PROCESS OPTIMIZATION OF CARBON FIBER CONTINUOUS ULTRASONIC WELDING
Topic(s) : Manufacturing
Co-authors :
Saber MAAMRI (SPAIN), Jorge BAUTISTA PÉREZ (SPAIN), María Elena HERNÁNDEZ GARCÍA , Beatriz GARCÍA VASALLO (SPAIN), Roberto GUZMÁN DE VILLORIAAbstract :
Carbon fibre-reinforced thermoplastics are increasingly utilized across various industries due to their impressive strength-to-weight ratio and other advantageous properties. In the aerospace sector, they play a vital role in the production of aircraft components such as wings, fuselages, and engine parts, contributing to enhanced performance and efficiency. In the context of structural composite components, conventional joining methods like mechanical fastening or adhesives have added weight to the structure. Ultrasonic welding is emerging as a preferred alternative due to its distinct advantages over traditional methods, including faster cycle times, minimal additional materials, and the creation of stronger joints.
Ultrasonic welding represents a solid-state joining process utilizing high-frequency vibrations (20-40 kHz) and low amplitude (20-100 μm) to generate frictional heat and viscoelastic heat [1]. This heat leads to the melting and fusion of the materials undergoing joining. In this process, the components to be joined are positioned between the sonotrode and a rigid anvil. The sonotrode applies high-frequency vibrations and pressure to the components, generating frictional heat that causes the materials to melt and fuse together. Crucial welding parameters such as amplitude, force, and welding time are meticulously controlled by the system to ensure a consistent and high-quality welding outcome.
Originally confined to spot-welding, recent advancements have expanded the capabilities of ultrasonic welding to include sequential or continuous welding. In continuous welding, the sonotrode moves continuously over the area to be joined, generating adequate heat to fuse the interfaces and form a joint. This process is governed by adjusting amplitude and welding time, with the speed of the sonotrode advancement during welding serving as a crucial parameter. Our research team has innovated a continuous welding technique, characterized by both efficiency and energy conservation, specifically tailored for welding thin layers of continuous fibre thermoplastics.
In this study, we have studied the impact of amplitude and welding velocity on the quality of welded samples, showing how welding parameters can influence the characteristics of the resulting welds. The analysis includes the examination of welding interface morphology, thermal properties such as crystallinity and glass transition, and the performance of a mechanical test to evaluate joint strength. By using our custom-made equipment, low porosity (lower than 2%) and high strength (36MPa) have been obtained.
Ultrasonic welding represents a solid-state joining process utilizing high-frequency vibrations (20-40 kHz) and low amplitude (20-100 μm) to generate frictional heat and viscoelastic heat [1]. This heat leads to the melting and fusion of the materials undergoing joining. In this process, the components to be joined are positioned between the sonotrode and a rigid anvil. The sonotrode applies high-frequency vibrations and pressure to the components, generating frictional heat that causes the materials to melt and fuse together. Crucial welding parameters such as amplitude, force, and welding time are meticulously controlled by the system to ensure a consistent and high-quality welding outcome.
Originally confined to spot-welding, recent advancements have expanded the capabilities of ultrasonic welding to include sequential or continuous welding. In continuous welding, the sonotrode moves continuously over the area to be joined, generating adequate heat to fuse the interfaces and form a joint. This process is governed by adjusting amplitude and welding time, with the speed of the sonotrode advancement during welding serving as a crucial parameter. Our research team has innovated a continuous welding technique, characterized by both efficiency and energy conservation, specifically tailored for welding thin layers of continuous fibre thermoplastics.
In this study, we have studied the impact of amplitude and welding velocity on the quality of welded samples, showing how welding parameters can influence the characteristics of the resulting welds. The analysis includes the examination of welding interface morphology, thermal properties such as crystallinity and glass transition, and the performance of a mechanical test to evaluate joint strength. By using our custom-made equipment, low porosity (lower than 2%) and high strength (36MPa) have been obtained.