The effect of tool temperature and dwell time on the quality and CBS properties of L-shaped CF/LM-PAEK corners manufactured by the thermo-stamping process

Abstract

This study fabricated L-shaped thermoplastic composite corners using continuous carbon fiber reinforced low-melt polyaryletherketone (CF/LM-PAEK) via the rapid thermo-stamping technique. It explores the impacts of tool temperature, dwell time, and stacking sequence on the quality and curved beam strength (CBS) of the corners. The results reveal that L-shaped corners produced under optimal stamping temperature and rate conditions exhibit no significant defects. When the temperature is below the glass transition temperature (Tg) of LM-PAEK resin, the spring-back angles of L-shaped corners with the same stacking sequence are consistent. Specifically, the spring-back angles for [0/90/0/90/0]_S and [0/-45/90/+45/0]_S layups range between 2.7° and 2.9°, while the average spring-back angles for [0]₁₀ and [+45/-45/+45/-45/0]_S layups are 1.8° and 0.6°, respectively. Above Tg, the spring-back angle initially increases sharply with rising tool temperature and then gradually decreases. With increasing dwell time, the spring-back angle gradually reduces and stabilizes after 90 s. Under identical stamping conditions, the [0]₁₀ layup demonstrates the best CBS performance, followed by [0/90/0/90/0]_S, [0/-45/90/+45/0]_S, and [+45/-45/+45/-45/0]_S. Additionally, increasing tool temperature and dwell time both enhance the CBS performance of the L-shaped corners, reaching a stable state at 220°C and 90 s, respectively.