Characterization and real-time process monitoring of thermoplastic composites manufacturing processes

Abstract

There is a renewed interest on thermoplastic composites by the aerospace industry. This is mainly due to the main advantages that thermoplastic composites may offer, along with the recent development of promising manufacturing techniques, which are very close to reach the maturity and the production rates that the industry demands. The main advantages that thermoplastic may offer mainly consist of high strength and impact resistance, unlimited shelf life, low water absorption, short processing times and the opportunity of alternative out-of-autoclave (ooA) processing technologies. Some examples of the mentioned promising technologies that are nowadays being improved are compression moulding, induction welding, over-moulding or automated fibre placement (AFP) with in-situ consolidation system (AFP-ISC). AFP-ISC process consists on the automated lamination of thermoplastic tapes which are melted by a heat source and consolidated by a compaction unit over a previously consolidated substrate. The part is quickly cooled down and solidified. In this way, melting and consolidation of the part can be performed in a single step This study aimed to characterize and compare different OoA manufacturing methods with a particular emphasis on laser-assisted AFP-ISC. In addition to that, the present investigation also aimed to develop a real-time process monitoring methodology by means of optical fibre Bragg grating sensors (FBG).