On improving process efficiency and weld quality in ultrasonic welding of misaligned thermoplastic composite adherends

This paper evaluates the potential of changing the welding force and the compliance of the energy director (ED) to reduce the effects caused by misaligned adherends, which were: increased through-thickness heating, reduced size of welded area and increased heating time. In the methodology that was followed, we welded adherends misaligned by...

Continuous Ultrasonic Welding of Thermoplastic Composites: An experimental study towards understanding factors influencing weld quality

One of the most promising welding techniques for thermoplastic composites is ultrasonic welding. It is mainly known as a spot welding technique. The relatively new technology continuous ultrasonic welding of thermoplastic composites makes it possible to obtain large fully welded seams with higher load carrying capabilities. However, at the start...

Ultrasonic welding of epoxy- to thermoplastic-based composites

Welding is a promising alternative to mechanical fastening, as currently used, to join dissimilar (i.e., thermoset- to thermoplastic-based) composite parts in modern aircraft. Thermoset composites can be indirectly welded through a thermoplastic coupling layer co-cured on the surface of the laminate that needs to be welded. One of the main...

Static ultrasonic welding of carbon fibre unidirectional thermoplastic materials and the influence of heat generation and heat transfer

Ultrasonic welding is a promising technology to join fibre-reinforced thermoplastic composites. While current studies are mostly limited to fabric materials the applicability to unidirectional materials, as found in aerospace structures, would offer opportunities for joining primary aircraft structures. However, due to the highly anisotropic...

A Study on Through-the-Thickness Heating in Continuous Ultrasonic Welding of Thermoplastic Composites

Continuous ultrasonic welding is a promising technique for joining thermoplastic composites structures together. The aim of this study was to gain further insight into what causes higher through-the-thickness heating in continuous ultrasonic welding of thermoplastic composites as compared to the static process. Thermocouples were used to measure...

Ultrasonic welding of CF/epoxy to CF/PEEK composites: Effect of the energy director material on the welding process

With its short heating times, ultrasonic welding is a highly promising technique for joining thermoplastic (TPC) to thermoset (TSC) composites, to prevent thermal degradation of the thermoset adherend. A neat thermoplastic coupling layer is co-cured on the surface to be welded to make the TSC “weldable”. For welding CF/PEEK to a TSC adherend,...

Ultrasonic Welding of Thermoplastic Composites

Ultrasonic welding is a very fast and energy-efficient technique for the joining of thermoplastic composites. This article looks into main aspects of ultrasonic welding of continuous fiber-reinforced thermoplastic composites, namely energy directors, process parameters, in situ process monitoring, welding of dissimilar composite materials and...

Investigating the use of Fused Deposition Modeling as Energy Director application method for Ultrasonic Welding of Thermoplastic Composites

The joining of high performance Thermoplastic Composite (TPC) structures by Ultrasonic Welding (USW) is considered a promising alternative for mechanical joining or adhesive bonding methods. The process is fast, clean, and highly automated. In the USW process, an intermediate, unreinforced polymer layer is required at the weld interface to...

Improving weld uniformity in continuous ultrasonic welding of thermoplastic composites

Continuous ultrasonic welding (CUW) is an innovative high-speed joining method for thermoplastic composites. Currently, thin flat energy directors (EDs) are used to focus the heat generation at the weld line. The resulting fracture surfaces exhibit large areas of intact ED, resulting in a non-uniform weld, and significantly lowering the strength...

Ultrasonic welding of CF/PPS composites with integrated triangular energy directors: melting, flow and weld strength development

This paper presents a fully experimental study on melting, flow and weld strength development during ultrasonic welding of CF/PPS composites with integrated triangular energy directors. The main goal of this research was assessing whether the heating time to achieve maximum weld strength could be significantly reduced as compared to...

On the effect of flat energy directors thickness on heat generation during ultrasonic welding of thermoplastic composites

This paper presents a detailed experimental assessment of the effect of the thickness of flat energy directors (ED) on heat generation at the interface during ultrasonic welding. Power and displacement data showed clear differences caused by the change of thickness, related to heat concentration at the weld line during the process. The extent...

Optimising Ultrasonic Welding of Carbon Fibre PEKK Composites

The interest of the aerospace industry in thermoplastic composites has increased over the last years. One of the advantages of using thermoplastics over thermosets is the possibility to use thermoplastic welding as a joining technique. Ultrasonic welding is considered one of the most promising variants: it is very fast, results in high-quality...

Ultrasonic welding of thermoplastic composites with flat energy directors: Influence of the thickness of the energy director on the welding process

This paper presents a detailed experimental examination of the influence of the thickness of flat energy directors (ED) on the ultrasonic welding (USW) process for carbon fibre/polyetherimide composites. Three thicknesses of flat ED were compared: 0.06 mm, 0.25 mm and 0.50 mm. Power and displacement data for 0.06 mm-thick EDs did not clearly...

Utlrasonic welding of thermoplastic composites with flat energy directors: Influence of the thickness of the energy director on the welding process

This paper presents a detailed experimental examination of the influence of the thickness of flat energy directors (ED) on the ultrasonic welding (USW) process for carbon fibre/polyetherimide composites. Three thicknesses of flat ED were compared: 0.06 mm, 0.25 mm and 0.50 mm. Power and displacement data for 0.06 mm-thick EDs did not clearly...