slot broad, length and space between two slots. The amplitude increases formerly and decreases after to the increase of slot broad, length and space between two slots. There exists best slot broad, length and space between two slots.(3) The frequency equation of the large size tool is obtained by use of the apparent elasticity method, and the results and simulated values were compared. The results showed that the simulation result is consistent with the theory. The theory is better for dealing with center cells, and there are bigger errors in dealing with the edge cells. The better theory is expected.