Alternative Methods for Ultrasonic Welding of Advanced Thermoplastic Composites

Abstract

The fusion bonding of advanced thermoplastic composites has a variety of applications in aerospace, automotive, medical, consumer electronics and energy markets. High-power ultrasonic welding is a state-of-the-art manufacturing process being used to join these materials. This welding process uses high frequency, moderate force, and low amplitude mechanical vibrations to generate heat. When adequate temperatures are reached at the weld interface, localized melting occurs and upon cooling, an intermolecular bond is formed between the materials. It is the viscoelastic nature of polymers that facilitates heating, enabling the bonding process. This project was done in collaboration with Agile Ultrasonics Corp, an American company based out of Hilliard, OH. Agile entered the industry in 2017, specializing in the joining and consolidation of thermoplastic materials, including carbon-fiber-reinforced polymers (specifically: PEEK - Polyether ether ketone, PAEK - Polyaryletherketone, PEKK - Polyetherketoneketone, PPS - Polyphenylene sulfide) [1]. Agile collaborates with industry-leading manufacturers of aerospace and consumer electronic components on a variety of system design projects. They have been developing a unique process that continuously joins fiber reinforced thermoplastic tape, braid, or pre-consolidated plate materials. One of the primary objectives of this project is to help refine this process and make it more robust. The majority of the content in this report focuses on investigating anvil materials with properties that can improve the quality of the scan welds being produced by Agile. More specifically, this project investigates the effect that the elastic modulus within compliant anvil materials has on the amount of heat being generated at the weld joint. The first section will focus on background information, and the following two will go into the work that was performed and the test results. Data was collected on various materials and a variety of tests were designed and performed to find an array of compliant substrates that can be used by Agile.