| Abstract Scope |
The significance of temperature development in automated fiber placement of thermoplastic composites is highlighted due to its profound influence on void dynamics, interfacial bonding, crystallization, residual stresses, and dimensional stability. This has been shown in research works that have been previously conducted to measure temperature during in-situ consolidation process. However, experimental endeavors utilizing contact temperature sensors (e.g., thermocouples) have primarily focused on monitoring temperatures in the substrate or underlying laminate. There is a lack of robust technique for temperature measurements within the incoming tape. This is critical since this is the topmost critical region of process. While non-contact temperature measurements using infrared cameras are common in laser-assisted AFP equipment for monitoring temperature in the heating region, they are incapable of capturing incoming tape temperature in shadowed region or consolidation area. Moreover, in hot-gas-torch-assisted AFP systems, thermal cameras face limitations even in measuring temperatures in the heating region due to the disruptive influence of turbulent hot flow. This work introduces an innovative experimental methodology for detailed temperature measurement in incoming tape throughout heating, consolidation, and cooling phases. Long fine thermocouple is intricately embedded within the section of composite prepreg tape, with its wires extended along the length of tape. These tape samples, containing implanted thermocouple, are meticulously manufactured including autoclave processes, while maintaining similarity to initial supplied prepreg tapes in terms of cross-sectional dimensions. Subsequently, the samples are fed into the AFP head for temperature recording during material deposition. Several experiments have been conducted to confirm the repeatability of this technique. |