ULTRASONIC WELDING OF THERMOPLASTIC COMPOSITES FOR IN-SPACE MANUFACTURING AND 3D PRINTED STRUCTURE REINFORCEMENT APPLICATIONS

Thermoplastic composites demonstrate enhanced performance over thermoset composites in specific applications, largely attributable to their inherent weldability, which provides a considerable advantage in manufacturing and structural integrity. The ability to weld these materials simplifies the manufacturing process by enabling precise assembly of complex geometries, thereby reducing production costs and increasing throughput. Moreover, the weldability of thermoplastics improves maintainability, facilitating the efficient reconfiguration [6], repair or replacement of damaged components. This capability not only prolongs the operational lifespan of the materials but also reduces system downtime, ultimately enhancing overall performance and reliability. In this paper, we explore the ultrasonic welding of thermoplastic composites, which employs high-frequency mechanical vibrations to induce heat at material interfaces via intermolecular friction and viscoelastic heating mechanisms. Two case studies focused on the ultrasonic welding of carbon fiber reinforced thermoplastic (CFRTP) and glass fiber reinforced thermoplastic (GFRTP) composites are presented, examining both plunge and continuous (scan) welding techniques using Agile Ultrasonics technology [4]. The applications discussed include: (1) ultrasonic welding trials conducted on prototype CFRTP composite L-brackets for a lunar tower, integral to NASA’s Thermoplastic Development for Exploration Applications (TDEA) project aimed at in-space manufacturing of CFRTP composite structures; and (2) ultrasonic welding trials of pre-impregnated and preconsolidated multi-axial GFRTP laminates onto 3D-printed polymer assemblies produced by Avient Corporation for exoskeletal reinforcement [3].