Abstract

Automated Fiber Placement (AFP) is one of the new manufacturing processes for composites that has many advantages such as fast rate of material deposition, repeatability, and reduction of material waste. Thermoplastic composites compared with thermoset composites show a lot of advantages such as higher impact resistance, recyclability etc. and they are very suitable for primary structures of an aircraft. However, manufacturing of thermoplastic composites requires more efforts because of the very high viscosity of thermoplastic resin.
This study proposed a manufacturing procedure to make flat thermoplastic laminates with different layup sequences by using a heated mandrel during layup process with AFP. It is shown that using a mandrel heated to a temperature higher than glass transition can make flat laminates. Processing parameters which consist of hot gas temperature, compaction force, layup speed, mandrel temperature, were found for different laminates. Moreover, repass after material deposition helps to reduce void content inside the laminates.
The obtained flat laminates show the crystallized thermoplastic resin. The high degree of crystallinity is recommended to have good mechanical properties. Tensile, compression and in-plane shear tests were carried out to determine mechanical properties of the laminates made by AFP. Results are compared with those made by autoclave. Test results show that laminates made by AFP have higher tensile modulus, higher compression modulus, similar tensile strength, and almost equal of shear modulus. However, a reduction in compression strength is observed.