Thermocouple based process optimization for laser assisted automated fiber placement of CF/LM-PAEK

Self-commitments and increasing legal requirements lead to the compulsion to reduce carbon dioxide emissions in commercial aerospace. One viable approach is the reduction of structural mass, that would reduce emissions for every flight. This is especially true for high cadence singe aisle aircrafts. However, high quantities are required in this segment. To achieve these goals the newly developed low-melt Poly-Aryl-Ether-Ketone (LM-PAEK), a high-performance carbon fiber-reinforced thermoplastic composite was chosen to build a full-scale multi-functional fuselage demonstrator (MFFD) in order to delevelop an automated process that shows these savings. Single-step automated Fiber Placement (AFP) with in-situ consolidation offers distinct advantages in this field with its short curing times and especially by eliminating high amounts of waste otherwise caused by vacuum bagging and related tasks for post-consolidation in an autoclave. In order to ready this technology for future aircraft production this paper demonstrates how the processing window for LM-PAEK tape (TC1225) provided by TORAY was established. By closely linking robot and end-effector data with positionally accurate thermocouple measurements, the determined mechanical properties at coupon level and micro-sections of the manufactured specimens can be precisely correlated. This holistic approach is independent of the placement equipment and may enable global comparability within the community working in the field of thermoplastic AFP. In conclusion the procedure is evaluated and possible simplifications are discussed.