Welding of plastics using ultrasonics
Ultrasonic welding of plastic materials creates a molecular bond within the weld seam. Longitudinal vibrations in frequencies of 20 kHz, 30 kHz, and 35 kHz with tool amplitudes between 5 µm and 50 µm are introduced into the plastic materials under the action of force. Ultrasonic vibrations are focused by means of special design of the components or tools. This specific geometry within a component is referred to as energy director. The contact points in the joining area are actively molded by means of energy input to achieve elastic deformation. Friction occurring between the contact surfaces and within the molecule chains generates heat that causes the material to melt.