Measurement of vibration transmitted through welded object and welding strength in ultrasonic welding

Abstract

Abstract Ultrasonic welding of plastics has been used in a wide range of industries and improving welding quality and production speed are still important issues. This paper introduces a method to evaluate the welding condition during welding. In this method, vibrations propagated during welding were acquired using a piezoelectric element. By fast fourier transform analysis, tracking analysis, and calculation of the data, the total harmonic distortion with the welding time was obtained. The welding condition can be determined by comparing the welding strength against the welding time obtained from the 180° peeling test. As a result, it was found that the propagated vibration has characteristics that indicate the completion of welding, making it possible to efficiently evaluate the quality of the weld.