Automated Tape Placement and Plasma Surface Modification for High-Performance Hybrid Thermoplastic Composites

Thermoplastic composites are increasingly used in structural applications due to their recyclability, fast processing, and ability to withstand demanding mechanical and thermal conditions. Among them, long fiber thermoplastics (LFTs) offer a balance between strength, manufacturability, and cost-effectiveness, making them attractive for automotive, aerospace, and industrial uses. However, their discontinuous fiber nature often limits structural performance in critical areas.

In this work, hybrid composite structures were developed by overmolding continuous carbon fiber-reinforced thermoplastic tape onto glass fiber-reinforced LFT substrates using automated tape placement (ATP). ATP provides precise process control, localized reinforcement, and compatibility with complex geometries, enabling improvements in mechanical performance without compromising production efficiency. Experimental evaluation confirmed notable gains in tensile and flexural strength, along with strong interfacial bonding.

To further enhance bonding quality, atmospheric plasma treatment was applied to the thermoplastic tape prior to placement. Plasma exposure altered the surface chemistry and topography, improving wettability and interfacial adhesion. Composites manufactured with treated tapes exhibited higher mechanical properties and different failure modes, indicating stronger fiber-matrix interaction.

A theoretical model was also developed to predict the evolution of surface roughness and contact angle as functions of plasma parameters and polymer characteristics. This model provides a useful tool for optimizing surface activation and understanding interface behavior in thermoplastic composites.

This work demonstrates the potential of combining ATP overmolding and plasma-assisted surface engineering to create high-performance hybrid thermoplastic composites tailored for structural applications.