Investigation of Ultrasonic Welding Strength in Glass-fiber Reinforced Thermoset Polymer Materials

This paper presents the preliminary results of welding the glass fiber reinforced thermoset polymers with thermoplastic interlayers using an ultrasonic technique. The main purpose of this research is to understand the possible mechanisms of surface adhesion and to find out the possible approaches applying thermoplastic materials as the middle layers to provide a better connection with higher strength, shorter time, and low cost. To make the samples, we used two materials of epoxy resin and hardener. We used SolidWorks software to design suitable patterns in order to cut them on the surface of the samples using laser technique. Polymethyl methacrylate (PMMA) and polypropylene (PP) between two thermoset polymers are used as the middle layers (filler material), in order to make a better connection of thermoset composites using ultrasonic welding technique at a frequency of ۲۰ kHz. Finally, ۲ bars pressure, ۲ seconds as welding time, and ۳ seconds for holding time as the main welding parameters were selected for the polymethyl methacrylate middle layer. Also, for the polypropylene middle layer, ۲ bars pressure, ۱.۸ second as welding time, and ۳ seconds as holding time were selected. Experimental researches show that ultrasonic welding can be used effectively in industrial uses.

Keywords:

ultrasonic welding , thermoplastic and thermosets , resin epoxy , polymethyl methacrylate , polypropylene.