Ultrasonic Plastic Welding Zone Material Welding Behavioral Research

Ultrasonic plastic welding (UPW) is a cost-effective, efficient and clean fusion bonding technique of TPC (Thermal Plastic Composites), and of great value in application. At present basic theory and welding criterion of UPW are defective, research on welding mechanism and melt behavior of the welding region is not enough for the difficulty in study. To gain satisfactory mechanical strength, many experiments have to be done for optimum process parameters, in which both time and money are wasted in vain. Furthermore, many welding quality problems have not been solved yet. For these reasons UPW is restricted in popularizing in modern industry greatly.Research on ultrasonic plastic welding mechanism and the fusion bonding behavior of plastic in melt region is focused in this paper, the goal is to improve mechanical strength of the welding joints. Together with temperature field simulation by means of finite element method(realized by ANSYS), temperature field measurement is carried out to analyze the fusion bonding behavior rules of rigid PVC.The main topics of this paper are as follows:1. An automatic measurement system is setup to capture the transient temperature signal,including software and circuit design. Temperature data is captured successfully.2. The temperature field of the PVC specimens with energy director in ultrasonic welding issimulated by the finite element method (FEM). The simulation result is in agreement with the temperature measurement result, which proves that the simulation is reliable. With the result of FEM and temperature data acquisition, the temperature field change characteristic is analyzed.3. The fusion bonding behavior of welding region is discussed on the basis of experimentsand FEM simulation result, including plastic specimens with different melting point and with energy director. This contributes to the explanation of ultrasonic plastic welding mechanism and the improvement of fusion bonding strength of UPW.4. The research on fusion bonding behavior of energy director ensures its advantaged influence on ultrasonic plastic welding.