Studies on temperature distribution In various joint designs and design of Horns for ultrasonic welding of Thermoplastics

Abstract

Use of engineering plastics in structural and non structural newlineapplications is rapidly increasing As the demand for plastics increases so newlinedoes the requirements for joining of plastics Of the many techniques that are newlineavailable for joining of thermoplastics ultrasonic welding is one of the newlinesuitable processes Polymers are categorized according to their molecular newlinestructure as amorphous and semi crystalline Ultrasonic welding of these two newlinetypes of thermoplastics is expected to be different As heating is confined to newlinethe interface area quality of weld mainly depends on temperature at the newlineinterface So study on temperature distribution during welding is very newlineimportant to predict the quality of weld Viscoelastic heating is most critical newlineto ultrasonic welding of thermoplastics because it is the main mechanism by newlinewhich heat is developed at the interface Heat developed due to viscoelastic newlineheating depends on applied frequency square of amplitude and loss modulus newlineUltrasonic welding is generally divided into near field welding in which newlinethe horn is located within a distance of 6mm from the joint and far field newlinewelding where the horn is located at a distance which is more than 6mm from newlinethe joint newline newline